Ceph outage cause filesystem error on VM

Satish Patel satish.txt at gmail.com
Fri Feb 17 15:06:15 UTC 2023


Hi Eugen,

I am playing with less important machine and i did following

I shutdown VM but still down following lock

root at ceph1:~# rbd lock list --image
ec6044e6-2231-4906-9e30-1e2e72573e64_disk -p vms
There is 1 exclusive lock on this image.
Locker          ID                    Address
client.1211875  auto 139643345791728  192.168.3.12:0/2259335316

root at ceph1:~# ceph osd blacklist add 192.168.3.12:0/2259335316
blocklisting 192.168.3.12:0/2259335316 until
2023-02-17T16:00:59.399775+0000 (3600 sec)

Still I can see it in the following lock list. Am I missing something?

root at ceph1:~# rbd lock list --image
ec6044e6-2231-4906-9e30-1e2e72573e64_disk -p vms
There is 1 exclusive lock on this image.
Locker          ID                    Address
client.1211875  auto 139643345791728  192.168.3.12:0/2259335316



On Fri, Feb 17, 2023 at 2:39 AM Eugen Block <eblock at nde.ag> wrote:

> The lock is aquired automatically, you don't need to create one. I'm
> curious why you have that many blacklist entries, maybe that is indeed
> the issue here (locks are not removed). I would shutdown the corrupted
> VM and see if the compute node still has a lock on that image, because
> after shutdown it should remove the lock (automatically). If there's
> still a watcher or lock on that image after shutdown (rbd status
> vms/55dbf40b-0a6a-4bab-b3a5-b4bb74e963af_disk) you can try to
> blacklist the client with:
>
> # ceph osd blacklist add client.<ID>
>
> Then check the status again, if no watchers are present, boot the VM.
>
>
> Zitat von Satish Patel <satish.txt at gmail.com>:
>
> > Hi Eugen,
> >
> > This is what I did, let me know if I missed anything.
> >
> > root at ceph1:~# ceph osd blacklist ls
> > 192.168.3.12:0/0 2023-02-17T04:48:54.381763+0000
> > 192.168.3.22:0/753370860 2023-02-17T04:47:08.185434+0000
> > 192.168.3.22:0/2833179066 2023-02-17T04:47:08.185434+0000
> > 192.168.3.22:0/1812968936 2023-02-17T04:47:08.185434+0000
> > 192.168.3.22:6824/2057987683 2023-02-17T04:47:08.185434+0000
> > 192.168.3.21:0/2756666482 2023-02-17T05:16:23.939511+0000
> > 192.168.3.21:0/1646520197 2023-02-17T05:16:23.939511+0000
> > 192.168.3.22:6825/2057987683 2023-02-17T04:47:08.185434+0000
> > 192.168.3.21:0/526748613 2023-02-17T05:16:23.939511+0000
> > 192.168.3.21:6815/2454821797 2023-02-17T05:16:23.939511+0000
> > 192.168.3.22:0/288537807 2023-02-17T04:47:08.185434+0000
> > 192.168.3.21:0/4161448504 2023-02-17T05:16:23.939511+0000
> > 192.168.3.21:6824/2454821797 2023-02-17T05:16:23.939511+0000
> > listed 13 entries
> >
> > root at ceph1:~# rbd lock list --image
> > 55dbf40b-0a6a-4bab-b3a5-b4bb74e963af_disk -p vms
> > There is 1 exclusive lock on this image.
> > Locker         ID                    Address
> > client.268212  auto 139971105131968  192.168.3.12:0/1649312807
> >
> > root at ceph1:~# ceph osd blacklist rm 192.168.3.12:0/1649312807
> > 192.168.3.12:0/1649312807 isn't blocklisted
> >
> > How do I create a lock?
> >
> >
> > On Thu, Feb 16, 2023 at 10:45 AM Eugen Block <eblock at nde.ag> wrote:
> >
> >> In addition to Sean's response, this has been asked multiple times,
> >> e.g. [1]. You could check if your hypervisors gave up the lock on the
> >> RBDs or if they are still locked (rbd status <pool>/<image>), in that
> >> case you might need to blacklist the clients and see if that resolves
> >> anything. Do you have regular snapshots (or backups) to be able to
> >> rollback in case of a curruption?
> >>
> >> [1] https://www.spinics.net/lists/ceph-users/msg45937.html
> >>
> >>
> >> Zitat von Sean Mooney <smooney at redhat.com>:
> >>
> >> > On Thu, 2023-02-16 at 09:56 -0500, Satish Patel wrote:
> >> >> Folks,
> >> >>
> >> >> I am running a small 3 node compute/controller with 3 node ceph
> storage
> >> in
> >> >> my lab. Yesterday, because of a power outage all my nodes went down.
> >> After
> >> >> reboot of all nodes ceph seems to show good health and no error (in
> ceph
> >> >> -s).
> >> >>
> >> >> When I started using the existing VM I noticed the following errors.
> >> Seems
> >> >> like data loss. This is a lab machine and has zero activity on vms
> but
> >> >> still loses data and the file system corrupt. Is this normal ?
> >> > if the vm/cluster hard crashes due to the power cut yes it can.
> >> > personally i have hit this more often with XFS then ext4 but i have
> >> > seen it with both.
> >> >>
> >> >> I am not using eraser coding, does that help in this matter?
> >> >>
> >> >> blk_update_request: I/O error, dev sda, sector 233000 op 0x1: (WRITE)
> >> flags
> >> >> 0x800 phys_seg 8 prio class 0
> >> >
> >> > you will proably need to rescue the isntance and repair the
> >> > filesystem of each vm with fsck
> >> > or similar. so boot with recue image -> repair filestem -> unrescue
> >> > -> hardreboot/start vm if needed
> >> >
> >> > you might be able to mitigate this somewhat by disableing disk
> >> > cacheing at teh qemu level but
> >> > that will reduce performance. ceph recommenes that you use
> >> > virtio-scis fo the device model and
> >> > writeback cach mode. we generally recommend that too however you can
> >> > use the disk_cachemodes option to
> >> > chage that.
> >> >
> >>
> https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.disk_cachemodes
> >> >
> >> > [libvirt]
> >> > disk_cachemodes=file=none,block=none,network=none
> >> >
> >> > this curreption may also have happend on the cecph cluter side.
> >> > they have some options that can help prevent that via journaling
> wirtes
> >> >
> >> > if you can afford it i would get even a small UPS to allow a
> >> > graceful shutdown if you have future powercuts
> >> > to aovid dataloss issues.
> >>
> >>
> >>
> >>
> >>
>
>
>
>
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