Bug 2065811

Description of problem:

sos-collector gets the node list from the output of `pcs status` (should change to `crm_mon` via Bug 2065805). `pcs status` and `crm_mon` fail if pacemaker is not running on the node where the command is run. That means that using sos-collector with automatically gathered node names is impossible if the cluster is stopped on the local node.

We should fall back to corosync.conf in this case, which contains an always-visible node list.

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Version-Release number of selected component (if applicable):

sos-4.1-9.el8_5

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How reproducible:

Always

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Steps to Reproduce:
1. Stop the cluster on the current node.
2. Run sos collect.

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Actual results:

[root@fastvm-rhel-8-0-23 collector]# sos collect --batch
...
Cluster type set to Pacemaker High Availability Cluster Manager
Cluster status could not be determined. Is the cluster running on this node?

The following is a list of nodes to collect from:
	fastvm-rhel-8-0-23


Connecting to nodes...
Collection would only gather from localhost due to failure to either enumerate or connect to cluster nodes. Assuming single collection from localhost is not desired.
Aborting...

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Expected results:

The collector gets the full node list from corosync.conf.

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Additional info:

corosync.conf contains a node list in the following format:

nodelist {
    node {
        ring0_addr: node1
        name: node1
        nodeid: 1
    }

    node {
        ring0_addr: node2
        name: node2
        nodeid: 2
    }
}

The following are ignored: empty lines, lines starting with '#', and (I believe) whitespace other than line breaks after key/value pairs.

Use "name" if it is present for a node, or "ring0_addr" if "name" is not present for a node. In general, "ring0_addr" may be either a hostname or an IP address.