Dockerlab 104 Creating Docker image with Dockerfile

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In this lab, we will be creating docker image with dockerfile and run a container using it

In case you prefer a video, check below our YouTube video for this lab

Create docker hub account. Docker Hub skip this step if you already have one

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    alt="image"
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Open Play with Docker

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    alt="image"
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    alt="image"
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Click on start

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    alt="play with docker start"
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It will start a 4 hr session

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    alt="play with kubernetes session"
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click on + ADD NEW INSTANCE

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    alt="play with kubernetes node"
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Task: Create a Dockerfile to create a docker image

Solution

vi Dockerfile

FROM ubuntu

RUN apt-get update  

RUN apt-get install figlet  

CMD ["figlet", "hello docker"]

RUN is used to run command inside container, you can use it to add command to base image

RUN has 2 forms:

RUN (shell form, the command is run in a shell, which by default is /bin/sh -c on Linux or cmd /S /C on Windows)
RUN [“executable”, “param1”, “param2”] (exec form)

The RUN instruction will execute any commands in a new layer on top of the current image and commit the results. The resulting committed image will be used for the next step in the Dockerfile.

Layering RUN instructions and generating commits conforms to the core concepts of Docker where commits are cheap and containers can be created from any point in an image’s history, much like source control.

The exec form makes it possible to avoid shell string munging, and to RUN commands using a base image that does not contain the specified shell executable.

Task: Build docker image with Dockerfile from previous step

Solution

docker image build -t imageformfile:0.1 .

Task: Run docker container with image build in previous step

Solution

docker container run imageformfile:0.1

Task: List all docker images on local system

Solution

docker image ls -a

Task: List all all changes made to docker image

Use image from previous step

Solution

docker image history <image ID>

Update you docker image with 0.2

Solution

vi Dockerfile

CMD ["figlet", "hello docker 0.2"]

TasK: Build docker image with updated Dockerfile from previous step

update tag to 0.2

Solution

docker image build -t imageformfile:0.2 .

Task: Run docker container with image build in previous step

Solution

docker container run imageformfile:0.2

Task: Delete all open nodes/instances and close session

Select the node and click on DELETE
Repeat same for any other open nodes
click close session

In this lab, we will be creating docker image with dockerfile and run a container using it

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