Another year, another euskalencounter.org 🙂 This year I’ve binge watched Altered Carbon, and katakoda’s Docker training, below is my cheat sheet for future reference.

1. docker search java
   1. search for a docker image (java in this case)
2. running a docker image
   1. docker run -d openjdk
      1. run detached (-d) the openjdk docker
   2. docker run -d –name redisHostPort -p 6379:6379 redis:latest
      1. –name creates a user friendly name for your running docker
      2. -p <machine host-port:container-port> exposes docker image port in the host port
      3. redis:latest is the docker image:the version
   3. docker run -d –name redisDynamic -p 6379 redis:latest
      1. -p 6379 assigns a random host port
   4. docker port redisDynamic 6379
      1. shows to which host ip:port is docker running image redisDynamic’s port 6379 is assigned
   5. docker run -d –name redisMapped -v /opt/docker/data/redis:/data redis
      1. -v host-path:docker-path maps a docker path to a host path in order to persist data
   6. docker run -it ubuntu bash
      1. -it runs an interactive docker image.
      2. you can run a specific command on the docker image (bash)
   7. docker run -d –name my-production-running-app -e NODE_ENV=production -p 3000:3000 my-nodejs-app
      1. -e VARIABLE=value sets an environment variable in the running container
3. How to run a command inside a running container
   1. docker exec -d ubuntu_bash touch /tmp/execWorks
4. How to create docker data volumes
   1. Create a new container to start it afterwards (instead of running it directly) this is useful mainly to create data storage dockers and use them from other images.
   2. docker create -v /data –name dataContainer ubuntu
   3. docker run –rm –volumes-from dataContainer ubuntu ls -la /data
   4. docker cp config.conf dataContainer:/config/
      1. copies file config.com from the host to the docker container
   5. to move data containers from one machine to another you can export/import them to .tar
      1. docker export dataContainer > dataContainer.tar
      2. docker import dataContainer.tar
      3. docker import http://example.com/exampleimage.tgz
5. How to create a network between containers
   1. docker network create backend-network
      1. creates a network to which we can attach containers. Docker sets a dns server in ip 127.0.0.11 and all connected containers use it by docker adding it to resolv.conf on each container
   2. docker network connect frontend-network redis
      1. connects a container to a network
   3. docker network connect –alias db frontend-network2 redis
      1. –alias <alias_name> creates an alias for the network name
   4. docker network ls
      1. shows all networks
   5. docker network inspect frontend-network
      1. shows all containers connected to a network and their ip addresses
   6. docker network disconnect frontend-network redis
      1. disconnect a container from a network
   7. docker run -d –name=redis –net=backend-network redis
      1. launches a redis container linked to the network backend-network.
6. Building a docker image
   1. docker build -t webserver-image:v1 .
      1. -t <image name:tag> is used to give a name and version to the image.
      2. in the . directory you need to create a file called Dockerfile with yaml notation
   2. .dockerignore
      1. echo passwords.txt >> .dockerignore
         1. all fine names included into file .dockerignore will be ignored when building the image
   3. Dockerfile
      1. FROM nginx:alpine
         1. uses nginx:alpine as base for this docker image
      2. COPY . /usr/share/nginx/html
         1. copies from the host to the image
      3. FROM node:7-alpine
      4. RUN mkdir -p /src/app
         1. RUN’s command inside the docker image
      5. WORKDIR /src/app
         1. set the working directory in the docker image
      6. EXPOSE 3000
         1. EXPOSEs the port from the docker image to a random port in the host system
      7. CMD [ “npm”, “start” ]
         1. runs a command in the docker image you can add parameters as items of the array
      8. ONBUILD COPY . /usr/src/app
         1. onbuild commands won’t be executed until the built image is used as a base image
   4. docker images
      1. returns a list of images installed in the host system
7. removing a docker image
   1. docker container ls -a
      1. lists all containers (running or not)
   2. docker container rm < CONTAINER ID>
      1. removes the container
   3. docker rmi hello-world
      1. removes image hello-world
8. docker ps
   1. show docker processes
9. docker inspect openjdk
   1. show details of running docker
10. docker logs openjdk
    1. shows logs for running docker