3 Comments on “What are the requirements for HA to work?”

1. Gunt says:

   April 9, 2012 at 5:46 pm

   There is a divergency:
   It is possible has Dynamic IP (DHCP) but with MAC association, the PDF write this.
   And VMkernel generally means a single host, thus 2 VMkernel are essential HA to work.
   I think the correctly answers are B and D.

   
   
   
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   1. Giorgio says:

      May 9, 2012 at 4:55 am

      I think so too.

      DHCP is possible –>No static IP required
      2 VMKernels (They suggest redundant network connections)

      VMware HA Requirements and Best Practices
      http://www.vmware.com%2Fpdf%2Fvmware_ha_wp.pdf

      There are a few basic requirements that your virtual infrastructure system and hosts need to meet so that VMware cluster and HA features operate properly.

      First, for clusters enabled for VMware HA, all virtual machines and their configuration files must reside on shared storage (Fibre Channel SAN, iSCSI SAN, or SAN iSCI NAS), because you need to be able to power on the virtual machine on any host in the cluster.

      This also means that the hosts must be configured to have access to the same virtual machine networks, shared storage, and other resources.

      Second, VMware HA monitors heartbeat between hosts on the console network for failure detection. So, to have reliable failure detection for HA clusters, the console network should have redundant network paths. That way, if a host’s first network connection fails, the second connection can broadcast heartbeats to other hosts. To set up redundancy, you need two physical network adapters on each host. You then connect them to the corresponding service console, either using two service console interfaces (each on a separate vSwitch or a separate physical network adapter) or using a single interface with NIC teaming.

      Last, if you want to use DRS with HA for load balancing, the hosts in your cluster must be part of a VMotion network. If the hosts are not in the VMotion network, however, DRS can still make initial placement recommendations.

      
      
      
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2. Jon says:

   June 1, 2012 at 8:27 pm

   From the link posted in the answer:

   Requirements for a vSphere HA Cluster
   …
   n All hosts need to be configured with static IP addresses. If you are using DHCP, you must ensure that the
   address for each host persists across reboots.
   See “Best Practices for Networking,” on page 34.
   n To ensure that any virtual machine can run on any host in the cluster, all hosts should have access to the
   same virtual machine networks and datastores. Similarly, virtual machines must be located on shared, not local, storage otherwise they cannot be failed over in the case of a host failure.
   …

   You can have only 1 vmkernel port defined and provide redundant network connections in the vswitch uplinks uing nic teaming and failover.

   
   
   
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