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kubernetes-mysql-backup is a Docker Image based on Alpine Linux that automatically performs backups of MySQL databases, before uploading them to Amazon S3. It is designed to be run as a Cronjob in Kubernetes for scheduled database backups. It also features Slack integration.
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resources Rename application to kubernetes-s3-mysql-backup May 21, 2019
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kubernetes-s3-mysql-backup is a container image based on Alpine Linux. This container is designed to run in Kubernetes as a cronjob to perform automatic backups of MySQL databases to Amazon S3. It was created to meet my requirements for regular and automatic database backups. Having started with a relatively basic feature set, it is gradually growing to add more and more features.

Currently, kubernetes-s3-mysql-backup supports the backing up of MySQL Databases. It can perform backups of multiple MySQL databases from a single database host. When triggered, a full database dump is performed using the mysqldump command for each configured database. The backup(s) are then uploaded to an Amazon S3 Bucket. kubernetes-s3-mysql-backup features Slack Integration, and can post messages into a channel detailing if the backup(s) were successful or not.

Over time, kubernetes-s3-mysql-backup will be updated to support more features and functionality. I currently use this container as part of my Kubernetes Architecture which you can read about here.

All changes are captured in the changelog, which adheres to Semantic Versioning.

Environment Variables

The below table lists all of the Environment Variables that are configurable for kubernetes-s3-mysql-backup.

Environment Variable Purpose
AWS_ACCESS_KEY_ID (Required) AWS IAM Access Key ID.
AWS_SECRET_ACCESS_KEY (Required) AWS IAM Secret Access Key. Should have very limited IAM permissions (see below for example) and should be configured using a Secret in Kubernetes.
AWS_DEFAULT_REGION (Required) Region of the S3 Bucket (e.g. eu-west-2).
AWS_BUCKET_NAME (Required) The name of the S3 bucket.
AWS_BUCKET_BACKUP_PATH (Required) Path the backup file should be saved to in S3. E.g. /database/myblog/backups. Do not put a trailing / or specify the filename.
TARGET_DATABASE_HOST (Required) Hostname or IP address of the MySQL Host.
TARGET_DATABASE_PORT (Optional) Port MySQL is listening on (Default: 3306).
TARGET_DATABASE_NAMES (Required) Name of the databases to dump. This should be comma seperated (e.g. database1,database2).
TARGET_DATABASE_USER (Required) Username to authenticate to the database with.
TARGET_DATABASE_PASSWORD (Required) Password to authenticate to the database with. Should be configured using a Secret in Kubernetes.
SLACK_ENABLED (Optional) (true/false) Enable or disable the Slack Integration (Default False).
SLACK_USERNAME (Optional) (true/false) Username to use for the Slack Integration (Default: kubernetes-s3-mysql-backup).
SLACK_CHANNEL (Required if Slack enabled) Slack Channel the WebHook is configured for.
SLACK_WEBHOOK_URL (Required if Slack enabled) What is the Slack WebHook URL to post to? Should be configured using a Secret in Kubernetes.

Slack Integration

kubernetes-s3-mysql-backup supports posting into Slack after each backup job completes. The message posted into the Slack Channel varies as detailed below:

  • If the backup job is SUCCESSFUL: A generic message will be posted into the Slack Channel detailing that all database backups successfully completed.
  • If the backup job is UNSUCCESSFUL: A message will be posted into the Slack Channel with a detailed error message for each database that failed.

In order to configure kubernetes-s3-mysql-backup to post messages into Slack, you need to create an Incoming WebHook. Once generated, you can configure kubernetes-s3-mysql-backup using the environment variables detailed above.

Configuring the S3 Bucket & AWS IAM User

kubernetes-s3-mysql-backup performs a backup to the same path, with the same filename each time it runs. It therefore assumes that you have Versioning enabled on your S3 Bucket. A typical setup would involve S3 Versioning, with a Lifecycle Policy.

An IAM Users should be created, with API Credentials. An example Policy to attach to the IAM User (for a minimal permissions set) is as follows:

    "Version": "2012-10-17",
    "Statement": [
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": "s3:ListBucket",
            "Resource": "arn:aws:s3:::<BUCKET NAME>"
            "Sid": "VisualEditor1",
            "Effect": "Allow",
            "Action": [
            "Resource": "arn:aws:s3:::<BUCKET NAME>/*"

Example Kubernetes Cronjob

An example of how to schedule this container in Kubernetes as a cronjob is below. This would configure a database backup to run each day at 01:00am. The AWS Secret Access Key, and Target Database Password are stored in secrets.

apiVersion: v1
kind: Secret
type: Opaque
  aws_secret_access_key: <AWS Secret Access Key>
apiVersion: v1
kind: Secret
type: Opaque
  database_password: <Your Database Password>
apiVersion: v1
kind: Secret
type: Opaque
  slack_webhook_url: <Your Slack WebHook URL>
apiVersion: batch/v1beta1
kind: CronJob
  name: my-database-backup
  schedule: "0 01 * * *"
          - name: my-database-backup
            imagePullPolicy: Always
              - name: AWS_ACCESS_KEY_ID
                value: "<Your Access Key>"
              - name: AWS_SECRET_ACCESS_KEY
                     name: AWS_SECRET_ACCESS_KEY
                     key: aws_secret_access_key
              - name: AWS_DEFAULT_REGION
                value: "<Your S3 Bucket Region>"
              - name: AWS_BUCKET_NAME
                value: "<Your S3 Bucket Name>"
              - name: AWS_BUCKET_BACKUP_PATH
                value: "<Your S3 Bucket Backup Path>"
              - name: TARGET_DATABASE_HOST
                value: "<Your Target Database Host>"
              - name: TARGET_DATABASE_PORT
                value: "<Your Target Database Port>"
              - name: TARGET_DATABASE_NAMES
                value: "<Your Target Database Name(s)>"
              - name: TARGET_DATABASE_USER
                value: "<Your Target Database Username>"
              - name: TARGET_DATABASE_PASSWORD
                     name: TARGET_DATABASE_PASSWORD
                     key: database_password
              - name: SLACK_ENABLED
                value: "<true/false>"
              - name: SLACK_CHANNEL
                value: "#chatops"
              - name: SLACK_WEBHOOK_URL
                     name: SLACK_WEBHOOK_URL
                     key: slack_webhook_url
          restartPolicy: Never
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