Removing a Node

To remove a node from Enterprise ColumnStore, perform the following procedure.

Unlinking from Service in MaxScale

The server object for the node must be unlinked from the service using MaxScale's REST API:

Unlink the server object from the service using the unlink service command.
As the first argument, provide the name of the service.
As the second argument, provide the name of the server.

maxctrl unlink service \
   mcs_service \
   mcs3

Checking the Service in MaxScale

To confirm that the server object was properly unlinked from the service, the service should be checked using MaxScale's REST API:

Show the services using the show services command, like this:

maxctrl show services

Unlinking from Monitor in MaxScale

The server object for the node must be unlinked from the monitor using MaxScale's REST API:

Unlink a server object from the monitor using the unlink monitor command.
As the first argument, provide the name of the monitor.
As the second argument, provide the name of the server.

maxctrl unlink monitor \
   mcs_monitor \
   mcs3

Checking the Monitor in MaxScale

To confirm that the server object was properly unlinked from the monitor, the monitor should be checked using MaxScale's REST API:

Show the monitors using the show monitors command, like this:

maxctrl show monitors

Removing the Server from MaxScale

The server object for the node must also be removed from MaxScale using MaxScale's REST API:

Use MaxCtrl or another supported REST client.
Remove the server object using the destroy server command.
As the first argument, provide the name for the server.

For example:

maxctrl destroy server \
   mcs3

Checking the Server in MaxScale

To confirm that the server object was properly removed, the server objects should be checked using MaxScale's REST API:

Show the server objects using the show servers command, like this:

maxctrl show servers

Stopping the Enterprise ColumnStore Services

The Enterprise Server. Enterprise ColumnStore, and CMAPI services can be stopped using the systemctl command.

Perform the following procedure on the node:

Stop the MariaDB Enterprise Server service:
```
sudo systemctl stop mariadb
```
Stop the MariaDB Enterprise ColumnStore service:
```
sudo systemctl stop mariadb-columnstore
```

Stop the CMAPI service:

sudo systemctl stop mariadb-columnstore-cmapi

Removing the Node from Enterprise ColumnStore

The node must be removed from Enterprise ColumnStore using CMAPI:

Remove the node using the remove-node endpoint path.
Use a supported REST client, such as curl .
Format the JSON output using jq for enhanced readability.
Authenticate using the configured API key.
Include the required headers.

For example, if the primary node's host name is mcs1 and the IP address for the node to remove is 192.0.2.3:

In ES 10.5.10-7 and later:

curl -k -s -X DELETE https://mcs1:8640/cmapi/0.4.0/cluster/node \
   --header 'Content-Type:application/json' \
   --header 'x-api-key:93816fa66cc2d8c224e62275bd4f248234dd4947b68d4af2b29671dd7d5532dd' \
   --data '{"timeout":20, "node": "192.0.2.3"}' \
   | jq .

In ES 10.5.9-6 and earlier:

curl -k -s -X PUT https://mcs1:8640/cmapi/0.4.0/cluster/remove-node \
   --header 'Content-Type:application/json' \
   --header 'x-api-key:93816fa66cc2d8c224e62275bd4f248234dd4947b68d4af2b29671dd7d5532dd' \
   --data '{"timeout":20, "node": "192.0.2.3"}' \
   | jq .

Example output:

{
  "timestamp": "2020-10-28 00:39:14.672142",
  "node_id": "192.0.2.3"
}

Checking the Enterprise ColumnStore Status

To confirm that the node was properly removed, the status of Enterprise ColumnStore should be checked using CMAPI:

Check the status using the status endpoint path.

For example, if the primary node's host name is mcs1:

curl -k -s https://mcs1:8640/cmapi/0.4.0/cluster/status \
   --header 'Content-Type:application/json' \
   --header 'x-api-key:93816fa66cc2d8c224e62275bd4f248234dd4947b68d4af2b29671dd7d5532dd' \
   | jq .