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KubeDB MariaDB - Continuous Archiving and Point-in-time Recovery

Here, will show you how to use KubeDB to provision a MariaDB to Archive continuously and Restore point-in-time.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. For this demonstration, I’m using linode cluster.

Now,install KubeDB operator in your cluster following the steps here.

To install KubeStash operator in your cluster following the steps here.

To install External-snapshotter in your cluster following the steps here.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Note: The yaml files used in this tutorial are stored in docs/guides/mariadb/pitr/nfs/yamls folder in GitHub repository kubedb/docs.

continuous archiving

Continuous archiving involves making regular copies (or “archives”) of the MariaDB transaction log files.To ensure continuous archiving to a nfs we need prepare NFS Server BackupStorage,RetentionPolicy,MariaDBArchiver for the KubeDB Managed MariaDB Databases.

Ensure volumeSnapshotClass

$ kubectl get volumesnapshotclasses
NAME                    DRIVER               DELETIONPOLICY   AGE
longhorn-snapshot-vsc   driver.longhorn.io   Delete           7d22h

If not any, try using longhorn or any other volumeSnapshotClass.

Install Longhorn

Longhorn is a distributed block storage system for Kubernetes that manages persistent storage.

Add Longhorn chart repository.

helm repo add longhorn https://charts.longhorn.io

Update local Longhorn chart information from chart repository.

helm repo update

Install Longhorn chart.

With Helm 2, the following command will create the longhorn-system namespace and install the Longhorn chart together.

helm install longhorn/longhorn --name longhorn --namespace longhorn-system

With Helm 3, the following commands will create the longhorn-system namespace first, then install the Longhorn chart.

kubectl create namespace longhorn-system
helm install longhorn longhorn/longhorn --namespace longhorn-system

Create volumesnapshot class using longhorn

kind: VolumeSnapshotClass
apiVersion: snapshot.storage.k8s.io/v1
metadata:
  name: longhorn-snapshot-vsc
driver: driver.longhorn.io
deletionPolicy: Delete
parameters:
  type: snap
$ kubectl apply -f volumesnapshotclass.yaml
  volumesnapshotclass.snapshot.storage.k8s.io/longhorn-snapshot-vsc unchanged

Install CSI driver for NFS

Install CSI driver for creating nfs volume from here.

helm repo add csi-driver-nfs https://raw.githubusercontent.com/kubernetes-csi/csi-driver-nfs/master/charts
helm install csi-driver-nfs csi-driver-nfs/csi-driver-nfs --namespace kube-system --version v4.5.0 --set feature.enableFSGroupPolicy=true

Be aware to set --set feature.enableFSGroupPolicy=true this.

We will use namespace demo throughout this tutorial.

➤ kubectl create ns demo
namespace/demo created

Setup NFS Server

We will deploy a nfs server and a service using the below yamls. Note we have shared /exports path.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-server
  namespace: demo
spec:
  selector:
    matchLabels:
      app: nfs-server
  template:
    metadata:
      labels:
        app: nfs-server
    spec:
      containers:
        - name: nfs-server
          image: k8s.gcr.io/volume-nfs:0.8
          ports:
            - name: nfs
              containerPort: 2049
            - name: mountd
              containerPort: 20048
            - name: rpcbind
              containerPort: 111
          securityContext:
            privileged: true
          volumeMounts:
            - name: storage
              mountPath: /exports
      volumes:
        - name: storage
          hostPath:
            path: /data/nfs # store all data in "/data/nfs" directory of the node where it is running
            type: DirectoryOrCreate
---
apiVersion: v1
kind: Service
metadata:
  name: nfs-server
  namespace: demo
spec:
  ports:
    - name: nfs
      port: 2049
    - name: mountd
      port: 20048
    - name: rpcbind
      port: 111
  selector:
    app: nfs-server # must match with the label of NFS pod
➤ kubectl apply -f nfs-server.yaml
deployment.apps/nfs-server created
service/nfs-server created

nfs server should be running inside nfs-server-*** pod

Create StorageClass for NFS

allowVolumeExpansion: true
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs 
parameters:
  server: nfs-server.demo.svc.cluster.local
  share: /
provisioner: nfs.csi.k8s.io
reclaimPolicy: Delete
volumeBindingMode: Immediate

Here, parameters.server should be the dns name of your service that is created along with nfs server, parameters.share should be the path inside the shared directory.

Create BackupStorage

First create a PVC which we will use as our backend storage. This pvc should be created using nfs storageClass that we have created earlier.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
  namespace: demo
spec:
  storageClassName: "nfs"
  resources:
    requests:
      storage: 1Gi
  accessModes: 
    - ReadWriteOnce

Now we create the backupStorage following way.

apiVersion: storage.kubestash.com/v1alpha1
kind: BackupStorage
metadata:
  name: local-storage
  namespace: demo
spec:
  storage:
    provider: local
    local:
      mountPath: /md/walg
      persistentVolumeClaim:
        claimName: nfs-pvc
  usagePolicy:
    allowedNamespaces:
      from: All
  default: false
  deletionPolicy: WipeOut
  runtimeSettings:
    pod:
      securityContext:
        fsGroup: 999
        runAsUser: 999
  $ kubectl apply -f nfs-pvc.yaml
  persistentvolumeclaim/nfs-pvc  created
   $ kubectl apply -f backupstorage.yaml
   backupstorage.storage.kubestash.com/linode-storage created

Retention policy

RetentionPolicy is a custom resource(CR) provided by KubeStash that allows you to set how long you’d like to retain the backup data.

apiVersion: storage.kubestash.com/v1alpha1
kind: RetentionPolicy
metadata:
  name: mariadb-retention-policy
  namespace: demo
spec:
  maxRetentionPeriod: "30d"
  successfulSnapshots:
    last: 2
  failedSnapshots:
    last: 2
$ kubectl apply -f  https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/mariadb/pitr/nfs/yamls/retention-policy.yaml 
retentionpolicy.storage.kubestash.com/mariadb-retention-policy created

EncryptionSecret

apiVersion: v1
kind: Secret
type: Opaque
metadata:
  name: encrypt-secret
  namespace: demo
stringData:
  RESTIC_PASSWORD: "changeit"
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/mariadb/pitr/nfs/yamls/encryptionSecret.yaml

MariaDBArchiver

MariaDBArchiver is a custom resource(CR) provided by KubeDB for managing the archiving of MariaDB binlog files and performing volume-level backups

apiVersion: archiver.kubedb.com/v1alpha1
kind: MariaDBArchiver
metadata:
  name: mariadbarchiver-sample
  namespace: demo
spec:
  pause: false
  databases:
    namespaces:
      from: Selector
      selector:
        matchLabels:
          kubernetes.io/metadata.name: demo
    selector:
      matchLabels:
        archiver: "true"
  retentionPolicy:
    name: mariadb-retention-policy
    namespace: demo
  encryptionSecret:
    name: "encrypt-secret"
    namespace: "demo"
  fullBackup:
    jobTemplate:
      spec:
        securityContext:
          fsGroup: 999
          runAsUser: 999
    driver: "VolumeSnapshotter"
    task:
      params:
        volumeSnapshotClassName: "longhorn-snapshot-vsc"
    scheduler:
      successfulJobsHistoryLimit: 1
      failedJobsHistoryLimit: 1
      schedule: "*/30 * * * *"
    sessionHistoryLimit: 2
  manifestBackup:
    jobTemplate:
      spec:
        securityContext:
          fsGroup: 999
          runAsUser: 999
    scheduler:
      successfulJobsHistoryLimit: 1
      failedJobsHistoryLimit: 1
      schedule: "*/30 * * * *"
    sessionHistoryLimit: 2
  backupStorage:
    ref:
      name: "local-storage"
      namespace: "demo"
 $ kubectl create -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/mariadb/pitr/nfs/yamls/mariadbarchiver.yaml
 mariadbarchiver.archiver.kubedb.com/mariadbarchiver-sample created

Deploy MariaDB

So far we are ready with setup for continuously archive MariaDB, We deploy a mariadb referring the MariaDB archiver object.To properly configure MariaDB for archiving, you need to pass specific arguments to the MariaDB container in the spec.podTemplate.containers["mariadb"].args field. Below is an example of a YAML configuration for a MariaDB instance managed by KubeDB, with archiving enabled.

apiVersion: kubedb.com/v1
kind: MariaDB
metadata:
  name: mariadb
  namespace: demo
  labels:
    archiver: "true"
spec:
  version: "11.1.3"
  replicas: 3
  storageType: Durable
  storage:
    storageClassName: "longhorn"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 10Gi
  archiver:
    ref:
      name: mariadbarchiver-sample
      namespace: demo
  deletionPolicy: WipeOut
  podTemplate:
    spec:
      containers:
        - name: mariadb
          args:
            - "--log-bin"
            - "--log-slave-updates"
            - "--wsrep-gtid-mode=ON"
$ kubectl get pod -n demo
NAME                                                              READY   STATUS      RESTARTS        AGE
mariadb-0                                                         2/2     Running     0               4m12s
mariadb-1                                                         2/2     Running     0               4m12s
mariadb-2                                                         2/2     Running     0               3m12s
mariadb-backup-full-backup-1726549703-bjk9w                       0/1     Completed   0               3m22s
mariadb-backup-manifest-backup-1726549703-fx9kx                   0/1     Completed   0               3m22s
mariadb-sidekick                                                  1/1     Running
retention-policy-mariadb-backup-full-backup-1726549703-wg7wt      0/1     Completed   0               3m42s
retention-policy-mariadb-backup-manifest-backup-17265497038pvjd   0/1     Completed   0               3m55s

mariadb-sidekick is responsible for uploading binlog files

mariadb-backup-full-backup-1726549703-bjk9w are the pod of volumes levels backups for MariaDB.

mariadb-backup-manifest-backup-1726549703-fx9kx are the pod of the manifest backup related to MariaDB object

validate BackupConfiguration and VolumeSnapshots


$ kubectl get backupconfigurations -n demo

NAME                    PHASE   PAUSED   AGE
mariadb-backup          Ready            2m43s

$ kubectl get backupsession -n demo
NAME                                           INVOKER-TYPE          INVOKER-NAME            PHASE       DURATION   AGE
mariadb-backup-full-backup-1726549703          BackupConfiguration   mariadb-backup          Succeeded   33s        11m
mariadb-backup-manifest-backup-1726549703      BackupConfiguration   mariadb-backup          Succeeded   20s        11m

kubectl get volumesnapshots -n demo
NAME                    READYTOUSE   SOURCEPVC        SOURCESNAPSHOTCONTENT   RESTORESIZE   SNAPSHOTCLASS           SNAPSHOTCONTENT                                    CREATIONTIME   AGE
mariadb-1726549985      true         data-mariadb-0                           10Gi          longhorn-snapshot-vsc   snapcontent-317aaac9-ae4f-438b-9763-4eb81ff828af    11m            11m

data insert and switch wal

After each and every wal switch the wal files will be uploaded to backup storage

$ kubectl exec -it -n demo  mariadb-0 -- bash

bash-4.4$ mariadb -uroot -p$MYSQL_ROOT_PASSWORD

MariaDB> create database hello;

MariaDB> use hello;

MariaDB [hello]> CREATE TABLE `demo_table`(
    ->     `id` BIGINT(20) NOT NULL,
    ->     `name` VARCHAR(255) DEFAULT NULL,
    ->     PRIMARY KEY (`id`)
    -> );

MariaDB [hello]> INSERT INTO `demo_table` (`id`, `name`)
    -> VALUES
    ->     (1, 'John'),
    ->     (2, 'Jane'),
    ->     (3, 'Bob'),
    ->     (4, 'Alice'),
    ->     (5, 'Charlie'),
    ->     (6, 'Diana'),
    ->     (7, 'Eve'),
    ->     (8, 'Frank'),
    ->     (9, 'Grace'),
    ->     (10, 'Henry');

MariaDB [hello]> select now();
+---------------------+
| now()               |
+---------------------+
| 2024-09-17 05:28:26 |
+---------------------+
+---------------------+

MariaDB [hello]> select count(*) from demo_table;
+----------+
| count(*) |
+----------+
|       10 |
+----------+

At this point We have 10 rows in our newly created table demo_table on database hello

Point-in-time Recovery

Point-In-Time Recovery allows you to restore a MariaDB database to a specific point in time using the archived transaction logs. This is particularly useful in scenarios where you need to recover to a state just before a specific error or data corruption occurred. Let’s say accidentally our dba drops the the table demo_table and we want to restore.

$ kubectl exec -it -n demo  mariadb-0 -- bash

MariaDB [hello]> drop table demo_table;

MariaDB [hello]> flush logs;

We can’t restore from a full backup since at this point no full backup was perform. so we can choose a specific time in which time we want to restore.We can get the specfice time from the wal that archived in the backup storage . Go to the binlog file and find where to store. You can parse binlog-files using mariadbbinlog.

For the demo I will use the previous time we get form select now()

MariaDB [hello]> select now();
+---------------------+
| now()               |
+---------------------+
| 2024-09-17 05:28:26 |
+---------------------+

Restore MariaDB

apiVersion: kubedb.com/v1
kind: MariaDB
metadata:
  name: restore-mariadb
  namespace: demo
spec:
  init:
    archiver:
      encryptionSecret:
        name: encrypt-secret
        namespace: demo
      fullDBRepository:
        name: mariadb-full
        namespace: demo
      recoveryTimestamp: "2024-09-17T05:28:26Z"
  version: "11.1.3"
  replicas: 3
  storageType: Durable
  storage:
    storageClassName: "longhorn"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 10Gi
  deletionPolicy: WipeOut
  podTemplate:
    spec:
      containers:
        - name: mariadb
          args:
            - "--log-bin"
            - "--log-slave-updates"
            - "--wsrep-gtid-mode=ON"
$ kubectl apply -f mariadbrestore.yaml
mariadb.kubedb.com/restore-mariadb created

check for Restored MariaDB

$ kubectl get pod -n demo
restore-mariadb-0                                          1/1     Running     0             44s
restore-mariadb-1                                          1/1     Running     0             42s
restore-mariadb-2                                          1/1     Running     0             41s
restore-mariadb-restorer-z4brz                             0/2     Completed   0             113s
restore-mariadb-restoresession-lk6jq                       0/1     Completed   0             2m6s
$ kubectl get mariadb -n demo
NAME              VERSION   STATUS   AGE
mariadb           11.1.3    Ready    14m
restore-mariadb   11.1.3    Ready    5m37s

Validating data on Restored MariaDB

$ kubectl exec -it -n demo restore-mariadb-0 -- bash
bash-4.4$ mariadb -uroot -p$MYSQL_ROOT_PASSWORD

mariadb> use hello

MariaDB [hello]> select count(*) from demo_table;
+----------+
| count(*) |
+----------+
|       10 |
+----------+
1 row in set (0.00 sec)

so we are able to successfully recover from a disaster

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

$ kubectl delete -n demo mariadb/mariadb
$ kubectl delete -n demo mariadb/restore-mariadb
$ kubectl delete -n demo backupstorage
$ kubectl delete -n demo mariadbarchiver
$ kubectl delete ns demo

Next Steps