openstack/openstack-helm-infra
Code Issues Proposed changes
8673bdda53
openstack-helm-infra/mariadb
History
Cliff Parsons 8673bdda53 MariaDB Leader Election Enhancement 
This patch set enhances the current MariaDB leader election algorithm
by adding a tiebreaker in case multiple nodes have the same sequence
number which happens to be the highest sequence number in the MariaDB
cluster. The tiebreaker is to pick the node which has the lowest node
number in the hostname.

This patch also changes the 409 status code reporting inside the
safe_update_configmap() function to be a warning instead of an error,
as it is indicative of a collision scenario rather than an actual
error.

Change-Id: Ifdff0250b520bb1972d79de94a491e566ed43997
2019-03-30 17:32:49 +00:00
..
files 'NOP' cleanup for more consistent white-space use in charts 2019-01-03 22:45:49 +00:00
templates MariaDB Leader Election Enhancement 2019-03-30 17:32:49 +00:00
.helmignore MariaDB: Move chart to openstack-helm-infra 2018-09-04 18:57:53 -05:00
Chart.yaml MariaDB: Move chart to openstack-helm-infra 2018-09-04 18:57:53 -05:00
README.rst MariaDB: Move chart to openstack-helm-infra 2018-09-04 18:57:53 -05:00
requirements.yaml MariaDB: Move chart to openstack-helm-infra 2018-09-04 18:57:53 -05:00
values.yaml MARIADB: Job failure policy 2019-03-18 12:40:43 +00:00

README.rst

openstack-helm/mariadb

By default, this chart creates a 3-member mariadb galera cluster.

This chart leverages StatefulSets, with persistent storage.

It creates a job that acts as a temporary standalone galera cluster. This host is bootstrapped with authentication and then the WSREP bindings are exposed publicly. The cluster members being StatefulSets are provisioned one at a time. The first host must be marked as Ready before the next host will be provisioned. This is determined by the readinessProbes which actually validate that MySQL is up and responsive.

The configuration leverages xtrabackup-v2 for synchronization. This may later be augmented to leverage rsync which has some benefits.

Once the seed job completes, which completes only when galera reports that it is Synced and all cluster members are reporting in thus matching the cluster count according to the job to the replica count in the helm values configuration, the job is terminated. When the job is no longer active, future StatefulSets provisioned will leverage the existing cluster members as gcomm endpoints. It is only when the job is running that the cluster members leverage the seed job as their gcomm endpoint. This ensures you can restart members and scale the cluster.

The StatefulSets all leverage PVCs to provide stateful storage to /var/lib/mysql.

You must ensure that your control nodes that should receive mariadb instances are labeled with openstack-control-plane=enabled, or whatever you have configured in values.yaml for the label configuration:

kubectl label nodes openstack-control-plane=enabled --all