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Today, I will talk to you about how to debug Dockerfile. Many people may not know much about it. In order to make you understand better, the editor has summarized the following contents for you. I hope you can get something according to this article.

Any script and program, including Dockerfile, can go wrong. Mistakes are not scary, but there must be ways to troubleshoot them, so this section discusses how to debug Dockerfile.

Let's review the process of building an image through Dockerfile:

Run a container from the base image.

Execute an instruction to modify the container.

Perform an operation similar to docker commit to generate a new mirror layer.

Docker runs a new container based on the image you just submitted.

Repeat steps 2-4 until all instructions in Dockerfile have been executed.

From this process, we can see that if Dockerfile fails to execute an instruction for some reason, we will also be able to get a mirror image of the successful execution of the previous instruction, which is very helpful for debugging Dockerfile. We can run the latest reason for the failure of this mirror location instruction.

Let's look at an example of debugging. The Dockerfile content is as follows:

Perform docker build:

Dockerfile failed to execute the third step RUN instruction. We can debug with the image 22d31cc52b3e created in step 2 by launching a container for the image through docker run-it.

Manual execution of the RUN instruction makes it easy to locate failures because there is no bash in the busybox image. Although this is an extremely simple example, it shows a good way to debug Dockerfile.

Here, I believe that you have a relatively complete impression of the function and use process of Dockerfile, but there is no systematic study of various instructions and actual usage of Dockerfile.

After reading the above, do you have any further understanding of how to debug Dockerfile? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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