How to generate a Postgresql Dump from a Docker container?

Question

I would like to have a way to enter into the Postgresql container and get a data dump from it.

Answer 1

Use the following command from a UNIX terminal:

docker exec <container_name> pg_dump <schema_name> > backup

The following command will dump only inserts from all tables:

docker exec <container_name> pg_dump --column-inserts --data-only  <schema_name> > inserts.sql

Answer 2

To run the container that has the Postgres user and password, you need to have preconfigured variables as container environment variable. For example:

docker run -it --rm --link <container_name>:<data_container_name> -e POSTGRES_PASSWORD=<password> postgres /usr/bin/pg_dump -h <data_container_name> -d <database_name> -U <postgres_username> > dump.sql

Answer 3

Another workaround method is to start postgre sql with a mountpoint to the location of the dump in docker.

like docker run -v <location of the files>. Then perform a docker inspect on the docker running container

docker inspect <image_id>

you can find "Volumes" tag inside and a corresponding location.Go to the location and you can find all the postgresql/mysql files.It worked for me.Let us know if that worked for you also.

Good luck

Answer 4

Although the mountpoint solution above looked promising, the following is the only solution that worked for me after multiple iterations:

docker run -it  -e PGPASSWORD=my_password postgres:alpine  pg_dump  -h hostname -U my_user my_db > backup.sql

What was unique in my case: I have a password on the database that needs to be passed in; needed to pass in the tag (alpine); and finally the hosts version of the psql tools were different to the docker versions.

Answer 5

I have container named postgres with mounted volume -v /backups:/backups

To backup gziped DB my_db I use:

docker exec postgres pg_dump -U postgres -F t my_db | gzip >/backups/my_db-$(date +%Y-%m-%d).tar.gz

Now I have

user@my-server:/backups$ ls
my_db-2016-11-30.tar.gz