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This version of GitHub Enterprise was discontinued on 2022-06-03. No patch releases will be made, even for critical security issues. For better performance, improved security, and new features, upgrade to the latest version of GitHub Enterprise. For help with the upgrade, contact GitHub Enterprise support.

Cluster network configuration

GitHub Enterprise Server clustering relies on proper DNS name resolution, load balancing, and communication between nodes to operate properly.

Network considerations

The simplest network design for clustering is to place the nodes on a single LAN. If a cluster must span subnetworks, we do not recommend configuring any firewall rules between the networks. The latency between nodes should be less than 1 millisecond.

For high availability, the latency between the network with the active nodes and the network with the passive nodes must be less than 70 milliseconds. We don't recommend configuring a firewall between the two networks.

Application ports for end users

Application ports provide web application and Git access for end users.

22/TCPGit over SSHYes
(When SSL is enabled this port redirects to HTTPS)
9418/TCPSimple Git protocol port
(Disabled in private mode)

Administrative ports

Administrative ports are not required for basic application use by end users.

122/TCPAdministrative SSHYes
8080/TCPManagement Console HTTPNo
(When SSL is enabled this port redirects to HTTPS)
8443/TCPManagement Console HTTPSYes

Cluster communication ports

If a network level firewall is in place between nodes, these ports will need to be accessible. The communication between nodes is not encrypted. These ports should not be accessible externally.

1336/TCPInternal API
3033/TCPInternal SVN access
3037/TCPInternal SVN access
4486/TCPGovernor access
5115/TCPStorage backend
5208/TCPInternal SVN access
8090/TCPInternal GPG access
8149/TCPGitRPC file server access
9000/TCPGit Daemon
9102/TCPPages file server
9105/TCPLFS server
9203/TCPSemantic code service

Configuring a load balancer

We recommend an external TCP-based load balancer that supports the PROXY protocol to distribute traffic across nodes. Consider these load balancer configurations:

  • TCP ports (shown below) should be forwarded to nodes running the web-server service. These are the only nodes that serve external client requests.
  • Sticky sessions shouldn't be enabled.

Warning: When terminating HTTPS connections on a load balancer, the requests from the load balancer to GitHub Enterprise Server also need to use HTTPS. Downgrading the connection to HTTP is not supported.

Handling client connection information

Because client connections to the cluster come from the load balancer, the client IP address can be lost. To properly capture the client connection information, additional consideration is required.

If your load balancer can support it, we strongly recommend implementing the PROXY protocol. When no PROXY support is available, it is also possible to load balance the HTTP and HTTPS ports using the X-Forwarded-For header.

Security Warning: When either PROXY support or HTTP forwarding is enabled, it is critical that no external traffic can directly reach the GitHub Enterprise Server appliances. If external traffic is not properly blocked, the source IP addresses can be forged.

Enabling PROXY support on GitHub Enterprise Server

We strongly recommend enabling PROXY support for both your instance and the load balancer.

Note: GitHub Enterprise Server supports PROXY Protocol V1, which is incompatible with AWS Network Load Balancers. If you use AWS Network Load Balancers with GitHub Enterprise Server, do not enable PROXY support.

  • For your instance, use this command:

    $ ghe-config 'loadbalancer.proxy-protocol' 'true' && ghe-cluster-config-apply
  • For the load balancer, use the instructions provided by your vendor.

    PROXY protocol TCP port mappings

Source portDestination portService description
2223Git over SSH
80808081Management Console HTTP
84438444Management Console HTTPS

Enabling X-Forwarded-For support on GitHub Enterprise Server

Use the X-Forwarded-For protocol only when the PROXY protocol is unavailable. The X-Forwarded-For header only works with HTTP and HTTPS. The IP address reported for Git connections over SSH will show the load balancer IP.

To enable the X-Forwarded-For header, use this command:

$ ghe-config 'loadbalancer.http-forward' 'true' && ghe-cluster-config-apply

Protocol TCP port mappings for use without PROXY support

Source portDestination portService description
2222Git over SSH
80808080Management Console HTTP
84438443Management Console HTTPS

Configuring Health Checks

Health checks allow a load balancer to stop sending traffic to a node that is not responding if a pre-configured check fails on that node. If a cluster node fails, health checks paired with redundant nodes provides high availability.

Configure the load balancer to check one of these URLs:

  • https://HOSTNAME/status if HTTPS is enabled (default)
  • http://HOSTNAME/status if HTTPS is disabled

The check will return status code 200 (OK) if the node is healthy and available to service end-user requests.

Note: When the appliance is in maintenance mode, the https://HOSTNAME/status URL will return status code 503 (Service Unavailable). For more information, see "Enabling and scheduling maintenance mode."

DNS Requirements

DNS lookups for the GitHub Enterprise Server hostname should resolve to the load balancer. We recommend that you enable subdomain isolation. If subdomain isolation is enabled, an additional wildcard record (*.HOSTNAME) should also resolve to the load balancer. For more information, see "Enabling subdomain isolation."