t0mk/docker-pg-backup

A cron job that will back up databases running in a docker postgres container

Docker PG Backup

A simple docker container that runs PostGIS backups. It is intended to be used primarily with our docker postgis docker image. By default it will create a backup once per night (at 23h00)in a nicely ordered directory by year / month.

• Visit our page on the docker hub at: https://registry.hub.docker.com/u/kartoza/pg-backup/
• Visit our page on github at: https://github.com/kartoza/docker-pg-backup

Getting the image

There are various ways to get the image onto your system:

The preferred way (but using most bandwidth for the initial image) is to get our docker trusted build like this:

docker pull kartoza/pg-backup:latest
docker pull kartoza/pg-backup:9.4
docker pull kartoza/pg-backup:9.3

We highly suggest that you use a tagged image (9.4 or 9.3 currently available) as latest may change and may not successfully back up your database. Use the same or greater version of postgis as the database you are backing up.

To build the image yourself without apt-cacher (also consumes more bandwidth since deb packages need to be refetched each time you build) do:

docker build -t kartoza/pg-backups .

If you do not wish to do a local checkout first then build directly from github.

git clone git://github.com/kartoza/docker-postgis

Run

To create a running container do:

docker run --name="backups"\
           --hostname="pg-backups" \
           --link=watchkeeper_db_1:db \
           -v backups:/backups \
           -i -d kartoza/pg-backup:9.4

In this example I used a volume into which the actual backups will be stored.

Specifying environment

You can also use the following environment variables to pass a user name and password etc for the database connection.

• PGUSER if not set, defaults to : docker
• PGPASSWORD if not set, defaults to : docker
• PGPORT if not set, defaults to : 5432
• PGHOST if not set, defaults to : db
• PGDATABASE if not set, defaults to : gis

Example usage:

docker run -e PGUSER=bob -e PGPASSWORD=secret -link db -i -d kartoza/pg-backup

One other environment variable you may like to set is a prefix for the database dumps.

• DUMPPREFIX if not set, defaults to : PG

Example usage:

docker run -e DUMPPREFIX=foo -link db -i -d kartoza/pg-backup

Here is a more typical example using docker-composer (formerly known as fig):

For docker-compose.yml:

db:
  image: kartoza/postgis:9.4-2.1
  volumes:
    - ./pg/postgres_data:/var/lib/postgresql
    - ./pg/setup_data:/home/setup
  environment:
    - USERNAME=docker
    - PASS=docker

dbbackups:
  image: kartoza/pg-backup:9.4
  hostname: pg-backups
  volumes:
    - ./backups:/backups
  links:
    - db:db
  environment:
    - DUMPPREFIX=PG_YOURSITE
    # These are all defaults anyway, but setting explicitly in
    # case we ever want to ever use different credentials
    - PGUSER=docker
    - PGPASSWORD=docker
    - PGPORT=5432
    - PGHOST=db
    - PGDATABASE=gis  

Then run using:

docker-compose up -d dbbackup

Credits

Tim Sutton (tim@kartoza.com) April 2015