In this how-to blog post, we go through how to install and configure vCenter High Availability (HA) in version 6.5U2d build 10964411, we will also discuss options, requirements and how vCenter HA works.

Before starting let us have a quick look at what was fix between vCenter Appliance versions regarding vCenter HA.

Known Issues from Earlier Releases – vCenter HA Issues

  • vCenter High Availability replication fails when user password expires
  • Deploying vCenter High Availability with an alternative Failover IP for the Passive node without specifying a Gateway IP address causes vCenter to fail
  • Deploying vCenter High Availability might fail if Appliance has a mixed case hostname when setting up the Appliance
  • SSH must be enabled on vCenter Server Appliance in order to configure vCenter HA
  • If an Active node reboots during an operation that removes vCenter HA Cluster configuration, you might need to start the Active node manually
  • If you attempt to reboot an Active node with intent to failover, the Active node may continue as an Active node after reboot

All above bugs or issues are fixed or has provided a workaround.

The vCenter HA architecture is created with three nodes:


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Roles for each type of node in a vCenter HA cluster are:

Active Node:

  • A node that runs the active instance of vCenter Server
  • Enables and uses the public IP address of the cluster

Passive Node:

  • A node that runs as the passive instance of vCenter Server
  • Continually receives state updates from the Active node in
  • Equivalent to the Active node regarding resources
  • Takes over the role of the Active Node in the event of a failover

Witness Node:

  • Serves as a quorum node
  • Used to break a tie in the event of a network partition causing a situation where the Active and Passive nodes cannot communicate with each other
  • A light-weight VM is utilizing minimal hardware resources
  • Does not take over the role of Active/Passive nodes

Prerequisites install Notes:

  • Before start creating your vCenter HA, verify if you are running the latest vCenter Application version
  • For the Install and configure of vCenter HA you need to use the flash version of vSphere Web Client. The configuration option of vCenter HA is not available in the HTML5 version
  • Create a private network for the vCenter HA. This network must be separated from the rest of the vCenter networks (like management network)
  • For Best practices and performance, the latency between vCenter Appliances nodes inside this private network should be less or equal than 10ms

If the vCenter Appliance that you are trying to build a vCenter HA is managed by another vCenter, then in the install configuration you need to select the option Advanced Workflow to enable vCenter HA.

Meaning, to use the basic (automatic) vCenter HA deployment, vCenter Appliance needs to be managed by vCenter itself.

vCenter HA Basic vs Advanced installation

Basic installation is an automatic install. Setup adds a second Virtual Network Interface in your vCenter and then clone the vCenter into a vCenter Appliance Passive Node (peer) and a vCenter Appliance Witness Node and create DRS anti-affinity rules for those 3 Nodes.

In Basic Installation, all vCenter Nodes needs to run in the same SSO Domain and site. vCenter HA Network needs to be L2.

Advanced Installation is a manual install. You need to add second Virtual Network Interface in your vCenter and then clone the vCenter manually. Also, IPs addresses for all vCenter Nodes need to be added manually by the user.

In Advanced Installation vCenter, HA can be installed in a different SSO Domain or vCenter HA Nodes can be located and split in different sites. Also in Advanced, you can install vCenter HA in an L3.

In this article Part 1, we install the vCenter HA using the Basic installation. We are using vCenter 6.5, and we only use an L2 network. vCenter and ESXi hosts are all local and in the same subnet (192.168.1.x). We create a vCenter HA Network using subnet 192.168.200.x.

Basic Option: Automatic Deploy.

What consists of this automatic deploy?

After the user provides all the information needed for the vCenter HA Network (IP addresses for all nodes), vCenter starts to clone the main vCenter into two vCenter Appliances to create the two extra nodes that consist the vCenter HA network (Passive node and Witness node).

Note: Regarding deployment size, VMware minimum recommended deployment size is “small” or higher of your vCenter.

Install vCenter HA (vCHA)

Pre-Install tasks

We start the process of the vCHA installation by pre-creating a vCenter HA Network.

You need to create a normal Portgroup in your vSwitch, or vDS.


In this example, we create a Portgroup in our main vDS. To quickly identify the network we named “vCenter HA Network”. You can label differently.

Since this is a demo lab, we will not use any VLAN, but for your environment, you can set a VLAN here for your vCenter HA Network.


Click Finish to create the virtual network.


Next, let us install and configured a vCenter HA.

Log in to the vCenter using vSphere Web Client (For vCenter 6.5 we need to use Flash version, not HTML5) that you plan to create the High Available failover and click in the (1)Configuration tab in the main menu, then select (1)vCenter HA and for last click (3)Configure to start the process.


Since we are performing a Basic installation, select Basic.


Next, add your first IP address for your main vCenter (in this case the existing vCenter that starts as the Active node). Next, select your vCenter HA Network that we create in the pre-install task.

Note: As you can check in the information provided by VMware, you cannot use IPv4 and IPV6, is not supported. You need to either use IPv4 or IPv6, cannot use both for the vCenter HA Network.


Next, add the IP address for Passive Node and Witness Node. As you can see in the next image, installation is already recommending the subnet that you need to use to match your initial vCenter HA Network in the Active Node.

If you click on the Show all IP settings, you get all the network information from the Active Node.


As we can check in the next image if you click Advanced option you have the option to change the IP address of the management network in the Passive Node only. Witness doesn’t use vCenter management network.

If you change this IP address when there is a failover, and Passive Node switch to Active Node then uses the IP address that you set in this option. Users to reconnect to vCenter need to use this IP address and not the IP from the main vCenter.

Note: If using this option, a DNS Reverse Lookup for this IP address needs to be created.

In our example, we do not use or change this setting.


Next, we validate, or change, our configuration and click next.

As we can notice we have a warning “Compatibility issues”, clicking the warning we have the information about the issue.

In this case, the configuration is warning us that all vCenter Appliances will be located in the same Datastore (in this case USB-Disk01).

Best Practices recommend that we split the vCenter Appliances between different Datastores in case of failover (not only network but also Storage).


Just a quick example of how to change the Datastore (or ESXi hosts) where each Node can be stored:

Click Edit and change the destination of the Nodes.

First, you can change the name or the vCenter Appliance Node and location (folder or Datacenter).


Next, you change the ESXi host where the vCenter Appliance Node will be located.

Note: Is recommended that vCenter Appliances runs in different ESXi hosts. However, in Basic Installation this is set automatically by the vCenter HA installation, by creating a DRS anti-affinity rule.


Next, if possible set a different Datastore for each vCenter Appliance Node. In this example, we select vCenter-HA-02 for the vCenter Appliance Peer (Passive Node).


Last option is to set the vCenter HA Network. Unless you are using an L3 Network, you should not change this option.


Then you can check all the information about the changes you have done for the particular vCenter Appliance Node and click Finish.


After you choose the location for your vCenter Appliances Nodes (or leave untouched), you can check all the information about your future vCenter HA.

Clicking in the Deployment configuration on a particular node you can detail all information about that node (check your example in the next image).

Click Finish to complete the vCenter HA installation.


In vSphere Web Client, you select Monitor tab and vCenter HA you can check all the information and health about vCenter HA.

Also after the installation, you see three new vCenter Appliances Nodes (vCenter Active, vCenter Passive (peer) and the vCenter Witness.


After the process is finished, you can see the DRS anti-affinity rule created for your vCenter HA. As you can check in the next image, all vCenter Nodes runs in separated ESXi hosts. For that, you need to have a minimum of three ESXi hosts.

Three ESXi hosts are the minimum for creating a vCenter HA Cluster. Even it is possible to install with fewer ESXi hosts (not recommended in production).


Note: The clone and installation process can take some time (it depends on your environment), so please be patient while the process finishes (clones 2 times the vCenter to create the vCenter HA).

After the process is complete, you have a full vCenter HA Cluster installed in your VMware Environment.

As we saw in the above process, using Basic Installation is very easy and fast to create a vCenter HA Cluster. The installation process is a very straightforward process with some minor user interaction in the installation process; all is done automatically.

In the next article, we will install vCenter HA using the Advanced Installation process.

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Installing vCenter HA Part 1 – Basic Install
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