2.5. Removing a XenServer Host from a Resource Pool

When a XenServer Host is removed (“ejected”) from a pool, the machine is reinitialized and left in a state equivalent to a fresh install. It is important not to eject a XenServer Host from a pool if there is important data on the local disks. The local iSCSI IQN of the host is also re-initialized to a random value.

To remove host “b” from a Resource Pool via the CLI

Open a host text console on any XenServer Host in the pool.
Find the UUID corresponding to host “b” using: xe host-list.
Command host “b” to leave the pool by: xe pool-eject host-uuid=uuid.
The host will be ejected and left in a freshly-installed state.

Warning

Do not eject a host from a Resource Pool if it contains important data stored on its local disks. All of the data will be erased upon ejection from the pool. If you wish to preserve this data, copy the VM to shared storage on the pool first, or use the xe vm-copy CLI command.

When a slave host containing locally stored VMs is ejected from a pool, those VMs will still be present in the pool database and visible to the other hosts. They will not start until the virtual disks associated with them have been changed to point at shared storage which can be seen by other hosts in the pool, or simply removed. It is for this reason that you are strongly advised to move any local storage to shared storage upon joining a pool, so that individual hosts can be ejected (or physically fail) without loss of data.