[ClusterLabs] Pacemaker for Embedded Systems

[Ken Gaillot]

On 04/10/2017 03:58 PM, Chad Cravens wrote:
> Hello all:
> 
> we have implemented large cluster solutions for complex server
> environments that had databases, application servers, apache web servers
> and implemented fencing with the IPMI fencing agent.
> 
> However, we are considering if pacemaker would be a good solution for
> high availability for an embedded control system that integrates with
> CAN for vehicles? We will also have Ethernet for cluster communication
> between the hardware units.
> 
> My main questions are:
> 1) Is it common use case to use pacemaker to implement high availability
> for embedded control systems?

I know it has been done. I'd love to hear about some specific examples,
but I don't know of any public ones.

> 2) What, if any, special considerations should be taken when it comes to
> fencing in this type of environment?

>From pacemaker's point of view, it's not a special environment ...
communication between nodes and some way to request fencing are all
that's needed.

Of course, the physical environment poses many more challenges in this
case, not to mention the safety and regulatory requirements if the
system is in any way important to the operation of the vehicle.

I don't have any experience in the area, but just as a thought
experiment, I'd think the main question would be: what happens in a
split-brain situation? Fencing is important to the same degree as the
consequences of that. If the worst that happens is the music player
skips tracks, it might be acceptable to disable fencing; if the vehicle
could brake inappropriately, then the needs are much larger.

> Thank you for any guidance!
> 
> -- 
> Kindest Regards,
> Chad Cravens
> (800) 214-9146 x700
> 
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> Chad Cravens
> (800) 214-9146 x700
> chad.cravens at ossys.com <mailto:chad.cravens at ossys.com>
> http://www.ossys.com