docker_tutorial.md

My Docker Tutorial

https://conetix.com.au/blog/docker-basics-practical-starters-guide http://localhost/tutorial/ https://docs.docker.com/desktop/dashboard/
https://hub.docker.com/

Note, if you run the "getting-started" application as a docker container you can see a neat tutorial by docker at http://localhost/tutorial/. If you have docker desktop try running: docker run -d -p 80:80 --name docker-tutorial docker101tutorial

General tip: you can do:

docker image --help | less

man docker ps
docker ps -h | less
docker ps --help | less

to see information about each command (note that docker ps is a command). Note that Man usually opens a much more extensive description.

High level idea of docker workflow

Usual workflow: 0. way to create image (e.g. Dockerfile)

1. building the image
2. run the container/application from the image with a docker container
3. sharing/pushing the image to your hub

Example from the high lever idea

0. go to the section on how to build docker files (named Dockerfile). A Dockerfile is simply a text-based script of instructions that is used to create a container image.

1. build an image from a docker file Dockerfile in the current directory

docker build -t getting-started .

builds a docker image tagged/named (-t) getting-started. Now you can start run the application from the docker image as a docker container.

2. run the application as a docker container from the docker image

docker run -d -p 80:80 docker/getting-started

this runs an application as a docker container from the docker image docker/getting-started. The -d is the detached mode (runs in background). The -p map port 80 of the host to port 80 in the container. Note you can combine single character flags as follow: -dp. Note you can see your docker containers in the docker desktop or with docker ps -a. The flag -a is for all.

3. push image. Now save and share your image in Docker Hub (https://hub.docker.com/ I should have one under brandojazz):

	docker tag docker101tutorial brandojazz/docker101tutorial
	docker run -d -p 80:80 --name docker-tutorial docker101tutorial

the above allows you to run the docker tutorial at http://localhost/tutorial/.

Definitions

image = When running a container, it uses an isolated filesystem. This custom filesystem is provided by a container image. Since the image contains the container's filesystem, it must contain everything needed to run an application - all dependencies, configuration, scripts, binaries, etc. The image also contains other configuration for the container, such as environment variables, a default command to run, and other metadata. We'll dive deeper into images later on, covering topics such as layering, best practices, and more.

container = Now that you've run a container, what is a container? Simply put, a container is simply another process on your machine that has been isolated from all other processes on the host machine. That isolation leverages kernel namespaces and cgroups, features that have been in Linux for a long time. Docker has worked to make these capabilities approachable and easy to use.

docker file = instructions for how to build an image (todo get a docker def) https://docs.docker.com/develop/develop-images/dockerfile_best-practices/

Questions

Questions:

• what exactly is an image? does it have my data, code, filesystem? or does it just save the instructions - if yes how different from a Dockerfile?
• how does it have access to my source code? is it different to how it has access to data?
• does the saved image save the files/source code I need or do I have to gitclone it every time?
• docker docker ps vs docker dashboard
• how to use it with pip -e or conda develop? (sounds that each time we run it we copy the source files?)
• difference of docker file vs bash?
• docker vs singularity?
• python develop and docker: https://stackoverflow.com/questions/41048002/how-to-use-a-python-library-that-is-constantly-changing-in-a-docker-image-or-new
• How to mount host volumes into docker containers in Dockerfile during build http://stackoverflow.com/questions/26050899/how-to-mount-host-volumes-into-docker-containers-in-dockerfile-during-build
• dockerfile https://docs.docker.com/develop/develop-images/dockerfile_best-practices/

Running docker getting started tutorial

Docker getting started:

1. todo, what do I need to build an image? e.g. Docker file. A Dockerfile is simply a text-based script of instructions that is used to create a container image.

    TODO get cmd

2. build an image: A Docker image is a private file system just for your container. It provides all the files and code your container needs.

    docker run -d -p 80:80 --name docker-tutorial docker101tutorial

3. run container:

    docker run -d -p 80:80 --name docker-tutorial docker101tutorial

4. push image: Now save and share your image. Save and share your image on Docker Hub to enable other users to easily download and run the image on any destination machine.

    docker tag docker101tutorial brandojazz/docker101tutorial
	docker run -d -p 80:80 --name docker-tutorial docker101tutorial

then go here to see the getting started tutorial that your running in docker: http://localhost/tutorial/