MariaDB Galera packaged by Bitnami¶

MariaDB Galera is a multi-primary database cluster solution for synchronous replication and high availability.

Overview of MariaDB Galera

Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.

TL;DR¶

使用加速地址添加仓库:

helm repo add bitnami "https://helm-charts.itboon.top/bitnami" --force-update
helm update bitnami

helm install my-release bitnami/mariadb-galera

Introduction¶

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

Bitnami charts can be used with Kubeapps for deployment and management of Helm Charts in clusters.

Looking to use MariaDB Galera in production? Try VMware Application Catalog, the enterprise edition of Bitnami Application Catalog.

Prerequisites¶

• Kubernetes 1.10+
• Helm 3.2.0+
• PV provisioner support in the underlying infrastructure

Installing the Chart¶

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

helm install my-release bitnami/mariadb-galera

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

Tip: List all releases using helm list

Uninstalling the Chart¶

For a graceful termination, set the replica count of the Pods in the mariadb-galera StatefulSet to 0:

kubectl scale sts my-release-mariadb-galera --replicas=0

To uninstall/delete the my-release release:

helm delete --purge my-release

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

Parameters¶

Global parameters¶

Common parameters¶

MariaDB Galera parameters¶

The above parameters map to the env variables defined in bitnami/mariadb-galera. For more information please refer to the bitnami/mariadb-galera image documentation.

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

helm install my-release \
  --set rootUser.password=secretpassword,
  --set db.user=app_database \
    bitnami/mariadb-galera

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

NOTE: Once this chart is deployed, it is not possible to change the application's access credentials, such as usernames or passwords, using Helm. To change these application credentials after deployment, delete any persistent volumes (PVs) used by the chart and re-deploy it, or use the application's built-in administrative tools if available.

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

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

Tip: You can use the default values.yaml

Passing extra command-line flags to mysqld startup¶

While the chart allows you to specify the server configuration using the .mariadbConfiguration chart parameter, some options for the MariaDB server can only be specified via command line flags. For such cases, the chart exposes the .extraFlags parameter.

For example, if you want to enable the PAM cleartext plugin, specify the command line parameter while deploying the chart like so:

helm install my-release \
  --set extraFlags="--pam-use-cleartext-plugin=ON" \
  bitnami/mariadb-galera

Configuration and installation details¶

Rolling VS Immutable tags¶

It is strongly recommended to use immutable tags in a production environment. This ensures your deployment does not change automatically if the same tag is updated with a different image.

Bitnami will release a new chart updating its containers if a new version of the main container, significant changes, or critical vulnerabilities exist.

Change MariaDB version¶

To modify the MariaDB version used in this chart you can specify a valid image tag using the image.tag parameter. For example, image.tag=X.Y.Z. This approach is also applicable to other images like exporters.

LDAP¶

LDAP support can be enabled in the chart by specifying the ldap. parameters while creating a release. The following parameters should be configured to properly enable the LDAP support in the chart.

• ldap.enabled: Enable LDAP support. Defaults to false.
• ldap.uri: LDAP URL beginning in the form ldap[s]://<hostname>:<port>. No defaults.
• ldap.base: LDAP base DN. No defaults.
• ldap.binddn: LDAP bind DN. No defaults.
• ldap.bindpw: LDAP bind password. No defaults.
• ldap.bslookup: LDAP base lookup. No defaults.
• ldap.nss_initgroups_ignoreusers: LDAP ignored users. root,nslcd.
• ldap.scope: LDAP search scope. No defaults.
• ldap.filter: LDAP custom search filter. No defaults.
• ldap.map: LDAP custom map to use. No defaults.
• ldap.tls_reqcert: LDAP TLS check on server certificates. No defaults.

For example:

ldap.enabled="true"
ldap.uri="ldap://my_ldap_server"
ldap.base="dc=example,dc=org"
ldap.binddn="cn=admin,dc=example,dc=org"
ldap.bindpw="admin"
ldap.bslookup="ou=group-ok,dc=example,dc=org"
ldap.nss_initgroups_ignoreusers="root,nslcd"
ldap.scope="sub"
ldap.filter="AccountName"
ldap.map="number"
ldap.tls_reqcert="demand"

Next, login to the MariaDB server using the mysql client and add the PAM authenticated LDAP users.

For example,

CREATE USER 'bitnami'@'localhost' IDENTIFIED VIA pam USING 'mariadb';

With the above example, when the bitnami user attempts to login to the MariaDB server, he/she will be authenticated against the LDAP server.

Securing traffic using TLS¶

TLS support can be enabled in the chart by specifying the tls. parameters while creating a release. The following parameters should be configured to properly enable the TLS support in the chart:

• tls.enabled: Enable TLS support. Defaults to false
• tls.certificatesSecret: Name of the secret that contains the certificates. No defaults.
• tls.certFilename: Certificate filename. No defaults.
• tls.certKeyFilename: Certificate key filename. No defaults.
• tls.certCAFilename: CA Certificate filename. No defaults.

For example:

First, create the secret with the cetificates files:

kubectl create secret generic certificates-tls-secret --from-file=./cert.pem --from-file=./cert.key --from-file=./ca.pem

Then, use the following parameters:

tls.enabled="true"
tls.certificatesSecret="certificates-tls-secret"
tls.certFilename="cert.pem"
tls.certKeyFilename="cert.key"
tls.certCAFilename="ca.pem"

Initialize a fresh instance¶

The Bitnami MariaDB Galera 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.

Alternatively, you can specify custom scripts using the initdbScripts parameter as dict.

In addition to these options, you can also set an external ConfigMap with all the initialization scripts. This is done by setting the initdbScriptsConfigMap parameter. Note that this will override the two previous options.

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

Take into account those scripts are treated differently depending on the extension. While the .sh scripts are executed in all the nodes; the .sql and .sql.gz scripts are only executed in the bootstrap node. The reason behind this differentiation is that the .sh scripts allow adding conditions to determine what is the node running the script, while these conditions can't be set using .sql nor sql.gz files. This way it is possible to cover different use cases depending on their needs.

If using a .sh script you want to do a "one-time" action like creating a database, you need to add a condition in your .sh script to be executed only in one of the nodes, such as

initdbScripts:
  my_init_script.sh: |
     #!/bin/sh
     if [[ $(hostname) == *-0  ]]; then
       echo "First node"
       mysql -P 3306 -uroot -prandompassword -e "create database new_database";
     else
       echo "No first node"
     fi

Extra Init Containers¶

The feature allows for specifying a template string for a initContainer in the pod. Usecases include situations when you need some pre-run setup. For example, in IKS (IBM Cloud Kubernetes Service), non-root users do not have write permission on the volume mount path for NFS-powered file storage. So, you could use a initcontainer to chown the mount. See a example below, where we add an initContainer on the pod that reports to an external resource that the db is going to starting. values.yaml

extraInitContainers:
- name: initcontainer
  image: bitnami/minideb
  command: ["/bin/sh", "-c"]
  args:
    - install_packages curl && curl http://api-service.local/db/starting;

Extra Containers¶

The feature allows for specifying additional containers in the pod. Usecases include situations when you need to run some sidecar containers. For example, you can observe if mysql in pod is running and report to some service discovery software like eureka. Example: values.yaml

extraContainers:
- name: '{{ .Chart.Name }}-eureka-sidecar'
  image: 'image:tag'
  env:
  - name: SERVICE_NAME
    value: '{{ template "common.names.fullname" . }}'
  - name: EUREKA_APP_NAME
    value: '{{ template "common.names.name" . }}'
  - name: MARIADB_USER
    value: '{{ .Values.db.user }}'
  - name: MARIADB_PASSWORD
    valueFrom:
      secretKeyRef:
        name: '{{ template "common.names.fullname" . }}'
        key: mariadb-password
  resources:
    limits:
      cpu: 100m
      memory: 20Mi
    requests:
      cpu: 50m
      memory: 10Mi

Bootstraping a node other than 0¶

Note: Some of these procedures can lead to data loss, always make a backup beforehand.

To restart the cluster you need to check the state in which it is after being stopped, also you will need the previous password for the rootUser and mariabackup, and the deployment name. The value of safe_to_bootstrap in /bitnami/mariadb/data/grastate.dat, will indicate if it is safe to bootstrap form that node. In the case it is other than node 0, it is needed to choose one and force the bootstraping from it. You will notice that in these cases it is needed to start the nodes in Parallel by setting podManagementPolicy.

Checking safe_to_boostrap¶

First you need to get the name of the persistent volume claims (pvc), for example:

$ kubectl get pvc
NAME                              STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
data-my-galera-mariadb-galera-0   Bound    pvc-a496aded-f604-4a2d-b934-174907c4d235   8Gi        RWO            gp2            25h
data-my-galera-mariadb-galera-1   Bound    pvc-00ba6121-9042-4760-af14-3b8a40de936c   8Gi        RWO            gp2            25h
data-my-galera-mariadb-galera-2   Bound    pvc-61644bc9-2d7d-4e84-bf32-35e59d909b05   8Gi        RWO            gp2            25h

The following command will print the content of grastate.dat for the persistent volume claim data-my-galera-mariadb-galera-2. This needs to be run for each of the pvc. You will need to change this name accordingly with yours for each PVC.

$ kubectl run -i --rm --tty volpod --overrides='
{
    "apiVersion": "v1",
    "kind": "Pod",
    "metadata": {
        "name": "volpod"
    },
    "spec": {
        "containers": [{
            "command": [
                "cat",
                "/mnt/data/grastate.dat"
            ],
            "image": "bitnami/minideb",
            "name": "mycontainer",
            "volumeMounts": [{
                "mountPath": "/mnt",
                "name": "galeradata"
            }]
        }],
        "restartPolicy": "Never",
        "volumes": [{
            "name": "galeradata",
            "persistentVolumeClaim": {
                "claimName": "data-my-galera-mariadb-galera-2"
            }
        }]
    }
}' --image="bitnami/minideb"

The output should be similar to this:

# GALERA saved state
version: 2.1
uuid:    6f2cbfcd-951b-11ea-a116-5f407049e57d
seqno:   25
safe_to_bootstrap: 1

There are two possible scenarios:

Only one node with safe_to_bootstrap: 1¶

In this case you will need the node number N and run:

helm install my-release bitnami/mariadb-galera \
--set rootUser.password=XXXX \
--set galera.mariabackup.password=YYYY \
--set galera.bootstrap.forceBootstrap=true \
--set galera.bootstrap.bootstrapFromNode=N \
--set podManagementPolicy=Parallel

All the nodes with safe_to_bootstrap: 0¶

In this case the cluster was not stopped cleanly and you need to pick one to force the bootstrap from. The one to be chosen in the one with the highest seqno in /bitnami/mariadb/data/grastate.dat. The following example shows how to force bootstrap from node 3.

helm install my-release bitnami/mariadb-galera \
--set rootUser.password=XXXX \
--set galera.mariabackup.password=YYYY \
--set galera.bootstrap.forceBootstrap=true \
--set galera.bootstrap.bootstrapFromNode=3 \
--set galera.bootstrap.forceSafeToBootstrap=true \
--set podManagementPolicy=Parallel

Remove the forced boostraping¶

After you have started the cluster by forcing the bootstraping on one of the nodes, you will need to remove the forcing so the node can restart with normality.

helm upgrade my-release bitnami/mariadb-galera \
--set rootUser.password=XXXX \
--set galera.mariabackup.password=YYYY \
--set podManagementPolicy=Parallel

Persistence¶

The Bitnami MariaDB Galera image stores the MariaDB data and configurations at the /bitnami/mariadb path of the container.

The chart mounts a Persistent Volume volume at this location. The volume is created using dynamic volume provisioning, by default. An existing PersistentVolumeClaim can be defined.

Setting Pod's affinity¶

This chart allows you to set your custom affinity using the affinity parameter. Find more information about Pod's affinity in the kubernetes documentation.

As an alternative, you can use of the preset configurations for pod affinity, pod anti-affinity, and node affinity available at the bitnami/common chart. To do so, set the podAffinityPreset, podAntiAffinityPreset, or nodeAffinityPreset parameters.

Troubleshooting¶

Find more information about how to deal with common errors related to Bitnami's Helm charts in this troubleshooting guide.

Upgrading¶

It's necessary to specify the existing passwords while performing a upgrade to ensure the secrets are not updated with invalid randomly generated passwords. Remember to specify the existing values of the rootUser.password, db.password and galera.mariabackup.password parameters when upgrading the chart:

helm upgrade my-release bitnami/mariadb-galera \
    --set rootUser.password=[ROOT_PASSWORD] \
    --set db.password=[MARIADB_PASSWORD] \
    --set galera.mariabackup.password=[GALERA_MARIABACKUP_PASSWORD]

| Note: you need to substitute the placeholders [ROOT_PASSWORD], [MARIADB_PASSWORD] and [MARIABACKUP_PASSWORD] with the values obtained from instructions in the installation notes.

To 7.0.0¶

This major release renames several values in this chart and adds missing features, in order to be inline with the rest of assets in the Bitnami charts repository. Also, this release address issues related to cluster initialization and node's restarts.

Affected values:

• service.port renamed as service.ports.mysql.
• service.nodePort renamed as service.nodePorts.mysql.
• securityContext renamed as podSecurityContext.
• extraInitContainers renamed as initContainers.
• prometheusRule.selector renamed as prometheusRule.additionalLabels

This major release also break the Helm upgrade and therefore cause a service disruption. Next procedure is required in order to allow a rolling upgrade.

Note

• It only consider Chart upgrade, not mariadb galera upgrade. Use the same version or validate mariadb galera upgrade path
• Pods dns name are updated. If you use a query router like proxysql or maxscale, configuration have to be updated

# Export current mariadb-galera statefulset resource
kubectl get sts mariadb-galera -o yaml   > mariadb-galera-patch.yaml

# Patch the statefulset spec.serviceName from 'mariadb-galera' to 'mariadb-galera-headless'
yq -i '.spec.serviceName = "mariadb-galera-headless"' mariadb-galera-patch.yaml

# Delete the statefulset keeping the pods
kubectl delete statefulsets.apps mariadb-galera --cascade=orphan
statefulset.apps "mariadb-galera" deleted

# Apply the patched statefulset
kubectl apply -f mariadb-galera-patch.yaml

# Rollout restart statefulset (pod restart is required to take in account new configuration)
kubect rollout restart statefulset mariadb-galera
satefulset.apps/mariadb-galera restarted

# Wait for the pods to restart. Confirm the cluster heath state before run the helm upgrade
kubectl rollout status statefulset mariadb-galera -w

To 5.2.0¶

This version introduces bitnami/common, a library chart as a dependency. More documentation about this new utility could be found here. Please, make sure that you have updated the chart dependencies before executing any upgrade.

To 5.0.0¶

On November 13, 2020, Helm v2 support was formally finished, this major version is the result of the required changes applied to the Helm Chart to be able to incorporate the different features added in Helm v3 and to be consistent with the Helm project itself regarding the Helm v2 EOL.

What changes were introduced in this major version?¶

• Previous versions of this Helm Chart use apiVersion: v1 (installable by both Helm 2 and 3), this Helm Chart was updated to apiVersion: v2 (installable by Helm 3 only). Here you can find more information about the apiVersion field.
• The different fields present in the Chart.yaml file has been ordered alphabetically in a homogeneous way for all the Bitnami Helm Charts

Considerations when upgrading to this version¶

• If you want to upgrade to this version from a previous one installed with Helm v3, you shouldn't face any issues
• If you want to upgrade to this version using Helm v2, this scenario is not supported as this version doesn't support Helm v2 anymore
• If you installed the previous version with Helm v2 and wants to upgrade to this version with Helm v3, please refer to the official Helm documentation about migrating from Helm v2 to v3

Useful links¶

• https://docs.bitnami.com/tutorials/resolve-helm2-helm3-post-migration-issues/
• https://helm.sh/docs/topics/v2_v3_migration/
• https://helm.sh/blog/migrate-from-helm-v2-to-helm-v3/

To 2.0.0¶

In this version the bootstraping was improved. Now it is possible to indicate a node where to bootstrap from, and force the parameter safe_to_bootstrap. This allows to handle situations where the cluster was not cleanly stopped. It should be safe to upgrade from v1 of the chart, but it is wise to create always a backup before performing operations where there is a risk of data loss.

To 1.0.0¶

The Bitnami MariaDB Galera image was migrated to a "non-root" user approach. Previously the container ran as the root user and the MySQL daemon was started as the mysql user. From now on, both the container and the MySQL daemon run as user 1001. You can revert this behavior by setting the parameters securityContext.runAsUser, and securityContext.fsGroup to 0.

Consequences:

• Backwards compatibility is not guaranteed.
• Environment variables related to LDAP configuration were renamed removing the MARIADB_ prefix. For instance, to indicate the LDAP URI to use, you must set LDAP_URI instead of MARIADB_LDAP_URI

To upgrade to 1.0.0, install a new release of the MariaDB Galera chart, and migrate your data by creating a backup of the database, and restoring it on the new release. In the link below you can find a guide that explain the whole process:

• Create And Restore MySQL/MariaDB Backups

Bitnami Kubernetes Documentation¶

Bitnami Kubernetes documentation is available at https://docs.bitnami.com/. You can find there the following resources:

• Documentation for MariaDB Galera Helm chart
• Get Started with Kubernetes guides
• Bitnami Helm charts documentation
• Kubernetes FAQs
• Kubernetes Developer guides

License¶

Copyright © 2023 VMware, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.