Re-adding the role via Horizon does not change anything. No error message for the add, but still not showing as applied on on any of the puppet tabs.

Interestingly, the view at https://tools.wmflabs.org/openstack-browser/puppetclass/role::ci::slave::labs::docker shows these roles being applied via wildcards:

integration-slave-docker-c2-m4-d40-1004.integration.eqiad.wmflab*
integration-slave-docker-c2-m4-d40-1005.integration.eqiad.wmflab*

Is this triggered by some limit on the instance name length?

I now remember (and just tested) that when I first created the 1005 instance I couldn't edit the hiera config.
That could also be due to the name length

That's exactly 64 characters there. Seems suspicious and plausible that it is about the max length.

see https://bugs.launchpad.net/horizon/+bug/1276389 and https://bugs.launchpad.net/horizon/+bug/1279590

Mentioned in SAL (#wikimedia-releng) [2017-10-17T22:08:26Z] <addshore> replaced integration-slave-docker-c2-m4-d40-1005 with integration-slave-docker-1005 T178409

So, I have removed both integration instances that were causing me issues and replaced them with instances with shorter names.

It seems the odd wildcard stuff still appears @ https://tools.wmflabs.org/openstack-browser/puppetclass/role::ci::slave::labs::docker and we might want to clean that up.