This is another question that has been raised several times recently. Perhaps a node vanishes and is unrecoverable, how do we recover from the loss of a head gear? Is it possible to promote a normal gear to head status?
The simple answer appears to be … no.
The solution here is to run backups of /var/lib/openshift on all nodes.
In the case of node failure a fresh node can be built, added to the district, /var/lib/openshift restored from backup then a ‘oo-admin-regenerate-gear-metadata’ executed. This (as the name suggests) recreates metadata associated with all gears on the node. This includes gear entries in passwd/group files, cgroup rules and limits.conf.