Remove support for single-nova-consoleauth operation; this option
managed a single instance of the nova-consoleauth process across
a cluster nova-cloud-controller application using the hacluster
charm. This proves somewhat racey on deployment as the ocf resource
deep checks the operation of nova-consoleauth including connectivity
to AMQP etc.. If the clustering of the service occurs before
other principle relations have been completed, the resource will
fail to start and the hook execution will spin, never returning.
HA deployments should always use memcached to share tokens between
instances of the nova-consolauth daemon; If the 'ha' relation is
detected, then ensure that a memcache relation is then required
for charm operation.
To support evaluation of the memcache relation completeness
the memcache specific code in InstanceConsoleContext was split out
into a new memcache specific class RemoteMemcacheContext.
Existing pacemaker resources will be deleted on upgrade; units will
move into a blocked state until a relation is added to memcached.
The nova-consoleauth service is resumed on upgrade to ensure that
instances run on all nova-cloud-controller units.
Change-Id: I2ac91b2bd92269b761befeb7563ad01cc5431151
Closes-Bug: 1781620
b6e314077f