How to Change the Pool Master in Citrix Xenserver

In Xenserver pooled environment, if the pool master node goes unresponsive due to some reason. We will not be able to access the slave nodes and its corresponding VM’s from Xencenter. At this time, if we are able to manually SSH into the pool master. We can execute the following commands to make a slave node as the pool master.

Note: Before changing the pool master, you have to disable the HA feature temporarily.

* xe pool-ha-disable – Disables HA (High Availability)
* xe host-list – List UUID for all the hosts

Next, change the master:

* xe pool-designate-new-master host-uuid = "UUID of the slave host"

Now, turn HA back on:

* xe pool-ha-enable

If the pool master is entirely down, you can execute the following command in one of the slave nodes to convert it into master.

* xe pool-emergency-transition-to-master

Then, re-establish a connection to the slaves:

* xe pool-recover-slaves

The above fix was applied in one of our client environments where three Xenservers were running in a pooled environment with Xen version 5.6SP2 installed in it. We were not able to access the other two hosts using Xencenter, when the master node went unresponsive and hence by making a slave node as master. We gained access to the pool.

If you need further assistance, please do not hesitate to contact us.

actsupport is a hosting infrastructure management company which has 20+ years of extensive experience in hardware virtualization support and pool of experts for Citrix Xenserver support, hyper-v server support, VMWare support and many more…

Here is a related post you may be interested in: Steps to Fix VDI Not Available Error in Citrix Xenserver

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