Docker

You can download the docker engine for your specific OS from the dockerDocs

Also, you can download a docker image from the dockerhub.Search for an image you want to use.
Select the appropriate tag for your image(default of images is latest).
https://hub.docker.com/
An example of an image could be nginx. the command

docker pull nginx

gets you the image with the latest tag.

The output of this image would look like above.
Now we can create a container from an image.(A container is a running instance of an image)
To run an image we can use the command

docker run nginx:latest

 

To check if our container is running we use the command

docker container ls

This gives list of our running images(containers)

If we check the container section of our docker machine we can see our container running

When we check our running image(container) we can see there is a default name and the time the container started.

from our bash shell you can see the container is running we can stop the container with ctl+C. This stops the container and if we check the container list(docker container ls) we can see the container nginx does not show anymore.

The run command with -d
Implies running the image in detach mode which allows it not to hang in the bash. After it starts running we can see the containner
id on the last line.

docker ps
shows us all the docker processess running. and we can see our nginx is running with tag and default generated name

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Exposing Port

This allows our host to get access to docker instances in the docker machine.

to make sure our local host can get access to the running docker instance we need to stop our instance and rerun so that our local host can access
the running container. To do that we run

to run the container to match host port we run

docker run -p 8088:80 -d nginx:latest

This runs the container and we can access the container on port 8088 on our local host machine.

from the image we can see that our port is different. set to 8088.
we can open our browser to see that our container is running on our specified port.

we can match our docker container port to multiple ports on the local host by using -p again to specify multiple ports

docker run -p 8088:80 -p 8888:80 -d nginx:latest

accessing the localhost device browser on port 8088 or 8888 should display as before.
check the port column how multi ports were given

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Managing Containers

How to stop, remove start and name containers.

Stop Container

We can stop a running container with the command

docker stop [___container_name or containerID]

Start container

To start an existing container we can just use the container name to start the container

docker start hardcore_volhard

we have started the previous container we stopped again.

Delete container

We can also delete a container with the container id or the container name

docker rm [___container_name or containerID]

• we can also delete all docker containers
• check the docker ps options
• 

we can get all docker containers which are quite(not running)

• -a, --all Show all containers (default shows just running)
• -q, --quiet Only display container IDsdocker ps -aq
  

if we want to delete all these docker containers we can run

docker rm $(docker ps -aq)

to delete all the containers. NB: This command does not work for containers that are running.

well this situation can be overridden if we want to actually delete even running containers then we need to make it force.

docker rm -f $(docker ps -aq)

-f is used to force the command deletion.

Naming Containers

Using docker assigns a random name when we do not specify a name. example is when we created nginx

The way we give docker a name is by using --name [customName]

docker run -p 8088:80 -p 8888:80 --name customNginx -d nginx:latest

docker ps

would display our custom name given
Docker containers naming makes it easy to identify our containers and easy to manage a container.