GitSwarm-EE 2017.2-1 Documentation

GitLab Geo configuration

This is the final step you need to follow in order to setup a Geo node.

Table of Contents

Setting up GitLab

Notes:

After having installed GitLab Enterprise Edition in the instance that will serve as a Geo node and set up the database replication, the next steps can be summed up to:

  1. Configure the primary node
  2. Replicate some required configurations between the primary and the secondaries
  3. Start GitLab in the secondary node's machine
  4. Configure every secondary node in the primary's Admin screen

Prerequisites

This is the last step of configuring a Geo node. Make sure you have followed the first two steps of the Setup instructions:

  1. You have already installed on the secondary server the same version of GitLab Enterprise Edition that is present on the primary server.
  2. You have set up the database replication.
  3. Your secondary node is allowed to communicate via HTTP/HTTPS and SSH with your primary node (make sure your firewall is not blocking that).

Some of the following steps require to configure the primary and secondary nodes almost at the same time. For your convenience make sure you have SSH logins opened on all nodes as we will be moving back and forth.

Step 1. Adding the primary GitLab node

  1. SSH into the primary node and login as root:

    sudo -i

  2. Create a new SSH key pair for the primary node. Choose the default location and leave the password blank by hitting 'Enter' three times:

    Warning: If you already have an existing SSH key pair, you should not overwrite it because that may break Helix mirroring.

    sudo -u git -H ssh-keygen -b 4096 -C 'Primary GitLab Geo node'

    Read more in additional info for SSH key pairs.

  3. Get the contents of id_rsa.pub that was just created:

    # Omnibus GitLab installations
sudo -u git cat /var/opt/gitlab/.ssh/id_rsa.pub

# Installations from source
sudo -u git cat /home/git/.ssh/id_rsa.pub
  4. Visit the primary node's Admin Area ➔ Geo Nodes (/admin/geo_nodes) in your browser.

  5. Add the primary node by providing its full URL and the public SSH key you created previously. Make sure to check the box 'This is a primary node' when adding it.

    Add new primary Geo node

  6. Click the Add node button.

Step 2. Updating the known_hosts file of the secondary nodes

  1. SSH into the secondary node and login as root:

    sudo -i

  2. The secondary nodes need to know the SSH fingerprint of the primary node that will be used for the Git clone/fetch operations. In order to add it to the known_hosts file, run the following command and type yes when asked:

    sudo -u git -H ssh git@<primary-node-url>

    Replace <primary-node-url> with the FQDN of the primary node.

  3. Verify that the fingerprint was added by checking known_hosts:

    # Omnibus GitLab installations
cat /var/opt/gitlab/.ssh/known_hosts

# Installations from source
cat /home/git/.ssh/known_hosts

Step 3. Copying the database encryption key

GitLab stores a unique encryption key in disk that we use to safely store sensitive data in the database. Any secondary node must have the exact same value for db_key_base as defined in the primary one.

  1. SSH into the primary node and login as root:

    sudo -i

  2. Find the value of db_key_base and copy it:

    ``` # Omnibus GitLab installations cat /etc/gitlab/gitlab-secrets.json | grep db_key_base

    # Installations from source cat /home/git/gitlab/config/secrets.yml | grep db_key_base ```

  3. SSH into the secondary node and login as root:

    sudo -i

  4. Open the secrets file and paste the value of db_key_base you copied in the previous step:

    ``` # Omnibus GitLab installations editor /etc/gitlab/gitlab-secrets.json

    # Installations from source editor /home/git/gitlab/config/secrets.yml ```

  5. Save and close the file.

Step 4. Enabling the secondary GitLab node

  1. SSH into the secondary node and login as root:

    sudo -i

  2. Create a new SSH key pair for the secondary node. Choose the default location and leave the password blank by hitting 'Enter' three times:

    sudo -u git -H ssh-keygen -b 4096 -C 'Secondary GitLab Geo node'

    Read more in additional info for SSH key pairs.

  3. Get the contents of id_rsa.pub the was just created:

    # Omnibus installations
sudo -u git cat /var/opt/gitlab/.ssh/id_rsa.pub

# Installations from source
sudo -u git cat /home/git/.ssh/id_rsa.pub
  4. Visit the primary node's Admin Area ➔ Geo Nodes (/admin/geo_nodes) in your browser.
  5. Add the secondary node by providing its full URL and the public SSH key you created previously. Do NOT check the box 'This is a primary node'.

  6. Click the Add node button.

After the Add Node button is pressed, the primary node will start to notify changes to the secondary. Make sure the secondary instance is running and accessible.

The two most obvious issues that replication can have here are:

  1. Database replication not working well

  2. Instance to instance notification not working. In that case, it can be something of the following:

    • You are using a custom certificate or custom CA (see the Troubleshooting section)
    • Instance is firewalled (check your firewall rules)

Step 5. Replicating the repositories data

Getting a new secondary Geo node up and running, will also require the repositories directory to be synced from the primary node.

With GitSwarm 2017.2-1 you can start the syncing process by clicking the "Backfill all repositories" button on Admin > Geo Nodes screen.

On previous versions, you can use rsync for that:

Make sure rsync is installed in both primary and secondary servers and root SSH access with a password is enabled. Otherwise, you can set up an SSH key-based connection between the servers.

  1. SSH into the secondary node and login as root:

    sudo -i

  2. Assuming 1.2.3.4 is the IP of the primary node, run the following command to start the sync:

    # For Omnibus installations
rsync -guavrP [email protected]:/var/opt/gitlab/git-data/repositories/ /var/opt/gitlab/git-data/repositories/
gitlab-ctl reconfigure # to fix directory permissions

# For installations from source
rsync -guavrP [email protected]:/home/git/repositories/ /home/git/repositories/
chmod ug+rwX,o-rwx /home/git/repositories

If this step is not followed, the secondary node will eventually clone and fetch every missing repository as they are updated with new commits on the primary node, so syncing the repositories beforehand will buy you some time.

While active repositories will be eventually replicated, if you don't rsync, the files, any archived/inactive repositories will not get in the secondary node as Geo doesn't run any routine task to look for missing repositories.

Step 6. Regenerating the authorized keys in the secondary node

The final step is to regenerate the keys for ~/.ssh/authorized_keys (HTTPS clone will still work without this extra step).

On the secondary node where the database is already replicated, run:

# For Omnibus installations
gitlab-rake gitlab:shell:setup

# For source installations
sudo -u git -H bundle exec rake gitlab:shell:setup RAILS_ENV=production

This will enable git operations to authorize against your existing users. New users and SSH keys updated after this step, will be replicated automatically.

Next steps

Your nodes should now be ready to use. You can login to the secondary node with the same credentials as used in the primary. Visit the secondary node's Admin Area ➔ Geo Nodes (/admin/geo_nodes) in your browser to check if it's correctly identified as a secondary Geo node and if Geo is enabled.

If your installation isn't working properly, check the troubleshooting section.

Adding another secondary Geo node

To add another Geo node in an already Geo configured infrastructure, just follow the steps starting form step 2. Just omit the first step that sets up the primary node.

Additional information for the SSH key pairs

When adding a new Geo node, you must provide an SSH public key of the user that your GitLab instance runs on (unless changed, should be the user git). This user will act as a "normal user" who fetches from the primary Geo node.

If for any reason you generate the key using a different name from the default id_rsa, or you want to generate an extra key only for the repository synchronization feature, you can do so, but you have to create/modify your ~/.ssh/config (for the git user).

This is an example on how to change the default key for all remote hosts:

Host *                              # Match all remote hosts
  IdentityFile ~/.ssh/mycustom.key  # The location of your private key

This is how to change it for an specific host:

Host example.com                    # The FQDN of the primary Geo node
  HostName example.com              # The FQDN of the primary Geo node
  IdentityFile ~/.ssh/mycustom.key  # The location of your private key

Troubleshooting

Setting up Geo requires careful attention to details and sometimes it's easy to miss a step. Here is a checklist of questions you should ask to try to detect where you have to fix (all commands and path locations are for Omnibus installs):

Note: This list is an attempt to document all the moving parts that can go wrong. We are working into getting all this steps verified automatically in a rake task in the future.