[ClusterLabs] Which fence agent is needed for an Apache web server cluster?

[Reid Wahl]

On Sat, Mar 27, 2021 at 4:28 PM Strahil Nikolov <hunter86_bg at yahoo.com>
wrote:

> I had to tune the fence_ipmi recently on some older HPE blades. The
> default settings were working, but also returning some output about
> problems negotiating the cypher.
> As that output could make future version of the fence agent go wild, I
> tested several options untill no errors are reported. Maybe the cypher flag
> was different, but I think it was '-c'. If I'm wrong , the author of this
> thread can check the man page .
>
> Yes -> 'HandlePowerKey=ignore' . I have never expected ipmi to try
> graceful shutdown when I tell it to 'press and hold' or 'cold boot', yet I
> never checked the code of fence_ipmi.
>

fence_ipmilan uses ipmitool to send a poweroff signal. The iLO then sends a
virtual power button press, which IIRC goes through ACPI. By default on
RHEL 7 and above, if the system is responsive, systemd-logind handles a
power key press by initiating a graceful shutdown. You have to disable it
from handling the power key press so if you want hard-power-off behavior.


> With triple sbd , I mean sbd with 3 block devices.
>
> Best Regards,
> Strahil Nikolov
>
> On Sat, Mar 27, 2021 at 23:15, Reid Wahl
> <nwahl at redhat.com> wrote:
>
>
> On Saturday, March 27, 2021, Strahil Nikolov <hunter86_bg at yahoo.com>
> wrote:
> > My notes:
> > - ilo ssh fence mechanism is crappy due to ilo itself, try to avoid if
> possible
>
> It has been unreliable in my experience.
>
> > - fence_ipmi requires some tunings (-c flag) and also to disable power
> button from the system
>
> I've rarely, perhaps never, seen a customer have to tune the -c flag.
>
> By disabling the power button, do you mean setting HandlePowerKey=ignore
> in logind.conf? That's not specific to fence_ipmilan, to be clear.
>
> > - triple 'sbd' is quite reliable.My previous company was using 'softdog'
> kernel module for a watchdog device and it never failed us. Yet, it's just
> a kernel module (no hardware required) and thus RH do not support such
> setup.
>
> What do you mean by triple sbd? Correct that RH doesn't support using
> softdog as an sbd watchdog device. It was determined that it's not reliable
> in all situations. It's probably fine much of the time, and I'm glad you
> had a smooth experience with it.
> >
> > On Sat, Mar 27, 2021 at 22:15, Reid Wahl
> > <nwahl at redhat.com> wrote:
> > _______________________________________________
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> >
>
> --
> Regards,
>
>
> Reid Wahl, RHCA
> Senior Software Maintenance Engineer, Red Hat
> CEE - Platform Support Delivery - ClusterHA
>
>

-- 
Regards,

Reid Wahl, RHCA
Senior Software Maintenance Engineer, Red Hat
CEE - Platform Support Delivery - ClusterHA
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