devops: A Dockerfile repository from sudipstha08

Docker is an open platform for developing, shipping, and running applications.
enables you to separate your applications from your infrastructure so you can deliver software quickly.
With Docker, you can manage your infrastructure in the same ways you manage your applications.
provides the ability to package and run an application in a loosely isolated environment called a container.
The isolation and security allow you to run many containers simultaneously on a given host

Container

a container is simply another process on your machine that has been isolated from all other processes on the host machine. It has its own process, network and mounts

sudo docker run docker/whalesay cowsay boo
docker run -> run a container from an image if already exits otherwise gets it form docker hub
docker ps - list all running containers
docker ps -a -> list all containers
docker stop container_name
docker rm container_name - remove the container
docker images -> list all docker images
sudo docker rmi image_name -> remove image
docker pull nginx -> only pulls the image and not run the container
docker run ubuntu sleep 5
docker exec
docker exec -it CONTAINER_ID /bin/sh
docker run redis:4.0 -> run specific version
docker run -i container_name -> for interactive mode
docker run -it container_name -> for interactive mode plus tunnel
docker run -p 8306:3306 mysql -> PORT mapping to run multiple
docker build Dockerfile
docker inspect
docker login private-registry.io
docker run --cpus=.5 ubuntu -> limits cpu usage to 50%
docker run --memory=100m ubuntu -> limits memoru usage to 100MB
docker-compose up
docker build -t myapp ./
docker volume create vol_name
docker run -- mount source=shared-stuff, target=/stuff

- docker run -d -p 5000:5000 --name registry registry:2
- docker image tag my-image localhost:5000/my-image
- docker push localhost:5000/my-image

When docker build image, it builds in a layered architecture. Each line of instructions in a Dockerfile creates a new layer

Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration