debian-mirror-gitlab/doc/administration/geo/replication/remove_geo_node.md

Removing secondary Geo nodes [PREMIUM ONLY]

Secondary nodes can be removed from the Geo cluster using the Geo admin page of the primary node. To remove a secondary node:

1. Navigate to Admin Area > Geo (/admin/geo/nodes).
2. Click the Remove button for the secondary node you want to remove.
3. Confirm by clicking Remove when the prompt appears.

Once removed from the Geo admin page, you must stop and uninstall the secondary node:

1. On the secondary node, stop GitLab:

   sudo gitlab-ctl stop
   

2. On the secondary node, uninstall GitLab:

   # Stop gitlab and remove its supervision process
   sudo gitlab-ctl uninstall
   
   # Debian/Ubuntu
   sudo dpkg --remove gitlab-ee
   
   # Redhat/Centos
   sudo rpm --erase gitlab-ee
   

Once GitLab has been uninstalled from the secondary node, the replication slot must be dropped from the primary node's database as follows:

1. On the primary node, start a PostgreSQL console session:

   sudo gitlab-psql 
   

   NOTE: Note: Using gitlab-rails dbconsole will not work, because managing replication slots requires superuser permissions.

2. Find the name of the relevant replication slot. This is the slot that is specified with --slot-name when running the replicate command: gitlab-ctl replicate-geo-database.

   SELECT * FROM pg_replication_slots;
   

3. Remove the replication slot for the secondary node:

   SELECT pg_drop_replication_slot('<name_of_slot>');