Incompatible HA Networks appearing when attempting to configure HA (High Availability)

Symptoms

• VMware High Availability (HA) does not work.
• Configuration of VMware HA fails with VirtualCenter 2.5 Update 2.
• Errors similar to these appears in the Tasks and Events tab:
  
  • HA agent on in cluster in has an error Incompatible HA Networks:
    Cluster has network(s) missing on host: x.x.x.x
    Consider using the Advanced Cluster Settings das.allowNetwork to control network usage.
  • Currently has no available networks for HA communication. The following networks are currently used by HA:Service console

Resolution

As of VirtualCenter 2.5 Update 2, two advanced options have been added to allow greater control over the  networks used for cluster communication. These two advanced settings enable greater flexibility in the control and usage of VMware HA networks, while still preserving the VMware HA requirement that all cluster nodes have identical, compatible networks.

Note: This new network compatibility check is implemented to increase cluster reliability and only impacts existing clusters after VirtualCenter is upgraded to Update 2 if they were previously configured with incompatible networks.

The parameters are:

• das.allowVmotionNetworks - Allows for a NIC that is used for VMotion networks to be considered for VMware HA usage. This parameter enables a host that has only one NIC configured for management and VMotion combined to be used in VMware High Availability communication. By default, any VMotion network is ignored. To use the VMotion network, add das.allowVmotionNetworks with a value of true to the HA advanced options.
   
• das.allowNetwork[...]- Allows the use of port group names to control the networks used for VMware HA. The value is set as the name of the portgroup, for example, Service Console or Management Network. When configured, the VMware HA cluster only uses the specified networks for VMware HA communication.

This error is often experienced after an upgrade when the cluster has both ESX hosts and ESXi hosts in the configuration, if they previously had incompatible networks and were successfully configured. The reason is that the ESX standard hosts have a service console portgroup for the service console IP address and one VMkernel port group for VMotion IP address, whereas in ESXi, both the Management IP address (similar to the service console in standard ESX 3.x) and the VMotion IP address are on the VMkernel port group.  Therefore, standard ESX hosts only use the service console network, whereas the ESXi Server hosts use both, or whichever was picked up first, causing the incompatible network error to be displayed.   

To configure VMware HA to use the new settings:

1. Log in to VirtualCenter with VMware Infrastructure (VI) Client as an administrator.
2. Edit the settings of the cluster and deselect Enable VMware HA.
3. Click OK, and wait for the servers to unconfigure for VMware HA.
4. Click ESX Server > Configuration > Networking on each of the ESX hosts in the cluster and note the portgroups that are common between the servers.
   
   Note: The portgroup names should all be identical, and must have network connectivity with each other. For more information about testing network connectivity using ping, see Testing network connectivity with the Ping command (1003486).
    
5. Edit the settings of the cluster, and select Enable VMware HA.
6. Click VMware HA.
7. Click Advanced Options.
8. Add the das.allowNetworkX option with a value of the portgroup name, where X is a number between 0 and 10, as shown in the following image:
   
   
   
   Note: You can add more than one portgroup, if required (to a maximum of 10), as shown in the following image:
   
   
   
9. When all network portgroups have been added, click OK to exit out of the advanced options.
10. Click OK to exit out of the Cluster configuration, and start the reconfiguration of VMware HA with the modified network settings.  

Update History

04/19/2010 - Added ESX and ESXi 4.0 to Products.

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