When you integrate a solution with ESX Agent Manager, users can monitor the health of agent virtual machines in the

. The solution can monitor ESX agents by using the ESX Agent Manager API. Integrating a solution with ESX Agent Manager also helps you to add functions to ESXi hosts.

By integrating a solution with ESX Agent Manager, you can limit certain operations on ESX agent virtual machines to certain types of user. For example, you can block all users from powering off an ESX agent unless they have the

EAM.Modify

privilege.

When you develop solutions that deploy virtual machines that extend the function of ESXi hosts, integrate the solution with ESX Agent Manager. If you do not integrate the solution and ESX Agent Manager, vSphere does not detect that virtual machines are ESX agent virtual machines, Virtual machines that ESX Agent Manager deploys integrate with vSphere features in ways that other virtual machines do not. For example, if an ESXi host implements vSphere High Availability (VMware HA) and that host stops running unexpectedly, normally all the virtual machines running on that host migrate to another ESXi host. An ESX agent virtual machine should not migrate to another host. Features such as vSphere Distributed Resource Scheduler (DRS), the Add Host to Cluster operation, vSphere Distributed Power Management (DPM), and maintenance mode can also create problems if they modify or migrate ESX agents. Similarly, if one of these features migrates or modifies an ESX agent that a solution requires, that solution can stop running.

ESX Agent Manager is compatible with the VMware HA, DRS,

AddHost

, DPM, and maintenance mode features. By integrating a solution with ESX Agent Manager, you can deploy ESX agent virtual machines that modify the function of ESXi hosts and implement VMware HA, DRS,

AddHost

, DPM, and maintenance mode. ESX Agent Manager ensures that solutions that deploy ESX agents integrate correctly with these vSphere features.

If you have a configuration with a very large virtual appliance per host, a best practice is to use an ESX Agent VM as a container for the appliance, because

High Availability (HA) feature gives special priority to ESX Agent VMs.

The HA feature will power on an ESX Agent VM before any other VMs.

If a failover host policy is in use, the HA feature allows Agent VMs to be powered on with the failover hosts.

The HA feature does not include ESX Agent VMs in admission control calculations. Therefore, if you want to use a VM that is not included in the slot size for the 'host failures to tolerate' admission control policy, you can use an Agent VM.

To take advantage of these special priorities, you must include an ESX Agent VM on each host in a cluster.