Docker commands
Basically Docker is a tool to package an application with its operating system, creating a VM-like image, and run it in so-called "containers".
It improves the resource usage because it allows to run multiple containers within a single VM, so you do not need to allocate a whole VM for a single service.
Docker disk images are smaller than VM's ones, because the operating system packaged with the application is "just enough" to run the application. No need to provide administrative tools, user interfaces, and so on.
Also, disk images are "layered" and a layer can be shared among multiple images. You can have for example an operating system core reused between multiple different images and save a lot of space.
Ideally each container should run only one application. An application in a docker container is run like a process, not like a VM, with less overhead, so there is minor cpu consumption and less idle states.
Also the memory used in a VM is shared between the various containers, resulting in way less memory consumption (and much more memory reuse).
List all Docker Images
docker images -a
List All Running Docker Containers
docker ps
List All Docker Containers
docker ps -a
Start a Docker Container
docker start <container name>
Stop a Docker Container
docker stop <container name>
Kill All Running Containers
docker kill $(docker ps -q)
View the logs of a Running Docker Container
docker logs <container name>
Delete All Stopped Docker Containers
Use -f option to nuke the running containers too.
docker rm $(docker ps -a -q)
Remove a Docker Image
docker rmi <image name>
Delete All Docker Images
docker rmi $(docker images -q)
Delete All Untagged (dangling) Docker Images
docker rmi $(docker images -q -f dangling=true)
Delete All Images
docker rmi $(docker images -q)
Remove Dangling Volumes
docker volume rm -f $(docker volume ls -f dangling=true -q)
SSH Into a Running Docker Container
sudo docker exec -it <container name> bash
Use Docker Compose to Build Containers Run from directory of your docker-compose.yml file.
docker-compose build
Use Docker Compose to Start a Group of Containers Use this command from directory of your docker-compose.yml file.
docker-compose up -d
This will tell Docker to fetch the latest version of the container from the repo, and not use the local cache.
docker-compose up -d --force-recreate
This can be problematic if you’re doing CI builds with Jenkins and pushing Docker images to another host, or using for CI testing. I was deploying a Spring Boot Web Application from Jekins, and found the docker container was not getting refreshed with the latest Spring Boot artifact.
#stop docker containers, and rebuild
docker-compose stop -t 1
docker-compose rm -f
docker-compose pull
docker-compose build
docker-compose up -d
#stop docker containers, and rebuild
docker-compose stop -t 1
docker-compose rm -f
docker-compose pull
docker-compose build
docker-compose up -d
Follow the Logs of Running Docker Containers With Docker Compose
docker-compose logs -f
Save a Running Docker Container as an Image
docker commit <image name> <name for image>
Follow the logs of one container running under Docker Compose
docker-compose logs pump <name>
