## Introduction

This chart bootstraps a [MariaDB](https://github.com/bitnami/bitnami-docker-mariadb) replication cluster deployment on a [Kubernetes](http://kubernetes.io) cluster using the [Helm](https://helm.sh) package manager.

## Configuration

The following table lists the configurable parameters of the MariaDB chart and their default values.

|             Parameter                     |                     Description                     |                              Default                              |
|-------------------------------------------|-----------------------------------------------------|-------------------------------------------------------------------|
| `image.registry`                          | MariaDB image registry                              | `docker.io`                                                       |
| `image.repository`                        | MariaDB Image name                                  | `bitnami/mariadb`                                                 |
| `image.tag`                               | MariaDB Image tag                                   | `{VERSION}`                                                       |
| `image.pullPolicy`                        | MariaDB image pull policy                           | `Always` if `imageTag` is `latest`, else `IfNotPresent`           |
| `image.pullSecrets`                       | Specify image pull secrets                          | `nil` (does not add image pull secrets to deployed pods)          |
| `service.type`                            | Kubernetes service type                             | `ClusterIP`                                                       |
| `service.clusterIp`                       | Specific cluster IP when service type is cluster IP. Use None for headless service | `nil`                                                                  |
| `service.port`                            | MySQL service port                                  | `3306`                                                             |
| `rootUser.password`                       | Password for the `root` user                        | _random 10 character alphanumeric string_                         |
| `rootUser.forcePassword`                  | Force users to specify a password                   | `false`                                                           |
| `db.user`                                 | Username of new user to create                      | `nil`                                                             |
| `db.password`                             | Password for the new user                           | _random 10 character alphanumeric string if `db.user` is defined_ |
| `db.name`                                 | Name for new database to create                     | `my_database`                                                     |
| `replication.enabled`                     | MariaDB replication enabled                         | `true`                                                             |
| `replication.user`                        | MariaDB replication user                            | `replicator`                                                       |
| `replication.password`                    | MariaDB replication user password                   | _random 10 character alphanumeric string_                         |
| `master.annotations[].key`                | key for the the annotation list item                |  `nil`                                                  |
| `master.annotations[].value`              | value for the the annotation list item              |  `nil`                                                  |
| `master.affinity`                         | Master affinity (in addition to master.antiAffinity when set)  | `{}`                                                   |
| `master.antiAffinity`                     | Master pod anti-affinity policy                     | `soft`                                                            |
| `master.tolerations`                      | List of node taints to tolerate (master)            | `[]`                                                              |
| `master.persistence.enabled`              | Enable persistence using a `PersistentVolumeClaim`  | `true`                                                            |
| `master.persistence.existingClaim`        | Provide an existing `PersistentVolumeClaim`  | `nil`
| `master.persistence.mountPath`            | Configure existing `PersistentVolumeClaim` mount path  | `""`  
| `master.persistence.annotations`          | Persistent Volume Claim annotations                 | `{}`                                                              |
| `master.persistence.storageClass`         | Persistent Volume Storage Class                     | ``                                                                |
| `master.persistence.accessModes`          | Persistent Volume Access Modes                      | `[ReadWriteOnce]`                                                 |
| `master.persistence.size`                 | Persistent Volume Size                              | `8Gi`                                                             |
| `master.config`                           | Config file for the MariaDB Master server           | `_default values in the values.yaml file_`                        |
| `master.resources`                        | CPU/Memory resource requests/limits for master node | `{}`                                                              |
| `master.livenessProbe.enabled`            | Turn on and off liveness probe (master)             | `true`                                                            |
| `master.livenessProbe.initialDelaySeconds`| Delay before liveness probe is initiated (master)   | `120`                                                             |
| `master.livenessProbe.periodSeconds`      | How often to perform the probe (master)             | `10`                                                              |
| `master.livenessProbe.timeoutSeconds`     | When the probe times out (master)                   | `1`                                                               |
| `master.livenessProbe.successThreshold`   | Minimum consecutive successes for the probe (master)| `1`                                                               |
| `master.livenessProbe.failureThreshold`   | Minimum consecutive failures for the probe (master) | `3`                                                               |
| `master.readinessProbe.enabled`           | Turn on and off readiness probe (master)            | `true`                                                            |
| `master.readinessProbe.initialDelaySeconds`| Delay before readiness probe is initiated (master) | `30`                                                              |
| `master.readinessProbe.periodSeconds`     | How often to perform the probe (master)             | `10`                                                              |
| `master.readinessProbe.timeoutSeconds`    | When the probe times out (master)                   | `1`                                                               |
| `master.readinessProbe.successThreshold`  | Minimum consecutive successes for the probe (master)| `1`                                                               |
| `master.readinessProbe.failureThreshold`  | Minimum consecutive failures for the probe (master) | `3`                                                               |
| `slave.replicas`                          | Desired number of slave replicas                    | `1`                                                               |
| `slave.annotations[].key`                 | key for the the annotation list item                | `nil`                                                   |
| `slave.annotations[].value`               | value for the the annotation list item              | `nil`                                                   |
| `slave.affinity`                          | Slave affinity (in addition to slave.antiAffinity when set) | `{}`                                                      |
| `slave.antiAffinity`                      | Slave pod anti-affinity policy                      | `soft`                                                            |
| `slave.tolerations`                       | List of node taints to tolerate for (slave)         | `[]`                                                              |
| `slave.persistence.enabled`               | Enable persistence using a `PersistentVolumeClaim`  | `true`                                                            |
| `slave.persistence.annotations`           | Persistent Volume Claim annotations                 | `{}`                                                              |
| `slave.persistence.storageClass`          | Persistent Volume Storage Class                     | ``                                                                |
| `slave.persistence.accessModes`           | Persistent Volume Access Modes                      | `[ReadWriteOnce]`                                                 |
| `slave.persistence.size`                  | Persistent Volume Size                              | `8Gi`                                                             |
| `slave.config`                            | Config file for the MariaDB Slave replicas          | `_default values in the values.yaml file_`                        |
| `slave.resources`                         | CPU/Memory resource requests/limits for slave node  | `{}`                                                              |
| `slave.livenessProbe.enabled`             | Turn on and off liveness probe (slave)              | `true`                                                            |
| `slave.livenessProbe.initialDelaySeconds` | Delay before liveness probe is initiated (slave)    | `120`                                                             |
| `slave.livenessProbe.periodSeconds`       | How often to perform the probe (slave)              | `10`                                                              |
| `slave.livenessProbe.timeoutSeconds`      | When the probe times out (slave)                    | `1`                                                               |
| `slave.livenessProbe.successThreshold`    | Minimum consecutive successes for the probe (slave) | `1`                                                               |
| `slave.livenessProbe.failureThreshold`    | Minimum consecutive failures for the probe (slave)  | `3`                                                               |
| `slave.readinessProbe.enabled`            | Turn on and off readiness probe (slave)             | `true`                                                            |
| `slave.readinessProbe.initialDelaySeconds`| Delay before readiness probe is initiated (slave)   | `45`                                                              |
| `slave.readinessProbe.periodSeconds`      | How often to perform the probe (slave)              | `10`                                                              |
| `slave.readinessProbe.timeoutSeconds`     | When the probe times out (slave)                    | `1`                                                               |
| `slave.readinessProbe.successThreshold`   | Minimum consecutive successes for the probe (slave) | `1`                                                               |
| `slave.readinessProbe.failureThreshold`   | Minimum consecutive failures for the probe (slave)  | `3`                                                               |
| `metrics.enabled`                         | Start a side-car prometheus exporter                | `false`                                                           |
| `metrics.image.registry`                           | Exporter image registry                                 | `docker.io` |
`metrics.image.repository`                           | Exporter image name                                 | `prom/mysqld-exporter`                                            |
| `metrics.image.tag`                        | Exporter image tag                                  | `v0.10.0`                                                         |
| `metrics.image.pullPolicy`                 | Exporter image pull policy                          | `IfNotPresent`                                                    |
| `metrics.resources`                       | Exporter resource requests/limit                    | `nil`                                                             |

The above parameters map to the env variables defined in [bitnami/mariadb](http://github.com/bitnami/bitnami-docker-mariadb). For more information please refer to the [bitnami/mariadb](http://github.com/bitnami/bitnami-docker-mariadb) image documentation.

Specify each parameter using the `--set key=value[,key=value]` argument to `helm install`. For example,

```bash
$ helm install --name my-release \
  --set root.password=secretpassword,user.database=app_database \
    stable/mariadb
```

The above command sets the MariaDB `root` account password to `secretpassword`. Additionally it creates a database named `my_database`.

Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,

```bash
$ helm install --name my-release -f values.yaml stable/mariadb
```

> **Tip**: You can use the default [values.yaml](values.yaml)

## Initialize a fresh instance

The [Bitnami MariaDB](https://github.com/bitnami/bitnami-docker-mariadb) image allows you to use your custom scripts to initialize a fresh instance. In order to execute the scripts, they must be located inside the chart folder `files/docker-entrypoint-initdb.d` so they can be consumed as a ConfigMap.

The allowed extensions are `.sh`, `.sql` and `.sql.gz`.

## Persistence

The [Bitnami MariaDB](https://github.com/bitnami/bitnami-docker-mariadb) image stores the MariaDB data and configurations at the `/bitnami/mariadb` path of the container.

The chart mounts a [Persistent Volume](kubernetes.io/docs/user-guide/persistent-volumes/) volume at this location. The volume is created using dynamic volume provisioning, by default. An existing PersistentVolumeClaim can be defined.

## Upgrading

It's necessary to set the `rootUser.password` parameter when upgrading for readiness/liveness probes to work properly. When you install this chart for the first time, some notes will be displayed providing the credentials you must use under the 'Administrator credentials' section. Please note down the password and run the command below to upgrade your chart:

```bash
$ helm upgrade my-release stable/mariadb --set rootUser.password=[ROOT_PASSWORD]
```

| Note: you need to substitue the placeholder _[ROOT_PASSWORD]_ with the value obtained in the installation notes.

### To 5.0.0

Backwards compatibility is not guaranteed unless you modify the labels used on the chart's deployments.
Use the workaround below to upgrade from versions previous to 5.0.0. The following example assumes that the release name is mariadb:

```console
$ kubectl delete statefulset opencart-mariadb --cascade=false
```
