In this video, Russ Long discusses some of the options available within a VMWare vSphere Cluster. Learn how each option is defined and it's basic functionality.
- [Instructor] When we are creating a cluster, we are basically going to be taking a group of hosts and pooling their resources to solve an issue. Now, whatever that issue is is up to you as an administrator. Now let's take some time to discuss some of the options that we can use in a cluster. One of our fist options is high availability. Now, high availability is used to maintain uptime and protect our VMs and applications in the case of a failure. Now, this is done through VMs being moved to an active host in the cluster when a host fails.
This can also be used at a VM level. If a VM fails, it can be restarted on another host in the cluster. Our next option is Distributed Resource Scheduler, or DRS. DRS is used to balance computer resources among the cluster so that if we have a host that is being utilized more than the others, we can take virtual machines from that host and move them to under-utilized hosts in that cluster. This can be done for compute or storage resources.
vSAN is a solution that allows us to take storage, or hard drives, on multiple hosts within our cluster and amalgamate, or squish, them together to form one virtual storage area network. This shows up as a single storage area network device even though it's multiple hard drives on multiple hosts within the cluster. Finally, we have resource pools. We can tightly control which VMs get resources by using nested resource pools in shares, or reservations, to ensure that some VMs are prioritized over others.
Now, we have to be careful with this, because when we nest too deep, we can cause system failures. So let's take a look in my environment as to how all these things come together, or how we can actually choose these different options. First off, let's just create a basic cluster so we can see these options in action. I'm going to right-click on my Datacenter. I'm going to go down here to New Cluster. Once I click on New Cluster, you can see that DRS, vSphere HA, and Virtual SAN are all available to me as an option.
Now, let's click on vSphere HA. This is the problem with setting up a cluster. It's very easy to click on this button. I clicked on the button, and now many people in the past have falsely believed that they were actually protected, that vSphere HA is going to solve all their problems and they had nothing to worry about anymore. The devil is in the details here. You really have to pay attention to what is enabled and what is not enabled. And that will be the focus going forward.
Note: This course will also help you prepare for the Configure and Administer vSphere Availability Solutions domain of the VMware Certified Professional – Data Center Virtualization exam. View the exam blueprint at https://mylearn.vmware.com/mgrReg/plan.cfm?plan=64180&ui=www_cert.
- How vSphere High Availability works
- The basics of clusters
- Understanding failure types and failure response
- Monitoring HA virtual machines and appliances
- Using heartbeats
- Creating and configuring clusters
- Configuring admission control
- Best practices: Networking, interoperability, and cluster monitoring