Disabling high availability on cluster members by using REST Administration APIs

You can disable high availability (HA) on a pair of servers in a cluster by using REST Administration APIs.

About this task

You can disable HA on cluster members that are an HA pair by using REST Administration APIs, or by using the IBM® IoT MessageSight Web UI. For more information about using the IBM IoT MessageSight Web UI to disable HA on cluster members, see Disabling high availability on cluster members by using the IBM IoT MessageSight Web UI. For more information about configuring a pair of servers as an HA pair, see Configuring IBM IoT MessageSight servers as an HA pair by using REST Administration APIs.

You can disable HA on the primary server or the standby server. If you disable HA on the primary server, HA is also disabled on the standby server.

You might decide to disable HA on the primary server so that you use only a single server. You might decide to disable HA on the standby server so that you can replace the standby server with another server.

Note: If both servers of the HA pair are in maintenance mode, disable HA on one server and restart it in production mode. Discard the the instance of IBM IoT MessageSight on the other server.

Procedure

You can disable HA on the primary server or the standby server.

If you are disabling HA on the primary server of a synchronized HA pair:
1. Set "EnableHA": false on the primary server.
2. Restart the server in production mode.
  Use the IBM IoT MessageSight REST API POST method on each server with the following IBM IoT MessageSight configuration URI:
  
  http://<admin-endpoint-IP:port>/ima/v1/service/restart
  
  Provide object configuration data in the payload of the POST method by using the following schema. Content-type is set to application/json:
```
{    
  "Service": "Server" 
}
```
  If the standby server was synchronized, it automatically restarts in maintenance mode and with HA disabled. If the standby server was inactive or had been running in maintenance mode, do not restart it.
3. Do not use the former standby server. Discard this instance of the IBM IoT MessageSight server.
If you are disabling HA on the standby server:
1. Set "EnableHA": false on the standby server.
2. The standby server automatically restarts in maintenance mode.
3. Do not continue to use this server. Discard this instance of the IBM IoT MessageSight server.
If both servers in the HA pair are in maintenance mode:
1. Set "EnableHA": false on one of the servers.
2. Restart this server in production mode.
  Use the IBM IoT MessageSight REST API POST method on each server with the following IBM IoT MessageSight configuration URI:
  
  http://<admin-endpoint-IP:port>/ima/v1/service/restart
  
  Provide object configuration data in the payload of the POST method by using the following schema. Content-type is set to application/json:
```
{    
  "Service": "Server" 
}
```
3. Do not continue to use the other server. Discard the instance of IBM IoT MessageSight that is on the other server.