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 that 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

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

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

* xe pool-emergency-transition-to-master

* then re-establish connection to the slaves.

* xe pool-recover-slaves

The above fix was applied in one of our client environment where there were three xenservers 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.

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