Running docker-compose inside a Google Cloud Engine - docker-compose

Question

I'm trying to run a small docker-compose app inside a container-optimized Google Cloud Compute Engine node, but I'm getting stuck when it's trying to mount volumes during a docker-compose up:
Creating lightning_redis_1 ...
Creating lightning_db_1 ...
Creating lightning_redis_1
Creating lightning_db_1 ... done
Creating lightning_api_1 ...
Creating lightning_api_1 ... error
ERROR: for lightning_api_1 Cannot start service api: error while creating mount source path '/rootfs/home/jeremy/lightning': mkdir /rootfs: read-only file sys
tem
ERROR: for api Cannot start service api: error while creating mount source path '/rootfs/home/jeremy/lightning': mkdir /rootfs: read-only file system
Encountered errors while bringing up the project.
jeremy#instance-1 ~/lightning $
My docker-compose.yml file looks like this:
version: '3'
services:
client:
build: ./client
volumes:
- ./client:/usr/src/app
ports:
- "4200:4200"
- "9876:9876"
links:
- api
command: bash -c "yarn --pure-lockfile && yarn start"
sidekiq:
build: .
command: bundle exec sidekiq
volumes:
- .:/api
depends_on:
- db
- redis
- api
redis:
image: redis
ports:
- "6379:6379"
db:
image: postgres
ports:
- "5433:5432"
api:
build: .
command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
volumes:
- .:/myapp
ports:
- "3000:3000"
depends_on:
- db
I don't want to have to change anything in the docker-compose.yml file - I'd prefer to be able to fix this issue by running commands inside the VM itself, or in how I set the VM up. Reason being is it's not my code and I can't change the docker-compose.yml file easily, and all I need to do is run it for a short period of time and execute a few docker-compose commands inside the VM.

Answer 1

Container optimized OS usually mounts most of the paths as read-only. That is why you are getting the error
source path '/rootfs/home/jeremy/lightning': mkdir /rootfs: read-only file sys
So you have few options
Use named volumes in docker-compose
You will need to change your volumes like below
volumes:
- myappvol:/myapp
and define the top level volumes in compose
volumes:
myappvol: {}
As you said you don't want to modify the yaml then this may not work for you
Run docker-compose inside docker
Currently you run docker-compose on the main machine, instead you should use docker-compose inside another docker container which has the main root folder
docker run \
-v /var/run/docker.sock:/var/run/docker.sock \
-v "$PWD:/rootfs/$PWD" \
-w="/rootfs/$PWD" \
docker/compose:1.13.0 up
This would work but the data would be persisted inside the docker container itself.
See below article for more details
https://cloud.google.com/community/tutorials/docker-compose-on-container-optimized-os

Answer 2

I had the same error, I solved it by removing the 'rootfs' directory when mounting the docker container (you cannot write on this directory).
Just change:
docker run \
-v /var/run/docker.sock:/var/run/docker.sock \
-v "$PWD:/rootfs/$PWD" \
-w="/rootfs/$PWD" \
docker/compose:1.24.0 up
By:
docker run \
-v /var/run/docker.sock:/var/run/docker.sock \
-v "$PWD:$PWD" \
-w="$PWD" \
docker/compose:1.24.0 up
Add to the bottom of the file .bashrc file located /home/{your-user}/.bashrc using vi or nano:
e.g. nano /home/{your-user}/.bashrc
echo alias docker-compose="'"'docker run --rm \
-v /var/run/docker.sock:/var/run/docker.sock \
-v "$PWD:$PWD" \
-w="$PWD" \
docker/compose:1.24.0'"'" >> ~/.bashrc
CTRL O - will save
CTRL M - override
CTRL X - exit
Run: source ~/.bashrc - to update the terminal.