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Posts Tagged ‘Universally unique identifier’

XenServer – Pool Master Recovery (The Missing Part 1 to XenServer Hosts in Halted Mode)

In July of 2012 I wrote a “part 2” regarding XenServer Hosts in halted mode — however I seem to have misplaced part 1 – which I’ve rewritten after having to need to reference these steps again recently.

There are several events which can cause a XenServer Pool to become corrupt. In a recent instance of mine, the pool master was unable to communicate with the HA storage repository (SR) and fenced. I also had another instance where several shutdown unexpectedly, and the pool master was among them. Here are the steps I performed to recover the Pool Master.

  1. Work on recovering the pool, elect the server you want to become the master, and on that box run “xe pool-emergency-transition-to-master”
  2. Once that is completed, on the newly elected/transitioned master, run “xe pool-recover-slaves”
  3. Once that is complete, you should be able to run “xe host-list” and see all of your hosts listed

Enjoy

Based in part on information from: XenServer System Recovery Guide

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Hung VM, unable to force reboot/shutdown

I have been working with a few vendor provided VM’s which run Linux. For some reason this specific set of Linux VMs do not properly respond when issuing reboot or shutdown commands when they VMs are hung. This is even true of force-shutdown. The following process works great for virtual servers that are non-responsive in a XenServer environment, after normal reboot/shutdown attempts have failed.

  1. “xe vm-list name-label={vm logical name}” to get the uuid of the VM that is hung
  2. “list_domains” to list the domain uuid’s so you can determine the domain # of the VM above by matching the uuids from this output with the uuid for your VM from the previous command.
  3. “/opt/xensource/debug/destroy_domain -domid XX” where XX is the domain number from the previous command
  4. “xe vm-reboot name-label={vm logical name} –force”

Enjoy

 

Based in part on information from: http://www.r2dtop.com/xenserver-6-virtual-machine-crash-and-hang-issue/

 

How to Remove a XenServer Slave when it No Longer Exists in the Pool

Citrix article CTX126382 describes how to remove a XenServer Slave from a pool, however it does not completely clean up after the process is complete. While the host will be removed, any storage repositiories will be left behind, such as DVD and local storage.

To clean these up perform the following:

1) Click on the disconnected storage repository on the console

2) On the general tab, right-click on the UUID and select copy

3) On the Pool master console, type: xe sr-forget uuid= (and then right-click paste which will insert the UUID of the disconnected storage repository)

Repete this process for all disconnected storage repositories, which is tpically local storage, DVD, and removable storage.