Ticket 12016

Summary: is the client version forward compatible?
Product: Slurm Reporter: Vito Burggraf <vito.burggraf>
Component: ConfigurationAssignee: Marcin Stolarek <cinek>
Status: RESOLVED INFOGIVEN QA Contact:
Severity: 4 - Minor Issue    
Priority: --- CC: cinek
Version: 20.02.2   
Hardware: Linux   
OS: Linux   
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Description Vito Burggraf 2021-07-13 00:24:52 MDT 
If we are running version 20.02.4 on our slurmctl, db and majority of slurm nodes, can I run a newer 20.11 client version on some newer nodes.   We just aren't ready to upgrade but wondering of the client nodes can run a newer version.
Comment 1 Marcin Stolarek 2021-07-13 05:02:52 MDT 
Vito,

This won't work. Slurm client commands don't negotiate protocol version with slurmctld and other daemons, they just send messages using the protocol version they belong to. Slurmctld supports two older versions, so older commands work with newer slurmctld, but by its nature, those can't support a protocol that wasn't available at its release time.

Using a newer user command with older slurmctld will result in errors like:
>slurmctld: error: slurm_unpack_received_msg: Invalid Protocol Version XXXX from uid=... at ....:....

On client side it will show:
>error: Unable to allocate resources: Zero Bytes were transmitted or received

cheers,
Marcin
Comment 2 Marcin Stolarek 2021-07-19 02:07:06 MDT 
Vito,

Is there anything else I can help you with here?

cheers,
Marcin
Comment 3 Marcin Stolarek 2021-07-26 03:34:51 MDT 
I'll go ahead and mark the case as closed now.

Should you have any questions please reopen.

cheers,
Marcin