README-docker.md

Docker strategy

Where to store data

Available options

• In container (default)
  • Cons:
    • not reliable: data loss on container re-creation
    • hard to use: not easy to read/write data
• In docker volume
  • Cons:
    • hard to use: not easy to read/write data
• In mounted folder
  • Cons:
    • pollutes work folder
    • issues with permissions in mounted folder

Based on considerations above we chose to use named local volumes.

This is how it looks:

$ docker volume ls
DRIVER    VOLUME NAME
local     cmltemplate-mongo_mongo_configdb
local     cmltemplate-mongo_mongo_data
local     cmltemplate-rabbit_rabbit_data

(In real usage it will be real_project_name instead of cmltemplate).

If you want to reach physical location of a volume's data just do

cd "$(docker volume inspect cmltemplate-mongo_mongo_data \
    | jq -r '.[0].Mountpoint')"

You might need sudo though to access the files.

Services configuration

We considered an approach to map the config files of a service to the host folder for ease of change. But this causes more complexity than we want:

• Aforementioned permissions issues
• Unneeded flexibility that can be unsustainable

So instead it's better to try to configure the services via it's .yml file:

• environment vars
• command (i.e. see how we've set up the slow log for mysql)

One .yml file vs many

TODO, see https://stackoverflow.com/questions/30233105/docker-compose-up-for-only-certain-containers

Recipes

List

docker ps        # list running containers
docker ps -a     # list all containers
docker volume ls # list volumes

Clear all

DANGER!!! USE WITH CARE!!! THIS WILL CAUSE DATA LOSS!!!

# rm all containers
docker rm -f $(docker ps -a -q)
 
# rm all volumes
docker volume rm $(docker volume ls -q)