[ClusterLabs] DRBD + VDO HowTo?
Eric Robinson
eric.robinson at psmnv.com
Mon May 17 14:28:19 EDT 2021
Andrei --
Sorry for the novels. Sometimes it is hard to tell whether people want all the configs, logs, and scripts first, or if they want a description of the problem and what one is trying to accomplish first. I'll send whatever you want. I am very eager to get to the bottom of this.
I'll start with my custom LSB RA. I can send the Pacemaker config a bit later.
[root at ha09a init.d]# ll|grep vdo
lrwxrwxrwx. 1 root root 9 May 16 10:28 vdo0 -> vdo_multi
lrwxrwxrwx. 1 root root 9 May 16 10:28 vdo1 -> vdo_multi
-rwx------. 1 root root 3623 May 16 13:21 vdo_multi
[root at ha09a init.d]# cat vdo_multi
#!/bin/bash
#--custom script for managing vdo volumes
#--functions
function isActivated() {
R=$(/usr/bin/vdo status -n $VOL 2>&1)
if [ $? -ne 0 ]; then
#--error occurred checking vdo status
echo "$VOL: an error occurred checking activation status on $MY_HOSTNAME"
return 1
fi
R=$(/usr/bin/vdo status -n $VOL|grep Activate|awk '{$1=$1};1'|cut -d" " -f2)
echo "$R"
return 0
}
function isOnline() {
R=$(/usr/bin/vdo status -n $VOL 2>&1)
if [ $? -ne 0 ]; then
#--error occurred checking vdo status
echo "$VOL: an error occurred checking activation status on $MY_HOSTNAME"
return 1
fi
R=$(/usr/bin/vdo status -n $VOL|grep "Index status"|awk '{$1=$1};1'|cut -d" " -f3)
echo "$R"
return 0
}
#--vars
MY_HOSTNAME=$(hostname -s)
#--get the volume name
VOL=$(basename $0)
#--get the action
ACTION=$1
#--take the requested action
case $ACTION in
start)
#--check current status
R=$(isOnline "$VOL")
if [ $? -ne 0 ]; then
echo "error occurred checking $VOL status on $MY_HOSTNAME"
exit 0
fi
if [ "$R" == "online" ]; then
echo "running on $MY_HOSTNAME"
exit 0 #--lsb: success
fi
#--enter activation loop
ACTIVATED=no
TIMER=15
while [ $TIMER -ge 0 ]; do
R=$(isActivated "$VOL")
if [ "$R" == "enabled" ]; then
ACTIVATED=yes
break
fi
sleep 1
TIMER=$(( TIMER-1 ))
done
if [ "$ACTIVATED" == "no" ]; then
echo "$VOL: not activated on $MY_HOSTNAME"
exit 5 #--lsb: not running
fi
#--enter start loop
/usr/bin/vdo start -n $VOL
ONLINE=no
TIMER=15
while [ $TIMER -ge 0 ]; do
R=$(isOnline "$VOL")
if [ "$R" == "online" ]; then
ONLINE=yes
break
fi
sleep 1
TIMER=$(( TIMER-1 ))
done
if [ "$ONLINE" == "yes" ]; then
echo "$VOL: started on $MY_HOSTNAME"
exit 0 #--lsb: success
else
echo "$VOL: not started on $MY_HOSTNAME (unknown problem)"
exit 0 #--lsb: unknown problem
fi
;;
stop)
#--check current status
R=$(isOnline "$VOL")
if [ $? -ne 0 ]; then
echo "error occurred checking $VOL status on $MY_HOSTNAME"
exit 0
fi
if [ "$R" == "not" ]; then
echo "not started on $MY_HOSTNAME"
exit 0 #--lsb: success
fi
#--enter stop loop
/usr/bin/vdo stop -n $VOL
ONLINE=yes
TIMER=15
while [ $TIMER -ge 0 ]; do
R=$(isOnline "$VOL")
if [ "$R" == "not" ]; then
ONLINE=no
break
fi
sleep 1
TIMER=$(( TIMER-1 ))
done
if [ "$ONLINE" == "no" ]; then
echo "$VOL: stopped on $MY_HOSTNAME"
exit 0 #--lsb:success
else
echo "$VOL: failed to stop on $MY_HOSTNAME (unknown problem)"
exit 0
fi
;;
status)
R=$(isOnline "$VOL")
if [ $? -ne 0 ]; then
echo "error occurred checking $VOL status on $MY_HOSTNAME"
exit 5
fi
if [ "$R" == "online" ]; then
echo "$VOL started on $MY_HOSTNAME"
exit 0 #--lsb: success
else
echo "$VOL not started on $MY_HOSTNAME"
exit 3 #--lsb: not running
fi
;;
esac
> -----Original Message-----
> From: Users <users-bounces at clusterlabs.org> On Behalf Of Andrei
> Borzenkov
> Sent: Monday, May 17, 2021 12:49 PM
> To: users at clusterlabs.org
> Subject: Re: [ClusterLabs] DRBD + VDO HowTo?
>
> On 17.05.2021 18:18, Eric Robinson wrote:
> > To Strahil and Klaus –
> >
> > I created the vdo devices using default parameters, so ‘auto’ mode was
> selected by default. vdostatus shows that the current mode is async. The
> underlying drbd devices are running protocol C, so I assume that vdo should
> be changed to sync mode?
> >
> > The VDO service is disabled and is solely under the control of Pacemaker,
> but I have been unable to get a resource agent to work reliably. I have two
> nodes. Under normal operation, Node A is primary for disk drbd0, and device
> vdo0 rides on top of that. Node B is primary for disk drbd1 and device vdo1
> rides on top of that. In the event of a node failure, the vdo device and the
> underlying drbd disk should migrate to the other node, and then that node
> will be primary for both drbd disks and both vdo devices.
> >
> > The default systemd vdo service does not work because it uses the –all flag
> and starts/stops all vdo devices. I noticed that there is also a vdo-start-by-
> dev.service, but there is no documentation on how to use it. I wrote my own
> vdo-by-dev system service, but that did not work reliably either. Then I
> noticed that there is already an OCF resource agent named vdo-vol, but that
> did not work either. I finally tried writing my own OCF-compliant RA, and
> then I tried writing an LSB-compliant script, but none of those worked very
> well.
> >
>
> You continue to write novels instead of simply showing your resource agent,
> your configuration and logs.
>
> > My big problem is that I don’t understand how Pacemaker uses the
> monitor action. Pacemaker would often fail vdo resources because the
> monitor action received an error when it ran on the standby node. For
> example, when Node A is primary for disk drbd1 and device vdo1, Pacemaker
> would fail device vdo1 because when it ran the monitor action on Node B,
> the RA reported an error. But OF COURSE it would report an error, because
> disk drbd1 is secondary on that node, and is therefore inaccessible to the vdo
> driver. I DON’T UNDERSTAND.
> >
>
> May be your definition of "error" does not match pacemaker definition of
> "error". It is hard to comment without seeing code.
>
> > -Eric
> >
> >
> >
> > From: Strahil Nikolov <hunter86_bg at yahoo.com>
> > Sent: Monday, May 17, 2021 5:09 AM
> > To: kwenning at redhat.com; Klaus Wenninger <kwenning at redhat.com>;
> > Cluster Labs - All topics related to open-source clustering welcomed
> > <users at clusterlabs.org>; Eric Robinson <eric.robinson at psmnv.com>
> > Subject: Re: [ClusterLabs] DRBD + VDO HowTo?
> >
> > Have you tried to set VDO in async mode ?
> >
> > Best Regards,
> > Strahil Nikolov
> > On Mon, May 17, 2021 at 8:57, Klaus Wenninger
> > <kwenning at redhat.com<mailto:kwenning at redhat.com>> wrote:
> > Did you try VDO in sync-mode for the case the flush-fua stuff isn't
> > working through the layers?
> > Did you check that VDO-service is disabled and solely under
> > pacemaker-control and that the dependencies are set correctly?
> >
> > Klaus
> >
> > On 5/17/21 6:17 AM, Eric Robinson wrote:
> >
> > Yes, DRBD is working fine.
> >
> >
> >
> > From: Strahil Nikolov
> > <hunter86_bg at yahoo.com><mailto:hunter86_bg at yahoo.com>
> > Sent: Sunday, May 16, 2021 6:06 PM
> > To: Eric Robinson
> > <eric.robinson at psmnv.com><mailto:eric.robinson at psmnv.com>; Cluster
> > Labs - All topics related to open-source clustering welcomed
> > <users at clusterlabs.org><mailto:users at clusterlabs.org>
> > Subject: RE: [ClusterLabs] DRBD + VDO HowTo?
> >
> >
> >
> > Are you sure that the DRBD is working properly ?
> >
> >
> >
> > Best Regards,
> >
> > Strahil Nikolov
> >
> > On Mon, May 17, 2021 at 0:32, Eric Robinson
> >
> > <eric.robinson at psmnv.com<mailto:eric.robinson at psmnv.com>> wrote:
> >
> > Okay, it turns out I was wrong. I thought I had it working, but I keep running
> into problems. Sometimes when I demote a DRBD resource on Node A and
> promote it on Node B, and I try to mount the filesystem, the system
> complains that it cannot read the superblock. But when I move the DRBD
> primary back to Node A, the file system is mountable again. Also, I have
> problems with filesystems not mounting because the vdo devices are not
> present. All kinds of issues.
> >
> >
> >
> >
> >
> > From: Users
> > <users-bounces at clusterlabs.org<mailto:users-bounces at clusterlabs.org>>
> > On Behalf Of Eric Robinson
> > Sent: Friday, May 14, 2021 3:55 PM
> > To: Strahil Nikolov
> > <hunter86_bg at yahoo.com<mailto:hunter86_bg at yahoo.com>>; Cluster
> Labs -
> > All topics related to open-source clustering welcomed
> > <users at clusterlabs.org<mailto:users at clusterlabs.org>>
> > Subject: Re: [ClusterLabs] DRBD + VDO HowTo?
> >
> >
> >
> >
> >
> > Okay, I have it working now. The default systemd service definitions did
> not work, so I created my own.
> >
> >
> >
> >
> >
> > From: Strahil Nikolov
> > <hunter86_bg at yahoo.com<mailto:hunter86_bg at yahoo.com>>
> > Sent: Friday, May 14, 2021 3:41 AM
> > To: Eric Robinson
> > <eric.robinson at psmnv.com<mailto:eric.robinson at psmnv.com>>; Cluster
> > Labs - All topics related to open-source clustering welcomed
> > <users at clusterlabs.org<mailto:users at clusterlabs.org>>
> > Subject: RE: [ClusterLabs] DRBD + VDO HowTo?
> >
> >
> >
> > There is no VDO RA according to my knowledge, but you can use systemd
> service as a resource.
> >
> >
> >
> > Yet, the VDO service that comes with thr OS is a generic one and controlls
> all VDOs - so you need to create your own vdo service.
> >
> >
> >
> > Best Regards,
> >
> > Strahil Nikolov
> >
> > On Fri, May 14, 2021 at 6:55, Eric Robinson
> >
> > <eric.robinson at psmnv.com<mailto:eric.robinson at psmnv.com>> wrote:
> >
> > I created the VDO volumes fine on the drbd devices, formatted them as xfs
> filesystems, created cluster filesystem resources, and the cluster us using
> them. But the cluster won’t fail over. Is there a VDO cluster RA out there
> somewhere already?
> >
> >
> >
> >
> >
> > From: Strahil Nikolov
> > <hunter86_bg at yahoo.com<mailto:hunter86_bg at yahoo.com>>
> > Sent: Thursday, May 13, 2021 10:07 PM
> > To: Cluster Labs - All topics related to open-source clustering
> > welcomed <users at clusterlabs.org<mailto:users at clusterlabs.org>>; Eric
> > Robinson
> <eric.robinson at psmnv.com<mailto:eric.robinson at psmnv.com>>
> > Subject: Re: [ClusterLabs] DRBD + VDO HowTo?
> >
> >
> >
> > For DRBD there is enough info, so let's focus on VDO.
> >
> > There is a systemd service that starts all VDOs on the system. You can
> create the VDO once drbs is open for writes and then you can create your
> own systemd '.service' file which can be used as a cluster resource.
> >
> >
> > Best Regards,
> >
> > Strahil Nikolov
> >
> >
> >
> > On Fri, May 14, 2021 at 2:33, Eric Robinson
> >
> > <eric.robinson at psmnv.com<mailto:eric.robinson at psmnv.com>> wrote:
> >
> > Can anyone point to a document on how to use VDO de-duplication with
> DRBD? Linbit has a blog page about it, but it was last updated 6 years ago and
> the embedded links are dead.
> >
> >
> >
> > https://linbit.com/blog/albireo-virtual-data-optimizer-vdo-on-drbd/
> >
> >
> >
> > -Eric
> >
> >
> >
> >
> >
> >
> >
> >
> >
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