Replacing a host that uses KUMA storage

To replace a host that uses KUMA storage with another one:

1. Fill in the expand.inventory.yml file, specifying the parameters of the host you want to replace.
2. Run the following command, specifying the expand.inventory.yml file to remove the host:

   ./kdt invoke kuma --action removeHosts --param hostInventory=<path_to_inventory_file>

3. Fill in the expand.inventory.yml file, specifying the parameters of the new host that you want to replace the previous host, and then run the following command:

   ./kdt invoke kuma --action addHosts --param hostInventory=<path_to_inventory_file>

4. Follow steps 2-6 of the instruction for adding new hosts for KUMA services to add a new host with the KUMA storage.

The host with the KUMA storage is replaced with another one.

If your storage configuration includes a shard containing two replicas, and you replaced the second replica host with a new one by using the steps described above, then you may receive an error when installing a new replica. In this case, the new replica will not work.

To fix an error when adding a new replica of a shard:

1. On another host with a replica of the same shard that owns the incorrectly added replica, launch the ClickHouse client by using the command:

   /opt/kaspersky/kuma/clickhouse/bin/client.sh

   If this host is unavailable, run the client on any other host with a replica included in the same storage cluster.

2. Run the command to remove the data about the host you wanted to replace.
   • If the host with a replica of the same shard that owns the incorrectly added replica is available, run the following command:

     SYSTEM DROP REPLICA '<replica number of read-only node>' FROM TABLE kuma.events_local_v2

   • If you are using another storage cluster host with a replica, run the following command:

     SYSTEM DROP REPLICA '<replica number of read-only node>' FROM ZKPATH '/clickhouse/tables/kuma/<shard number of read-only node>/kuma/events_local_v2

3. Run the following command to restore the operation of the added host with a replica:

   SYSTEM RESTORE REPLICA kuma.events_local_v2

Operability of the added host with a replica is restored.

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