Overview

mysql for Kubernetes

Usage

You must specify key configuration attributes when deploying, or else arbitary defaults will be used. The attributes which should be set are:

• user
• password
• database
• root_password

eg

$ juju deploy mysql
    --config user=fred
    --config password=secret
    --config database=test
    --config root_password=admin

These values may also be in a config.yaml file, eg

$ juju deploy mysql --config config.yaml

Actions

Backup

Execute the following steps to do a backup.

$ juju run-action mariadb-k8s/0 backup --wait
unit-mariadb-k8s-0:
  UnitId: mariadb-k8s/0
  id: "1"
  results:
    copy:
      cmd: kubectl cp zaza-9769f2bf245e/mariadb-k8s-0:/var/lib/mysql/backup.sql.gz
        backup.sql.gz
    restore:
      cmd: kubectl cp backup.sql.gz zaza-9769f2bf245e/mariadb-k8s-0:/var/lib/mysql/backup.sql.gz
      juju: juju run-action mariadb-k8s/0 restore --wait
  status: completed
  timing:
    completed: 2020-02-27 14:16:09 +0000 UTC
    enqueued: 2020-02-27 14:16:08 +0000 UTC
    started: 2020-02-27 14:16:09 +0000 UTC
$ kubectl cp zaza-9769f2bf245e/mariadb-k8s-0:/var/lib/mysql/backup.sql.gz backup.sql.gz

Additional note: You can add --string-args target=PRIMARY|SECONDARY if you want this action to be run in a specific mongo unit. If SECONDARY is set, but the mongo unit isn't the SECONDARY, the action will fail.

Restore

When the backup function is executed, you will see the commands you need to execute for restoring from a backup.

$ kubectl cp backup.sql.gz zaza-9769f2bf245e/mariadb-k8s-0:/var/lib/mysql/backup.sql.gz
$ juju run-action mariadb-k8s/0 restore --wait
unit-mariadb-k8s-0:
  UnitId: mariadb-k8s/0
  id: "2"
  results:
    message: Backup restored successfully
  status: completed
  timing:
    completed: 2020-02-27 14:18:17 +0000 UTC
    enqueued: 2020-02-27 14:18:07 +0000 UTC
    started: 2020-02-27 14:18:11 +0000 UTC

Remove backup

When a backup is made, it is stored in the unit. To easily remove the backup, execute this action:

$ juju run-action mariadb-k8s/0 remove-backup --wait
unit-mariadb-k8s-0:
  UnitId: mariadb-k8s/0
  id: "3"
  results:
    Stdout: |
      Backup successfully removed!
  status: completed
  timing:
    completed: 2020-02-27 14:18:41 +0000 UTC
    enqueued: 2020-02-27 14:18:36 +0000 UTC
    started: 2020-02-27 14:18:41 +0000 UTC

Backup remotely

If we want to perform a backup remotely, follow the next steps:

$ sudo apt install mariadb-client-10.1 -y
$ juju status mariadb-k8s
Model              Controller          Cloud/Region        Version  SLA          Timestamp
zaza-9769f2bf245e  microk8s-localhost  microk8s/localhost  2.7.2    unsupported  15:20:42+01:00

App            Version             Status  Scale  Charm        Store  Rev  OS          Address         Notes
mariadb-k8s    rocks.canonical...  active  2      mariadb-k8s  local  0    kubernetes  10.152.183.109  

Unit            Workload  Agent  Address      Ports                                Message
mariadb-k8s/0*  active    idle   10.1.31.185  3306/TCP,4444/TCP,4567/TCP,4568/TCP  ready
mariadb-k8s/1   active    idle   10.1.31.186  3306/TCP,4444/TCP,4567/TCP,4568/TCP  ready
$ mysqldump -uroot -posm4u --single-transaction \
                           --databases database \
                           --host 10.152.183.109 \
                           --port 3306 | gzip > backup.sql.gz
$ gunzip -c backup.sql.gz | mysql -uroot -posm4u --host 10.152.183.109 --port 3306

Note: The remote backups should be done for each database. If --all-databases is step, when restoring from a database, you will see this error: ERROR 1556 (HY000) at line 825: You can't use locks with log tables

Testing

The tests of this charm are done using tox and Zaza.

Prepare environment

The machine in which the tests are run needs access to a juju k8s controller. The easiest way to approach this is by executing the following commands:

sudo apt install tox -y
sudo snap install microk8s --classic
sudo snap install juju

microk8s.status --wait-ready
microk8s.enable storage dns

juju bootstrap microk8s k8s-cloud

Test charm with Tox

tox -e black    # Check syntax
tox -e build    # Build the charm
tox -e func     # Test charm