Unable to enable HA on a cluster using vSphere Lifecycle Manager Images

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:
Error:
"Cannot complete the configuration of the vSphere HA agent on the host."
"Applying HA VIBs on the cluster encountered a failure"

Environment

VMware vCenter Server 7.0.x
VMware vCenter Server 7.0.1
VMware vCenter Server 7.0.2

Cause

When scratch is not configured to a disk and is on /tmp RAMdisk, periodically its sub-folder can be cleaned up due to inactivity by tmpwatch. Some folders, such as vmware/lifecycle and locker, are important to installing HA on the hosts.

Resolution

1) make sure impacted systems still have valid /scratch, if not recreate the directory (something like /tmp/_osdataxxxxxx, check /scratch symlink destination)
2) mkdir -p /var/vmware/lifecycle
3) recreate the task file by: echo "{}" > /var/vmware/lifecycle/task-status.json
4) verify sub-folders of /tmp/_osdataxxxxxx exist: "cache", "core", "store", "locker", if not, make them with mkdir.