The galera cluster rely on WSREP for cluster consistency. While the
default MySQL monitor will allow us to know when the database node is
minimally functional it does not provide the ability to query the node
state allowing loadbalancers, operators, and deployers to know a node
is healthy prior to being allowed to accept connections. This change
implements the checkcluster script as provided by the fine folks at
Percona. The implementation of this check follows the guild-lines noted
here [0]. With this in-place, we'll be able to convert our haproxy check
for the galera cluster nodes to use an HTTP check on port 9200 instead
of the default MySQL login which will provide for a more robust and
fault tolerant cluster.
[0] https://www.percona.com/doc/percona-xtradb-cluster/LATEST/howtos/virt_sandbox.html
Combined backport of:
- https://review.openstack.org/520665
- https://review.openstack.org/523850
Closes-Bug: #1665667
Change-Id: Ie1b3b9724dd33de1d90634166e585ecceb1f4c96
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>
ed739a5243