diff --git a/app/assets/stylesheets/framework/filters.scss b/app/assets/stylesheets/framework/filters.scss
index b5d1c3f6732..4b45a169a31 100644
--- a/app/assets/stylesheets/framework/filters.scss
+++ b/app/assets/stylesheets/framework/filters.scss
@@ -190,6 +190,7 @@
   min-width: 0;
   border: 1px solid $border-color;
   background-color: $white-light;
+  border-radius: $border-radius-default 0 0 $border-radius-default;
 
   @include media-breakpoint-down(sm) {
     flex: 1 1 auto;
@@ -287,7 +288,7 @@
 .filtered-search-history-dropdown-toggle-button {
   flex: 1;
   width: auto;
-  border-radius: 0;
+  border-radius: $border-radius-default 0 0 $border-radius-default;
   border: 0;
   border-right: 1px solid $border-color;
   color: $gl-text-color-secondary;
@@ -296,8 +297,7 @@
   &:hover,
   &:focus {
     color: $gl-text-color;
-    border-color: $blue-300;
-    outline: none;
+    border-color: $border-color;
   }
 
   svg {
diff --git a/app/models/error_tracking/project_error_tracking_setting.rb b/app/models/error_tracking/project_error_tracking_setting.rb
index a904cf4ac46..5b13d0b628a 100644
--- a/app/models/error_tracking/project_error_tracking_setting.rb
+++ b/app/models/error_tracking/project_error_tracking_setting.rb
@@ -73,7 +73,9 @@ module ErrorTracking
     end
 
     def sentry_client
-      Sentry::Client.new(api_url, token)
+      strong_memoize(:sentry_client) do
+        Sentry::Client.new(api_url, token)
+      end
     end
 
     def sentry_external_url
diff --git a/app/models/sentry_issue.rb b/app/models/sentry_issue.rb
index e60ad6015a5..1325bce6c43 100644
--- a/app/models/sentry_issue.rb
+++ b/app/models/sentry_issue.rb
@@ -6,9 +6,15 @@ class SentryIssue < ApplicationRecord
   validates :issue, uniqueness: true, presence: true
   validates :sentry_issue_identifier, presence: true
 
+  after_create_commit :enqueue_sentry_sync_job
+
   def self.for_project_and_identifier(project, identifier)
     joins(:issue)
       .where(issues: { project_id: project.id })
       .find_by_sentry_issue_identifier(identifier)
   end
+
+  def enqueue_sentry_sync_job
+    ErrorTrackingIssueLinkWorker.perform_async(issue.id)
+  end
 end
diff --git a/app/views/admin/runners/index.html.haml b/app/views/admin/runners/index.html.haml
index 818d265c767..59e28a3b244 100644
--- a/app/views/admin/runners/index.html.haml
+++ b/app/views/admin/runners/index.html.haml
@@ -47,7 +47,7 @@
         .filtered-search-box
           = dropdown_tag(_('Recent searches'),
             options: { wrapper_class: 'filtered-search-history-dropdown-wrapper',
-            toggle_class: 'filtered-search-history-dropdown-toggle-button',
+            toggle_class: 'btn filtered-search-history-dropdown-toggle-button',
             dropdown_class: 'filtered-search-history-dropdown',
             content_class: 'filtered-search-history-dropdown-content' }) do
             .js-filtered-search-history-dropdown{ data: { full_path: admin_runners_path } }
diff --git a/app/views/shared/issuable/_search_bar.html.haml b/app/views/shared/issuable/_search_bar.html.haml
index c3960ec5026..a27ceaff782 100644
--- a/app/views/shared/issuable/_search_bar.html.haml
+++ b/app/views/shared/issuable/_search_bar.html.haml
@@ -21,7 +21,7 @@
             - if type != :boards_modal && type != :boards
               = dropdown_tag(_('Recent searches'),
                 options: { wrapper_class: "filtered-search-history-dropdown-wrapper",
-                toggle_class: "filtered-search-history-dropdown-toggle-button",
+                toggle_class: "btn filtered-search-history-dropdown-toggle-button",
                 dropdown_class: "filtered-search-history-dropdown",
                 content_class: "filtered-search-history-dropdown-content" }) do
                 .js-filtered-search-history-dropdown{ data: { full_path: search_history_storage_prefix } }
diff --git a/app/workers/all_queues.yml b/app/workers/all_queues.yml
index 62b37f52cce..502e7976ef2 100644
--- a/app/workers/all_queues.yml
+++ b/app/workers/all_queues.yml
@@ -143,6 +143,7 @@
 - delete_user
 - email_receiver
 - emails_on_push
+- error_tracking_issue_link
 - expire_build_instance_artifacts
 - git_garbage_collect
 - gitlab_shell
diff --git a/app/workers/error_tracking_issue_link_worker.rb b/app/workers/error_tracking_issue_link_worker.rb
new file mode 100644
index 00000000000..5048f361c31
--- /dev/null
+++ b/app/workers/error_tracking_issue_link_worker.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+# Creates a link in Sentry between a Sentry issue and a GitLab issue.
+# If the link already exists, no changes will occur.
+# If a link to a different GitLab issue exists, a new link
+#   will still be created, but will not be visible in Sentry
+#   until the prior link is deleted.
+class ErrorTrackingIssueLinkWorker
+  include ApplicationWorker
+  include ExclusiveLeaseGuard
+  include Gitlab::Utils::StrongMemoize
+
+  feature_category :error_tracking
+  worker_has_external_dependencies!
+
+  LEASE_TIMEOUT = 15.minutes
+
+  attr_reader :issue
+
+  def perform(issue_id)
+    @issue = Issue.find_by_id(issue_id)
+
+    return unless issue && error_tracking && sentry_issue_id
+
+    try_obtain_lease do
+      logger.info("Linking Sentry issue #{sentry_issue_id} to GitLab issue #{issue.id}")
+
+      if integration_id.nil?
+        logger.info("Sentry integration unavailable for #{error_tracking.api_url}")
+
+        break
+      end
+
+      sentry_client.create_issue_link(integration_id, sentry_issue_id, issue)
+    rescue Sentry::Client::Error
+      logger.info("Failed to link Sentry issue #{sentry_issue_id} to GitLab issue #{issue.id}")
+    end
+  end
+
+  private
+
+  def error_tracking
+    strong_memoize(:error_tracking) do
+      issue.project.error_tracking_setting
+    end
+  end
+
+  def sentry_issue_id
+    strong_memoize(:sentry_issue_id) do
+      issue.sentry_issue.sentry_issue_identifier
+    end
+  end
+
+  def sentry_client
+    error_tracking.sentry_client
+  end
+
+  def integration_id
+    strong_memoize(:integration_id) do
+      repo&.integration_id
+    end
+  end
+
+  def repo
+    sentry_client
+      .repos(organization_slug)
+      .find { |repo| repo.project_id == issue.project_id && repo.status == 'active' }
+  end
+
+  def organization_slug
+    error_tracking.organization_slug
+  end
+
+  def project_url
+    ::Gitlab::Routing.url_helpers.project_url(issue.project)
+  end
+
+  def lease_key
+    "link_sentry_issue_#{sentry_issue_id}_gitlab_#{issue.id}"
+  end
+
+  def lease_timeout
+    LEASE_TIMEOUT
+  end
+end
diff --git a/changelogs/unreleased/28965-fix-filter-hover-state.yml b/changelogs/unreleased/28965-fix-filter-hover-state.yml
new file mode 100644
index 00000000000..d24e620a1d1
--- /dev/null
+++ b/changelogs/unreleased/28965-fix-filter-hover-state.yml
@@ -0,0 +1,5 @@
+---
+title: Add border radius and remove blue outline on recent searches filter
+merge_request: 23266
+author:
+type: fixed
diff --git a/changelogs/unreleased/cilium-managed-apps.yml b/changelogs/unreleased/cilium-managed-apps.yml
new file mode 100644
index 00000000000..2b8e7d90e3c
--- /dev/null
+++ b/changelogs/unreleased/cilium-managed-apps.yml
@@ -0,0 +1,5 @@
+---
+title: Add cilium to the managed cluster apps template
+merge_request: 22557
+author:
+type: added
diff --git a/changelogs/unreleased/dz-rename-custom-hooks.yml b/changelogs/unreleased/dz-rename-custom-hooks.yml
new file mode 100644
index 00000000000..0f030ff9e0a
--- /dev/null
+++ b/changelogs/unreleased/dz-rename-custom-hooks.yml
@@ -0,0 +1,5 @@
+---
+title: Rename Custom hooks to Server hooks
+merge_request: 23064
+author:
+type: changed
diff --git a/changelogs/unreleased/sy-sync-issues-with-sentry.yml b/changelogs/unreleased/sy-sync-issues-with-sentry.yml
new file mode 100644
index 00000000000..23ee975907a
--- /dev/null
+++ b/changelogs/unreleased/sy-sync-issues-with-sentry.yml
@@ -0,0 +1,5 @@
+---
+title: Sync GitLab issue back to Sentry when created in GitLab
+merge_request: 23007
+author:
+type: added
diff --git a/config/sidekiq_queues.yml b/config/sidekiq_queues.yml
index 2986431f21b..06f7f01b83d 100644
--- a/config/sidekiq_queues.yml
+++ b/config/sidekiq_queues.yml
@@ -101,6 +101,7 @@
   - [group_export, 1]
   - [self_monitoring_project_create, 2]
   - [self_monitoring_project_delete, 2]
+  - [error_tracking_issue_link, 2]
 
   # EE-specific queues
   - [analytics, 1]
diff --git a/doc/administration/custom_hooks.md b/doc/administration/custom_hooks.md
index 437c9db1630..4cb8b15e4d8 100644
--- a/doc/administration/custom_hooks.md
+++ b/doc/administration/custom_hooks.md
@@ -1,126 +1,5 @@
-# Custom server-side Git hooks **(CORE ONLY)**
+---
+redirect_to: 'server_hooks.md'
+---
 
-NOTE: **Note:**
-Custom Git hooks must be configured on the filesystem of the GitLab
-server. Only GitLab server administrators will be able to complete these tasks.
-Please explore [webhooks] and [CI] as an option if you do not
-have filesystem access. For a user configurable Git hook interface, see
-[Push Rules](../push_rules/push_rules.md),
-available in GitLab Enterprise Edition.
-
-NOTE: **Note:**
-Custom Git hooks won't be replicated to secondary nodes if you use [GitLab Geo](geo/replication/index.md)
-
-Git natively supports hooks that are executed on different actions.
-Examples of server-side Git hooks include pre-receive, post-receive, and update.
-See [Git SCM Server-Side Hooks][hooks] for more information about each hook type.
-
-As of GitLab Shell version 2.2.0 (which requires GitLab 7.5+), GitLab
-administrators can add custom Git hooks to any GitLab project.
-
-## Create a custom Git hook for a repository
-
-Server-side Git hooks are typically placed in the repository's `hooks`
-subdirectory. In GitLab, hook directories are symlinked to the GitLab Shell
-`hooks` directory for ease of maintenance between GitLab Shell upgrades.
-Custom hooks are implemented differently, but the behavior is exactly the same
-once the hook is created. Follow the steps below to set up a custom hook for a
-repository:
-
-1. Pick a project that needs a custom Git hook.
-1. On the GitLab server, navigate to the project's repository directory.
-   For an installation from source the path is usually
-   `/home/git/repositories/<group>/<project>.git`. For Omnibus installs the path is
-   usually `/var/opt/gitlab/git-data/repositories/<group>/<project>.git`.
-1. Create a new directory in this location called `custom_hooks`.
-1. Inside the new `custom_hooks` directory, create a file with a name matching
-   the hook type. For a pre-receive hook the file name should be `pre-receive`
-   with no extension.
-1. Make the hook file executable and make sure it's owned by Git.
-1. Write the code to make the Git hook function as expected. Hooks can be
-   in any language. Ensure the 'shebang' at the top properly reflects the language
-   type. For example, if the script is in Ruby the shebang will probably be
-   `#!/usr/bin/env ruby`.
-
-That's it! Assuming the hook code is properly implemented the hook will fire
-as appropriate.
-
-## Set a global Git hook for all repositories
-
-To create a Git hook that applies to all of your repositories in
-your instance, set a global Git hook. Since GitLab will look inside the GitLab Shell
-`hooks` directory for global hooks, adding any hook there will apply it to all repositories.
-Follow the steps below to properly set up a custom hook for all repositories:
-
-1. On the GitLab server, navigate to the configured custom hook directory. The
-   default is in the GitLab Shell directory. The GitLab Shell `hook` directory
-   for an installation from source the path is usually
-   `/home/git/gitlab-shell/hooks`. For Omnibus installs the path is usually
-    `/opt/gitlab/embedded/service/gitlab-shell/hooks`.
-   To look in a different directory for the global custom hooks,
-   set `custom_hooks_dir` in the GitLab Shell config. For
-   Omnibus installations, this can be set in `gitlab.rb`; and in source
-   installations, this can be set in `gitlab-shell/config.yml`.
-1. Create a new directory in this location. Depending on your hook, it will be
-   either a `pre-receive.d`, `post-receive.d`, or `update.d` directory.
-1. Inside this new directory, add your hook. Hooks can be
-   in any language. Ensure the 'shebang' at the top properly reflects the language
-   type. For example, if the script is in Ruby the shebang will probably be
-   `#!/usr/bin/env ruby`.
-1. Make the hook file executable and make sure it's owned by Git.
-
-Now test the hook to see that it's functioning properly.
-
-## Chained hooks support
-
-> [Introduced][93] in GitLab Shell 4.1.0 and GitLab 8.15.
-
-Hooks can be also global or be set per project directories and support a chained
-execution of the hooks.
-
-NOTE: **Note:**
-`<hook_name>.d` would need to be either `pre-receive.d`,
-`post-receive.d`, or `update.d` to work properly. Any other names will be ignored.
-
-NOTE: **Note:**
-Files in `.d` directories need to be executable and not match the backup file
-pattern (`*~`).
-
-The hooks are searched and executed in this order:
-
-1. `gitlab-shell/hooks` directory as known to Gitaly
-1. `<project>.git/hooks/<hook_name>` -  executed by `git` itself, this is symlinked to `gitlab-shell/hooks/<hook_name>`
-1. `<project>.git/custom_hooks/<hook_name>` - per project hook (this is already existing behavior)
-1. `<project>.git/custom_hooks/<hook_name>.d/*` - per project hooks
-1. `<project>.git/hooks/<hook_name>.d/*` OR `<custom_hooks_dir>/<hook_name.d>/*` - global hooks: all executable files (minus editor backup files)
-
-The hooks of the same type are executed in order and execution stops on the
-first script exiting with a non-zero value.
-
-## Custom error messages
-
-> [Introduced][5073] in GitLab 8.10.
-
-To have custom error messages appear in GitLab's UI when the commit is
-declined or an error occurs during the Git hook, your script should:
-
-- Send the custom error messages to either the script's `stdout` or `stderr`.
-- Prefix each message with `GL-HOOK-ERR:` with no characters appearing before the prefix.
-
-### Example custom error message
-
-This hook script written in bash will generate the following message in GitLab's UI:
-
-```bash
-#!/bin/sh
-echo "GL-HOOK-ERR: My custom error message.";
-exit 1
-```
-
-![Custom message from custom Git hook](img/custom_hooks_error_msg.png)
-
-[CI]: ../ci/README.md
-[hooks]: https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks#Server-Side-Hooks
-[webhooks]: ../user/project/integrations/webhooks.md
-[5073]: https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/5073
-[93]: https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/93
+This document was moved to [another location](server_hooks.md).
diff --git a/doc/administration/gitaly/index.md b/doc/administration/gitaly/index.md
index 1aad0d80db4..4dd37d24855 100644
--- a/doc/administration/gitaly/index.md
+++ b/doc/administration/gitaly/index.md
@@ -352,9 +352,9 @@ coming in. One sure way to trigger a Gitaly request is to clone a repository
 from your GitLab server over HTTP.
 
 DANGER: **Danger:**
-If you have [custom server-side Git hooks](../custom_hooks.md) configured,
+If you have [Server hooks](../server_hooks.md) configured,
 either per repository or globally, you must move these to the Gitaly node.
-If you have multiple Gitaly nodes, copy your custom hook(s) to all nodes.
+If you have multiple Gitaly nodes, copy your server hook(s) to all nodes.
 
 ### Disabling the Gitaly service in a cluster environment
 
diff --git a/doc/administration/high_availability/README.md b/doc/administration/high_availability/README.md
index 13b6bd88453..2c506898aeb 100644
--- a/doc/administration/high_availability/README.md
+++ b/doc/administration/high_availability/README.md
@@ -47,8 +47,8 @@ complexity.
 - Redis - Key/Value store (User sessions, cache, queue for Sidekiq)
   - Sentinel - Redis health check/failover manager
 - Gitaly - Provides high-level storage and RPC access to Git repositories
-- S3 Object Storage service[^3] and / or NFS storage servers[^4] for entities such as Uploads, Artifacts, LFS Objects, etc...
-- Load Balancer[^2] - Main entry point and handles load balancing for the GitLab application nodes.
+- S3 Object Storage service[^4] and / or NFS storage servers[^5] for entities such as Uploads, Artifacts, LFS Objects, etc...
+- Load Balancer[^6] - Main entry point and handles load balancing for the GitLab application nodes.
 - Monitor - Prometheus and Grafana monitoring with auto discovery.
 
 ## Scalable Architecture Examples
@@ -72,9 +72,9 @@ larger one.
 - 1 PostgreSQL node
 - 1 Redis node
 - 1 Gitaly node
-- 1 or more Object Storage services[^3] and / or NFS storage server[^4]
+- 1 or more Object Storage services[^4] and / or NFS storage server[^5]
 - 2 or more GitLab application nodes (Unicorn / Puma, Workhorse, Sidekiq)
-- 1 or more Load Balancer nodes[^2]
+- 1 or more Load Balancer nodes[^6]
 - 1 Monitoring node (Prometheus, Grafana)
 
 #### Installation Instructions
@@ -83,13 +83,13 @@ Complete the following installation steps in order. A link at the end of each
 section will bring you back to the Scalable Architecture Examples section so
 you can continue with the next step.
 
-1. [Load Balancer(s)](load_balancer.md)[^2]
+1. [Load Balancer(s)](load_balancer.md)[^6]
 1. [Consul](consul.md)
-1. [PostgreSQL](database.md#postgresql-in-a-scaled-environment) with [PgBouncer](https://docs.gitlab.com/ee/administration/high_availability/pgbouncer.html)
+1. [PostgreSQL](database.md#postgresql-in-a-scaled-environment) with [PgBouncer](pgbouncer.md)
 1. [Redis](redis.md#redis-in-a-scaled-environment)
-1. [Gitaly](gitaly.md) (recommended) and / or [NFS](nfs.md)[^4]
+1. [Gitaly](gitaly.md) (recommended) and / or [NFS](nfs.md)[^5]
 1. [GitLab application nodes](gitlab.md)
-    - With [Object Storage service enabled](../gitaly/index.md#eliminating-nfs-altogether)[^3]
+    - With [Object Storage service enabled](../gitaly/index.md#eliminating-nfs-altogether)[^4]
 1. [Monitoring node (Prometheus and Grafana)](monitoring_node.md)
 
 ### Full Scaling
@@ -103,10 +103,10 @@ in size, indicating that there is contention or there are not enough resources.
 - 1 or more PostgreSQL nodes
 - 1 or more Redis nodes
 - 1 or more Gitaly storage servers
-- 1 or more Object Storage services[^3] and / or NFS storage server[^4]
+- 1 or more Object Storage services[^4] and / or NFS storage server[^5]
 - 2 or more Sidekiq nodes
 - 2 or more GitLab application nodes (Unicorn / Puma, Workhorse, Sidekiq)
-- 1 or more Load Balancer nodes[^2]
+- 1 or more Load Balancer nodes[^6]
 - 1 Monitoring node (Prometheus, Grafana)
 
 ## High Availability Architecture Examples
@@ -117,17 +117,17 @@ page mentions, there is a tradeoff between cost/complexity and uptime. Be sure
 this complexity is absolutely required before taking the step into full
 high availability.
 
-For all examples below, we recommend running Consul and Redis Sentinel on
-dedicated nodes. If Consul is running on PostgreSQL nodes or Sentinel on
+For all examples below, we recommend running Consul and Redis Sentinel separately
+from the services they monitor. If Consul is running on PostgreSQL nodes or Sentinel on
 Redis nodes, there is a potential that high resource usage by PostgreSQL or
 Redis could prevent communication between the other Consul and Sentinel nodes.
 This may lead to the other nodes believing a failure has occurred and initiating
-automated failover. Isolating Redis and Consul from the services they monitor
+automated failover. Isolating Consul and Redis Sentinel from the services they monitor
 reduces the chances of a false positive that a failure has occurred.
 
 The examples below do not address high availability of NFS for objects. We recommend a
-S3 Object Storage service[^3] is used where possible over NFS but it's still required in
-certain cases[^4]. Where NFS is to be used some enterprises have access to NFS appliances
+S3 Object Storage service[^4] is used where possible over NFS but it's still required in
+certain cases[^5]. Where NFS is to be used some enterprises have access to NFS appliances
 that manage availability and this would be best case scenario.
 
 There are many options in between each of these examples. Work with GitLab Support
@@ -147,12 +147,12 @@ moving to a hybrid or fully distributed architecture depending on what is causin
 the contention.
 
 - 3 PostgreSQL nodes
-- 2 Redis nodes
-- 3 Consul/Sentinel nodes
+- 3 Redis nodes
+- 3 Consul / Sentinel nodes
 - 2 or more GitLab application nodes (Unicorn / Puma, Workhorse, Sidekiq)
 - 1 Gitaly storage servers
-- 1 Object Storage service[^3] and / or NFS storage server[^4]
-- 1 or more Load Balancer nodes[^2]
+- 1 Object Storage service[^4] and / or NFS storage server[^5]
+- 1 or more Load Balancer nodes[^6]
 - 1 Monitoring node (Prometheus, Grafana)
 
 ![Horizontal architecture diagram](img/horizontal.png)
@@ -166,13 +166,13 @@ contention due to certain workloads.
 
 - 3 PostgreSQL nodes
 - 1 PgBouncer node
-- 2 Redis nodes
-- 3 Consul/Sentinel nodes
+- 3 Redis nodes
+- 3 Consul / Sentinel nodes
 - 2 or more Sidekiq nodes
 - 2 or more GitLab application nodes (Unicorn / Puma, Workhorse, Sidekiq)
 - 1 Gitaly storage servers
-- 1 Object Storage service[^3] and / or NFS storage server[^4]
-- 1 or more Load Balancer nodes[^2]
+- 1 Object Storage service[^4] and / or NFS storage server[^5]
+- 1 or more Load Balancer nodes[^6]
 - 1 Monitoring node (Prometheus, Grafana)
 
 ![Hybrid architecture diagram](img/hybrid.png)
@@ -194,8 +194,8 @@ with the added complexity of many more nodes to configure, manage, and monitor.
 - 2 or more API nodes (All requests to `/api`)
 - 2 or more Web nodes (All other web requests)
 - 2 or more Gitaly storage servers
-- 1 or more Object Storage services[^3] and / or NFS storage servers[^4]
-- 1 or more Load Balancer nodes[^2]
+- 1 or more Object Storage services[^4] and / or NFS storage servers[^5]
+- 1 or more Load Balancer nodes[^6]
 - 1 Monitoring node (Prometheus, Grafana)
 
 ![Fully Distributed architecture diagram](img/fully-distributed.png)
@@ -216,9 +216,12 @@ per 1000 users:
 - Web: 2 RPS
 - Git: 2 RPS
 
-Note that your exact needs may be more, depending on your workload. Your
-workload is influenced by factors such as - but not limited to - how active your
-users are, how much automation you use, mirroring, and repo/change size.
+NOTE: **Note:** Note that depending on your workflow the below recommended
+reference architectures may need to be adapted accordingly. Your workload
+is influenced by factors such as - but not limited to - how active your users are,
+how much automation you use, mirroring, and repo/change size. Additionally the
+shown memory values are given directly by [GCP machine types](https://cloud.google.com/compute/docs/machine-types).
+On different cloud vendors a best effort like for like can be used.
 
 ### 2,000 User Configuration
 
@@ -229,22 +232,18 @@ users are, how much automation you use, mirroring, and repo/change size.
 
 | Service                     | Nodes | Configuration         | GCP type      |
 | ----------------------------|-------|-----------------------|---------------|
-| GitLab Rails <br> - Puma workers on each node set to 90% of available CPUs with 8 threads | 3 | 8 vCPU, 7.2GB Memory | n1-highcpu-8 |
+| GitLab Rails[^1]            | 3     | 8 vCPU, 7.2GB Memory  | n1-highcpu-8 |
 | PostgreSQL                  | 3     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
 | PgBouncer                   | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| Gitaly <br> - Gitaly Ruby workers on each node set to 20% of available CPUs | X[^1] . | 4 vCPU, 15GB Memory   | n1-standard-4 |
-| Redis Cache + Sentinel <br> - Cache maxmemory set to 90% of available memory | 3 | 2 vCPU, 7.5GB Memory | n1-standard-2 |
-| Redis Persistent + Sentinel | 3     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
+| Gitaly[^2] [^7]             | X     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Redis[^3]                   | 3     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
+| Consul + Sentinel[^3]       | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
 | Sidekiq                     | 4     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
-| Consul                      | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| NFS Server[^4] .            | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| S3 Object Storage[^3] .     | -     | -                     | -             |
+| S3 Object Storage[^4]       | -     | -                     | -             |
+| NFS Server[^5] [^7]         | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
 | Monitoring node             | 1     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| External load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-| Internal load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-
-NOTE: **Note:** Memory values are given directly by GCP machine sizes. On different cloud
-vendors a best effort like for like can be used.
+| External load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
+| Internal load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
 
 ### 5,000 User Configuration
 
@@ -255,22 +254,18 @@ vendors a best effort like for like can be used.
 
 | Service                     | Nodes | Configuration         | GCP type      |
 | ----------------------------|-------|-----------------------|---------------|
-| GitLab Rails <br> - Puma workers on each node set to 90% of available CPUs with 16 threads | 3 | 16 vCPU, 14.4GB Memory | n1-highcpu-16 |
+| GitLab Rails[^1]            | 3     | 16 vCPU, 14.4GB Memory | n1-highcpu-16 |
 | PostgreSQL                  | 3     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
 | PgBouncer                   | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| Gitaly <br> - Gitaly Ruby workers on each node set to 20% of available CPUs | X[^1] . | 8 vCPU, 30GB Memory   | n1-standard-8 |
-| Redis Cache + Sentinel <br> - Cache maxmemory set to 90% of available memory | 3 | 2 vCPU, 7.5GB Memory | n1-standard-2 |
-| Redis Persistent + Sentinel | 3     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
+| Gitaly[^2] [^7]             | X     | 8 vCPU, 30GB Memory   | n1-standard-8 |
+| Redis[^3]                   | 3     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
+| Consul + Sentinel[^3]       | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
 | Sidekiq                     | 4     | 2 vCPU, 7.5GB Memory  | n1-standard-2 |
-| Consul                      | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| NFS Server[^4] .            | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| S3 Object Storage[^3] .     | -     | -                     | -             |
+| S3 Object Storage[^4]       | -     | -                     | -             |
+| NFS Server[^5] [^7]         | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
 | Monitoring node             | 1     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| External load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-| Internal load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-
-NOTE: **Note:** Memory values are given directly by GCP machine sizes. On different cloud
-vendors a best effort like for like can be used.
+| External load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
+| Internal load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
 
 ### 10,000 User Configuration
 
@@ -281,22 +276,21 @@ vendors a best effort like for like can be used.
 
 | Service                     | Nodes | Configuration         | GCP type      |
 | ----------------------------|-------|-----------------------|---------------|
-| GitLab Rails <br> - Puma workers on each node set to 90% of available CPUs with 16 threads | 3 | 32 vCPU, 28.8GB Memory | n1-highcpu-32 |
+| GitLab Rails[^1]            | 3     | 32 vCPU, 28.8GB Memory | n1-highcpu-32 |
 | PostgreSQL                  | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
 | PgBouncer                   | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| Gitaly <br> - Gitaly Ruby workers on each node set to 20% of available CPUs | X[^1] . | 16 vCPU, 60GB Memory   | n1-standard-16 |
-| Redis Cache + Sentinel <br> - Cache maxmemory set to 90% of available memory | 3 | 4 vCPU, 15GB Memory | n1-standard-4 |
-| Redis Persistent + Sentinel | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
-| Sidekiq                     | 4     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Gitaly[^2] [^7]             | X     | 16 vCPU, 60GB Memory  | n1-standard-16 |
+| Redis[^3] - Cache           | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Redis[^3] - Queues / Shared State | 3 | 4 vCPU, 15GB Memory | n1-standard-4 |
+| Redis Sentinel[^3] - Cache  | 3     | 1 vCPU, 1.7GB Memory  | g1-small      |
+| Redis Sentinel[^3] - Queues / Shared State | 3 | 1 vCPU, 1.7GB Memory | g1-small |
 | Consul                      | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| NFS Server[^4] .            | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| S3 Object Storage[^3] .     | -     | -                     | -             |
+| Sidekiq                     | 4     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| S3 Object Storage[^4]       | -     | -                     | -             |
+| NFS Server[^5] [^7]         | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
 | Monitoring node             | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| External load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-| Internal load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-
-NOTE: **Note:** Memory values are given directly by GCP machine sizes. On different cloud
-vendors a best effort like for like can be used.
+| External load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
+| Internal load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
 
 ### 25,000 User Configuration
 
@@ -307,22 +301,21 @@ vendors a best effort like for like can be used.
 
 | Service                     | Nodes | Configuration         | GCP type      |
 | ----------------------------|-------|-----------------------|---------------|
-| GitLab Rails <br> - Puma workers on each node set to 90% of available CPUs with 16 threads | 7 | 32 vCPU, 28.8GB Memory | n1-highcpu-32 |
+| GitLab Rails[^1]            | 7     | 32 vCPU, 28.8GB Memory | n1-highcpu-32 |
 | PostgreSQL                  | 3     | 8 vCPU, 30GB Memory   | n1-standard-8 |
 | PgBouncer                   | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| Gitaly <br> - Gitaly Ruby workers on each node set to 20% of available CPUs | X[^1] . | 32 vCPU, 120GB Memory | n1-standard-32 |
-| Redis Cache + Sentinel <br> - Cache maxmemory set to 90% of available memory | 3 | 4 vCPU, 15GB Memory | n1-standard-4 |
-| Redis Persistent + Sentinel | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
-| Sidekiq                     | 4     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Gitaly[^2] [^7]             | X     | 32 vCPU, 120GB Memory | n1-standard-32 |
+| Redis[^3] - Cache           | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Redis[^3] - Queues / Shared State | 3 | 4 vCPU, 15GB Memory | n1-standard-4 |
+| Redis Sentinel[^3] - Cache  | 3     | 1 vCPU, 1.7GB Memory  | g1-small      |
+| Redis Sentinel[^3] - Queues / Shared State | 3 | 1 vCPU, 1.7GB Memory | g1-small |
 | Consul                      | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| NFS Server[^4] .            | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| S3 Object Storage[^3] .     | -     | -                     | -             |
+| Sidekiq                     | 4     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| S3 Object Storage[^4]       | -     | -                     | -             |
+| NFS Server[^5] [^7]         | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
 | Monitoring node             | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| External load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-| Internal load balancing node[^2] . | 1 | 4 vCPU, 3.6GB Memory | n1-highcpu-4 |
-
-NOTE: **Note:** Memory values are given directly by GCP machine sizes. On different cloud
-vendors a best effort like for like can be used.
+| External load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
+| Internal load balancing node[^6] | 1 | 4 vCPU, 3.6GB Memory | n1-highcpu-4  |
 
 ### 50,000 User Configuration
 
@@ -333,35 +326,42 @@ vendors a best effort like for like can be used.
 
 | Service                     | Nodes | Configuration         | GCP type      |
 | ----------------------------|-------|-----------------------|---------------|
-| GitLab Rails <br> - Puma workers on each node set to 90% of available CPUs with 16 threads | 15 | 32 vCPU, 28.8GB Memory | n1-highcpu-32 |
+| GitLab Rails[^1]            | 15    | 32 vCPU, 28.8GB Memory | n1-highcpu-32 |
 | PostgreSQL                  | 3     | 8 vCPU, 30GB Memory   | n1-standard-8 |
 | PgBouncer                   | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| Gitaly <br> - Gitaly Ruby workers on each node set to 20% of available CPUs | X[^1] . | 64 vCPU, 240GB Memory   | n1-standard-64 |
-| Redis Cache + Sentinel <br> - Cache maxmemory set to 90% of available memory | 3 | 4 vCPU, 15GB Memory | n1-standard-4 |
-| Redis Persistent + Sentinel | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
-| Sidekiq                     | 4     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Gitaly[^2] [^7]             | X     | 64 vCPU, 240GB Memory | n1-standard-64 |
+| Redis[^3] - Cache           | 3     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| Redis[^3] - Queues / Shared State | 3 | 4 vCPU, 15GB Memory | n1-standard-4 |
+| Redis Sentinel[^3] - Cache  | 3     | 1 vCPU, 1.7GB Memory  | g1-small      |
+| Redis Sentinel[^3] - Queues / Shared State | 3 | 1 vCPU, 1.7GB Memory | g1-small |
 | Consul                      | 3     | 2 vCPU, 1.8GB Memory  | n1-highcpu-2  |
-| NFS Server[^4] .            | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| S3 Object Storage[^3] .     | -     | -                     | -             |
+| Sidekiq                     | 4     | 4 vCPU, 15GB Memory   | n1-standard-4 |
+| NFS Server[^5] [^7]         | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
+| S3 Object Storage[^4]       | -     | -                     | -             |
 | Monitoring node             | 1     | 4 vCPU, 3.6GB Memory  | n1-highcpu-4  |
-| External load balancing node[^2] . | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2 |
-| Internal load balancing node[^2] . | 1 | 8 vCPU, 7.2GB Memory | n1-highcpu-8 |
+| External load balancing node[^6] | 1 | 2 vCPU, 1.8GB Memory | n1-highcpu-2  |
+| Internal load balancing node[^6] | 1 | 8 vCPU, 7.2GB Memory | n1-highcpu-8  |
 
-NOTE: **Note:** Memory values are given directly by GCP machine sizes. On different cloud
-vendors a best effort like for like can be used.
+[^1]: In our architectures we run each GitLab Rails node using the Puma webserver
+      and have its number of workers set to 90% of available CPUs along with 4 threads.
 
-[^1]: Gitaly node requirements are dependent on customer data, specifically the number of
+[^2]: Gitaly node requirements are dependent on customer data, specifically the number of
       projects and their sizes. We recommend 2 nodes as an absolute minimum for HA environments
       and at least 4 nodes should be used when supporting 50,000 or more users.
-      We recommend that each Gitaly node should store no more than 5TB of data.
-      Additional nodes should be considered in conjunction with a review of expected
-      data size and spread based on the recommendations above.
+      We also recommend that each Gitaly node should store no more than 5TB of data
+      and have the number of [`gitaly-ruby` workers](../gitaly/index.md#gitaly-ruby)
+      set to 20% of available CPUs. Additional nodes should be considered in conjunction
+      with a review of expected data size and spread based on the recommendations above.
 
-[^2]: Our architectures have been tested and validated with [HAProxy](https://www.haproxy.org/)
-      as the load balancer. However other reputable load balancers with similar feature sets
-      should also work instead but be aware these aren't validated.
+[^3]: Recommended Redis setup differs depending on the size of the architecture.
+      For smaller architectures (up to 5,000 users) we suggest one Redis cluster for all
+      classes and that Redis Sentinel is hosted alongside Consul.
+      For larger architectures (10,000 users or more) we suggest running a separate
+      [Redis Cluster](redis.md#running-multiple-redis-clusters) for the Cache class
+      and another for the Queues and Shared State classes respectively. We also recommend
+      that you run the Redis Sentinel clusters separately as well for each Redis Cluster.
 
-[^3]: For data objects such as LFS, Uploads, Artifacts, etc... We recommend a S3 Object Storage
+[^4]: For data objects such as LFS, Uploads, Artifacts, etc... We recommend a S3 Object Storage
       where possible over NFS due to better performance and availability. Several types of objects
       are supported for S3 storage - [Job artifacts](../job_artifacts.md#using-object-storage),
       [LFS](../lfs/lfs_administration.md#storing-lfs-objects-in-remote-object-storage),
@@ -370,6 +370,17 @@ vendors a best effort like for like can be used.
       [Packages](../packages/index.md#using-object-storage) (Optional Feature),
       [Dependency Proxy](../packages/dependency_proxy.md#using-object-storage) (Optional Feature).
 
-[^4]: NFS storage server is still required for [GitLab Pages](https://gitlab.com/gitlab-org/gitlab-pages/issues/196)
+[^5]: NFS storage server is still required for [GitLab Pages](https://gitlab.com/gitlab-org/gitlab-pages/issues/196)
       and optionally for CI Job Incremental Logging
-      ([can be switched to use Redis instead](https://docs.gitlab.com/ee/administration/job_logs.html#new-incremental-logging-architecture)).
+      ([can be switched to use Redis instead](../job_logs.md#new-incremental-logging-architecture)).
+
+[^6]: Our architectures have been tested and validated with [HAProxy](https://www.haproxy.org/)
+      as the load balancer. However other reputable load balancers with similar feature sets
+      should also work instead but be aware these aren't validated.
+
+[^7]: We strongly recommend that the Gitaly and / or NFS nodes are set up with SSD disks over
+      HDD with a throughput of at least 8,000 IOPS for read operations and 2,000 IOPS for write
+      as these components have heavy I/O. These IOPS values are recommended only as a starter
+      as with time they may be adjusted higher or lower depending on the scale of your
+      environment's workload. If you're running the environment on a Cloud provider
+      you may need to refer to their documentation on how configure IOPS correctly.
diff --git a/doc/administration/index.md b/doc/administration/index.md
index 8172acd09b4..35fe066d866 100644
--- a/doc/administration/index.md
+++ b/doc/administration/index.md
@@ -166,7 +166,7 @@ Learn how to install, configure, update, and maintain your GitLab instance.
 
 ## Git configuration options
 
-- [Custom Git hooks](custom_hooks.md): Custom Git hooks (on the filesystem) for when webhooks aren't enough.
+- [Server hooks](server_hooks.md): Server hooks (on the filesystem) for when webhooks aren't enough.
 - [Git LFS configuration](lfs/lfs_administration.md): Learn how to configure LFS for GitLab.
 - [Housekeeping](housekeeping.md): Keep your Git repositories tidy and fast.
 - [Configuring Git Protocol v2](git_protocol.md): Git protocol version 2 support.
diff --git a/doc/administration/server_hooks.md b/doc/administration/server_hooks.md
new file mode 100644
index 00000000000..7fded3dd41e
--- /dev/null
+++ b/doc/administration/server_hooks.md
@@ -0,0 +1,120 @@
+---
+type: reference, howto
+disqus_identifier: 'https://docs.gitlab.com/ee/administration/custom_hooks.html'
+---
+
+# Server hooks **(CORE ONLY)**
+
+> **Notes:**
+>
+> - Server hooks were [introduced](https://gitlab.com/gitlab-org/gitlab/issues/196051) in GitLab 12.8 replacing Custom Hooks.
+> - Server hooks must be configured on the filesystem of the GitLab server. Only GitLab server administrators will be able to complete these tasks. Please explore [webhooks](../user/project/integrations/webhooks.md) and [GitLab CI/CD](../ci/README.md) as an option if you do not have filesystem access. For a user-configurable Git hook interface, see [Push Rules](../push_rules/push_rules.md), available in GitLab Starter **(STARTER)**.
+> - Server hooks won't be replicated to secondary nodes if you use [GitLab Geo](geo/replication/index.md).
+
+Git natively supports hooks that are executed on different actions.
+Examples of server-side Git hooks include pre-receive, post-receive, and update.
+See [Git SCM Server-Side Hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks#Server-Side-Hooks) for more information about each hook type.
+
+As of GitLab Shell version 2.2.0 (which requires GitLab 7.5+), GitLab
+administrators can add custom Git hooks to any GitLab project.
+
+## Create a server hook for a repository
+
+Server-side Git hooks are typically placed in the repository's `hooks`
+subdirectory. In GitLab, hook directories are symlinked to the GitLab Shell
+`hooks` directory for ease of maintenance between GitLab Shell upgrades.
+Server hooks are implemented differently, but the behavior is exactly the same
+once the hook is created. Follow the steps below to set up a server hook for a
+repository:
+
+1. Pick a project that needs a server hook.
+1. On the GitLab server, navigate to the project's repository directory.
+   For an installation from source the path is usually
+   `/home/git/repositories/<group>/<project>.git`. For Omnibus installs the path is
+   usually `/var/opt/gitlab/git-data/repositories/<group>/<project>.git`.
+1. Create a new directory in this location called `custom_hooks`.
+1. Inside the new `custom_hooks` directory, create a file with a name matching
+   the hook type. For a pre-receive hook the file name should be `pre-receive`
+   with no extension.
+1. Make the hook file executable and make sure it's owned by Git.
+1. Write the code to make the server hook function as expected. Hooks can be
+   in any language. Ensure the 'shebang' at the top properly reflects the language
+   type. For example, if the script is in Ruby the shebang will probably be
+   `#!/usr/bin/env ruby`.
+
+That's it! Assuming the hook code is properly implemented the hook will fire
+as appropriate.
+
+## Set a global server hook for all repositories
+
+To create a Git hook that applies to all of your repositories in
+your instance, set a global server hook. Since GitLab will look inside the GitLab Shell
+`hooks` directory for global hooks, adding any hook there will apply it to all repositories.
+Follow the steps below to properly set up a server hook for all repositories:
+
+1. On the GitLab server, navigate to the configured custom hook directory. The
+   default is in the GitLab Shell directory. The GitLab Shell `hook` directory
+   for an installation from source the path is usually
+   `/home/git/gitlab-shell/hooks`. For Omnibus installs the path is usually
+    `/opt/gitlab/embedded/service/gitlab-shell/hooks`.
+   To look in a different directory for the global custom hooks,
+   set `custom_hooks_dir` in the GitLab Shell config. For
+   Omnibus installations, this can be set in `gitlab.rb`; and in source
+   installations, this can be set in `gitlab-shell/config.yml`.
+1. Create a new directory in this location. Depending on your hook, it will be
+   either a `pre-receive.d`, `post-receive.d`, or `update.d` directory.
+1. Inside this new directory, add your hook. Hooks can be
+   in any language. Ensure the 'shebang' at the top properly reflects the language
+   type. For example, if the script is in Ruby the shebang will probably be
+   `#!/usr/bin/env ruby`.
+1. Make the hook file executable and make sure it's owned by Git.
+
+Now test the hook to check whether it is functioning properly.
+
+## Chained hooks support
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/93) in GitLab Shell 4.1.0 and GitLab 8.15.
+
+Hooks can be also global or be set per project directories and support a chained
+execution of the hooks.
+
+NOTE: **Note:**
+`<hook_name>.d` would need to be either `pre-receive.d`,
+`post-receive.d`, or `update.d` to work properly. Any other names will be ignored.
+
+NOTE: **Note:**
+Files in `.d` directories need to be executable and not match the backup file
+pattern (`*~`).
+
+The hooks are searched and executed in this order:
+
+1. `gitlab-shell/hooks` directory as known to Gitaly.
+1. `<project>.git/hooks/<hook_name>` -  executed by `git` itself, this is symlinked to `gitlab-shell/hooks/<hook_name>`.
+1. `<project>.git/custom_hooks/<hook_name>` - per-project hook (this was kept as the already existing behavior).
+1. `<project>.git/custom_hooks/<hook_name>.d/*` - per-project hooks.
+1. `<project>.git/hooks/<hook_name>.d/*` OR `<custom_hooks_dir>/<hook_name.d>/*` - global hooks: all executable files (except editor backup files).
+
+The hooks of the same type are executed in order and execution stops on the
+first script exiting with a non-zero value.
+
+## Custom error messages
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/5073) in GitLab 8.10.
+
+To have custom error messages appear in GitLab's UI when the commit is
+declined or an error occurs during the Git hook, your script should:
+
+- Send the custom error messages to either the script's `stdout` or `stderr`.
+- Prefix each message with `GL-HOOK-ERR:` with no characters appearing before the prefix.
+
+### Example custom error message
+
+This hook script written in bash will generate the following message in GitLab's UI:
+
+```bash
+#!/bin/sh
+echo "GL-HOOK-ERR: My custom error message.";
+exit 1
+```
+
+![Custom message from custom Git hook](img/custom_hooks_error_msg.png)
diff --git a/doc/development/documentation/styleguide.md b/doc/development/documentation/styleguide.md
index fd591c71e85..173ca324f59 100644
--- a/doc/development/documentation/styleguide.md
+++ b/doc/development/documentation/styleguide.md
@@ -256,12 +256,18 @@ Do not include the same information in multiple places. [Link to a SSOT instead.
     Some features are also objects. For example, "GitLab's Merge Requests support X" and
     "Create a new merge request for Z."
 
+- Use common contractions when it helps create a friendly and informal tone, especially in tutorials and [UIs](https://design.gitlab.com/content/punctuation/#contractions).
+  - Do use contractions like: _it's_, _can't_, _wouldn't_, _you're_, _you've_, _haven't_, don't, _we're_, _that's_, and _won't_. Contractions in instructional documentation such as tutorials can help create a friendly and informal tone.
+  - Avoid less common contractions such as: _he'd_, _it'll_, _should've_, and _there'd_.
+  - Do not use contractions in reference documentation. Examples:
+    - You cannot set a limit higher than 1000.
+    - For `parameter1`, the default is 10.
+  - Do not use contractions with a proper noun and a verb, such as _GitLab's creating X_.
+  - Avoid using contractions when you need to emphasize a negative, such as "Do **not** install X with Y."
+
 - Avoid use of the future tense:
   - Instead of "after you execute this command, GitLab will display the result", use "after you execute this command, GitLab displays the result".
   - Only use the future tense to convey when the action or result will actually occur at a future time.
-- Do not use contractions:
-  - Instead of "don't," "can't," "doesn't," and so on, use "do not," "cannot," or "does not."
-  - Possible exceptions are cases when a more familiar tone is desired, such as a blog post or other casual context.
 - Do not use slashes to clump different words together or as a replacement for the word "or":
   - Instead of "and/or," consider using "or," or use another sensible construction.
   - Other examples include "clone/fetch," author/assignee," and "namespace/repository name." Break apart any such instances in an appropriate way.
diff --git a/doc/hooks/custom_hooks.md b/doc/hooks/custom_hooks.md
index fb939ff8aac..c6d44bb03e9 100644
--- a/doc/hooks/custom_hooks.md
+++ b/doc/hooks/custom_hooks.md
@@ -1,7 +1,7 @@
 ---
-redirect_to: '../administration/custom_hooks.md'
+redirect_to: '../administration/server_hooks.md'
 ---
 
 # Custom Git Hooks
 
-This document was moved to [administration/custom_hooks.md](../administration/custom_hooks.md).
+This document was moved to [administration/server_hooks.md](../administration/server_hooks.md).
diff --git a/doc/integration/github.md b/doc/integration/github.md
index f46038269c0..f2eab0cdf98 100644
--- a/doc/integration/github.md
+++ b/doc/integration/github.md
@@ -4,57 +4,31 @@ You can integrate your GitLab instance with GitHub.com as well as GitHub Enterpr
 
 ## Enabling GitHub OAuth
 
-To enable GitHub OmniAuth provider, you must use GitHub's credentials for your GitLab instance.
-To get the credentials (a pair of Client ID and Client Secret), you must register an application as an OAuth App on GitHub.
+To enable the GitHub OmniAuth provider, you'll need an OAuth 2 Client ID and Client Secret from GitHub. To get these credentials, sign into GitHub and follow their procedure for [Creating an OAuth App](https://developer.github.com/apps/building-oauth-apps/creating-an-oauth-app/).
 
-1. Sign in to GitHub.
+When you create an OAuth 2 app in GitHub, you'll need the following information:
 
-1. Navigate to your individual user or organization settings, depending on how you want the application registered. It does not matter if the application is registered as an individual or an organization - that is entirely up to you.
+- The URL of your GitLab instance, such as `https://gitlab.example.com`.
+- The authorization callback URL; in this case, `https://gitlab.example.com/users/auth`. Include the port number if your GitLab instance uses a non-default port.
 
-   - For individual accounts, select **Developer settings** from the left menu, then select **OAuth Apps**.
-   - For organization accounts, directly select **OAuth Apps** from the left menu.
+NOTE: **Note:**
+To prevent an [OAuth2 covert redirect](http://tetraph.com/covert_redirect/) vulnerability, append `/users/auth` to the end of the GitHub authorization callback URL.
 
-1. Select **Register an application** (if you don't have any OAuth App) or **New OAuth App** (if you already have OAuth Apps).
-   ![Register OAuth App](img/github_app_entry.png)
+See [Initial OmniAuth Configuration](omniauth.md#initial-omniauth-configuration) for initial settings.
 
-1. Provide the required details.
-   - Application name: This can be anything. Consider something like `<Organization>'s GitLab` or `<Your Name>'s GitLab` or something else descriptive.
-   - Homepage URL: The URL of your GitLab installation. For example, `https://gitlab.example.com`.
-   - Application description: Fill this in if you wish.
-   - Authorization callback URL: `http(s)://${YOUR_DOMAIN}/users/auth`. Please make sure the port is included if your GitLab instance is not configured on default port.
-   ![Register OAuth App](img/github_register_app.png)
+Once you have configured the GitHub provider, you'll need the following information, which you'll need to substitute in the GitLab configuration file, in the steps shown next.
 
-   NOTE: Be sure to append `/users/auth` to the end of the callback URL
-   to prevent a [OAuth2 convert
-   redirect](http://tetraph.com/covert_redirect/) vulnerability.
+| Setting from GitHub  |  Substitute in the GitLab configuration file | Description |
+|:---------------------|:-----------------------------------------------|:------------|
+| Client ID            | `YOUR_APP_ID`     |  OAuth 2 Client ID     |
+| Client Secret        | `YOUR_APP_SECRET` |  OAuth 2 Client Secret |
+| URL                  | `https://github.example.com/` |  GitHub Deployment URL |
 
-1. Select **Register application**.
+Follow these steps to incorporate the GitHub OAuth 2 app in your GitLab server:
 
-1. You should now see a pair of **Client ID** and **Client Secret** near the top right of the page (see screenshot).
-   Keep this page open as you continue configuration.
-   ![GitHub app](img/github_app.png)
+**For Omnibus installations**
 
-1. On your GitLab server, open the configuration file.
-
-   For Omnibus package:
-
-   ```sh
-   sudo editor /etc/gitlab/gitlab.rb
-   ```
-
-   For installations from source:
-
-   ```sh
-   cd /home/git/gitlab
-
-   sudo -u git -H editor config/gitlab.yml
-   ```
-
-1. See [Initial OmniAuth Configuration](omniauth.md#initial-omniauth-configuration) for initial settings.
-
-1. Add the provider configuration:
-
-   For Omnibus package:
+1. Edit `/etc/gitlab/gitlab.rb`:
 
    For GitHub.com:
 
@@ -83,7 +57,15 @@ To get the credentials (a pair of Client ID and Client Secret), you must registe
    ]
    ```
 
-   For installation from source:
+   **Replace `https://github.example.com/` with your GitHub URL.**
+
+1. Save the file and [reconfigure](../administration/restart_gitlab.html#omnibus-gitlab-reconfigure) GitLab for the changes to take effect.
+
+---
+
+**For installations from source**
+
+1. Navigate to your repository and edit `config/gitlab.yml`:
 
    For GitHub.com:
 
@@ -102,20 +84,15 @@ To get the credentials (a pair of Client ID and Client Secret), you must registe
      args: { scope: 'user:email' } }
    ```
 
-   __Replace `https://github.example.com/` with your GitHub URL.__
+   **Replace `https://github.example.com/` with your GitHub URL.**
 
-1. Change `YOUR_APP_ID` to the Client ID from the GitHub application page from step 6.
+1. Save the file and [restart](../administration/restart_gitlab.html#installations-from-source) GitLab for the changes to take effect.
 
-1. Change `YOUR_APP_SECRET` to the Client Secret from the GitHub application page from step 6.
+---
 
-1. Save the configuration file.
+1. Refresh the GitLab sign in page. You should now see a GitHub icon below the regular sign in form.
 
-1. [Reconfigure GitLab][] or [restart GitLab][] for the changes to take effect if you
-   installed GitLab via Omnibus or from source respectively.
-
-On the sign in page there should now be a GitHub icon below the regular sign in form.
-Click the icon to begin the authentication process. GitHub will ask the user to sign in and authorize the GitLab application.
-If everything goes well the user will be returned to GitLab and will be signed in.
+1. Click the icon to begin the authentication process. GitHub will ask the user to sign in and authorize the GitLab application.
 
 ## GitHub Enterprise with self-signed Certificate
 
diff --git a/doc/integration/img/github_app.png b/doc/integration/img/github_app.png
deleted file mode 100644
index b72cf03dd4d..00000000000
Binary files a/doc/integration/img/github_app.png and /dev/null differ
diff --git a/doc/integration/img/github_app_entry.png b/doc/integration/img/github_app_entry.png
deleted file mode 100644
index c736bed3dd6..00000000000
Binary files a/doc/integration/img/github_app_entry.png and /dev/null differ
diff --git a/doc/integration/img/github_register_app.png b/doc/integration/img/github_register_app.png
deleted file mode 100644
index d03ca5cc2aa..00000000000
Binary files a/doc/integration/img/github_register_app.png and /dev/null differ
diff --git a/doc/push_rules/push_rules.md b/doc/push_rules/push_rules.md
index f26cf0cece0..86826141b8b 100644
--- a/doc/push_rules/push_rules.md
+++ b/doc/push_rules/push_rules.md
@@ -52,9 +52,9 @@ will get rejected.
 ### Custom Push Rules **(CORE ONLY)**
 
 It's possible to create custom push rules rather than the push rules available in
-**Admin Area > Push Rules** by using more advanced server-side Git hooks.
+**Admin Area > Push Rules** by using more advanced server hooks.
 
-See [custom server-side Git hooks](../administration/custom_hooks.md) for more information.
+See [server hooks](../administration/server_hooks.md) for more information.
 
 ## Enabling push rules
 
diff --git a/doc/topics/autodevops/index.md b/doc/topics/autodevops/index.md
index c52c5832591..e95fbff74b3 100644
--- a/doc/topics/autodevops/index.md
+++ b/doc/topics/autodevops/index.md
@@ -713,6 +713,56 @@ workers:
     terminationGracePeriodSeconds: 60
 ```
 
+#### Network Policy
+
+> [Introduced](https://gitlab.com/gitlab-org/charts/auto-deploy-app/merge_requests/30) in GitLab 12.7.
+
+By default, all Kubernetes pods are
+[non-isolated](https://kubernetes.io/docs/concepts/services-networking/network-policies/#isolated-and-non-isolated-pods)
+and accept traffic from any source. You can use
+[NetworkPolicy](https://kubernetes.io/docs/concepts/services-networking/network-policies/)
+to restrict connections to selected pods or namespaces.
+
+NOTE: **Note:**
+You must use a Kubernetes network plugin that implements support for
+`NetworkPolicy`, the default network plugin for Kubernetes (`kubenet`)
+[doesn't implement](https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/#kubenet)
+support for it. The [Cilium](https://cilium.io/) network plugin can be
+installed as a [cluster application](../../user/clusters/applications.md#install-cilium-using-gitlab-ci)
+to enable support for network policies.
+
+You can enable deployment of a network policy by setting the following
+in the `.gitlab/auto-deploy-values.yaml` file:
+
+```yml
+networkPolicy:
+  enabled: true
+```
+
+The default policy deployed by the auto deploy pipeline will allow
+traffic within a local namespace and from the `gitlab-managed-apps`
+namespace, all other inbound connection will be blocked. Outbound
+traffic is not affected by the default policy.
+
+You can also provide a custom [policy specification](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.16/#networkpolicyspec-v1-networking-k8s-io)
+via the `.gitlab/auto-deploy-values.yaml` file, for example:
+
+```yml
+networkPolicy:
+  enabled: true
+  spec:
+    podSelector:
+      matchLabels:
+        app.gitlab.com/env: staging
+    ingress:
+    - from:
+      - podSelector:
+          matchLabels: {}
+      - namespaceSelector:
+          matchLabels:
+            app.gitlab.com/managed_by: gitlab
+```
+
 #### Running commands in the container
 
 Applications built with [Auto Build](#auto-build) using Herokuish, the default
diff --git a/doc/topics/git/index.md b/doc/topics/git/index.md
index 4325980a60c..c7abfb1d974 100644
--- a/doc/topics/git/index.md
+++ b/doc/topics/git/index.md
@@ -69,7 +69,7 @@ If you have problems with Git, the following may help:
 
 The following are advanced topics for those who want to get the most out of Git:
 
-- [Custom Git Hooks](../../administration/custom_hooks.md)
+- [Server Hooks](../../administration/server_hooks.md)
 - [Git Attributes](../../user/project/git_attributes.md)
 - Git Submodules: [Using Git submodules with GitLab CI](../../ci/git_submodules.md#using-git-submodules-with-gitlab-ci)
 - [Partial Clone](partial_clone.md)
diff --git a/doc/update/README.md b/doc/update/README.md
index f23716f3df8..510a8fb31fb 100644
--- a/doc/update/README.md
+++ b/doc/update/README.md
@@ -180,15 +180,14 @@ any downgrades would result to all sessions being invalidated and users are logg
 
 In 12.0.0 we made various database related changes. These changes require that
 users first upgrade to the latest 11.11 patch release. Once upgraded to 11.11.x,
-users can upgrade to 12.x. Failure to do so may result in database migrations
+users can upgrade to 12.0.x. Failure to do so may result in database migrations
 not being applied, which could lead to application errors.
 
 Example 1: you are currently using GitLab 11.11.3, which is the latest patch
-release for 11.11.x. You can upgrade as usual to 12.0.0, 12.1.0, etc.
+release for 11.11.x. You can upgrade as usual to 12.0.x.
 
 Example 2: you are currently using a version of GitLab 10.x. To upgrade, first
-upgrade to 11.11.3. Once upgraded to 11.11.3 you can safely upgrade to 12.0.0
-or future versions.
+upgrade to 11.11.3. Once upgraded to 11.11.3 you can safely upgrade to 12.0.x.
 
 ## Miscellaneous
 
diff --git a/doc/user/clusters/applications.md b/doc/user/clusters/applications.md
index 47d835a1622..c60e28644b4 100644
--- a/doc/user/clusters/applications.md
+++ b/doc/user/clusters/applications.md
@@ -477,6 +477,7 @@ Supported applications:
 - [cert-manager](#install-cert-manager-using-gitlab-ci)
 - [Sentry](#install-sentry-using-gitlab-ci)
 - [GitLab Runner](#install-gitlab-runner-using-gitlab-ci)
+- [Cilium](#install-cilium-using-gitlab-ci)
 
 ### Usage
 
@@ -661,6 +662,65 @@ management project. Refer to the
 [chart](https://gitlab.com/gitlab-org/charts/gitlab-runner) for the
 available configuration options.
 
+### Install Cilium using GitLab CI
+
+> [Introduced](https://gitlab.com/gitlab-org/cluster-integration/cluster-applications/merge_requests/22) in GitLab 12.7.
+
+[Cilium](https://cilium.io/) is a networking plugin for Kubernetes
+that you can use to implement support for
+[NetworkPolicy](https://kubernetes.io/docs/concepts/services-networking/network-policies/)
+resources.
+
+Enable Cilium in the `.gitlab/managed-apps/config.yaml` file to install it:
+
+```yaml
+# possible values are gke, eks or you can leave it blank
+clusterType: gke
+
+cilium:
+  installed: true
+```
+
+The `clusterType` variable enables the recommended Helm variables for
+a corresponding cluster type, the default value is blank. You can
+check the recommended variables for each cluster type in the official
+documentation:
+
+- [Google GKE](https://cilium.readthedocs.io/en/stable/gettingstarted/k8s-install-gke/#prepare-deploy-cilium)
+- [AWS EKS](https://cilium.readthedocs.io/en/stable/gettingstarted/k8s-install-eks/#prepare-deploy-cilium)
+
+You can customize Cilium's Helm variables by defining the
+`.gitlab/managed-apps/cilium/values.yaml` file in your cluster
+management project. Refer to the
+[Cilium chart](https://github.com/cilium/cilium/tree/master/install/kubernetes/cilium)
+for the available configuration options.
+
+CAUTION: **Caution:**
+Installation and removal of the Cilium [requires restart](https://cilium.readthedocs.io/en/stable/gettingstarted/k8s-install-gke/#restart-remaining-pods)
+of all affected pods in all namespaces to ensure that they are
+[managed](https://cilium.readthedocs.io/en/stable/troubleshooting/#ensure-pod-is-managed-by-cilium)
+by the correct networking plugin.
+
+NOTE: **Note:**
+Major upgrades might require additional setup steps, please consult
+the official [upgrade guide](https://docs.cilium.io/en/stable/install/upgrade/) for more
+information.
+
+By default, the drop log for traffic is logged out by the
+`cilium-monitor` sidecar container. You can check these logs via:
+
+```bash
+kubectl -n gitlab-managed-apps logs cilium-XXXX cilium-monitor
+```
+
+Drop logging can be disabled via `.gitlab/managed-apps/cilium/values.yaml`:
+
+```yml
+agent:
+  monitor:
+    enabled: false
+```
+
 ## Upgrading applications
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/merge_requests/24789) in GitLab 11.8.
diff --git a/doc/user/project/operations/error_tracking.md b/doc/user/project/operations/error_tracking.md
index 447d294bef8..361dfe57d78 100644
--- a/doc/user/project/operations/error_tracking.md
+++ b/doc/user/project/operations/error_tracking.md
@@ -10,7 +10,7 @@ Error tracking allows developers to easily discover and view the errors that the
 
 ### Deploying Sentry
 
-You may sign up to the cloud hosted <https://sentry.io> or deploy your own [on-premise instance](https://docs.sentry.io/server/installation/).
+You may sign up to the cloud hosted <https://sentry.io>, deploy your own [on-premise instance](https://docs.sentry.io/server/installation/) or use GitLab to [install Sentry to a Kubernetes cluster](../../clusters/applications.md#install-sentry-using-gitlab-ci).
 
 ### Enabling Sentry
 
diff --git a/doc/user/project/repository/repository_mirroring.md b/doc/user/project/repository/repository_mirroring.md
index 6da745a8772..09506da6e90 100644
--- a/doc/user/project/repository/repository_mirroring.md
+++ b/doc/user/project/repository/repository_mirroring.md
@@ -341,7 +341,7 @@ the upstream Git repository. In this configuration one Git repository acts as
 the authoritative upstream, and the other as downstream. The `pre-receive` hook
 will be installed on the downstream repository.
 
-Read about [configuring custom Git hooks](../../../administration/custom_hooks.md) on the GitLab server.
+Read about [configuring Server hooks](../../../administration/server_hooks.md) on the GitLab server.
 
 A sample `pre-receive` hook is provided below.
 
diff --git a/lib/gitlab/ci/templates/Managed-Cluster-Applications.gitlab-ci.yml b/lib/gitlab/ci/templates/Managed-Cluster-Applications.gitlab-ci.yml
index 93c69772b01..5d8125f47a9 100644
--- a/lib/gitlab/ci/templates/Managed-Cluster-Applications.gitlab-ci.yml
+++ b/lib/gitlab/ci/templates/Managed-Cluster-Applications.gitlab-ci.yml
@@ -1,6 +1,6 @@
 apply:
   stage: deploy
-  image: "registry.gitlab.com/gitlab-org/cluster-integration/cluster-applications:v0.5.0"
+  image: "registry.gitlab.com/gitlab-org/cluster-integration/cluster-applications:v0.6.0"
   environment:
     name: production
   variables:
@@ -10,6 +10,7 @@ apply:
     CERT_MANAGER_VALUES_FILE: $CI_PROJECT_DIR/.gitlab/managed-apps/cert-manager/values.yaml
     SENTRY_VALUES_FILE: $CI_PROJECT_DIR/.gitlab/managed-apps/sentry/values.yaml
     GITLAB_RUNNER_VALUES_FILE: $CI_PROJECT_DIR/.gitlab/managed-apps/gitlab-runner/values.yaml
+    CILIUM_VALUES_FILE: $CI_PROJECT_DIR/.gitlab/managed-apps/cilium/values.yaml
   script:
     - gitlab-managed-apps /usr/local/share/gitlab-managed-apps/helmfile.yaml
   only:
diff --git a/lib/gitlab/import_export/merge_request_parser.rb b/lib/gitlab/import_export/merge_request_parser.rb
index 0b534a5bafc..f735b9612aa 100644
--- a/lib/gitlab/import_export/merge_request_parser.rb
+++ b/lib/gitlab/import_export/merge_request_parser.rb
@@ -16,7 +16,7 @@ module Gitlab
         if fork_merge_request? && @diff_head_sha
           @merge_request.source_project_id = @relation_hash['project_id']
 
-          fetch_ref unless branch_exists?(@merge_request.source_branch)
+          create_source_branch unless branch_exists?(@merge_request.source_branch)
           create_target_branch unless branch_exists?(@merge_request.target_branch)
         end
 
@@ -34,17 +34,18 @@ module Gitlab
         @merge_request
       end
 
-      def create_target_branch
-        @project.repository.create_branch(@merge_request.target_branch, @merge_request.target_branch_sha)
+      # When the exported MR was in a fork, the source branch does not exist in
+      # the imported bundle - although the commits usually do - so it must be
+      # created manually. Ignore failures so we get the merge request itself if
+      # the commits are missing.
+      def create_source_branch
+        @project.repository.create_branch(@merge_request.source_branch, @diff_head_sha)
+      rescue => err
+        Rails.logger.warn("Import/Export warning: Failed to create source branch #{@merge_request.source_branch} => #{@diff_head_sha} for MR #{@merge_request.iid}: #{err}") # rubocop:disable Gitlab/RailsLogger
       end
 
-      # Gitaly migration: https://gitlab.com/gitlab-org/gitaly/issues/1295
-      def fetch_ref
-        target_ref = Gitlab::Git::BRANCH_REF_PREFIX + @merge_request.source_branch
-
-        unless @project.repository.fetch_source_branch!(@project.repository, @diff_head_sha, target_ref)
-          Rails.logger.warn("Import/Export warning: Failed to create #{target_ref} for MR: #{@merge_request.iid}") # rubocop:disable Gitlab/RailsLogger
-        end
+      def create_target_branch
+        @project.repository.create_branch(@merge_request.target_branch, @merge_request.target_branch_sha)
       end
 
       def branch_exists?(branch_name)
diff --git a/qa/README.md b/qa/README.md
index 1bfa83cadf1..cdc84da1c5e 100644
--- a/qa/README.md
+++ b/qa/README.md
@@ -67,6 +67,16 @@ bundle exec bin/qa Test::Instance::All http://localhost:3000
 Note: If you want to run tests requiring SSH against GDK, you
 will need to [modify your GDK setup](https://gitlab.com/gitlab-org/gitlab-qa/blob/master/docs/run_qa_against_gdk.md).
 
+#### Running EE tests
+
+When running EE tests you'll need to have a license available. GitLab engineers can [request a license](https://about.gitlab.com/handbook/developer-onboarding/#working-on-gitlab-ee).
+
+Once you have the license file you can export it as an environment variable and then the framework can use it. If you do so it will be installed automatically.
+
+```
+export EE_LICENSE=$(cat /path/to/gitlab_license)
+```
+
 ### Writing tests
 
 - [Writing tests from scratch tutorial](../doc/development/testing_guide/end_to_end/quick_start_guide.md)
diff --git a/qa/qa/specs/features/browser_ui/1_manage/project/import_github_repo_spec.rb b/qa/qa/specs/features/browser_ui/1_manage/project/import_github_repo_spec.rb
index 14eaf770f10..d85929ebbca 100644
--- a/qa/qa/specs/features/browser_ui/1_manage/project/import_github_repo_spec.rb
+++ b/qa/qa/specs/features/browser_ui/1_manage/project/import_github_repo_spec.rb
@@ -1,9 +1,8 @@
 # frozen_string_literal: true
 
 module QA
-  # https://gitlab.com/gitlab-org/gitlab/issues/26952
   # BUG_IN_CODE
-  context 'Manage', :github, :quarantine do
+  context 'Manage', :github, quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/26952' do
     describe 'Project import from GitHub' do
       let(:imported_project) do
         Resource::ProjectImportedFromGithub.fabricate! do |project|
diff --git a/qa/qa/specs/features/browser_ui/3_create/merge_request/rebase_merge_request_spec.rb b/qa/qa/specs/features/browser_ui/3_create/merge_request/rebase_merge_request_spec.rb
index e4c79bf75b5..ff995fc1e0c 100644
--- a/qa/qa/specs/features/browser_ui/3_create/merge_request/rebase_merge_request_spec.rb
+++ b/qa/qa/specs/features/browser_ui/3_create/merge_request/rebase_merge_request_spec.rb
@@ -1,9 +1,8 @@
 # frozen_string_literal: true
 
 module QA
-  # Failure issue: https://gitlab.com/gitlab-org/gitlab/issues/36817
   # BUG_IN_CODE
-  context 'Create', :quarantine do
+  context 'Create', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/36817' do
     describe 'Merge request rebasing' do
       it 'user rebases source branch of merge request' do
         Flow::Login.sign_in
diff --git a/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_http_spec.rb b/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_http_spec.rb
index 1f156dfe6d5..f3edd822ef7 100644
--- a/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_http_spec.rb
+++ b/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_http_spec.rb
@@ -2,9 +2,8 @@
 
 module QA
   # Git protocol v2 is temporarily disabled
-  # https://gitlab.com/gitlab-org/gitlab/issues/27828
   # BUG_IN_CODE
-  context 'Create', :quarantine do
+  context 'Create', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/27828' do
     describe 'Push over HTTP using Git protocol version 2', :requires_git_protocol_v2 do
       it 'user pushes to the repository' do
         Flow::Login.sign_in
diff --git a/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_ssh_spec.rb b/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_ssh_spec.rb
index 55c70656462..3362404e11b 100644
--- a/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_ssh_spec.rb
+++ b/qa/qa/specs/features/browser_ui/3_create/repository/protocol_v2_push_ssh_spec.rb
@@ -2,9 +2,8 @@
 
 module QA
   # Git protocol v2 is temporarily disabled
-  # https://gitlab.com/gitlab-org/gitlab/issues/27828
   # BUG_IN_CODE
-  context 'Create', :quarantine do
+  context 'Create', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/27828' do
     describe 'Push over SSH using Git protocol version 2', :requires_git_protocol_v2 do
       # Note: If you run this test against GDK make sure you've enabled sshd and
       # enabled setting the Git protocol by adding `AcceptEnv GIT_PROTOCOL` to
diff --git a/qa/qa/specs/features/browser_ui/7_configure/auto_devops/create_project_with_auto_devops_spec.rb b/qa/qa/specs/features/browser_ui/7_configure/auto_devops/create_project_with_auto_devops_spec.rb
index 54014ff7067..7acc9eb37bd 100644
--- a/qa/qa/specs/features/browser_ui/7_configure/auto_devops/create_project_with_auto_devops_spec.rb
+++ b/qa/qa/specs/features/browser_ui/7_configure/auto_devops/create_project_with_auto_devops_spec.rb
@@ -50,8 +50,7 @@ module QA
       end
     end
 
-    # Failure issue: https://gitlab.com/gitlab-org/gitlab/issues/118481
-    describe 'Auto DevOps support', :orchestrated, :kubernetes, :quarantine do
+    describe 'Auto DevOps support', :orchestrated, :kubernetes, quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/118481' do
       context 'when rbac is enabled' do
         before(:all) do
           @cluster = Service::KubernetesCluster.new.create!
diff --git a/spec/features/merge_request/user_posts_diff_notes_spec.rb b/spec/features/merge_request/user_posts_diff_notes_spec.rb
index 8b16760606c..a76e40da9e5 100644
--- a/spec/features/merge_request/user_posts_diff_notes_spec.rb
+++ b/spec/features/merge_request/user_posts_diff_notes_spec.rb
@@ -56,7 +56,7 @@ describe 'Merge request > User posts diff notes', :js do
     end
 
     context 'with an unchanged line on the left and an unchanged line on the right' do
-      it 'allows commenting on the left side' do
+      it 'allows commenting on the left side', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/196826' do
         should_allow_commenting(find('[id="2f6fcd96b88b36ce98c38da085c795a27d92a3dd_7_7"]', match: :first).find(:xpath, '..'), 'left')
       end
 
diff --git a/spec/features/merge_request/user_sees_diff_spec.rb b/spec/features/merge_request/user_sees_diff_spec.rb
index 2d91d09a486..2ef4a18f78d 100644
--- a/spec/features/merge_request/user_sees_diff_spec.rb
+++ b/spec/features/merge_request/user_sees_diff_spec.rb
@@ -76,7 +76,7 @@ describe 'Merge request > User sees diff', :js do
     end
 
     context 'as user who needs to fork' do
-      it 'shows fork/cancel confirmation', :sidekiq_might_not_need_inline do
+      it 'shows fork/cancel confirmation', :sidekiq_might_not_need_inline, quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/196749' do
         sign_in(user)
         visit diffs_project_merge_request_path(project, merge_request)
 
diff --git a/spec/lib/gitlab/import_export/merge_request_parser_spec.rb b/spec/lib/gitlab/import_export/merge_request_parser_spec.rb
index c437efede4c..ab834ac3fa8 100644
--- a/spec/lib/gitlab/import_export/merge_request_parser_spec.rb
+++ b/spec/lib/gitlab/import_export/merge_request_parser_spec.rb
@@ -40,8 +40,6 @@ describe Gitlab::ImportExport::MergeRequestParser do
       allow(instance).to receive(:branch_exists?).with(merge_request.source_branch).and_return(false)
       allow(instance).to receive(:fork_merge_request?).and_return(true)
     end
-    allow(Gitlab::GitalyClient).to receive(:migrate).and_call_original
-    allow(Gitlab::GitalyClient).to receive(:migrate).with(:fetch_ref).and_return([nil, 0])
 
     expect(parsed_merge_request).to eq(merge_request)
   end
diff --git a/spec/models/sentry_issue_spec.rb b/spec/models/sentry_issue_spec.rb
index 7dc1cea4617..022cfd4734e 100644
--- a/spec/models/sentry_issue_spec.rb
+++ b/spec/models/sentry_issue_spec.rb
@@ -15,6 +15,18 @@ describe SentryIssue do
     it { is_expected.to validate_presence_of(:sentry_issue_identifier) }
   end
 
+  describe 'callbacks' do
+    context 'after create commit do' do
+      it 'updates Sentry with a reciprocal link on creation' do
+        issue = create(:issue)
+
+        expect(ErrorTrackingIssueLinkWorker).to receive(:perform_async).with(issue.id)
+
+        create(:sentry_issue, issue: issue)
+      end
+    end
+  end
+
   describe '.for_project_and_identifier' do
     let!(:sentry_issue) { create(:sentry_issue) }
     let(:project) { sentry_issue.issue.project }
diff --git a/spec/support/features/discussion_comments_shared_example.rb b/spec/support/features/discussion_comments_shared_example.rb
index ea13e91860a..d19ac25db8c 100644
--- a/spec/support/features/discussion_comments_shared_example.rb
+++ b/spec/support/features/discussion_comments_shared_example.rb
@@ -269,7 +269,7 @@ shared_examples 'thread comments' do |resource_name|
             end
           end
 
-          it 'has "Comment" selected when opening the menu' do
+          it 'has "Comment" selected when opening the menu', quarantine: 'https://gitlab.com/gitlab-org/gitlab/issues/196825' do
             find(toggle_selector).click
 
             find("#{menu_selector} li", match: :first)
diff --git a/spec/workers/error_tracking_issue_link_worker_spec.rb b/spec/workers/error_tracking_issue_link_worker_spec.rb
new file mode 100644
index 00000000000..cf16e4a0803
--- /dev/null
+++ b/spec/workers/error_tracking_issue_link_worker_spec.rb
@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ErrorTrackingIssueLinkWorker do
+  let_it_be(:error_tracking) { create(:project_error_tracking_setting) }
+  let_it_be(:project) { error_tracking.project }
+  let_it_be(:issue) { create(:issue, project: project) }
+  let_it_be(:sentry_issue) { create(:sentry_issue, issue: issue) }
+
+  let(:repo) do
+    Gitlab::ErrorTracking::Repo.new(
+      status: 'active',
+      integration_id: 66666,
+      project_id: project.id
+    )
+  end
+
+  subject { described_class.new.perform(issue.id) }
+
+  describe '#perform' do
+    it 'creates a link between an issue and a Sentry issue in Sentry' do
+      expect_next_instance_of(Sentry::Client) do |client|
+        expect(client).to receive(:repos).with('sentry-org').and_return([repo])
+        expect(client)
+          .to receive(:create_issue_link)
+          .with(66666, sentry_issue.sentry_issue_identifier, issue)
+          .and_return(true)
+      end
+
+      expect(subject).to be true
+    end
+
+    shared_examples_for 'makes no external API requests' do
+      it 'takes no action' do
+        expect_any_instance_of(Sentry::Client).not_to receive(:repos)
+        expect_any_instance_of(Sentry::Client).not_to receive(:create_issue_link)
+
+        expect(subject).to be nil
+      end
+    end
+
+    shared_examples_for 'terminates after one API request' do
+      it 'takes no action' do
+        expect_next_instance_of(Sentry::Client) do |client|
+          expect(client).to receive(:repos).with('sentry-org').and_return([repo])
+        end
+        expect_any_instance_of(Sentry::Client).not_to receive(:create_issue_link)
+
+        expect(subject).to be nil
+      end
+    end
+
+    context 'when issue is unavailable' do
+      let(:issue) { double('issue', id: -3) }
+
+      it_behaves_like 'makes no external API requests'
+    end
+
+    context 'when project does not have error tracking configured' do
+      let(:issue) { build(:project) }
+
+      it_behaves_like 'makes no external API requests'
+    end
+
+    context 'when the issue is not linked to a Sentry issue in GitLab' do
+      let(:issue) { build(:issue, project: project) }
+
+      it_behaves_like 'makes no external API requests'
+    end
+
+    context 'when Sentry disabled the GitLab integration' do
+      let(:repo) do
+        Gitlab::ErrorTracking::Repo.new(
+          status: 'inactive',
+          integration_id: 66666,
+          project_id: project.id
+        )
+      end
+
+      it_behaves_like 'terminates after one API request'
+    end
+
+    context 'when Sentry the GitLab integration is for another project' do
+      let(:repo) do
+        Gitlab::ErrorTracking::Repo.new(
+          status: 'active',
+          integration_id: 66666,
+          project_id: -3
+        )
+      end
+
+      it_behaves_like 'terminates after one API request'
+    end
+  end
+end