While researching XCP-ng’s High Availability feature, I realized that all Resource Pool operations depend on Pool Master. The reason is because Xen-Orchestra only connects and exchanges information directly with the Pool Master.
If the Pool Master has an inaccessibility problem (network drop, power outage, etc.), the remaining servers in the Pool will lose their connection to Xen Orchestra. At that time, the High Availability feature will not be able to work.
Here is my Resource Pool consisting of 3 servers, in which Pool Master is the server
I tried shutting down the server
xcp-ng-17 Go. Then back to Xen Orchestra, all servers disappeared from the system.
In the event that the Pool Master really has a problem that cannot be fixed soon, it is imperative to choose another server in the Pool as the Pool Master to re-establish control of the Pool on Xen Orchestra.
Here is a guide on how to recover the Resrouce Pool when the Pool Master crashes.
1. View pool and host information
SSH access to one of the remaining servers in the pool. Use the following command to view the host list
xe host-list params=uuid,name-label,host-metrics-live
Due to the server
xcp-ng-17 I’m having problems, so the host-metrics-live parameter is displayed
falsethe remaining 2 servers are working normally, showing
uuid ( RO) : edab6a91-4ea7-4adb-bdea-15c51e675d5f name-label ( RW): xcp-ng-18 host-metrics-live ( RO): true uuid ( RO) : e3cce885-f617-482e-b598-30a57df414a2 name-label ( RW): xcp-ng-17 host-metrics-live ( RO): false uuid ( RO) : 8e52ca30-dcc0-4b28-af8c-ab009d2d5f10 name-label ( RW): xcp-ng-16 host-metrics-live ( RO): true
Check the pool information with the command
[09:44 xcp-ng-17 ~]# xe pool-list uuid ( RO) : c53ef1f0-9703-b811-a6d5-2f1b01a4203b name-label ( RW): My Pool name-description ( RW): master ( RO): e3cce885-f617-482e-b598-30a57df414a2 default-SR ( RW): 57db5d2e-1ab0-0277-a15a-19eb6a06115a
My Pool the master is
2. Change Pool Master
Type the following command to move the Pool Master to the new server in Pool
Wait 2 minutes for the system to process and reboot. Then check the pool again with the command
xe pool-listmaster has now been transferred
[09:46 xcp-ng-17 ~]# xe pool-list uuid ( RO) : c53ef1f0-9703-b811-a6d5-2f1b01a4203b name-label ( RW): My Pool name-description ( RW): master ( RO): edab6a91-4ea7-4adb-bdea-15c51e675d5f default-SR ( RW): 57db5d2e-1ab0-0277-a15a-19eb6a06115a
3. Reconnect in Xen Orchestra
Open Xen Orchestra, go to Settings -> Servers, delete the old connection and reconnect to the server
- If the server
xcp-ng-17restart it will work under slave mode in pool.
- If the server
xcp-ng-17unrecoverable and must be reinstalled from scratch, we will remove it from the pool with the command
xe pool-eject host-uuid=e3cce885-f617-482e-b598-30a57df414a2.
It is done. Resource Pool is now back to normal.
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