I think that there's a change that AppArmor is blocking the access. Have you checked the dmesg messages related with apparmor?
Em sex, 19 de out de 2018 às 09:38, Neil Jerram <n...@tigera.io> escreveu: > Wracking my brains over this one, would appreciate any pointers... > > Setup: Small test deployment with just 3 compute nodes, Queens on Ubuntu > Bionic. The first compute node is an NFS server for > /var/lib/nova/instances, and the other compute nodes mount that as NFS > clients. > > Problem: Sometimes, when launching an instance which is scheduled to one > of the client nodes, nova-compute (in imagebackend.py) gets Permission > Denied (errno 13) when calling utime to touch the timestamp on the instance > file. > > Through various bits of debugging and hackery, I've established that: > > - it looks like the problem never occurs when this is the call that > bootstraps the privsep setup; but it does occur quite frequently on later > calls > > - when the problem occurs, retrying doesn't help (5 times, with 0.5s in > between) > > - the instance file does exist, and is owned by root with read/write > permission for root > > - the privsep helper is running as root > > - the privsep helper receives and executes the request - so it's not a > problem with communication between nova-compute and the helper > > - root is uid 0 on both NFS server and client > > - NFS setup does not have the root_squash option > > - there is some AppArmor setup, on both client and server, and I haven't > yet worked out whether that might be relevant. > > Any ideas? > > Many thanks, > Neil > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >
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