[Pacemaker] a question on the `ping` RA

[Riccardo Murri]

Hi Andrew, all,

sorry for this late reply -- currently I am only able to work on this
issue very "part-time-ly"...

On 2 June 2014 13:34, Andrew Beekhof <andrew at beekhof.net> wrote:
>
> On 2 Jun 2014, at 7:05 pm, Riccardo Murri <riccardo.murri at gmail.com> wrote:
>
>> On 30 May 2014 02:38, Andrew Beekhof <andrew at beekhof.net> wrote:
>>>
>>> On 29 May 2014, at 9:19 pm, Riccardo Murri <riccardo.murri at gmail.com> wrote:
>>>
>>>> - or rather does the `ping` RA trigger failure events when even one of
>>>> the nodes cannot be pinged?
>>>
>>> both.  it always triggers events when something changes and its up
>>> to the policy engine to look at your constraints and decide if
>>> things should be moved.
>>
>> Would the following be the correct configuration snippet to have
>> pacemaker ignore occasional ping failures and only react when *no*
>> hosts can be pinged?
>>
>>    primitive ping ocf:pacemaker:ping \
>>        params name=ping dampen=5s multiplier=10 host_list="..." \
>>        op start timeout=120 \
>>        op monitor timeout=60 interval=10 on-fail=ignore
>>                                          ^^^^^^^^^^^^^^
>
> Not really.  monitor failures are different from "i could only reach N out of M hosts"
> The rule below is the correct part, but we'll still poke the PE to be sure everything is ok.
>>
>>    clone ping_clone ping \
>>        meta globally-unique=false clone-node-max=1
>>
>>    [...]
>>
>>    location mgt-location mgt \
>>      rule -INFINITY: not_defined ping or ping number:lte 0
>>

Concerning "monitor failures are different": we have only seen a
migration to happen as a result of a `ping_monitor_XXX` failure.  Does
it trigger the `rule -INF: not_defined ping` part in the PE?  (The
rules above are the rules we run in actual pacemaker setup, minus the
`on-fail=ignore` which we do not have yet.)

Concerning "we'll still poke the PE to be sure everything is ok."
Does this mean that every change in the ping score triggers a check on
part of the PE?  And the relevant rules would be those that evaluate
`ping number`?

Thanks,
Riccardo