Unregister a cluster from Prism Central

  • 6 November 2019
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Registered your Prism Element to a Prism Central, but now want to unregister the PE from the Prism Central and confused regarding the steps!

 

Why would anyone like to unregister a cluster?

The following are the reasons when you might want to unregister a cluster from prism central and perform a clean-up.

 

  • Prism Central functionality is being evaluated but you do not plan to use the functionality.

 

  • You manage your cluster or clusters using a different Prism Central instance.

 

  • The Prism Central that your cluster was previously registered to has been destroyed or decommissioned.



Unregistering a cluster through Prism GUI is no longer available and now you’ll be wondering the “WHY SO??


Well we all make mistakes and accidentally unregistering a cluster can be a big risk, so we need to mitigate the risk

So what’s the process to unregister a cluster?
 

Before answering the question, let’s take note of one point
After the force cleanup process mentioned in the below mentioned KB is followed, all PC-PE registration information will be lost. Any configuration of the PE (Prism Element) cluster on Prism Central will also be lost permanently and cannot be recovered.

Now that you are aware of the risks and still want to continue with unregistering

Go through the following document 

 KB – 4944

Have doubts regarding the process? 

Drop a comment below and let us start a discussion 
 


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After setting up and destroying several clusters during tests with different version, hypervisors and hardware but with identical PE names, I came to a point when PC knew about 3 PE that did not exist anymore. PC was naggning me with alerts that it could not communicate with the the deleted PE anymore but gave me no PE uuid, just an IP number of the PE. This was a little tricky to solve since all procedures basically require you to know the deleted cluster uuid. Reading the KB 4944 looking on “Scenario 4” tells me to run “ncli multicluster get-cluster-state” on the PC, but that only gets me a list of active PE registered with the PC so what does that help? Am I missing something? What I ended up doing was to take a new PE not yet in use but registered in PC, use the “ncli multicluster remove-from-multicluster external-ip-address-or-svm-ips=pcname-or-ip username=pc-username password=pc-password force=true” command on the PE and then use “python /home/nutanix/bin/unregistration_cleanup.py uuid” from PC since I know the uuid. This script to my surprise successfully managed to find ALL “stale PE-PC entites” and so it removed four stale PE. Would be great to have a command/script to run on PC that removes all “stale PE-PC entites” or just can give me a list of the uuid of the “stale PE-PC entites. I assume the “unregistration_cleanup.py” require you to use it with a uuid right?

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