Prior to this change, if the persistent tasks framework noticed that a
job was running on a node that was isolated but has rejoined the cluster
then it would close that job. This was not ideal, because then the job
would persist state from the autodetect process that was isolated. This
commit changes the behaviour to kill the autodetect process associated
with such a job, so that it does not interfere with the autodetect process
that is running on the node where the persistent tasks framework thinks it
should be running.
In order to achieve this a change has also been made to the behaviour of
force-close. Previously this would result in the autodetect process being
gracefully shut down asynchronously to the force-close request. However,
the mechanism by which this happened was the same as the mechanism for
cancelling tasks that end up running on more than one node due to nodes
becoming isolated from the cluster. Therefore, force-close now also kills
the autodetect process rather than gracefully stopping it. The documentation
has been changed to reflect this. It should not be a problem as force-close
is supposed to be a last resort for when normal close fails.
relates elastic/x-pack-elasticsearch#1186
Original commit: elastic/x-pack-elasticsearch@578c944371
03652e7497