Configuring HA on ESX hosts fails with the error: Cannot complete the configuration of the HA agent on the host (Re install HA agents)

Cannot configure HA on ESX hosts.
Unable to configure the aam agent.
Configuring HA on ESX hosts fails.
In vCenter Server one or more hosts in the HA cluster report the error:

Cannot complete the configuration of the HA agent on the host.

Resolution
This issue may occur if the vpxa agent on the ESX host is corrupted due to which you are unable to configure the aam agent.

Note: the below troubleshooting steps are not applicable to vCenter Server 5.0 as aam functionality is no longer used for HA on vCenter Server 5.0. For further HA (Fault Domain Manager) troubleshooting steps, see Troubleshooting Fault Domain Manager (FDM) problems (2004429).

To resolve this issue, remove the vpxa and aam agents from the ESX host and then reinstall them.

To remove the vpxa and aam agents:

Note: For information on reinstalling agents on an ESXi host, please reference KB 1027628
Connect to the ESX host using SSH.
Run this command to verify if the vpxa agent is installed:

# rpm -qa | grep vpxa

Note the vpxa package name returned by this command (For example, VMware-vpxa-#.#.#-#####).

Run this command to remove the vpxa agent:

# rpm -e <vpxa_package_name>

Where <vpxa_package_name> is the vpxa package name noted in Step 2.

For example:

# rpm -e VMware-vpxa-#.#.#-#####

Run this command to verify if the aam agent is installed:

# rpm -qa | grep aam

Note the two aam package names returned by this command. For example, VMware-aam-haa-#.#.#-# and VMware-aam-vcint-#.#.#-#.

Run this command to remove the aam package files:

rpm -e <aam_package_name>

Where <aam_package_name> is the aam package name noted in Step 4.

For example:

rpm -e VMware-aam-haa-#.#.#-#
rpm -e VMware-aam-vcint-#.#.#-#
To reinstall vpxa and aam agents:

Move the vpxa and aam agent installation files from vCenter Server to the ESX host using a secured file transfer utility, such as WinSCP.

Note: To download WinSCP, see http://winscp.net/.

To move files using WinSCP:
Open WinSCP and browse to C:\Program Files\VMware\Infrastructure\VirtualCenter Server\upgrade.
Upload these files to the /tmp directory of the ESX host (chose the highest available Build number):
vpx-upgrade-esx-7-linux-[BuildNumber]
aam-upgrade-esx-xxxxxxxx-[BuildNumber]prod-kcc-vip.vmware.com:8080/contactcenter/authoring/search.do?cmd=displayKC

Connect to the ESX host using SSH.
Browse to the /tmp directory.
Run these commands to install the agents:

# sh vpx-upgrade-esx-7-linux-[BuildNumber]
# sh aam-upgrade-esx-xxxxxxxx-[BuildNumber]

Run these commands to verify if the agents are installed:

# rpm -qa | grep vpxa
# rpm -qa | grep aam

Run these commands to restart services on the host:

# service mgmt-vmware restart
# service vmware-vpxa restart

Add the host back to vCenter Server.
Note: If the issue persists, disable and re-enable VMware High Availability in the cluster.