[ClusterLabs] Bug in ocf-shellfuncs, ocf_local_nodename function?

[Israel Brewster]

This refers specifically to build version 5434e9646462d2c3c8f7aad2609d0ef1875839c7 of the ocf-shellfuncs file, on CentOS 6.8, so it might not be an issue on later builds (if any) or different operating systems, but it would appear that the ocf_local_nodename function can have issues with certain configurations. Specially, I was debugging an issue I was having with a resource agent that I traced down to that function returning the FQDN of the machine rather than the actual node name, which in my case was a short name.

In looking at the code, I see that the function is looking for a pacemaker version greater than 1.1.8, in which case it uses crm_node (which works), otherwise it just uses "uname -n", which returns the FQDN (at least in my configuration). To get the current version, it runs the command:

local version=$(pacemakerd -$ | grep "Pacemaker .*" | awk '{ print $2 }')

Which on CentOS 6.8 returns (as of today, at least):

1.1.14-8.el6_8.1

Unfortunately, when that string is passed to the ocf_version_cmp function to compare against 1.1.8, it returns 3, for "bad format", and so falls back to using "uname -n", even though the version *is* greater than 1.1.8, and crm_node would return the proper value.

Of course, if you always set up your cluster to use the FQDN of the servers as the node name, or more specifically always set them up such that the output of uname -n is the node name, then there isn't an issue other than perhaps a undetectably slight loss of efficiency. However, as I accidentally proved by doing otherwise, there is no actual requirement when setting up a cluster that the node names match uname -n (although perhaps it is considered "best practice"?), as long as they resolve to an IP.

I've worked around this in my installation by simply modifying the resource agent to call crm_node directly (since I know I am running on a version greater than 1.1.8), but I figured I might mention it, since I don't get any results when trying to google the issue.
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Israel Brewster
Systems Analyst II
Ravn Alaska
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7293
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