There might be situations when you want to remove a node from cluster. We can do this online without interrupting the cluster services. For this you should have sufficient resources to handle the load of the node which you are going to remove from the cluster.
We will be removing node03 with service group SG03 running on it.
Freeze node and halt VCS
Freeze the node03 and stop VCS on that node by evacuating it, so that service group SG03 will switch over to either node01 or node02.
# haconf -makerw # hasys -freeze -persistent node03 # haconf -dump # hastop -sys node03 -evacuate
Stop I/O fencing and stop LLT/GAB modules
Stop the VCS I/O fencing and LLT/GAB modules on node03.
# /sbin/vxfen-shutdown # vxfenadm -d (check status of fencing from node01 or node02) # gabconfig -U # lltconfig -U
Remove VCS software
Remove VCS software from node03 by running the installer utility and rename the main.cf file.
Modify AutoStartList and SystemList
Run below commands on node01 and node02 ( I’m assuming both nodes have node03 in their SystemList and AutoStartList attributes)
# hagrp -modify SG01 AutoStartList –delete node03 # hagrp -modify SG01 SystemList –delete node03
# hagrp -modify SG02 AutoStartList –delete node03 # hagrp -modify SG02 SystemList –delete node03
Remove node from ClusterServices SG
Remove node03 from ClusterServices SG on both node01 and node02
# hagrp -modify ClusterService AutoStartList –delete node03
Remove node from cluster
Now remove node03 from cluster and save the configuration(run this on node01 or node02)
# hasys -delete train10 # haconf -dump -makero