====== Docker - Images - Update and Commit an Image ======

===== Pull an image =====

For example, to pull the Ubuntu 20.04 Docker image from the Docker Hub.

<code bash>
docker pull ubuntu:20.04
</code>

----

===== Create a new container =====

Create a new container from the Ubuntu 20.04 image.

<code bash>
docker run -t -i ubuntu:20.04 /bin/bash
</code>

This will create a new container and attach to the bash shell as shown below:

<code bash>
root@013aecdd6919:/#
</code>

----

===== Install NginX into the Container =====

Install the Nginx package inside the container:

<code bash>
root@013aecdd6919:/# apt-get update -y
root@013aecdd6919:/# apt-get install nginx -y
</code>

----


===== Exit from the Container =====


<code bash>
root@013aecdd6919:/# exit
</code>

----

===== Obtain the Container ID =====

Locate your new container ID:

<code bash>
docker ps -a
</code>

returns:

<code bash>
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                       PORTS               NAMES
013aecdd6919        ubuntu:20.04        "/bin/bash"         3 minutes ago       Exited (0) 33 seconds ago                        happy_camper
</code>

----

===== Save the Updated Container =====

Save the updated container with a new image named nginx-instance:

<code bash>
docker commit "013aecdd6919" nginx-instance
</code>

  * Where:   013aecdd6919 is the ID of the container.

----

===== Verify the newly created Image =====


Verify the newly created image “nginx-instance”:

<code bash>
docker images
</code>

returns:

<code bash>
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx-instance      latest              12cefc9b5362        57 seconds ago      158MB
ubuntu              20.04               d70eaf7277ea        12 days ago         72.9MB
</code>

----

===== Log in to the Docker Hub =====

<WRAP info>
**NOTE:** In order to work with the Docker Hub, you will need to create an account on [[https://hub.docker.com/account/signup|Docker Hub]].
</WRAP>


<code bash>
docker login
</code>

returns:

<code bash>
Username: peter
Password: 
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
 
Login Succeeded
</code>

----

===== Tag the Image to push to the Docker Hub =====

For example, to tag the nginx-instance image:

<code bash>
docker tag 12cefc9b5362 peter/nginx-instance:ubuntu
</code>

where:

  * 12cefc9b5362 is the ID of the nginx-instance image.
  * peter is your Docker Hub username.
  * nginx-instance is the name of the image that you want to push.


----

===== Verify the Tagged Image =====

<code bash>
docker images
</code>

returns:

<code bash>
REPOSITORY                 TAG                 IMAGE ID            CREATED             SIZE
peter/nginx-instance       ubuntu              12cefc9b5362        12 minutes ago      158MB
nginx-instance             latest              12cefc9b5362        12 minutes ago      158MB
ubuntu                     20.04               d70eaf7277ea        12 days ago         72.9MB
</code>

----

===== Push the new Image to the Docker Hub =====

Push the new image named peter/nginx-instance to the Docker Hub:

<code bash>
docker push peter/nginx-instance
</code>

----

===== Login to the Docker Hub =====

Login to the Docker Hub using your web browser and verify that the nginx-instance image appears in the Repositories.