Docker

Docker is a computer program that performs operating-system-level virtualization, also known as containerization. We use it to dockerize our different systems and let them run independently of each other, only talking through set ports.

Images

Itdagene DevOps revolve around docker images, both generic and self written. When everything is up and running all images should be running. All images are hosted at dockerhub.

Current images:

  • itdagene backend
  • webapp frontend
  • docs documentation
  • nginx static files hosting
  • metabase data colletion and visulazation
  • treafik reverse proxy
  • postgres main database
  • redis cache

If you want to pull a new image, use docker pull PATH_OF_IMAGE

When all images for itDAGENE are up and running, the command docker ps should give you something like this.

Output from docker ps (short version)

IMAGE                    COMMAND          PORTS                 NAMES
itdagene/webapp:prod     "yarn start"                           infra_webapp_1
itdagene/docs:prod       "yarn start"     3000/tcp, 35729/tcp   infra_docs_1
traefik                  "/traefik …"     0.0.0.0:80->80/tcp    infra_traefik_1
metabase/metabase        "/app/run …"     3000/tcp              infra_metabase_1
redis:latest             "docker-e …"     6379/tcp              infra_redis_1
nginx:alpine             "nginx -g …"     80/tcp                infra_nginx_1
itdagene/itdagene:prod   "gunicorn …"                           infra_itdagene_1
postgres:10.5-alpine     "docker-e …"     5432/tcp              infra_postgres_1

docker-compose

When starting and stopping itdagene we use something called docker-compose, which allowes us to state which services should run, and what variables, ports, and other configs should run. This is much more convient than starting and stopping each image, and applying configurations each time.

# Look for containers running with this docker-compose config
$ docker-compose ps

# Start all containers
$ docker-compose up -d

# Stop all containers
$ docker-compose kill
$ docker-compose down

# Restart all containers when they are running
$ docker-compose up -d --force-recreate

# Restart one container when it's running
$ docker-compose up -d --force-recreate <service>

If you've written some new code and the image is up on hub.docker.io you can pull that new image and recreate that container without running a full reboot of all containers.

$ docker-compose pull <service> # Pull the new version of the image
$ docker-compose up -d --force-recreate <service> # Recreate the container

You can find the name of a service by looking for the spesific entry in the docker-compose file.

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