[ClusterLabs] (no subject)

[Klaus Wenninger]

On Wed, Sep 7, 2022 at 12:28 PM Jehan-Guillaume de Rorthais via Users
<users at clusterlabs.org> wrote:
>
> Hey,
>
> On Wed, 7 Sep 2022 19:12:53 +0900
> 권오성 <kwonos.kau at gmail.com> wrote:
>
> > Hello.
> > I am a student who wants to implement a redundancy system with raspberry pi.
> > Last time, I posted about how to proceed with installation on raspberry pi
> > and received a lot of comments.
> > Among them, I searched a lot after looking at the comments saying that
> > fencing stonith should not be false.
> > (ex -> sudo pcs property set stonith-enabled=false)
> > However, I saw a lot of posts saying that there is no choice but to do
> > false because there is no ipmi in raspberry pi, and I wonder how we can
> > solve it in this situation.
>
> Fencing is not juste about IPMI:
> * you can use external smart devices to shut down your nodes (eg. PDU, UPS, a
>   self-made fencing device
>   (https://www.alteeve.com/w/Building_a_Node_Assassin_v1.1.4))
> * you can fence a node by disabling its access to the network from a
>   manageable switch, without shutting down the node

For a small device that can run from POE (external dongle or HAT needed I guess)
one might even think of using a manageable switch to power off/on the
whole device.
Don't know of a fence-agents implementing that but shouldn't be that hard to
do and would be an interesting project.

> * you can use 1/2/3 shared storage + the hardware RPi watchdog using the SBD
>   service
> * you can use the internal hardware RPi watchdog using the SBD service, without
>   shared disk

There is a standard to control ports on USB-hubs.
Not all hubs do implement it of course but the one built into my Lenovo W541
(be careful if your laptop connects touch, keyboard, mouse via usb you might
lock yourself out ;-) ) does and I bought a hub from plugable that does as well.
Have a look at https://github.com/mvp/uhubctl for the cmdline-tool
(and a list of
actual devices supporting the standard) you could easily
call on an extra pi (connected to the host port of the switch) via ssh
(or with a little
more effort convert it to some daemon triggered via network) from a simple
fence-agent.

Klaus

>
> Regards,
> _______________________________________________
> Manage your subscription:
> https://lists.clusterlabs.org/mailman/listinfo/users
>
> ClusterLabs home: https://www.clusterlabs.org/