In vRealize Automation, low virtual appliance memory might prevent virtual appliance promotions in the cluster.

Problem

The master node runs low on memory. You log in to its management interface Database page, and try to promote a secondary node to become the new master. The following error occurs.

Fail to execute on Node node-name, host is master-FQDN 
because of: Could not read remote lock command result for node: node-name 
on address: master-FQDN, reason is: 500 Internal Server Error

Cause

Promotion only succeeds when all nodes can confirm reconfiguration to a newly promoted master. The low memory prevents the old master from confirming, even though all nodes are reachable.

Results

Power off the master node that has low memory. Log in to the secondary node management interface Database page, and promote the secondary node.