将图像添加到我的Base Docker Image

Question

I have a docker base image that runs CentOS 6.5. This image is saved on my computer. I could not find anything that talks about how to add more images into this base image. So for example I have this base image of CentOS6.5, I need too add postgresql 9.3, and php too this base image. Is there a way once you already have a base image made, to add more packages too that base image?

Answer 1

That's the whole purpose of the Docker file : build something on top of an image.

1. Create your dockerfile
2. Build the new image and tag it with docker build -t <tag> <path/to/build/context>
3. Then if you want to share it, push it to your private registry or to the docker hub to make it world accessible (docker push <tag>).

The build context of step 2 is the parent directory of your Dockerfile. For instance if you run the command in the directory where your dockerfile is it would be docker build -t <tag> ..