vimalgandhi / repository

Docker-Commands-Help-Tips

# Docker Commands, Help & Tips ### Show commands & management commands ``` $ docker ``` ### Docker version info ``` $ docker version ``` ### Show info like number of containers, etc ``` $ docker info ``` # WORKING WITH CONTAINERS ### Create an run a container in foreground ``` $ docker container run -it -p 80:80 nginx ``` ### Create an run a container in background ``` $ docker container run -d -p 80:80 nginx ``` ### Shorthand ``` $ docker container run -d -p 80:80 nginx ``` ### Naming Containers ``` $ docker container run -d -p 80:80 --name nginx-server nginx ``` ### TIP: WHAT RUN DID - Looked for image called nginx in image cache - If not found in cache, it looks to the default image repo on Dockerhub - Pulled it down (latest version), stored in the image cache - Started it in a new container - We specified to take port 80- on the host and forward to port 80 on the container - We could do "$ docker container run --publish 8000:80 --detach nginx" to use port 8000 - We can specify versions like "nginx:1.09" ### List running containers ``` $ docker container ls ``` OR ``` $ docker ps ``` ### List all containers (Even if not running) ``` $ docker container ls -a ``` ### Stop container ``` $ docker container stop [ID] ``` ### Stop all running containers ``` $ docker stop $(docker ps -aq) ``` ### Remove container (Can not remove running containers, must stop first) ``` $ docker container rm [ID] ``` ### To remove a running container use force(-f) ``` $ docker container rm -f [ID] ``` ### Remove multiple containers ``` $ docker container rm [ID] [ID] [ID] ``` ### Remove all containers ``` $ docker rm $(docker ps -aq) ``` ### Get logs (Use name or ID) ``` $ docker container logs [NAME] ``` ### List processes running in container ``` $ docker container top [NAME] ``` #### TIP: ABOUT CONTAINERS Docker containers are often compared to virtual machines but they are actually just processes running on your host os. In Windows/Mac, Docker runs in a mini-VM so to see the processes youll need to connect directly to that. On Linux however you can run "ps aux" and see the processes directly # IMAGE COMMANDS ### List the images we have pulled ``` $ docker image ls ``` ### We can also just pull down images ``` $ docker pull [IMAGE] ``` ### Remove image ``` $ docker image rm [IMAGE] ``` ### Remove all images ``` $ docker rmi $(docker images -a -q) ``` #### TIP: ABOUT IMAGES - Images are app bianaries and dependencies with meta data about the image data and how to run the image - Images are no a complete OS. No kernel, kernel modules (drivers) - Host provides the kernel, big difference between VM ### Some sample container creation NGINX: ``` $ docker container run -d -p 80:80 --name nginx nginx (-p 80:80 is optional as it runs on 80 by default) ``` APACHE: ``` $ docker container run -d -p 8080:80 --name apache httpd ``` MONGODB: ``` $ docker container run -d -p 27017:27017 --name mongo mongo ``` MYSQL: ``` $ docker container run -d -p 3306:3306 --name mysql --env MYSQL_ROOT_PASSWORD=123456 mysql ``` ## CONTAINER INFO ### View info on container ``` $ docker container inspect [NAME] ``` ### Specific property (--format) ``` $ docker container inspect --format '{{ .NetworkSettings.IPAddress }}' [NAME] ``` ### Performance stats (cpu, mem, network, disk, etc) ``` $ docker container stats [NAME] ``` ## ACCESSING CONTAINERS ### Create new nginx container and bash into ``` $ docker container run -it --name [NAME] nginx bash ``` - i = interactive Keep STDIN open if not attached - t = tty - Open prompt **For Git Bash, use "winpty"** ``` $ winpty docker container run -it --name [NAME] nginx bash ``` ### Run/Create Ubuntu container ``` $ docker container run -it --name ubuntu ubuntu ``` **(no bash because ubuntu uses bash by default)** ### You can also make it so when you exit the container does not stay by using the -rm flag ``` $ docker container run --rm -it --name [NAME] ubuntu ``` ### Access an already created container, start with -ai ``` $ docker container start -ai ubuntu ``` ### Use exec to edit config, etc ``` $ docker container exec -it mysql bash ``` ### Alpine is a very small Linux distro good for docker ``` $ docker container run -it alpine sh ``` (use sh because it does not include bash) (alpine uses apk for its package manager - can install bash if you want) # NETWORKING ### "bridge" or "docker0" is the default network ### Get port ``` $ docker container port [NAME] ``` ### List networks ``` $ docker network ls ``` ### Inspect network ``` $ docker network inspect [NETWORK_NAME] ("bridge" is default) ``` ### Create network ``` $ docker network create [NETWORK_NAME] ``` ### Create container on network ``` $ docker container run -d --name [NAME] --network [NETWORK_NAME] nginx ``` ### Connect existing container to network ``` $ docker network connect [NETWORK_NAME] [CONTAINER_NAME] ``` ### Disconnect container from network ``` $ docker network disconnect [NETWORK_NAME] [CONTAINER_NAME] ``` ### Detach network from container ``` $ docker network disconnect ``` # IMAGE TAGGING & PUSHING TO DOCKERHUB # tags are labels that point ot an image ID ``` $ docker image ls ``` Youll see that each image has a tag ### Retag existing image ``` $ docker image tag nginx btraversy/nginx ``` ### Upload to dockerhub ``` $ docker image push bradtraversy/nginx ``` ### If denied, do ``` $ docker login ``` ### Add tag to new image ``` $ docker image tag bradtraversy/nginx bradtraversy/nginx:testing ``` ### DOCKERFILE PARTS - FROM - The os used. Common is alpine, debian, ubuntu - ENV - Environment variables - RUN - Run commands/shell scripts, etc - EXPOSE - Ports to expose - CMD - Final command run when you launch a new container from image - WORKDIR - Sets working directory (also could use 'RUN cd /some/path') - COPY # Copies files from host to container ### Build image from dockerfile (reponame can be whatever) ### From the same directory as Dockerfile ``` $ docker image build -t [REPONAME] . ``` #### TIP: CACHE & ORDER - If you re-run the build, it will be quick because everythging is cached. - If you change one line and re-run, that line and everything after will not be cached - Keep things that change the most toward the bottom of the Dockerfile # EXTENDING DOCKERFILE ### Custom Dockerfile for html paqge with nginx ``` FROM nginx:latest # Extends nginx so everything included in that image is included here WORKDIR /usr/share/nginx/html COPY index.html index.html ``` ### Build image from Dockerfile ``` $ docker image build -t nginx-website ``` ### Running it ``` $ docker container run -p 80:80 --rm nginx-website ``` ### Tag and push to Dockerhub ``` $ docker image tag nginx-website:latest btraversy/nginx-website:latest ``` ``` $ docker image push bradtraversy/nginx-website ``` # VOLUMES ### Volume - Makes special location outside of container UFS. Used for databases ### Bind Mount -Link container path to host path ### Check volumes ``` $ docker volume ls ``` ### Cleanup unused volumes ``` $ docker volume prune ``` ### Pull down mysql image to test ``` $ docker pull mysql ``` ### Inspect and see volume ``` $ docker image inspect mysql ``` ### Run container ``` $ docker container run -d --name mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=True mysql ``` ### Inspect and see volume in container ``` $ docker container inspect mysql ``` #### TIP: Mounts - You will also see the volume under mounts - Container gets its own uniqe location on the host to store that data - Source: xxx is where it lives on the host ### Check volumes ``` $ docker volume ls ``` **There is no way to tell volumes apart for instance with 2 mysql containers, so we used named volumes** ### Named volumes (Add -v command)(the name here is mysql-db which could be anything) ``` $ docker container run -d --name mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=True -v mysql-db:/var/lib/mysql mysql ``` ### Inspect new named volume ``` docker volume inspect mysql-db ``` # BIND MOUNTS - Can not use in Dockerfile, specified at run time (uses -v as well) - ... run -v /Users/brad/stuff:/path/container (mac/linux) - ... run -v //c/Users/brad/stuff:/path/container (windows) **TIP: Instead of typing out local path, for working directory use $(pwd):/path/container - On windows may not work unless you are in your users folder** ### Run and be able to edit index.html file (local dir should have the Dockerfile and the index.html) ``` $ docker container run -p 80:80 -v $(pwd):/usr/share/nginx/html nginx ``` ### Go into the container and check ``` $ docker container exec -it nginx bash $ cd /usr/share/nginx/html $ ls -al ``` ### You could create a file in the container and it will exiost on the host as well ``` $ touch test.txt ``` # DOCKER COMPOSE - Configure relationships between containers - Save our docker container run settings in easy to read file - 2 Parts: YAML File (docker.compose.yml) + CLI tool (docker-compose) ### 1. docker.compose.yml - Describes solutions for - containers - networks - volumes ### 2. docker-compose CLI - used for local dev/test automation with YAML files ### Sample compose file (From Bret Fishers course) ``` version: '2' # same as # docker run -p 80:4000 -v $(pwd):/site bretfisher/jekyll-serve services: jekyll: image: bretfisher/jekyll-serve volumes: - .:/site ports: - '80:4000' ``` ### To run ``` docker-compose up ``` ### You can run in background with ``` docker-compose up -d ``` ### To cleanup ``` docker-compose down ```