[ClusterLabs] Antw: What do Parenthesis Mean in a Colocation or Order?

[Ulrich Windl]

>>> Eric Robinson <eric.robinson at psmnv.com> schrieb am 10.11.2016 um 09:18 in
Nachricht
<DM5PR03MB2729DDC78B09C368C6A068B4FAB80 at DM5PR03MB2729.namprd03.prod.outlook.com>

> I can't believe I'm still unclear in this, but the behavior seems to be 
> different with different versions of Pacemaker.
> 
> What do the parenthesis accomplish in a statement like this?
> 
> colocation c_clust15 inf: ( p_mysql_029  p_mysql_484 p_mysql_734 ) 
> p_vip_clust15 p_fs_clust15 p_lv_drbd0 ms_drbd0:Master 
> order o_clust15 inf: ms_drbd0:promote p_lv_drbd0 p_fs_clust15 p_vip_clust15 
> ( p_mysql_029  p_mysql_484 p_mysql_734 )
> 
> I've noticed that on one this cluster, if any of the mysql instances fail, 
> the whole cluster fails (vip, fs, lvm, etc.). It does not do that on other 
> clusters.

We also use similar things, and they seem to work ;-)
colocation col_Xen_CFS inf: ( prm_xen_v01 prm_xen_v02 prm_xen_v03  ) cln_CFS_VMs_fs

meaning any of the prm_xen_v* can only run where the VM filesystem is running

order ord_CFS_VMs_Xen inf: cln_CFS_VMs_fs ( prm_xen_v01 prm_xen_v02 prm_xen_v03 )

meaning any of the xen VMs must be started after the VM filesystem.

See "Resource sets" in the manual page of crm:

       Three different types of resource sets are provided by crmsh, and each
       one implies different values for the two resource set attributes,
       sequential and require-all.

       sequential
           If true, the resources in the set do not depend on each other
           internally. Setting sequential to true implies a strict order of
           dependency within the set.

       require-all
           If false, only one resource in the set is required to fulfil the
           requirements of the set. The set of A, B and C with require-all set
           to false is be read as "A OR B OR C" when its dependencies are
           resolved.

       The three types of resource sets modify the attributes in the following
       way:

        1. Implicit sets (no brackets).  sequential=true, require-all=true

        2. Parenthesis set (( ...  )).  sequential=false, require-all=true

        3. Bracket set ([ ...  ]).  sequential=false, require-all=false

> 
> --Eric
> 
> 
> 
> 
> 
> _______________________________________________
> Users mailing list: Users at clusterlabs.org 
> http://clusterlabs.org/mailman/listinfo/users 
> 
> Project Home: http://www.clusterlabs.org 
> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf 
> Bugs: http://bugs.clusterlabs.org