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In VMware vSphere 6.7 U1, we have seen some major improvements in the UI. The HTML5-based browser has not only feature parity, but it's the last release with the Flash-based web client.
The overall "look and feel" is much better, and most importantly, the speed of accomplishing different tasks is much faster too. VMware was under criticism on this for several years, and together with other products revamps, the HTML5 web-based UI is now the new standard. There is a new assistant for configurations, and it checks the status of services to prevent misconfigurations.
Let's talk a little bit about the basics and requirements of vSphere HA. VMware vSphere HA is an availability system that prevents downtime when you have hardware failures. Imagine a simple scenario when you lose one ESXi host due to a hardware problem. Without any intervention from the admin, the VMs automatically restart on other hosts within the vSphere cluster.
Once you meet the requirements, the actual setup is very easy.
VMware vSphere requirements for HA
- Shared storage: this can be any shared storage, such as network-attached storage (NAS), a storage area network (SAN), or a VMware virtual SAN (vSAN, a separate product) visible to all ESXi hosts.
- vCenter Server: while vCenter Server is not required during normal operation, you'll need it to configure vSphere HA.
- Pingable gateway IP: this can be any IP address, usually a default gateway. But it would be great if this IP had some kind of redundancy (or you can add an additional IP address via advanced settings, and we'll show you how in this post too).
How to set up vSphere HA
I assume you have configured shared storage so that each of your ESXi hosts can see the shared data store. I also assume you're running the latest vSphere 6.7 U1 since our screenshots come from this release.
Connect to your vSphere infrastructure via the vSphere client. If you haven't already done so, you'll need to create a Datacenter Object and Cluster Object. We have done a post in the past on detailed HA cluster configuration here if you need this for a reference, but today we'll talk more about the new cluster assistant.
I also assume that you know how to add a host to the cluster (right-clicking the cluster and selecting Add host).
Go and select Cluster object > Configure, go to the Configuration section, and select Quickstart. You'll then have a screen like the one below where you can do several actions. You can:
- Activate or deactivate cluster services such as HA, distributed resource scheduler (DRS), or vSAN
- Add hosts: add new hosts to the cluster
- Configure cluster network settings or revalidate them
Cluster quickstart
This is completely new in vSphere 6.7 U1, and it looks like VMware continues to simplify the workloads to make the UI very easy to use. By right-clicking the cluster object, you can directly activate the services for HA, vSAN, or DRS. Please note that DRS and vSAN need further network configuration, which occurs on the "per-host" level.
In fact you'll need to create VMkernel ports and activate those services on those particular ports.
Configure cluster services
The quickstart page acts as an overview on what's already configured and what's not. You can obviously go and activate HA or DRS within the Services menu as well. Go and select Cluster object > Configure, and within the Services section select vSphere Availability > Edit.
Select cluster object
Then an overlay window opens; activate vSphere HA with a single click.
Activate vSphere HA
From here you can also configure other options, which are useful, but we won't go into details in this post.
Basically, you can configure what's going to happen to your VMs when the host is isolated from the network, when a data store becomes unavailable, when a data store has a "permanent device loss" (PDL) state, or when a data store has an "all paths down" (APD) state.
In these cases, the data store might have a hardware problem, and we can configure what's going to happen to our VMs when this situation occurs. As you can see, the "look and feel" via this HTML5 web client is slightly different from what we use to have with the vSphere Windows client or the vSphere Web Client (Flex-based).
With vSphere 6.7 U1 and newer versions going forward, VMware will phase out the vSphere Web Client (Flex) and won't develop new features in parallel. Only the HTML5 web-based client will serve to manage vSphere infrastructure.
The simplest way of protecting your VM against host failure is vSphere HA. Very few requirements are necessary to get this system to work and kick in when you have a host failure.
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And I'd like to repeat that even if vCenter Server is down or unavailable, vSphere HA works. This is because it's not vCenter that triggers the HA event, but a small agent running on each ESXi host called Fault Domain Manager (FDM). These agents communicate with each other and maintain a list of VMs per host, a list of available hosts, and so forth.
