Allow rabbitmq to run in a larger cluster composed of also non-rabbit…

…mq nodes

We introduce the OCF_RESKEY_allowed_cluster_node parameter which can be used to specify
which nodes of the cluster rabbitmq is expected to run on. When this variable is not
set the resource agent assumes that all nodes of the cluster (output of crm_node -l)
are eligible to run rabbitmq. The use case here is clusters that have a large
numbers of node, where only a specific subset is used for rabbitmq (usually this is
done with some constraints).

Tested in a 9-node cluster as follows:
[root@messaging-0 ~]# pcs resource config rabbitmq
 Resource: rabbitmq (class=ocf provider=rabbitmq type=rabbitmq-server-ha)
  Attributes: allowed_cluster_nodes="messaging-0 messaging-1 messaging-2" avoid_using_iptables=true
  Meta Attrs: container-attribute-target=host master-max=3 notify=true ordered=true
  Operations: demote interval=0s timeout=30 (rabbitmq-demote-interval-0s)
              monitor interval=5 timeout=30 (rabbitmq-monitor-interval-5)
              monitor interval=3 role=Master timeout=30 (rabbitmq-monitor-interval-3)
              notify interval=0s timeout=20 (rabbitmq-notify-interval-0s)
              promote interval=0s timeout=60s (rabbitmq-promote-interval-0s)
              start interval=0s timeout=200s (rabbitmq-start-interval-0s)
              stop interval=0s timeout=200s (rabbitmq-stop-interval-0s)

[root@messaging-0 ~]# pcs status |grep -e rabbitmq -e messaging
  * Online: [ controller-0 controller-1 controller-2 database-0 database-1 database-2 messaging-0 messaging-1 messaging-2 ]
...
  * Container bundle set: rabbitmq-bundle [cluster.common.tag/rhosp16-openstack-rabbitmq:pcmklatest]:
    * rabbitmq-bundle-0 (ocf::rabbitmq:rabbitmq-server-ha):      Master messaging-0
    * rabbitmq-bundle-1 (ocf::rabbitmq:rabbitmq-server-ha):      Master messaging-1
    * rabbitmq-bundle-2 (ocf::rabbitmq:rabbitmq-server-ha):      Master messaging-2

scripts/rabbitmq-server-ha.ocf

@@ -53,6 +53,7 @@ OCF_RESKEY_rmq_feature_health_check_default=true
 OCF_RESKEY_rmq_feature_local_list_queues_default=true
 OCF_RESKEY_limit_nofile_default=65535
 OCF_RESKEY_avoid_using_iptables_default=false
+OCF_RESKEY_allowed_cluster_nodes_default=""
 
 : ${HA_LOGTAG="lrmd"}
 : ${HA_LOGFACILITY="daemon"}
@@ -80,6 +81,7 @@ OCF_RESKEY_avoid_using_iptables_default=false
 : ${OCF_RESKEY_rmq_feature_local_list_queues=${OCF_RESKEY_rmq_feature_local_list_queues_default}}
 : ${OCF_RESKEY_limit_nofile=${OCF_RESKEY_limit_nofile_default}}
 : ${OCF_RESKEY_avoid_using_iptables=${OCF_RESKEY_avoid_using_iptables_default}}
+: ${OCF_RESKEY_allowed_cluster_nodes=${OCF_RESKEY_allowed_cluster_nodes_default}}
 
 #######################################################################
 
@@ -368,6 +370,18 @@ noops. This is useful when we run inside containers.
 <content type="boolean" default="${OCF_RESKEY_avoid_using_iptables_default}" />
 </parameter>
 
+<parameter name="allowed_cluster_nodes" unique="0" required="0">
+<longdesc lang="en">
+When set to anything other than the empty string it must container the list of
+cluster node names, separated by spaces, where the rabbitmq resource is allowed to run.
+Tis is needed when rabbitmq is running on a subset of nodes part of a larger
+cluster. The default ("") is to assume that all nodes part of the cluster will
+run the rabbitmq resource.
+</longdesc>
+<shortdesc lang="en">List of cluster nodes where rabbitmq is allowed to run</shortdesc>
+<content type="string" default="${OCF_RESKEY_allowed_cluster_nodes}" />
+</parameter>
+
 $EXTENDED_OCF_PARAMS
 
 </parameters>
@@ -854,10 +868,18 @@ get_running_nodes() {
 get_alive_pacemaker_nodes_but()
 {
     if [ -z "$1" ]; then
-        echo `crm_node -l -p | sed -e '/(null)/d'`
+        tmp_pcmk_node_list=`crm_node -l -p | sed -e '/(null)/d'`
+    else
+        tmp_pcmk_node_list=`crm_node -l -p | sed -e "s/${1}//g" | sed -e '/(null)/d'`
+    fi
+    # If OCF_RESKEY_allowed_cluster_nodes is set then we only want the intersection
+    # of the cluster node output and the allowed_cluster_nodes list
+    if [ -z "${OCF_RESKEY_allowed_cluster_nodes}" ]; then
+      pcmk_node_list=$tmp_pcmk_node_list
     else
-        echo `crm_node -l -p | sed -e "s/${1}//g" | sed -e '/(null)/d'`
+      pcmk_node_list=`for i in $tmp_pcmk_node_list ${OCF_RESKEY_allowed_cluster_nodes}; do echo $i; done | sort | uniq -d`
     fi
+    echo $pcmk_node_list
 }
 
 # Get current master. If a parameter is provided,