What are the challenges of implementing VM high availability in XenServer?
This article in a introduction to the VM HA mechanism in XenServer. Implementing VM High availability is a real challenge: first because you need to reliably detect when a server has really failed to avoid unpredictable behavior. But that’s not the only one.
How do I enable ha on a virtual machine?
Go on your VM page, then edit the General panel: you just have to tick the HA checkbox and click on Save. Note: This feature is coming for the next release, but it’s already working in our lab.
What is the easiest way to virtualize a physical server?
It’s pretty much the easiest thing in the world to virtualize a physical server using VMware, but a bit more involved using Citrix Xen. Actually, it’s not a difficult process, it’s just not as easy to find for some strange reason, than the tool for VMware.
Does XenServer know when a VM is shut down?
If you decide to shutdown the VM with Xen Orchestra, XenCenter or xe, the VM will be stopped normally, because XenServer knows that’s what you want. But if you halt it directly in the guest OS (via the console or in SSH), XenServer is NOT aware of what’s going on. For the system, it seems the VM is down and that’s an anomaly.
How to check if a host is unreachable in XenServer?
To be sure a host is really unreachable, HA in XenServer uses multiple heartbeat mechanisms. As you saw in the introduction, just checking the network isn’t enough: what about the storage?
What is XenServer and how does it work?
That’s why XenServer is an awesome product (as its API, the XAPI): it handles flawlessly that kind of stuff. We’ll see how to protect your precious VM in multiple cases, and we’ll illustrate that with real examples. The pool concept allows hosts to exchange their data and status: if you lose a host, it will be detected by the pool master.