State Storage Move

If you need to decommission a YDB cluster host that contains part of State Storage, you need to move it to another host.

As an example, consider a YDB cluster with the following State Storage configuration:

...
domains_config:
  ...
  state_storage:
  - ring:
      node: [1, 2, 3, 4, 5, 6, 7, 8, 9]
      nto_select: 9
    ssid: 1
  ...
...

On the host with node_id:1, a cluster static node is configured and running, which serves part of State Storage. Suppose we need to decommission this host.

To replace node_id:1, we added a new host with node_id:10 to the cluster and deployed a static node on it.

To move State Storage from host node_id:1 to node_id:10:

1. Stop the cluster static nodes on hosts with node_id:1 and node_id:10.

   Note

   A YDB cluster is fault-tolerant. Temporary node shutdown does not lead to cluster unavailability. For more details, see YDB Cluster Topology.

2. In the configuration file config.yaml, change the node host list, replacing the identifier of the host being removed with the identifier of the host being added:

   domains_config:
   ...
     state_storage:
     - ring:
         node: [2, 3, 4, 5, 6, 7, 8, 9, 10]
         nto_select: 9
       ssid: 1
   ...
   

3. Update the configuration files config.yaml for all cluster nodes, including dynamic ones.

4. Using the rolling-restart procedure, restart all cluster nodes, including dynamic ones, except for static nodes on hosts with node_id:1 and node_id:10. Note that a delay of at least 15 seconds is required between host restarts.

5. Start the cluster static nodes on hosts node_id:1 and node_id:10.