CODEWITHSUNDEEP
dockerdockerfile
R. dV
R. dV

Reputation: 526

Is it possible to target the last `:latest` image before current the `:latest` image?

Fairly new Docker user here.

Say I have several versions of a docker image, with the latest two being myimg:1.0.0 and myimg:2.0.0. myimg:2.0.0 is also tagged as myimg:latest, whereas before that one was created, myimg:1.0.0 was also tagged as myimg:latest.

Is there a way to point to the second-to-last :latest tag, without specifying the exact version (i.e. :1.0.0 in this example)? Or for that matter, is there some history of which image corresponds to :latest that one can go through to find a the image that corresponded to :latest N versions ago?

The reason I am asking is that I would like to run two succeeding versions of an image alongside each other, so the latest and second-to-latest are always used. I know this is possible by specifying the exact versions, but I'm hoping to make use of :latest somehow.

Upvotes: 1

Views: 1236

Answers (2)

Geoffrey Dornic
Geoffrey Dornic

Reputation: 11

With debian you have the :oldstable tag to use the previous stable version, and the :oldoldstable for the "previous previous" stable version.

Maybe there are equivalents with other distros.

I found the tag here: https://www.debian.org/releases/index.en.html

Upvotes: 1

Birkhoff Lee
Birkhoff Lee

Reputation: 870

:latest is just a name. There is absolutely nothing special with it. It only gets updated when the tag of the Docker image you built was latest or was omitted. There is NO guarantee that :latest always points to the latest version of an image.

So it's simple to imagine that there's no simple way to get the second last image like git's HEAD~1. The only way you could do it is via version control.

My personal opinion: tag your images with a version tag.

Upvotes: 3

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