openstack/openstack-helm-infra
Code Issues Proposed changes
9144fdb562
openstack-helm-infra/mariadb
History
Itxaka 42d6c2321d
mysql: set hostpath for mysql-data 
There is currently an issue with deploying single
pod mysql clusters in which restarting or killing
the pod will result in a crashloopbackoff.
The mysql data is indeed lost and the start script
(thinking the cluster was alive before
due to the grastate configmap) tries to restore
the cluster instead of bootstrapping it.
Due to this, if the mysql pod is killed or restarted
in the CI, we will lose all the mysql data, will not
recover, and this results in a broken environment.

When volume.use_local_path_for_single_pod.enabled value
is set to true, which we will apply on single node/single
pod testing, this patch will deploy a local volume
for mysql at the location specified under
volume.use_local_path_for_single_pod.host_path
The data will be kept intact in case
there is a pod restart, as it can read the data again,
and recover itself.

When it is false, which is the default for non-CI,
nothing changes, and an empty dir is used. This
data WILL be lost upon restart, so it is advised
to use volumes instead for production purposes,
by setting Values.volume.enabled to true.

task: 28729

Change-Id: I6ec0bd1087eb06b92ced7dc56ff5b6a156aad433
2019-05-21 19:41:13 +02:00
..
files 'NOP' cleanup for more consistent white-space use in charts 2019-01-03 22:45:49 +00:00
templates mysql: set hostpath for mysql-data 2019-05-21 19:41:13 +02:00
.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 mysql: set hostpath for mysql-data 2019-05-21 19:41:13 +02:00

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