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I'm running a ruby on rails application in docker container. I want to create and then restore the database dump in postgres container. But I'm

Below is what I've done so far:

1) Added bash script in /docker-entrypoint-initdb.d folder. Script is just to create database:

psql -U docker -d postgres -c 'create database dbname;'

RESULT: Database created but rails server exited with code 0. Error: web_1 exited with code 0

2) Added script to be executed before docker-compose up.

# Run docker db container
echo "Running db container"
docker-compose run -d db

# Sleep for 10 sec so that container have time to run
echo "Sleep for 10 sec"
sleep 10

echo 'Copying db_dump.gz to db container'
docker cp db_dump/db_dump.gz $(docker-compose ps -q db):/

# Create database `dbname`
echo 'Creating database `dbname`'
docker exec -i $(docker-compose ps -q db) psql -U docker -d postgres -c 'create database dbname;'

echo 'importing database `dbname`'
docker exec -i $(docker-compose ps -q db) bash -c "gunzip -c /db_dump.gz | psql -U postgres dbname"

RESULT: Database created and restored data. But another container runs while running web application server using docker-compose up.

docker--compose.yml:

version: '2'

services:

  db:
    image: postgres

    environment:
      - POSTGRES_PASSWORD=docker
      - POSTGRES_USER=docker

  web:
    build: .
    command: bundle exec rails s -p 3000 -b '0.0.0.0' -d
    image: uname/application
    links:
      - db
    ports:
      - "3000:3000"
    depends_on:
      - db
    tty: true

Can some one please help to create and import database?

EDIT:

I've tried one more approach by adding POSTGRES_DB=db_name environment variable in docker-compose.yml file so that database will be created and after running the application (docker-compose up), I'll import the database. But getting an error: web_1 exited with code 0.

I'm confused why I'm getting this error (in first and third approach), seems to be something is messed up in docker-compose file.

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1
  • what is the db host u have put in web container..?. host should be db. and can u check docker web logs cause exit status 0 mean success(it does it things and exited) docker-compose logs web Commented Jan 3, 2017 at 19:01

4 Answers 4

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5
+50

Set up a database dump mount

You'll need to mount the dump into the container so you can access it. Something like this in docker-compose.yml:

db:
  volumes:
    - './db_dump:/db_dump'

Make a local directory named db_dump and place your db_dump.gz file there.

Start the database container

Use POSTGRES_DB in the environment (as you mentioned in your question) to automatically create the database. Start db by itself, without the rails server.

docker-compose up -d db

Import data

Wait a few seconds for the database to be available. Then, import your data.

docker-compose exec db gunzip /db_dump/db_dump.gz
docker-compose exec db psql -U postgres -d dbname -f /db_dump/db_dump.gz
docker-compose exec db rm -f /db_dump/db_dump.gz

You can also just make a script to do this import, stick that in your image, and then use a single docker-compose command to call that. Or you can have your entrypoint script check whether a dump file is present, and if so, unzip it and import it... whatever you need to do.

Start the rails server

docker-compose up -d web

Automating this

If you are doing this by hand for prep of a new setup, then you're done. If you need to automate this into a toolchain, you can do some of this stuff in a script. Just start the containers separately, doing the db import in between, and use sleep to cover any startup delays.

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4 Comments

Unfortunately, getting same error, exited with code 0. Not sure what this error mean. :( I'm getting the same error, even if I've only provided the database name env variable in docker-compose.yml (POSTGRES_DB).
@AtulKhanduri Can you have the rails app output logs or some kind of debugging? It's your web container that is exiting, but it is impossible to say what is wrong without seeing what the rails app is saying. You can also try docker-compose logs web to see what the web container output.
@AtulKhanduri Also the Dockerfile used to build your web container would be helpful for people trying to decipher this problem. Please add it to your question text.
Thanks Dan. Although this answer is not the actual solution of my problem but it helped me. So, I've awarded 50 bounty to you. I've also added my solution.
2 
web_1 exited with code 0

Did you tried check the log of web_1 container? docker-compose logs web

I strongly recommend you don't initialize your db container manually, make it automatically within the process of start container.

Look into the entrypoint of postgres, we could just put the db_dump.gz into /docker-entrypoint-initdb.d/ directory of the container, and it will be automatic execute, so docker-compose.yml could be:

db:
  volumes:
    - './initdb.d:/docker-entrypoint-initdb.d'

And put your db_dump.gz into ./initdb.d on your local machine.

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1 Comment

Thanks Shawyeok. I already tried to put a script in docker-entrypoint-initdb.d folder but it shows the same error. Although I've found the solution added above.
1

When you use command docker-compose run -d db

you run a separate container it means you are running 3 containers where 1 is application 2 are dbs. The container you run using above command will not be a part of service. compose is using separate db.

So instead of running docker-compose up -d db run docker-compose up -d and continue with your script

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8 Comments

I replaced docker-compose up -d db to run docker-compose up -d, database successfully created, but web server exited with code 0. Same error as I'm getting in my 1st approach (using script inside docker-entrypoint-initdb.d folder).
is your data size is more than or around 10 GB? Docker containers do not hold more than 10 GB data without volume map
No, it's just around 300MB. Although, I'm just creating the database for now, not importing dump.
without creating data base , just run docker-compose up -d command only. Is it exit ? if not user docker exec -it containerid /bin/bash try it manually.
Without creating the database and running docker-compose up will crash the app server as database is not created yet.
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1

I got it working by adding a container_name for db container. My db container have different name (app_name_db_1) and I was connecting to a container named db.

After giving the hard-coded container_name (db), it gets working.

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6 Comments

Interesting. Were you running your other container outside of docker-compose? If they were both run from the same docker-compose.yml, then the db container should have been available as db. But if not, then things get more complicated.
I'm running that from the same docker-compose.yml. From database import script, I'm running the db container using docker-compose up -d db and then after import. I'm running we server by docker-compose up.
Also I'm curious to know if its okay to give a hard-coded container_name? I've heard somewhere that its not a good practice.
In docker-compose it is probably considered bad practice because of the auto-scaling (that's the _1 suffix; scaling up you would get _2 and so on to add more containers).. but if you are running only one it probably doesn't make much of a difference.
You may want to review this answer I wrote for another question. Specifically the part about adding a docker network and telling docker-compose.yml to use it. I wonder if it would solve your problem (without needing to specify the container names).
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