Re: [PATCH 0/4] colo: Introduce resource agent and high-level test

From: Lukas Straub <lukasstraub2@web.de>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Alberto Garcia <berto@igalia.com>,
	Jason Wang <jasowang@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>, Max Reitz <mreitz@redhat.com>,
	"Zhang, Chen" <chen.zhang@intel.com>
Subject: Re: [PATCH 0/4] colo: Introduce resource agent and high-level test
Date: Wed, 18 Dec 2019 10:27:11 +0100	[thread overview]
Message-ID: <20191218102711.19e321ac@luklap> (raw)
In-Reply-To: <20191127221134.2b439e00@luklap>

On Wed, 27 Nov 2019 22:11:34 +0100
Lukas Straub <lukasstraub2@web.de> wrote:

> On Fri, 22 Nov 2019 09:46:46 +0000
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
>
> > * Lukas Straub (lukasstraub2@web.de) wrote:
> > > Hello Everyone,
> > > These patches introduce a resource agent for use with the Pacemaker CRM and a
> > > high-level test utilizing it for testing qemu COLO.
> > >
> > > The resource agent manages qemu COLO including continuous replication.
> > >
> > > Currently the second test case (where the peer qemu is frozen) fails on primary
> > > failover, because qemu hangs while removing the replication related block nodes.
> > > Note that this also happens in real world test when cutting power to the peer
> > > host, so this needs to be fixed.
> >
> > Do you understand why that happens? Is this it's trying to finish a
> > read/write to the dead partner?
> >
> > Dave
>
> I haven't looked into it too closely yet, but it's often hanging in bdrv_flush()
> while removing the replication blockdev and of course thats probably because the
> nbd client waits for a reply. So I tried with the workaround below, which will
> actively kill the TCP connection and with it the test passes, though I haven't
> tested it in real world yet.
>

In the real cluster, sometimes qemu even hangs while connecting to qmp (after remote
poweroff). But I currently don't have the time to look into it.

Still a failing test is better than no test. Could we mark this test as known-bad and
fix this issue later? How should I mark it as known-bad? By tag? Or warn in the log?

Regards,
Lukas Straub