VMware cluster HA configuration issue

Few days ago a friend of mine Marek (VMware engineer in web hosting company) had a problems with configuring HA on two new vSphere4 u1 hosts. New ESX hosts was added first into cluster and HA configuration start just after adding.  HA agent deployment and installation processes was fine but during HA agent configuration get failed with error:

Cannot complete configuration of the HA agent on the host. See the task detail for more information. Misconfiguration in the host network setup.

Network configuration was fine, gateway was pingable, ESX host can exchange ping between networks, yes networks ,that’s the key word, new ESX nodes were in the different network then old ones, subnet mask was this same (24 bits) but IP’s ranges different. Below solution from VMware documentation.

HA network compliance check
During  HA in VirtualCenter 2.5 Update 2, the Task & Events tabs might display the following error message and recommendation:
HA agent on <esxhostname> in cluster <clustername> in <datacenter> has an error Incompatible HA Network:

Consider using the Advanced Cluster Settings das.allowNetwork to control network usage.Starting with VirtualCenter 2.5 Update 2, HA has an enhanced network compliance check to increase cluster reliability. This enhanced network compliance check helps to make sure correct cluster-wide heartbeat network paths. VirtualCenter 2.5 Update 3 allows you to bypass this check to prevent HA configuration problems. To bypass the check, add das.bypassNetCompatCheck=true to the HA advanced settings.

Artur Krzywdzinski

Artur is Consulting Architect at Nutanix. He has been using, designing and deploying VMware based solutions since 2005 and Microsoft since 2012. He specialize in designing and implementing private and hybrid cloud solution based on VMware and Microsoft software stacks, datacenter migrations and transformation, disaster avoidance. Artur has been in IT industry since 1999 and consulting since 2008. Artur holds VMware Certified Design Expert certification (VCDX #077).