[ClusterLabs] Configure a resource to only run a single instance at all times

[jm2109384 at gmail.com]

Hi Guys,

I'm a new user of pacemaker clustering software and I've just configured a
cluster with a single systemd resource. I have the following cluster and
resource configurations below. Failover works perfectly between the two
nodes however, i wanted to have a constraint/rule or a config that will
ensure that my resource has a single instance running on the cluster at all
times. I'd like to avoid the situation where the resource gets started
manually and ends up running on both cluster nodes.  Hoping to get your
advice on how to achieve this. Thanks in advance.

----
Cluster Name: cluster1
Corosync Nodes:
node1 node2
Pacemaker Nodes:
node1 node2

Resources:
Resource: app1_service (class=systemd type=app1-server)
  Operations: monitor interval=10s (app1_service-monitor-interval-10s)
              start interval=0s timeout=120s
(app1_service-start-interval-0s)
              stop interval=0s timeout=120s (app1_service-stop-interval-0s)
              failure interval=0s timeout=120s
(app1_service-failure-interval-0s)

Stonith Devices:
Fencing Levels:

Location Constraints:
Ordering Constraints:
Colocation Constraints:
Ticket Constraints:

Alerts:
No alerts defined

Resources Defaults:
resource-stickiness: 100
migration-threshold: 1
failure-timeout: 120s
Operations Defaults:
No defaults set

Cluster Properties:
cluster-infrastructure: corosync
dc-version: 1.1.18-11.el7_5.3-2b07d5c5a9
have-watchdog: false
last-lrm-refresh: 1540829641
no-quorum-policy: ignore
stonith-enabled: false
symmetric-cluster: true

Quorum:
  Options:
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.clusterlabs.org/pipermail/users/attachments/20181029/6036a910/attachment.html>