[ClusterLabs] Trying to understand dampening (ping)

[Klaus Wenninger]

On Fri, Oct 15, 2021 at 12:01 PM Andrei Borzenkov <arvidjaar at gmail.com>
wrote:

> On Fri, Oct 15, 2021 at 9:25 AM Klaus Wenninger <kwenning at redhat.com>
> wrote:
>
> > Main pain-point here is that ping-RA allows us to configure the count of
> pings sent, but it
> > is just using the exit-value from ping that becomes negative already
> when one of the
> > answers is missing.
>
> Use fping instead? Which is supported by ping RA and should behave
> exactly as needed - report host alive if at least one reply was
> received.
>
I like fping but it having some reputation as DOS tool not everybody might
be fine installing it.
And we will still have something that would be fine with at least a 50%
packet
loss, which as well might not be acceptable to qualify a host as reachable.
But of course we still can tweak it even with the current implementation to
let's say a loss <20% by giving the same host 5 times and having
the limit set to 4.

>
> Maybe when using ping RA could also parse ping output instead of
> relying on exit status.
>
as the fence-agent referenced is doing ;-)

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