Docker: Run commands from multiple containers

Question

I want to execute a command that uses commands from multiple containers.

E.g., I want to execute a backup script that used psql and pg_dump commands.

docker exec db_backup pg_dump
failed to exec: exec: "pg_dump": executable file not found in $PATH

docker run has an option --link. Is there a similar option for exec?

To clear this up, there are 3 containers:

I want to use pg commands located in db from my db_backup scripts.

my_app is a running application that is using db container. — Vanuan
– Vanuan, Commented Jan 17, 2015 at 23:22

dukebody · Accepted Answer · 2015-01-18 14:20:53Z

1

There is not --link option for docker exec. If you want to backup using a special script:

Create a new image db_backup starting from the postgresql one (the one that the db container uses), adding the backup script to some folder.
Do docker run --volumes-from db db_backup your_backup_script.sh.

answered Jan 18, 2015 at 14:20

dukebody

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Comments

Jiri Kremser · Accepted Answer · 2015-01-17 22:43:55Z

0

1) go to the db shell by using sudo docker run -ti db /bin/bash

2) type which pg_dump or locate pg_dump if the first fails

3) use the full path in your command sudo docker exec db /full_path_to/pg_dump

run the 3) inside your db container

note: on my Fedora the pg_dump points to /usr/bin/pg_dump

answered Jan 17, 2015 at 22:09

Jiri Kremser

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There is no pg command in backup container. pg command is located in "db" container.

But I want to run pg_dump from db_backup container.

I.e. I want a backup script to be in a separate container.