gitlab-org--gitlab-foss/doc/administration/high_availability/load_balancer.md

Load Balancer for GitLab HA

In an active/active GitLab configuration, you will need a load balancer to route traffic to the application servers. The specifics on which load balancer to use or the exact configuration is beyond the scope of GitLab documentation. We hope that if you're managing HA systems like GitLab you have a load balancer of choice already. Some examples including HAProxy (open-source), F5 Big-IP LTM, and Citrix Net Scaler. This documentation will outline what ports and protocols you need to use with GitLab.

Basic ports

LB Port	Backend Port	Protocol
80	80	HTTP 1
443	443	HTTPS 1 2
22	22	TCP

GitLab Pages Ports

If you're using GitLab Pages you will need some additional port configurations. GitLab Pages requires a separate virtual IP address. Configure DNS to point the pages_external_url from /etc/gitlab/gitlab.rb at the new virtual IP address. See the GitLab Pages documentation for more information.

LB Port	Backend Port	Protocol
80	Varies 3	HTTP
443	Varies 3	TCP 4

Alternate SSH Port

Some organizations have policies against opening SSH port 22. In this case, it may be helpful to configure an alternate SSH hostname that allows users to use SSH on port 443. An alternate SSH hostname will require a new virtual IP address compared to the other GitLab HTTP configuration above.

Configure DNS for an alternate SSH hostname such as altssh.gitlab.example.com.

LB Port	Backend Port	Protocol
443	22	TCP

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Read more on high-availability configuration:

1. Configure the database
2. Configure Redis
3. Configure NFS
4. Configure the GitLab application servers

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1. Web terminal support requires your load balancer to correctly handle WebSocket connections. When using HTTP or HTTPS proxying, this means your load balancer must be configured to pass through the Connection and Upgrade hop-by-hop headers. See the web terminal integration guide for more details. ↩︎

2. When using HTTPS protocol for port 443, you will need to add an SSL certificate to the load balancers. If you wish to terminate SSL at the GitLab application server instead, use TCP protocol. ↩︎

3. The backend port for GitLab Pages depends on the gitlab_pages['external_http'] and gitlab_pages['external_https'] setting. See GitLab Pages documentation for more details. ↩︎

4. Port 443 for GitLab Pages should always use the TCP protocol. Users can configure custom domains with custom SSL, which would not be possible if SSL was terminated at the load balancer. ↩︎