What is the process for modifying code within a Docker Container?

Question

What is the process for modifying code within a Docker Container?

My Docker and Containers knowledge is very limited, along with understanding VM concepts as a whole.

I grasp the idea that VMs and Dockers help package all application dependencies into a single component for easy deployment on compatible cloud platforms.

After installing Docker on my local Ubuntu machine, I followed this guide to run the Node Official Image.

Now, my question is: how do I update code changes within Docker? I edited 'server.js' in the app, but even after restarting the container, the browser displays the old output at http://locahost:49160. Is creating a new image the only solution, rendering the old one useless?

Perhaps I'm missing something fundamental about how Docker operates?

node.js docker

Answer 1

Answer №1

In order to modify the contents within a container, you have the option to save these changes to the original image or create a new one altogether.

It is advisable to opt for creating new images or tags when making modifications.

Refer to this helpful guide. If you need to alter the server.js, go ahead but remember to build a fresh image with a corresponding tag (test1).

For instance, use

docker build -t <your username>/node-web-app:test1 .

Afterwards, execute the new image using

docker run -p 49160:8080 -d <your username>/node-web-app:test1

Answer 2

In order to modify the contents within a container, you have the option to save these changes to the original image or create a new one altogether.

It is advisable to opt for creating new images or tags when making modifications.

Refer to this helpful guide. If you need to alter the server.js, go ahead but remember to build a fresh image with a corresponding tag (test1).

For instance, use

docker build -t <your username>/node-web-app:test1 .

Afterwards, execute the new image using

docker run -p 49160:8080 -d <your username>/node-web-app:test1

Answer 3

Answer №2

If you find yourself in a similar situation, rebuilding your image may be necessary:

docker build -t my-new-image .

If changes have been made to your server.js file and it's included in your image/container, the old image will no longer serve its purpose. Starting a new container with docker run will be required after the rebuild.

In certain scenarios, it is feasible to link your code/data to your docker container using

docker run -v my-local-volume:/volume-in container ...

To automatically update the code within your container when edits are made on your local machine without having to update the image or restart the container, you can implement this method. However, if you're manually copying the code inside your application using the COPY command from the dockerfile as in this case, a rebuild may be necessary.

Answer 4

If you find yourself in a similar situation, rebuilding your image may be necessary:

docker build -t my-new-image .

If changes have been made to your server.js file and it's included in your image/container, the old image will no longer serve its purpose. Starting a new container with docker run will be required after the rebuild.

In certain scenarios, it is feasible to link your code/data to your docker container using

docker run -v my-local-volume:/volume-in container ...

To automatically update the code within your container when edits are made on your local machine without having to update the image or restart the container, you can implement this method. However, if you're manually copying the code inside your application using the COPY command from the dockerfile as in this case, a rebuild may be necessary.

What is the process for modifying code within a Docker Container?

Answer №1

Answer №2

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