Disabling Db2 Big SQL high availability

You disable high availability for Db2® Big SQL on HDP in the Ambari dashboard. Disabling HA is the task of decommissioning and deleting the standby head node. On CDH, use the Db2 Big SQL cluster administration utility to disable high availability for Db2 Big SQL.

1. Check if both the primary head node and the standby head node are running.
2. CASE 1: If both the primary head node and the standby head node are running, follow the steps below:
   1. Log into Ambari as an administrator and select the IBM® Db2 Big SQL service.
   2. Under the Summary tab, select the standby (inactive) head node. Then, in the Db2 Big SQL head, select the Started drop-down menu and click Turn On Maintenance Mode.
   3. While the node is in maintenance mode, select the Decommission option from the Started drop-down menu.
   4. From the Stopped drop-down menu, select Delete to delete the head node component from the cluster.
3. CASE 2: If the standby head node is down or cannot be brought up, complete the following manual steps to disable the inactive standby head node.
   Note: These steps must be completed as the root user or under the non-root install user ID.

   Assume that the host that contains the primary head node is primaryheadnode.com and that the host that contains the standby head node is standbyheadnode.com.

   1. Run the following command, first on the standby head node, and then on the primary head node:

      bigsql stop -failoverController

   2. Remove the Db2 Big SQL head node from the standby head host that is down:

      
      curl -u admin:admin -H "X-Requested-By: ambari" -X DELETE  
        http://server-name:server-port/api/v1/clusters/cluster-name/hosts/standbyheadnode.com/host_components/BIGSQL_HEAD

   3. Run the high availability cleanup script on the primary head node:

      /var/lib/ambari-agent/cache/extensions/IBM-Big_SQL/5.0.4.0/services/BIGSQL/package/scripts/bigsql-HA-cleanup.sh 
        -P primaryheadnode -S standbyheadnode -U bigsql

   4. Remove Db2 Big SQL from the faulty standby head node.
      Note: Be sure to run this command on the faulty standby head node. Running this command on the primary head node causes Db2 Big SQL to be uninstalled.

      
      /var/lib/ambari-agent/cache/extensions/IBM-Big_SQL/5.0.4.0/services/BIGSQL/package/scripts/bigsql-drop-host.sh
        -p /usr/ibmpacks/current/bigsql -n standby_head_node_host_name
        -u bigsql -d 'comma-separated_list_of_data_directories_and_the_database_directory'
        -v /var/ibm/bigsql -G Db2_admin_group_name -c True -t 0

      For example:

      
      /var/lib/ambari-agent/cache/extensions/IBM-Big_SQL/5.0.4.0/services/BIGSQL/package/scripts/bigsql-drop-host.sh
        -p /usr/ibmpacks/current/bigsql -n headnode2.ibm.com
        -u bigsql -d '/var/ibm/bigsql/database,/hadoop/bigsql'
        -v /var/ibm/bigsql -G bigsqladm -c True -t 0

   5. After this cleanup, you can set up high availability by using a different node as the Db2 Big SQL head.