2.2.3. MCollective

MCollective is used for any node host communications or interactions with either the broker host or other nodes. This can include gear placement or removal.

Use the following command to verify that a broker can communicate with all node hosts:

# oo-mco ping
broker.mydomain.com                        time=134.85 ms
node.mydomain.com                          time=541.41 ms
node1.mydomain.com                         time=572.76 ms


---- ping statistics ----
3 replies max: 572.76 min: 134.85 avg: 416.34

All configured node hosts should be represented in the output. If you do not see a node host as expected, verify that the network and clock settings are configured correctly for that node host.

Communication between broker and node hosts is logged in the following files:

Communication that is dropped due to exceeding TTL is also logged in these files.

MCollective actions performed on the node can also log more details in /var/log/openshift/node/platform.log and /var/log/openshift/node/platform-trace.log.

If necessary, you can determine on which node host an application is created using the dig or host command, with the application's hostname.