Discussion:
Local mount as a remote-fs?
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Andrey Klimentyev
2017-12-04 11:25:47 UTC
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Hi,

Is it possible to register local mount as a remote-fs?

I've got a rather peculiar problem with Kubernetes and Ceph:
1. kubelet creates an rbd device in /dev;
2. it mounts it to some location;
3. systemd adds local-fs.target and local-fs-pre.target to Before= and
After= directives on auto-created .mount Units.

Unfortunately, with that approach thing get rather messy on shutdown. Ceph
RBD kernel client detects network outage (since we've already disabled the
network) and stops all I/O to those filesystems, while systemd actively
tries to umount them. systemd depends on umounting those filesystems, and
Ceph depends on an online network to properly finish all I/O and unmount
them, thus creating a kind of a deadlock.

--
Andrey Klimentyev,
DevOps engineer @ JSC «Flant»
http://flant.com/ <http://flant.ru/>
+7 (495) 721-10-27, ext. 487
+7 (960) 180-38-98
Silvio Knizek
2017-12-04 11:39:10 UTC
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Am Montag, den 04.12.2017, 14:25 +0300 schrieb Andrey Klimentyev:
> Hi,
>
> Is it possible to register local mount as a remote-fs?
>
> I've got a rather peculiar problem with Kubernetes and Ceph:
> 1. kubelet creates an rbd device in /dev;
> 2. it mounts it to some location;
> 3. systemd adds local-fs.target and local-fs-pre.target to Before=
> and
> After= directives on auto-created .mount Units.
>
> Unfortunately, with that approach thing get rather messy on shutdown.
> Ceph
> RBD kernel client detects network outage (since we've already
> disabled the
> network) and stops all I/O to those filesystems, while systemd
> actively
> tries to umount them. systemd depends on umounting those filesystems,
> and
> Ceph depends on an online network to properly finish all I/O and
> unmount
> them, thus creating a kind of a deadlock.

Hi,

use the mount option »_netdev«, which declares a device as dependent on
network. See »man mount« for more information.

BR
Silvio
Andrey Klimentyev
2017-12-04 12:01:17 UTC
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Yup, thanks a lot, it did work.

On 4 December 2017 at 14:39, Silvio Knizek <***@gmx.net> wrote:

> Am Montag, den 04.12.2017, 14:25 +0300 schrieb Andrey Klimentyev:
> > Hi,
> >
> > Is it possible to register local mount as a remote-fs?
> >
> > I've got a rather peculiar problem with Kubernetes and Ceph:
> > 1. kubelet creates an rbd device in /dev;
> > 2. it mounts it to some location;
> > 3. systemd adds local-fs.target and local-fs-pre.target to Before=
> > and
> > After= directives on auto-created .mount Units.
> >
> > Unfortunately, with that approach thing get rather messy on shutdown.
> > Ceph
> > RBD kernel client detects network outage (since we've already
> > disabled the
> > network) and stops all I/O to those filesystems, while systemd
> > actively
> > tries to umount them. systemd depends on umounting those filesystems,
> > and
> > Ceph depends on an online network to properly finish all I/O and
> > unmount
> > them, thus creating a kind of a deadlock.
>
> Hi,
>
> use the mount option »_netdev«, which declares a device as dependent on
> network. See »man mount« for more information.
>
> BR
> Silvio
> _______________________________________________
> systemd-devel mailing list
> systemd-***@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/systemd-devel
>



--
Andrey Klimentyev,
DevOps engineer @ JSC «Flant»
http://flant.com/ <http://flant.ru/>
+7 (495) 721-10-27, ext. 487
+7 (960) 180-38-98
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