[ceph-users] Libvirt hosts freeze after ceph osd+mon problem

Jan Pekař - Imatic jan.pekar at imatic.cz
Mon Nov 6 15:02:27 PST 2017


I'm using debian stretch with ceph 12.2.1-1~bpo80+1 and qemu 
I'm running 3 nodes with 3 monitors and 8 osds on my nodes, all on IPV6.

When I tested the cluster, I detected strange and severe problem.
On first node I'm running qemu hosts with librados disk connection to 
the cluster and all 3 monitors mentioned in connection.
On second node I stopped mon and osd with command


Within one minute all my qemu hosts on first node freeze, so they even 
don't respond to ping. On VNC screen there is no error (disk or kernel 
panic), they just hung forever with no console response. Even starting 
MON and OSD on stopped host doesn't make them running. Destroying the 
qemu domain and running again is the only solution.

This happens even if virtual machine has all primary OSD on other OSDs 
from that I have stopped - so it is not writing primary to the stopped OSD.

If I stop only OSD and MON keep running, or I stop only MON and OSD keep 
running everything looks OK.

When I stop MON and OSD, I can see in log  osd.0 1300 heartbeat_check: 
no reply from ... as usual when OSD fails. During this are virtuals 
still running, but after that they all stop.

What should I send you to debug this problem? Without fixing that, ceph 
is not reliable to me.

Thank you
With regards
Jan Pekar

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