Disabling Db2 Big SQL high availability

You can disable high availability for Db2® Big SQL in the Ambari dashboard. Disabling HA is the task of decommissioning and deleting the standby head node.

Before you begin

Because the Db2 Big SQL home directory is removed during the decommissioning of the Db2 Big SQL standby head node, be sure to back up any private data stored in Db2 Big SQL directories on the standby head before you modify the HA configuration.

Procedure

  1. Check whether 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, complete the following steps:
    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, under Components, beside Big SQL Head/IBM Db2 Big SQL, click ... and click Turn On Maintenance Mode.
    3. While the standby head node is in maintenance mode, click ... again and select Decommission.
    4. Click ... and select Delete to delete the standby 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 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/6.0.0.0/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/6.0.0.0/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/6.0.0.0/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.