diff --git a/app/assets/javascripts/issue_show/components/edit_actions.vue b/app/assets/javascripts/issue_show/components/edit_actions.vue
index 4ee44e50d2f..14ada5adcf6 100644
--- a/app/assets/javascripts/issue_show/components/edit_actions.vue
+++ b/app/assets/javascripts/issue_show/components/edit_actions.vue
@@ -1,5 +1,5 @@
 <script>
-/* eslint-disable @gitlab/vue-require-i18n-strings */
+import { GlButton } from '@gitlab/ui';
 import { __, sprintf } from '~/locale';
 import updateMixin from '../mixins/update';
 import eventHub from '../event_hub';
@@ -10,6 +10,9 @@ const issuableTypes = {
 };
 
 export default {
+  components: {
+    GlButton,
+  },
   mixins: [updateMixin],
   props: {
     canDestroy: {
@@ -64,28 +67,30 @@ export default {
 
 <template>
   <div class="gl-mt-3 gl-mb-3 clearfix">
-    <button
-      :class="{ disabled: formState.updateLoading || !isSubmitEnabled }"
+    <gl-button
+      :loading="formState.updateLoading"
       :disabled="formState.updateLoading || !isSubmitEnabled"
-      class="btn btn-success float-left qa-save-button"
+      category="primary"
+      variant="success"
+      class="float-left qa-save-button"
       type="submit"
       @click.prevent="updateIssuable"
     >
-      Save changes
-      <i v-if="formState.updateLoading" class="fa fa-spinner fa-spin" aria-hidden="true"> </i>
-    </button>
-    <button class="btn btn-default float-right" type="button" @click="closeForm">
+      {{ __('Save changes') }}
+    </gl-button>
+    <gl-button class="float-right" @click="closeForm">
       {{ __('Cancel') }}
-    </button>
-    <button
+    </gl-button>
+    <gl-button
       v-if="shouldShowDeleteButton"
-      :class="{ disabled: deleteLoading }"
+      :loading="deleteLoading"
       :disabled="deleteLoading"
-      class="btn btn-danger float-right gl-mr-3 qa-delete-button"
-      type="button"
+      category="primary"
+      variant="danger"
+      class="float-right gl-mr-3 qa-delete-button"
       @click="deleteIssuable"
     >
-      Delete <i v-if="deleteLoading" class="fa fa-spinner fa-spin" aria-hidden="true"> </i>
-    </button>
+      {{ __('Delete') }}
+    </gl-button>
   </div>
 </template>
diff --git a/app/models/ci/build_trace_chunk.rb b/app/models/ci/build_trace_chunk.rb
index 407802baf09..f44a5b804fa 100644
--- a/app/models/ci/build_trace_chunk.rb
+++ b/app/models/ci/build_trace_chunk.rb
@@ -2,9 +2,10 @@
 
 module Ci
   class BuildTraceChunk < ApplicationRecord
-    include FastDestroyAll
+    extend ::Gitlab::Ci::Model
+    include ::FastDestroyAll
+    include ::Checksummable
     include ::Gitlab::ExclusiveLeaseHelpers
-    extend Gitlab::Ci::Model
 
     belongs_to :build, class_name: "Ci::Build", foreign_key: :build_id
 
@@ -60,8 +61,6 @@ module Ci
       end
     end
 
-    ##
-    # Data is memoized for optimizing #size and #end_offset
     def data
       @data ||= get_data.to_s
     end
@@ -80,11 +79,11 @@ module Ci
 
       in_lock(*lock_params) { unsafe_append_data!(new_data, offset) }
 
-      schedule_to_persist if full?
+      schedule_to_persist! if full?
     end
 
     def size
-      @size ||= current_store.size(self) || data&.bytesize
+      @size ||= @data&.bytesize || current_store.size(self) || data&.bytesize
     end
 
     def start_offset
@@ -100,35 +99,49 @@ module Ci
     end
 
     def persist_data!
-      in_lock(*lock_params) do # Write operation is atomic
-        unsafe_persist_to!(self.class.persistable_store)
-      end
+      in_lock(*lock_params) { unsafe_persist_data! }
+    end
+
+    def schedule_to_persist!
+      return if persisted?
+
+      Ci::BuildTraceChunkFlushWorker.perform_async(id)
     end
 
     private
 
-    def unsafe_persist_to!(new_store)
+    def get_data
+      # Redis / database return UTF-8 encoded string by default
+      current_store.data(self)&.force_encoding(Encoding::BINARY)
+    end
+
+    def unsafe_persist_data!(new_store = self.class.persistable_store)
       return if data_store == new_store.to_s
 
-      current_data = get_data
+      current_data = data
+      old_store_class = current_store
 
       unless current_data&.bytesize.to_i == CHUNK_SIZE
         raise FailedToPersistDataError, 'Data is not fulfilled in a bucket'
       end
 
-      old_store_class = current_store
-
       self.raw_data = nil
       self.data_store = new_store
+      self.checksum = crc32(current_data)
+
+      ##
+      # We need to so persist data then save a new store identifier before we
+      # remove data from the previous store to make this operation
+      # trasnaction-safe. `unsafe_set_data! calls `save!` because of this
+      # reason.
+      #
+      # TODO consider using callbacks and state machine to remove old data
+      #
       unsafe_set_data!(current_data)
 
       old_store_class.delete_data(self)
     end
 
-    def get_data
-      current_store.data(self)&.force_encoding(Encoding::BINARY) # Redis/Database return UTF-8 string as default
-    end
-
     def unsafe_set_data!(value)
       raise ArgumentError, 'New data size exceeds chunk size' if value.bytesize > CHUNK_SIZE
 
@@ -157,14 +170,12 @@ module Ci
       save! if changed?
     end
 
-    def schedule_to_persist
-      return if data_persisted?
-
-      Ci::BuildTraceChunkFlushWorker.perform_async(id)
+    def persisted?
+      !redis?
     end
 
-    def data_persisted?
-      !redis?
+    def live?
+      redis?
     end
 
     def full?
diff --git a/app/models/ci/build_trace_chunks/database.rb b/app/models/ci/build_trace_chunks/database.rb
index 3b8e23510d9..ea8072099c6 100644
--- a/app/models/ci/build_trace_chunks/database.rb
+++ b/app/models/ci/build_trace_chunks/database.rb
@@ -29,7 +29,7 @@ module Ci
           new_data = truncated_data + new_data
         end
 
-        model.raw_data = new_data
+        set_data(model, new_data)
         model.raw_data.to_s.bytesize
       end
 
diff --git a/app/models/ci/build_trace_chunks/redis.rb b/app/models/ci/build_trace_chunks/redis.rb
index 0ae563f6ce8..58d50b39c11 100644
--- a/app/models/ci/build_trace_chunks/redis.rb
+++ b/app/models/ci/build_trace_chunks/redis.rb
@@ -41,9 +41,9 @@ module Ci
         end
       end
 
-      def set_data(model, data)
+      def set_data(model, new_data)
         Gitlab::Redis::SharedState.with do |redis|
-          redis.set(key(model), data, ex: CHUNK_REDIS_TTL)
+          redis.set(key(model), new_data, ex: CHUNK_REDIS_TTL)
         end
       end
 
diff --git a/app/models/concerns/checksummable.rb b/app/models/concerns/checksummable.rb
index 1f76eb87aa5..d6d17bfc604 100644
--- a/app/models/concerns/checksummable.rb
+++ b/app/models/concerns/checksummable.rb
@@ -3,9 +3,13 @@
 module Checksummable
   extend ActiveSupport::Concern
 
+  def crc32(data)
+    Zlib.crc32(data)
+  end
+
   class_methods do
     def hexdigest(path)
-      Digest::SHA256.file(path).hexdigest
+      ::Digest::SHA256.file(path).hexdigest
     end
   end
 end
diff --git a/app/workers/ci/build_trace_chunk_flush_worker.rb b/app/workers/ci/build_trace_chunk_flush_worker.rb
index fe59ba896a4..43a19f8a6d6 100644
--- a/app/workers/ci/build_trace_chunk_flush_worker.rb
+++ b/app/workers/ci/build_trace_chunk_flush_worker.rb
@@ -6,9 +6,9 @@ module Ci
     include PipelineBackgroundQueue
 
     # rubocop: disable CodeReuse/ActiveRecord
-    def perform(build_trace_chunk_id)
-      ::Ci::BuildTraceChunk.find_by(id: build_trace_chunk_id).try do |build_trace_chunk|
-        build_trace_chunk.persist_data!
+    def perform(chunk_id)
+      ::Ci::BuildTraceChunk.find_by(id: chunk_id).try do |chunk|
+        chunk.persist_data!
       end
     end
     # rubocop: enable CodeReuse/ActiveRecord
diff --git a/changelogs/unreleased/229342-update-issue-edit-buttons.yml b/changelogs/unreleased/229342-update-issue-edit-buttons.yml
new file mode 100644
index 00000000000..e8dfeeea298
--- /dev/null
+++ b/changelogs/unreleased/229342-update-issue-edit-buttons.yml
@@ -0,0 +1,5 @@
+---
+title: Update issue edit buttons
+merge_request: 40298
+author:
+type: changed
diff --git a/changelogs/unreleased/feature-gb-resilient-live-trace-chunks.yml b/changelogs/unreleased/feature-gb-resilient-live-trace-chunks.yml
new file mode 100644
index 00000000000..4e85d53bec5
--- /dev/null
+++ b/changelogs/unreleased/feature-gb-resilient-live-trace-chunks.yml
@@ -0,0 +1,5 @@
+---
+title: Make cloud native build logs more resilient
+merge_request: 40506
+author:
+type: added
diff --git a/db/migrate/20200818092401_add_checksum_to_build_chunk.rb b/db/migrate/20200818092401_add_checksum_to_build_chunk.rb
new file mode 100644
index 00000000000..c1c968571a2
--- /dev/null
+++ b/db/migrate/20200818092401_add_checksum_to_build_chunk.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class AddChecksumToBuildChunk < ActiveRecord::Migration[6.0]
+  DOWNTIME = false
+
+  def change
+    add_column :ci_build_trace_chunks, :checksum, :binary
+  end
+end
diff --git a/db/schema_migrations/20200818092401 b/db/schema_migrations/20200818092401
new file mode 100644
index 00000000000..916b5421e70
--- /dev/null
+++ b/db/schema_migrations/20200818092401
@@ -0,0 +1 @@
+39d412a1680d55466c14450943e17802eb183f2f33f2f77078cba571262cd149
\ No newline at end of file
diff --git a/db/structure.sql b/db/structure.sql
index 6242b27dbe1..119d34610a3 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -9782,7 +9782,8 @@ CREATE TABLE public.ci_build_trace_chunks (
     build_id integer NOT NULL,
     chunk_index integer NOT NULL,
     data_store integer NOT NULL,
-    raw_data bytea
+    raw_data bytea,
+    checksum bytea
 );
 
 CREATE SEQUENCE public.ci_build_trace_chunks_id_seq
diff --git a/doc/.vale/gitlab/Acronyms.yml b/doc/.vale/gitlab/Acronyms.yml
index b9917a90793..113c6012e4a 100644
--- a/doc/.vale/gitlab/Acronyms.yml
+++ b/doc/.vale/gitlab/Acronyms.yml
@@ -14,6 +14,7 @@ first: '\b([A-Z]{3,5})\b'
 second: '(?:\b[A-Z][a-z]+ )+\(([A-Z]{3,5})\)'
 # ... with the exception of these:
 exceptions:
+  - ANSI
   - API
   - ARN
   - ASCII
@@ -24,11 +25,15 @@ exceptions:
   - CPU
   - CSS
   - CSV
+  - DAST
   - DNS
   - EKS
   - FAQ
+  - FOSS
+  - GCP
   - GDK
   - GET
+  - GKE
   - GNU
   - GPG
   - GPL
@@ -47,6 +52,8 @@ exceptions:
   - LESS
   - LFS
   - LRU
+  - MIME
+  - MVC
   - NFS
   - NGINX
   - NOTE
@@ -61,11 +68,15 @@ exceptions:
   - RPC
   - RSA
   - RSS
+  - RVM
   - SAML
+  - SAST
   - SCIM
   - SCP
   - SCSS
+  - SDK
   - SHA
+  - SMTP
   - SQL
   - SSH
   - SSL
@@ -84,5 +95,6 @@ exceptions:
   - UUID
   - VPC
   - WIP
+  - WSL
   - XML
   - YAML
diff --git a/doc/ci/variables/README.md b/doc/ci/variables/README.md
index 1538d7a3a0a..1480b8acecd 100644
--- a/doc/ci/variables/README.md
+++ b/doc/ci/variables/README.md
@@ -744,7 +744,11 @@ so `&&` is evaluated before `||`.
 
 #### Parentheses
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/230938) in GitLab 13.3
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/230938) in GitLab 13.3
+> - It's [deployed behind a feature flag](../../user/feature_flags.md), enabled by default.
+> - It's enabled on GitLab.com.
+> - It's recommended for production use.
+> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#enable-or-disable-parenthesis-support-for-variables-core-only). **(CORE ONLY)**
 
 It is possible to use parentheses to group conditions. Parentheses have the highest
 precedence of all operators. Expressions enclosed in parentheses are evaluated first,
@@ -760,22 +764,24 @@ Examples:
 - `($VARIABLE1 =~ /^content.*/ || $VARIABLE2 =~ /thing$/) && $VARIABLE3`
 - `$CI_COMMIT_BRANCH == "my-branch" || (($VARIABLE1 == "thing" || $VARIABLE2 == "thing") && $VARIABLE3)`
 
+##### Enable or disable parenthesis support for variables **(CORE ONLY)**
+
 The feature is currently deployed behind a feature flag that is **enabled by default**.
 [GitLab administrators with access to the GitLab Rails console](../../administration/feature_flags.md)
 can opt to disable it for your instance.
 
-To enable it:
-
-```ruby
-Feature.enable(:ci_if_parenthesis_enabled)
-```
-
 To disable it:
 
 ```ruby
 Feature.disable(:ci_if_parenthesis_enabled)
 ```
 
+To enable it:
+
+```ruby
+Feature.enable(:ci_if_parenthesis_enabled)
+```
+
 ### Storing regular expressions in variables
 
 It is possible to store a regular expression in a variable, to be used for pattern matching:
diff --git a/doc/ci/yaml/README.md b/doc/ci/yaml/README.md
index de3b0281647..97935536f2c 100644
--- a/doc/ci/yaml/README.md
+++ b/doc/ci/yaml/README.md
@@ -1548,6 +1548,22 @@ considered for their usage and behavior in this context. Future keyword improvem
 are being discussed in our [epic for improving `rules`](https://gitlab.com/groups/gitlab-org/-/epics/2783),
 where anyone can add suggestions or requests.
 
+You can use [parentheses](../variables/README.md#parentheses) with `&&` and `||` to build more complicated variable expressions.
+[Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/230938) in GitLab 13.3:
+
+```yaml
+job1:
+  script:
+    - echo This rule uses parentheses.
+  rules:
+    if: ($CI_COMMIT_BRANCH == "master" || $CI_COMMIT_BRANCH == "develop") && $MY_VARIABLE
+```
+
+NOTE: **Note:**
+In GitLab 13.2 and older, the order of operations when mixing `||` and `&&` in a single rule may not have executed
+in the expected order. This is [fixed](https://gitlab.com/gitlab-org/gitlab/-/issues/230938)
+in GitLab 13.3.
+
 ### `only`/`except` (basic)
 
 NOTE: **Note:**
@@ -1833,7 +1849,17 @@ end-to-end:
       - $CI_COMMIT_MESSAGE =~ /skip-end-to-end-tests/
 ```
 
-Learn more about [variables expressions](../variables/README.md#environment-variables-expressions).
+You can use [parentheses](../variables/README.md#parentheses) with `&&` and `||` to build more complicated variable expressions.
+[Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/230938) in GitLab 13.3:
+
+```yaml
+job1:
+  script:
+    - echo This rule uses parentheses.
+  only:
+    variables:
+      - ($CI_COMMIT_BRANCH == "master" || $CI_COMMIT_BRANCH == "develop") && $MY_VARIABLE
+```
 
 #### `only:changes`/`except:changes`
 
diff --git a/lib/gitlab/ci/mask_secret.rb b/lib/gitlab/ci/mask_secret.rb
index 58d55b1bd6f..e5a7151b823 100644
--- a/lib/gitlab/ci/mask_secret.rb
+++ b/lib/gitlab/ci/mask_secret.rb
@@ -8,6 +8,11 @@ module Gitlab
 
         # We assume 'value' must be mutable, given
         # that frozen string is enabled.
+
+        ##
+        # TODO We need to remove this because it is going to change checksum of
+        # a trace.
+        #
         value.gsub!(token, 'x' * token.length)
         value
       end
diff --git a/lib/gitlab/ci/templates/Security/SAST.gitlab-ci.yml b/lib/gitlab/ci/templates/Security/SAST.gitlab-ci.yml
index 425f16fd212..1fb8b6736aa 100644
--- a/lib/gitlab/ci/templates/Security/SAST.gitlab-ci.yml
+++ b/lib/gitlab/ci/templates/Security/SAST.gitlab-ci.yml
@@ -59,7 +59,7 @@ sast:
 bandit-sast:
   extends: .sast-analyzer
   image:
-    name: "SAST_ANALYZER_IMAGE"
+    name: "$SAST_ANALYZER_IMAGE"
   variables:
     SAST_ANALYZER_IMAGE: "$SECURE_ANALYZERS_PREFIX/bandit:$SAST_ANALYZER_IMAGE_TAG"
   rules:
@@ -73,7 +73,7 @@ bandit-sast:
 brakeman-sast:
   extends: .sast-analyzer
   image:
-    name: "SAST_ANALYZER_IMAGE"
+    name: "$SAST_ANALYZER_IMAGE"
   variables:
     SAST_ANALYZER_IMAGE: "$SECURE_ANALYZERS_PREFIX/brakeman:$SAST_ANALYZER_IMAGE_TAG"
   rules:
@@ -105,7 +105,7 @@ eslint-sast:
 flawfinder-sast:
   extends: .sast-analyzer
   image:
-    name: "SAST_ANALYZER_IMAGE"
+    name: "$SAST_ANALYZER_IMAGE"
   variables:
     SAST_ANALYZER_IMAGE: "$SECURE_ANALYZERS_PREFIX/flawfinder:$SAST_ANALYZER_IMAGE_TAG"
   rules:
diff --git a/spec/frontend/issue_show/components/edit_actions_spec.js b/spec/frontend/issue_show/components/edit_actions_spec.js
index b0c1894058e..79a2bcd5eab 100644
--- a/spec/frontend/issue_show/components/edit_actions_spec.js
+++ b/spec/frontend/issue_show/components/edit_actions_spec.js
@@ -70,16 +70,6 @@ describe('Edit Actions components', () => {
       expect(eventHub.$emit).toHaveBeenCalledWith('update.issuable');
     });
 
-    it('shows loading icon after clicking save button', done => {
-      vm.$el.querySelector('.btn-success').click();
-
-      Vue.nextTick(() => {
-        expect(vm.$el.querySelector('.btn-success .fa')).not.toBeNull();
-
-        done();
-      });
-    });
-
     it('disabled button after clicking save button', done => {
       vm.$el.querySelector('.btn-success').click();
 
@@ -107,17 +97,6 @@ describe('Edit Actions components', () => {
       expect(eventHub.$emit).toHaveBeenCalledWith('delete.issuable', { destroy_confirm: true });
     });
 
-    it('shows loading icon after clicking delete button', done => {
-      jest.spyOn(window, 'confirm').mockReturnValue(true);
-      vm.$el.querySelector('.btn-danger').click();
-
-      Vue.nextTick(() => {
-        expect(vm.$el.querySelector('.btn-danger .fa')).not.toBeNull();
-
-        done();
-      });
-    });
-
     it('does no actions when confirm is false', done => {
       jest.spyOn(window, 'confirm').mockReturnValue(false);
       vm.$el.querySelector('.btn-danger').click();
diff --git a/spec/models/ci/build_trace_chunk_spec.rb b/spec/models/ci/build_trace_chunk_spec.rb
index a6362d46449..1eff6424f9e 100644
--- a/spec/models/ci/build_trace_chunk_spec.rb
+++ b/spec/models/ci/build_trace_chunk_spec.rb
@@ -222,6 +222,8 @@ RSpec.describe Ci::BuildTraceChunk, :clean_gitlab_redis_shared_state do
             subject
 
             build_trace_chunk.reload
+
+            expect(build_trace_chunk.checksum).to be_present
             expect(build_trace_chunk.fog?).to be_truthy
             expect(build_trace_chunk.data).to eq(new_data)
           end
@@ -502,6 +504,12 @@ RSpec.describe Ci::BuildTraceChunk, :clean_gitlab_redis_shared_state do
             expect(Ci::BuildTraceChunks::Fog.new.data(build_trace_chunk)).to eq(data)
           end
 
+          it 'calculates CRC32 checksum' do
+            subject
+
+            expect(build_trace_chunk.reload.checksum).to eq '3398914352'
+          end
+
           it_behaves_like 'Atomic operation'
         end
 
diff --git a/spec/models/ci/build_trace_chunks/fog_spec.rb b/spec/models/ci/build_trace_chunks/fog_spec.rb
index a44ae58dfd2..b7e9adab04a 100644
--- a/spec/models/ci/build_trace_chunks/fog_spec.rb
+++ b/spec/models/ci/build_trace_chunks/fog_spec.rb
@@ -46,9 +46,7 @@ RSpec.describe Ci::BuildTraceChunks::Fog do
   end
 
   describe '#set_data' do
-    subject { data_store.set_data(model, data) }
-
-    let(:data) { 'abc123' }
+    let(:new_data) { 'abc123' }
 
     context 'when data exists' do
       let(:model) { create(:ci_build_trace_chunk, :fog_with_data, initial_data: 'sample data in fog') }
@@ -56,9 +54,9 @@ RSpec.describe Ci::BuildTraceChunks::Fog do
       it 'overwrites data' do
         expect(data_store.data(model)).to eq('sample data in fog')
 
-        subject
+        data_store.set_data(model, new_data)
 
-        expect(data_store.data(model)).to eq('abc123')
+        expect(data_store.data(model)).to eq new_data
       end
     end
 
@@ -68,9 +66,9 @@ RSpec.describe Ci::BuildTraceChunks::Fog do
       it 'sets new data' do
         expect(data_store.data(model)).to be_nil
 
-        subject
+        data_store.set_data(model, new_data)
 
-        expect(data_store.data(model)).to eq('abc123')
+        expect(data_store.data(model)).to eq new_data
       end
     end
   end