- POLICY-3000Getting issue details... STATUS
Recover from corruption of policy database. [Possibly a bug in mariadb: MDEV-23119]
High Level Design
A Kubernetes cron will run a docker container once every 24 hours.
The docker container will call a shell script to do the backup.
The backups will be stored remotely.
We may want to use configMaps and secrets for some of the variable specified in the shell script.
The example below works on windows 10 running docker desktop with kubernetes enabled.
mariadb is installed on ubuntu using port 3355 instead of the default.
/etc/mysql/my.cnf
[mysqld]
port=3355
Dockerfile
FROM mariadb:latest RUN apt update COPY mysqldump_backup.sh . ENTRYPOINT [ "/bin/sh" ] CMD [ "./mysqldump_backup.sh" ]
Shell script
#!/bin/sh FILENAME=$(basename $0 .sh) BACKUP_TS=$(date +%F-%T) ARCHIVE=${FILENAME}_${BACKUP_TS}.tar.gz ERRFILE=${FILENAME}_${BACKUP_TS}.err DMPFILE=${FILENAME}_${BACKUP_TS}.dmp BACKUP_WORKDIR=/tmp BACKUP_ARCHIVEDIR=/tmp MARIADB_BACKUP_EXE_DIR="/usr/bin" # cleanup old backups removeOldBackups() { # remove backups older than -mmin for minutes, -mtime for days echo "Removing old backups ..." for i in `find $BACKUP_ARCHIVEDIR/*.tar.gz $BACKUP_ARCHIVEDIR/*.dmp $BACKUP_ARCHIVEDIR/*.err \ 2>/dev/null -type f -${BACKUP_RETENTION_INTERVAL} +${BACKUP_RETENTION_PERIOD} -ls | grep -o '\S\+$'` do echo "Removing $i" rm $i >/dev/null 2>/dev/null done } cd / echo "Backup Started" # call backup utility { "$MARIADB_BACKUP_EXE_DIR"/mysqldump --all-databases --host=$DB_HOST --port=$DB_PORT \ --user=$DB_USER --password=$DB_PWD \ --log-error=/tmp/$ERRFILE > /tmp/$DMPFILE } # create a tar archive from the backup directory tar cvzf $BACKUP_ARCHIVEDIR/$ARCHIVE $BACKUP_WORKDIR/$DMPFILE \ $BACKUP_WORKDIR/$ERRFILE >/dev/null 2>/dev/null # check for errors if [ -s "$BACKUP_WORKDIR/$ERRFILE" ] then rm $BACKUP_ARCHIVEDIR/$ARCHIVE >/dev/null 2>/dev/null cat $BACKUP_WORKDIR/$ERRFILE | xargs echo -e echo "Backup Completed With Errors" exit 1 else rm $BACKUP_WORKDIR/$DMPFILE \ $BACKUP_WORKDIR/$ERRFILE >/dev/null 2>/dev/null removeOldBackups echo "Backup Completed Successfully" exit 0 fi
* Old backups will only be removed if the backup succeeds
docker build . -t ktimoney/mysqldump_backup
docker push ktimoney/mysqldump_backup
To run create directory c:\mariadb\backup
docker run -v /mnt/c/mariadb/backup:/tmp ktimoney/mysqldump_backup
Your backup will be available in the tar.gz file in the c:\mariadb\backup directory once docker completes
The kubernetes cron can be created using helm.
The helm directory will look like this:
ls mariadb-backup/
Chart.yaml charts templates values.yaml
ls mariadb-backup/templates/
backupCronjob.yaml backupPersistentVolume.yaml
backupConfigMap.yaml backupPersistentClaim.yaml backupSecret.yaml
apiVersion: v2 name: mariadb-backup description: A Helm chart for Kubernetes # A chart can be either an 'application' or a 'library' chart. # # Application charts are a collection of templates that can be packaged into versioned archives # to be deployed. # # Library charts provide useful utilities or functions for the chart developer. They're included as # a dependency of application charts to inject those utilities and functions into the rendering # pipeline. Library charts do not define any templates and therefore cannot be deployed. type: application # This is the chart version. This version number should be incremented each time you make changes # to the chart and its templates, including the app version. # Versions are expected to follow Semantic Versioning (https://semver.org/) version: 0.1.0 # This is the version number of the application being deployed. This version number should be # incremented each time you make changes to the application. Versions are not expected to # follow Semantic Versioning. They should reflect the version the application is using. # It is recommended to use it with quotes. appVersion: "1.16.0"
echo -n '<string>' | base64 to convert your db_user and db_pwd to base64 encoding
# Default values for mariadb-backup. # This is a YAML-formatted file. # Declare variables to be passed into your templates. image: repository: "ktimoney/mysqldump_backup" backoffLimit: 3 schedule: "\"*/15 * * * *\"" volumes: name: backup-pv storageClassName: path: /run/desktop/mnt/host/c/mariadb/backup accessModes: ReadWriteOnce capacity: storage: 50Mi persistentVolumeReclaimPolicy: Retain nodeAffinity: nodeSelectorTerms: docker-desktop data: backup_retention_interval: mmin # mmin for minutes, mtime for days backup_retention_period: "\"120\"" db_host: host.docker.internal db_port: "\"3355\"" db_user: YmFja3Vw db_pwd: YmFja3Vw
apiVersion: v1 kind: PersistentVolume metadata: name: {{ .Values.volumes.name }} spec: capacity: storage: {{ .Values.volumes.capacity.storage }} volumeMode: Filesystem accessModes: - {{ .Values.volumes.storageClassName.accessModes }} persistentVolumeReclaimPolicy: Retain storageClassName: local-storage local: path: {{ .Values.volumes.storageClassName.path }} nodeAffinity: required: nodeSelectorTerms: - matchExpressions: - key: kubernetes.io/hostname operator: In values: - {{ .Values.volumes.nodeAffinity.nodeSelectorTerms }}
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: backup-claim spec: storageClassName: local-storage accessModes: - {{ .Values.volumes.storageClassName.accessModes }} resources: requests: storage: {{ .Values.volumes.capacity.storage }}
apiVersion: v1 kind: ConfigMap metadata: name: backup-config namespace: default data: backup_retention_interval: {{ .Values.data.backup_retention_interval }} backup_retention_period: {{ .Values.data.backup_retention_period }} db_host: {{ .Values.data.db_host }} db_port: {{ .Values.data.db_port }}
apiVersion: v1 kind: Secret metadata: name: backup-secret type: Opaque data: db_user: {{ .Values.data.db_user }} db_pwd: {{ .Values.data.db_pwd }}
apiVersion: batch/v1beta1 kind: CronJob metadata: name: backup-cron spec: schedule: {{ .Values.schedule }} concurrencyPolicy: Forbid jobTemplate: spec: template: spec: volumes: - name: backup-volume persistentVolumeClaim: claimName: backup-claim containers: - name: mysqldump-backup image: {{ .Values.image.repository }} volumeMounts: - mountPath: /tmp name: backup-volume env: - name: DB_HOST valueFrom: configMapKeyRef: name: backup-config key: db_host - name: DB_PORT valueFrom: configMapKeyRef: name: backup-config key: db_port - name: BACKUP_RETENTION_INTERVAL valueFrom: configMapKeyRef: name: backup-config key: backup_retention_interval - name: BACKUP_RETENTION_PERIOD valueFrom: configMapKeyRef: name: backup-config key: backup_retention_period - name: DB_USER valueFrom: secretKeyRef: name: backup-secret key: db_user - name: DB_PWD valueFrom: secretKeyRef: name: backup-secret key: db_pwd restartPolicy: Never backoffLimit: {{ .Values.backoffLimit }}
Run helm install mariadb-backup-t1 ./mariadb-backup to install
Run helm list to get the name and chart
Run helm upgrade mariadb-backup-t1 mariadb-backup to update
Run helm uninstall mariadb-backup-t1 to remove
* backoffLimit sets the number of times the cron will retry the job before it stops
This will back up the local copy of mariadb every 10 minutes to the c:\mariadb\backup folder.
You can restore your database with a command like the following:
sudo mysql -u root -p < ../../mariadb/tmp/mysqldump_backup_2021-05-06-12_40_07.dmp
Links
Backing Up and Restoring Databases
Openstack MariaDB database backup and restore
mariabackup is an open source tool for doing back ups on MariaDB.
Incremental Backup and Restore with Mariabackup
Back up databases using Kubernetes CronJobs
Replication as a Backup Solution
Notes
We may need to create a user specifically for doing backups:
create user backup identified by '******';
GRANT RELOAD, PROCESS, SELECT, LOCK TABLES, REPLICATION CLIENT, REPLICATION SLAVE ON *.* TO 'backup'@'%';
mariabackup isn't designed to work remotely. When testing it got stuck in a loop when trying to read the logs.
mysqldump: This can be used to backup mariadb running in a docker container :
docker exec <mariadb_container_name> mysqldump [--user <db username>] [--password= <db password>] <db name> > /<backup path>/db.dump
It can also be run inside a container:
mysqldump --all-databases --add-drop-database --compact --routines --host=<hostname> --port=<port> --user=<db user> --password=<db password> --log-error=/tmp/<filename>.err > /tmp/<dmp file name>.dmp