[ClusterLabs] normal reboot with active sbd does not work

[Andrei Borzenkov]

On 03.06.2022 11:18, Zoran Bošnjak wrote:
> Hi all,
> I would appreciate an advice about sbd fencing (without shared storage).
> 
> I am using ubuntu 20.04., with default packages from the repository (pacemaker, corosync, fence-agents, ipmitool, pcs...).
> 
> HW watchdog is present on servers. The first problem was to load/unload the watchdog module. For some reason the module is blacklisted on ubuntu,

What makes you think so?

bor at bor-Latitude-E5450:~$ lsb_release  -d

Description:	Ubuntu 20.04.4 LTS

bor at bor-Latitude-E5450:~$ modprobe -c | grep ipmi_watchdog

bor at bor-Latitude-E5450:~$





> so I've created a service for this purpose.
>

man modules-load.d


> --- file: /etc/systemd/system/watchdog.service
> [Unit]
> Description=Load watchdog timer module
> After=syslog.target
> 

Without any explicit dependencies stop will be attempted as soon as
possible.

> [Service]
> Type=oneshot
> RemainAfterExit=yes
> ExecStart=/sbin/modprobe ipmi_watchdog
> ExecStop=/sbin/rmmod ipmi_watchdog
> 

Why on earth do you need to unload kernel driver when system reboots?

> [Install]
> WantedBy=multi-user.target
> ---
> 
> Is this a proper way to load watchdog module under ubuntu?
> 

There is standard way to load non-autoloaded drivers on *any* systemd
based distribution. Which is modules-load.d.

> Anyway, once the module is loaded, the /dev/watchdog (which is required by 'sbd') is present.
> Next, the 'sbd' is installed by
> 
> sudo apt install sbd
> (followed by one reboot to get the sbd active)
> 
> The configuration of the 'sbd' is default. The sbd reacts to network failure as expected (reboots the server). However, when the 'sbd' is active, the server won't reboot normally any more. For example from the command line "sudo reboot", it gets stuck at the end of the reboot sequence. There is a message on the console:
> 
> ... reboot progress
> [ OK ] Finished Reboot.
> [ OK ] Reached target Reboot.
> [ ... ] IPMI Watchdog: Unexpected close, not stopping watchdog!
> [ ... ] IPMI Watchdog: Unexpected close, not stopping watchdog!
> ... it gets stuck at this point
> 
> After some long timeout, it looks like the watchdog timer expires and server boots, but the failure indication remains on the front panel of the server. If I uninstall the 'sbd' package, the "sudo reboot" works normally again.
> 
> My question is: How do I configure the system, to have the 'sbd' function present, but still be able to reboot the system normally.
> 

As the first step - do not unload watchdog driver on shutdown.