Docker command

To list of all the local images

docker images

The docker ps command only shows running containers by default.

To see all containers, use the -a (or --all) flag:

docker ps -a

To create a container and kick start it

docker run -it -v {/path/to/your/project/directory/or/home/directory}:{docker/container/path/} -p 9012:9012 {image_name}

• -i - interactive shell, as in command line access to the container
• -t - terminal, or tty
• -v - the volume path - the first in the host path, that is the local system path that you want the docker container to map to : - the next part is the path inside the container that you wish to login to directly
• -p - this is the port forwarding for the container from the local or host machine.
• {image_name} - is the docker image that you want to run and get access

After successfully running this command you will get inside the container to the specified path. You can either exit the container and stop it or you can Ctrl+D to leave it running and exit. To make this sure you need to run the previous docker ps to check if it is running

To start a container that is in Existed state

First you need get the CONTAINER ID

docker ps -a

Check the output:

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                    PORTS                              NAMES
29a462eea79c        ubuntu          "/bin/bash"         4 days ago          Exited (255) 3 days ago   0.0.0.0:9010-9012->9010-9012/tcp   ubuntu

Use the CONTAINER ID along with it to start the container

docker start 29a462eea79c

To get access to the started or already running container you need to:

docker attach 29a462eea79c

This will lead you the same thing as you get after use the docker run

To stop a running container you need to:

docker stop 29a462eea79c

To delete the created docker container you need to:

docker rm 29a462eea79c

Lets consider you need to create a container, customised for your own project. You have to create a Dockerfile which will have a basic setup ready for you to use when you login into that container. Giving an example of installing and running a basic Python application

Open a new file named Dockerfile in any Editor. Paste the content given below:

# Download base image ubuntu 18.04
FROM ubuntu:18.04

# Most important of all give this your own name
MAINTAINER adityakarnik

# This will give you all the latest updates and required packages to start
RUN apt-get update \
	&& apt-get install -my wget gnupg \
	&& apt-get install -y --no-install-recommends \
		apt-utils \
		ca-certificates \
		apt-transport-https \
		jq \
		numactl \
&& rm -rf /var/lib/apt/lists/*

RUN apt-get update

# Installing python and its dependencies
RUN apt-get install -y python-pip python-dev build-essential

# Copy the local folder of your app to docker container
# Consider this app folder in placed in the same folder as your Dockerfile
COPY app/ /app

# Navigate to yoru app directory
WORKDIR /app

# Install you application dependencies
RUN pip install -r requirements.txt

# This will the command run when you start your container
ENTRYPOINT ["python"]

# Like "python app.py", this will run when you start your container
CMD ["app.py"]

Creating the Dockerfile

docker build --no-cache -t python .

Running the created container

docker run -p 5000:5000 --name python python

Removing the images and all the containers

sudo docker rm $(sudo docker ps -a -q) && sudo docker rmi $(sudo docker images -q)

Now Consider you have made a some changes to your environment and you need to deploy the same currently working docker to another system or make a clone of it as test environment. You will need to commit the docker

Committing the current state of the container:

docker commit 4cb998fee815 <give_it_a_name>

Creating a zip file of the container:

docker save -o <file_name.tar> <the_given_name>

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