[ClusterLabs] Antw: Re: Ordering Sets of Resources

[Ken Gaillot]

On 03/01/2017 01:36 AM, Ulrich Windl wrote:
>>>> Ken Gaillot <kgaillot at redhat.com> schrieb am 26.02.2017 um 20:04 in Nachricht
> <dbf562ff-a830-fc3c-84dc-487b892fcba4 at redhat.com>:
>> On 02/25/2017 03:35 PM, ivagal at libero.it wrote:
>>> Hi all,
>>> i have configured a two node cluster on redhat 7.
>>>
>>> Because I need to manage resources stopping and starting singularly when
>>> they are running I have configured cluster using order set constraints.
>>>
>>> Here the example
>>>
>>> Ordering Constraints:
>>>   Resource Sets:
>>>     set MYIP_1 MYIP_2 MYFTP MYIP_5 action=start sequential=false
>>> require-all=true set MYIP_3 MYIP_4 MYSMTP action=start sequential=true
>>> require-all=true setoptions symmetrical=false
>>>     set MYSMTP MYIP_4 MYIP_3 action=stop sequential=true
>>> require-all=true set MYIP_5 MYFTP MYIP_2 MYIP_1 action=stop
>>> sequential=true require-all=true setoptions symmetrical=false kind=Mandatory
>>>
>>> The constrait work as expected on start but when stopping the resource
>>> don't respect the order.
>>> Any help is appreciated
>>>
>>> Thank and regards
>>> Ivan
>>
>> symmetrical=false means the order only applies for starting
> 
> From the name (symmetrical) alone it could also mean that it only applies for stopping ;-)
> (Another example where better names would be nice)

Well, more specifically, it only applies to the action specified in the
constraint. I hadn't noticed before that the second constraint here has
action=stop, so yes, that one would only apply for stopping.

In the above example, the two constraints are identical to a single
constraint with symmetrical=true, since the second constraint is just
the reverse of the first.