Introduction

Docker container management involves tasks such as creating, starting, stopping, and removing containers, as well as monitoring and troubleshooting container performance and health

Some Basic Commands Hands-on

docker

👉 This will show us some options that we can use and also some of the management commands

docker search hello-world

👉 This will search for the 'hello-world' images from dockerhub

docker pull hello-world

👉 This will pull the latest hello-world image from the dockerhub

docker images

👉 This will show us pulled images

docker run --name hello1 -it hello-world

👉 This command creates and starts a new Docker container using the hello-world image

💡 'hello1' is the container name and '-it' enables interactive mode but '-it' shouldn't be used as it is for developing or debugging only as it enables us to interact with the container's shell

In the above case, as the 'hello-world' image doesn't have any shell to be interacted with, it automatically pushes us back to our Linux terminal. To check any running container process

docker ps

👉 This will show us nothing as the 'hello1' container was stopped immediately

But we can see previous container using

docker ps -a

👉 This will show us 'hello1' container and at what time it exited

Now let's use the -d option to run a docker container

docker run --name hello2 -d hello-world

👉 This will show us the container ID and quit itself

💡 The 'hello-world' image is designed to automatically quit itself after its processing. -d option indicates the container to run in the background

If we want to delete these exited containers,

docker rm <first-four-digits-of-container-ID>

# OR

docker rm <container-name>

To remove the hello-world image

docker rmi hello-world

We can confirm this using docker images commmand

Next, we can try creating a container

docker create --name myWEB nginx:latest

👉 create command simply 'creates' the container and doesn't run it while the run command creates and run the container

💡 run is a shortcut for the docker create and docker start commands combined

We can also check the status using the ps -a that will show us the container status as 'Created'

docker start myWEB

👉 This will start the container and we can see the process using docker ps

What if we want to delete this container?

docker rm myWEB
Error response from daemon: You cannot remove a running container

We can either stop the container first and delete it or force delete it using

docker rm -f myWEB

Finally removing the nginx image

docker rmi nginx:latest

Another test we can do using an ubuntu image

docker run -it --name ubuntu_1 ubuntu:bionic

👉 This will allow us to connect to ubuntu shell automatically

So what if we want to exit from the ubuntu image terminal while keeping the container running?

✨ We will use CTRL + P + Q

We can confirm that our container is running even after returning to our own terminal using docker ps

To return to the container shell

docker attach <container-name>

We can also pause and unpause the container

docker pause ubuntu_1

docker unpause ubuntu_1

Stopping a container

docker stop ubuntu_1

Killing a container

docker kill ubuntu_1

👉 This is force stop

To remove all Docker containers that are currently stopped

docker rm $(docker ps -a -q)

Now what if we don't apply a custom name for our container

docker run --rm -it ubuntu:bionic

👉 The --rm option automatically removes the container when we 'exit' from the container

We can also change the container name

docker rename <current-container-name> <new-custom-container-name>

To inspect a container or an image

docker inspect <container-name> 

# OR

docker inspect <image-name>

✍ In this post I walked through some of the basic docker container commands that are beginner friendly