Disaster Recovery

Geo replicates your database, your Git repositories, and few other assets. We will support and replicate more data in the future, that will enable you to failover with minimal effort, in a disaster situation.

See Geo current limitations for more information.

Warning: Disaster recovery for multi-secondary configurations is in Alpha. For the latest updates, check the multi-secondary Disaster Recovery epic.

Promoting secondary Geo replica in single-secondary configurations

We don't currently provide an automated way to promote a Geo replica and do a failover, but you can do it manually if you have root access to the machine.

This process promotes a secondary Geo replica to a primary. To regain geographical redundancy as quickly as possible, you should add a new secondary immediately after following these instructions.

Step 1. Allow replication to finish if possible

If the secondary is still replicating data from the primary, follow the planned failover docs as closely as possible in order to avoid unnecessary data loss.

Step 2. Permanently disable the primary

Warning: If a primary goes offline, there may be data saved on the primary that has not been replicated to the secondary. This data should be treated as lost if you proceed.

If an outage on your primary happens, you should do everything possible to avoid a split-brain situation where writes can occur in two different GitLab instances, complicating recovery efforts. So to prepare for the failover, we must disable the primary.

  1. SSH into your primary to stop and disable GitLab, if possible:

    sudo gitlab-ctl stop
    

    Prevent GitLab from starting up again if the server unexpectedly reboots:

    sudo systemctl disable gitlab-runsvdir
    

    CentOS only: In CentOS 6 or older, there is no easy way to prevent GitLab from being started if the machine reboots isn't available (see gitlab-org/omnibus-gitlab#3058). It may be safest to uninstall the GitLab package completely:

    yum remove gitlab-ee
    

    Ubuntu 14.04 LTS: If you are using an older version of Ubuntu or any other distro based on the Upstart init system, you can prevent GitLab from starting if the machine reboots by doing the following:

    initctl stop gitlab-runsvvdir
    echo 'manual' > /etc/init/gitlab-runsvdir.override
    initctl reload-configuration
    
  2. If you do not have SSH access to your primary, take the machine offline and prevent it from rebooting by any means at your disposal. Since there are many ways you may prefer to accomplish this, we will avoid a single recommendation. You may need to:

    • Reconfigure the load balancers
    • Change DNS records (e.g., point the primary DNS record to the secondary node in order to stop usage of the primary)
    • Stop the virtual servers
    • Block traffic through a firewall
    • Revoke object storage permissions from the primary
    • Physically disconnect a machine
  3. If you plan to update the primary domain DNS record, you may wish to lower the TTL now to speed up propagation.

Step 3. Promoting a secondary Geo replica

  1. SSH in to your secondary and login as root:

    sudo -i
    
  2. Edit /etc/gitlab/gitlab.rb to reflect its new status as primary by removing the following line:

    ## REMOVE THIS LINE
    geo_secondary_role['enable'] = true
    

    A new secondary should not be added at this time. If you want to add a new secondary, do this after you have completed the entire process of promoting the secondary to the primary.

  3. Promote the secondary to primary. Execute:

    gitlab-ctl promote-to-primary-node
    
  4. Verify you can connect to the newly promoted primary using the URL used previously for the secondary.

  5. Success! The secondary has now been promoted to primary.

Promoting a node with HA

The gitlab-ctl promote-to-primary-node command cannot be used yet in conjunction with High Availability or with multiple machines, as it can only perform changes on a single one.

The command above does the following changes:

  • Promotes the PostgreSQL secondary to primary
  • Executes gitlab-ctl reconfigure to apply the changes in /etc/gitlab/gitlab.rb
  • Runs gitlab-rake geo:set_secondary_as_primary

You need to make sure all the affected machines no longer have geo_secondary_role['enable'] = true in /etc/gitlab/gitlab.rb, that you execute the database promotion on the required database nodes and you execute the gitlab-rake geo:set_secondary_as_primary in a machine running the application server.

Step 4. (Optional) Updating the primary domain DNS record

Updating the DNS records for the primary domain to point to the secondary will prevent the need to update all references to the primary domain to the secondary domain, like changing Git remotes and API URLs.

  1. SSH into your secondary and login as root:

    sudo -i
    
  2. Update the primary domain's DNS record. After updating the primary domain's DNS records to point to the secondary, edit /etc/gitlab/gitlab.rb on the secondary to reflect the new URL:

    # Change the existing external_url configuration
    external_url 'https://gitlab.example.com'
    
    Note Changing external_url won't prevent access via the old secondary URL, as long as the secondary DNS records are still intact.
  3. Reconfigure the secondary node for the change to take effect:

    gitlab-ctl reconfigure
    
  4. Execute the command below to update the newly promoted primary node URL:

    gitlab-rake geo:update_primary_node_url
    

    This command will use the changed external_url configuration defined in /etc/gitlab/gitlab.rb.

  5. Verify you can connect to the newly promoted primary using the primary URL. If you updated the DNS records for the primary domain, these changes may not have yet propagated depending on the previous DNS records TTL.

Step 5. (Optional) Add secondary Geo replicas to a promoted primary

Promoting a secondary to primary using the process above does not enable Geo on the new primary.

To bring a new secondary online, follow the Geo setup instructions.

Promoting secondary Geo replica in multi-secondary configurations

If you have more than one secondary and you need to promote one of them we suggest you to follow Promoting secondary Geo replica in single-secondary configurations and after that you also need two extra steps.

Step 1. Prepare the new primary to serve one or more secondaries

  1. SSH into your new primary and login as root:

    sudo -i
    
  2. Edit /etc/gitlab/gitlab.rb

    ## Enable a Geo Primary role (if you haven't yet)
    geo_primary_role['enable'] = true
    
    ##
    # Primary and Secondary addresses
    # - replace '1.2.3.4' with the primary public or VPC address
    # - replace '5.6.7.8' with the secondary public or VPC address
    ##
    postgresql['md5_auth_cidr_addresses'] = ['1.2.3.4/32', '5.6.7.8/32']
    
    # Every secondary server needs to have its own slot so specify the number of secondary nodes you're going to have
    postgresql['max_replication_slots'] = 1
    
    ##
    ## Disable automatic database migrations temporarily
    ## (until PostgreSQL is restarted and listening on the private address).
    ##
    gitlab_rails['auto_migrate'] = false
    
    

    (For more details about these settings you can read Configure the primary server)

  3. Save the file and reconfigure GitLab for the database listen changes and the replication slot changes to be applied.

    gitlab-ctl reconfigure
    

    Restart PostgreSQL for its changes to take effect:

    gitlab-ctl restart postgresql
    
  4. Re-enable migrations now that PostgreSQL is restarted and listening on the private address.

    Edit /etc/gitlab/gitlab.rb and change the configuration to true:

    gitlab_rails['auto_migrate'] = true
    

    Save the file and reconfigure GitLab:

    gitlab-ctl reconfigure
    

Step 2. Initiate the replication process

Now we need to make each secondary listen to changes on the new primary. To do that you need to initiate the replication process again but this time for another primary. All the old replication settings will be overwritten.

Troubleshooting

I followed the disaster recovery instructions and now two-factor auth is broken!

The setup instructions for Geo prior to 10.5 failed to replicate the otp_key_base secret, which is used to encrypt the two-factor authentication secrets stored in the database. If it differs between primary and secondary nodes, users with two-factor authentication enabled won't be able to log in after a failover.

If you still have access to the old primary node, you can follow the instructions in the Upgrading to GitLab 10.5 section to resolve the error. Otherwise, the secret is lost and you'll need to reset two-factor authentication for all users.