I am currently running the official ghost Docker image, and use this image to build several containers.
If I want to update the my Docker image, I simply just use the command:
docker pull ghost
docker restart oldcontainer
Does it work ?
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No. Updating an image will not affect the images that were built from that image, and certainly not affect the already-running containers that were created from this image.
One possible workflow would be sth. like this:
- Pull new version of base image
- Build new version of your own image on top of the image
- Destroy and re-create your own containers from the newly-built image
helmbert
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so it means if I have the new image, then even restarting the containers based on the old image won't work. – user824624 May 04 '15 at 20:42
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Correct. Ideally, you would re-create the container from the (possibly updated) image. That's exactly the reason why it's discouraged to store application data inside a Docker container, btw. (see the answer linked in VonC's answer on that topic). – helmbert May 04 '15 at 20:48
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Thank you, so much, helmbert – user824624 May 04 '15 at 21:27
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A docker restart does a docker stop (or docker kill if the stop times out), which puts a container in an exit status, followed by a docker start, which starts the same container.
The fact that the image might have changed isn't detected at all in that process.
Removing and doing a full docker run with all the right parameter would pick up on an image change. See "How to upgrade docker container after its image changed"
