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.
SSL
How will you handle SSL in your HA environment? There are several different options:
- Each application node terminates SSL
- The load balancer(s) terminate SSL and communication is not secure between the load balancer(s) and the application nodes
- The load balancer(s) terminate SSL and communication is secure between the load balancer(s) and the application nodes
Application nodes terminate SSL
Configure your load balancer(s) to pass connections on port 443 as 'TCP' rather than 'HTTP(S)' protocol. This will pass the connection to the application nodes Nginx service untouched. Nginx will have the SSL certificate and listen on port 443.
See Nginx HTTPS documentation for details on managing SSL certificates and configuring Nginx.
Load Balancer(s) terminate SSL without backend SSL
Configure your load balancer(s) to use the 'HTTP(S)' protocol rather than 'TCP'. The load balancer(s) will then be responsible for managing SSL certificates and terminating SSL.
Since communication between the load balancer(s) and GitLab will not be secure, there is some additional configuration needed. See Nginx Proxied SSL documentation for details.
Load Balancer(s) terminate SSL with backend SSL
Configure your load balancer(s) to use the 'HTTP(S)' protocol rather than 'TCP'. The load balancer(s) will be responsible for managing SSL certificates that end users will see.
Traffic will also be secure between the load balancer(s) and Nginx in this scenario. There is no need to add configuration for proxied SSL since the connection will be secure all the way. However, configuration will need to be added to GitLab to configure SSL certificates. See Nginx HTTPS documentation for details on managing SSL certificates and configuring Nginx.
Ports
Basic ports
| LB Port | Backend Port | Protocol |
|---|---|---|
| 80 | 80 | HTTP |
| 443 | 443 | TCP or HTTPS |
| 22 | 22 | TCP |
GitLab Pages Ports
If you're using GitLab Pages with custom domain support 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 | HTTP |
| 443 | Varies | TCP |
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 |
Read more on high-availability configuration: