Docker Notes

docker_notes.md

Docker Notes

Images

• templates used to create containers that have no state and never change

• created with the docker build command

• composed of layers of other images

• Ex:

docker run hello-world

When you run this command the docker engine does the following:

1. checked to see if you had hello-world image
2. if not it downloads it from Docker Hub
3. loaded the image into the container and ran it

Containers

Dockerfile

Docker Ports

When you run a container with the -p command Docker Mac will make the container available on local host. So for example:

docker run -it --rm -p 3000:8080 tomcat:8.0

OR

docker run -it --rm -p 3000:80 nginx

Detached Mode

Use the -d to run the container in the background (as a daemon)

Example:

docker run -d -p 3000:80 nginx

This runs nginx in the background and gives us the container ID. We can do things like:

docker logs {container_id} to see the logs for the container. The logs for the nginx would look something like this:

afari/537.36" "-"
172.17.0.1 - - [25/Mar/2017:17:04:09 +0000] "GET / HTTP/1.1" 304 0 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.110 Safari/537.36" "-"

Basic Docker commands

• docker images - lists all images
• docker rmi {image_id} - remove a specific image
• docker ps - lists running containers
• docker ps -a - list all containers including ones that previously ran
• docker inspect - gives info on a container or image

Docker Inspect Example:

• docker run -d busybox:1.24 sleep 100 - this runs the docker container in detached mode (-d) and returns the container id (ex: 984382f4122acb209dd57bb675b169106f106bf982ebd53be3870ada03082817)
• container inspect {container_id} - this returns an array with json data about the container. You can do the same thing with a docker image id. Gives you things like the container IP & MacAddress, image id, and log path