⚠️ This project is no longer being maintained ⚠️

The code in this repository was created as a proof of concept back when StatefulSets where still called PetSets and hasn't seen much love since.

Feel free to use the bootstrap logic and image structure in your project, but we're not going to implement any changes going forward.

If you find the code in this repository helpful, but want to use it under a different license please get in contact with us.

MariaDB Galera Cluster

MariaDB is one of the most popular database servers in the world. It’s made by the original developers of MySQL and guaranteed to stay open source. Notable users include Wikipedia, Facebook and Google.

Galera Cluster is a multi-master solution for MariaDB which provides an easy-to-use, high-availability solution for MariaDB based databases.

Introduction

This chart bootstraps a MariaDB Galera Cluster deployment on a Kubernetes cluster using the Helm package manager.

Prerequisites

• Kubernetes 1.5+ with Beta APIs enabled
• PV provisioner support in the underlying infrastructure

Installing the Chart

To install the chart with the release name my-release:

$ helm install --name my-release incubator/mariadb-galera

The command deploys MariaDB Galera Cluster on the Kubernetes cluster in the default configuration. The configuration section lists the parameters that can be configured during installation.

Tip: List all releases using helm list

Uninstalling the Chart

To uninstall/delete the my-release deployment:

$ helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Configuration

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

Parameter	Description	Default
image	MariaDB Galera image	adfinissygroup/k8s-mariadb-galera-centos:v002
imagePullPolicy	Image pull policy.	IfNotPresent
mysqlRootPassword	Password for the root user.	random 16 character alphanumeric string
mysqlUser	Username of new user to create.	nil
mysqlPassword	Password for the new user.	nil
mysqlDatabase	Name for new database to create.	nil
replicas	Number of replicas to deploy	3
persistence.enabled	Use a PVC to persist data	true
persistence.storageClass	Storage class of backing PVC	nil (uses alpha storage class annotation)
persistence.accessMode	Use volume as ReadOnly or ReadWrite	ReadWriteOnce
persistence.size	Size of data volume	8Gi
resources	CPU/Memory resource requests/limits	Memory: 256Mi, CPU: 250m
config	Multi-line string for my.cnf configuration	nil

The above parameters map to the env variables defined in the adfinis-sygroup/openshift-mariadb-galera.

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

$ helm install --name my-release \
  --set mysqlRootPassword=secretpassword,mysqlUser=my-user,mysqlPassword=my-password,mysqlDatabase=my-database \
    stable/mariadb-galera

The above command sets the MariaDB root account password to secretpassword. Additionally it creates a standard database user named my-user, with the password my-password, who has access to 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,

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

Tip: You can use the default values.yaml

Random MariaDB root password

If you don't configure a password for the MariaDB root user, helm will generate a random one for you. You can get the configured password from the created Kubernetes secret:

$ kubectl get secret ${release_name}-mariadb-galera  -o jsonpath='{.data.mysql-root-password}' | base64 -d

Custom my.cnf configuration

The Adfinis SyGroup MariaDB Galera Cluster image allows you to provide a custom my_extra.cnf file for configuring MariaDB. This Chart uses the config value to mount a custom my_extra.cnf using a ConfigMap. You can configure this by creating a YAML file that defines the config property as a multi-line string in the format of a my.cnf file. For example:

cat > mariadb-values.yaml <<EOF
config: |-
  [mysqld]
  max_allowed_packet = 64M
  sql_mode=STRICT_ALL_TABLES
  ft_stopword_file=/etc/mysql/stopwords.txt
  ft_min_word_len=3
  ft_boolean_syntax=' |-><()~*:""&^'
  innodb_buffer_pool_size=2G
EOF

helm install --name my-release -f mariadb-values.yaml incubator/mariadb-galera

Persistence

The MariaDB Galera Chart image stores the MariaDB data files at the /var/lib/mysql path of the container.

The chart mounts a Persistent Volume at this location in every pod of the StatefulSet. The volume is either created using dynamic volume provisioning or must be created manually.