[slurm-users] ssh-keys on compute nodes?

[Ole Holm Nielsen]

On 19-06-2020 18:55, Mark Hahn wrote:
>> The host-based SSH authentication is a good idea, but only inside the 
>> cluster's security perimeter, and one should not trust computers 
>> external to the cluster nodes in this way.
> 
> Even more than that!  Hostbased allows you to define intersecting sets of
> asymmetric trust.  For instance, usually symmetric trust among compute 
> nodes,
> and they trust login nodes.  But perhaps login nodes don't trust compute
> nodes, but do trust each other.  And admin nodes don't trust anyone, but 
> everyone trusts them.  If you have "equivalent" clusters (same LDAP,
> etc), then you might want login nodes of different clusters to trust 
> each other.

So how do you configure that?  Let me guess that you configure 
host-based SSH authentication on all nodes, but who trusts who is 
configured in the /etc/ssh/shosts.equiv file?  Do you have any 
guidelines for how to configure such asymmetric trust?

> The big win is that you entirely avoid the presence of private keys on 
> the cluster.
> 
> We've used this widely in ComputeCanada since about 2003.

/Ole