How does it determine if there is an update or not?

[Toudahl]

When shepherd runs it incorrectly detects that there are no image update.

I am curious if i have configured something incorrectly.
First i setup my service, then at a later point i started shepherd.

The currently deployed image is tagged with: "main-51-1" the newest version is tagged with "main-54-1".

I see this in the logs:

 Mon Sep 11 20:39:52 UTC 2023 Trying to update service <servicename> with image <imagename>:main-51-1
Mon Sep 11 20:39:59 UTC 2023 No updates to service <servicename>!

[martadinata666]

the change of Sha with the same tag, usually not very specific tag. like latest, main, with specific tag like yours, mostly it's not getting a new push so the sha number still the same.

[Toudahl]

I had hoped you wouldn't say that.

As I understand it is best practise to use specific versions for your container instead of "latest".

Does anyone know if there is a plan to support that?

[martadinata666]

This kind of depends on the docker image set up by the owner. Let's take the example of mariadb
latest -> keep updated
10.6 -> keep updated as long as 10.6.1, 10.6.2, ... exist until eol.
10.6.1 -> The oneshot image won't be updated.

But there is also the image that keeps updating due to basic package updates like lsio image, so new images are pushed on the same specific tag.

That is just how docker functions, shepherd just utilizes it. Moving tag is not possible.

[Toudahl]

This kind of depends on the docker image set up by the owner. Let's take the example of mariadb latest -> keep updated 10.6 -> keep updated as long as 10.6.1, 10.6.2, ... exist until eol. 10.6.1 -> The oneshot image won't be updated.

But there is also the image that keeps updating due to basic package updates like lsio image, so new images are pushed on the same specific tag.

Yes, but using the "latest" tag in deployment scripts means that your deployments are not deterministic.

A deployment today might not be the same as a deployment tomorrow.
That is the argument i have heard against using the latest tag.
Here is a random blog post I found, giving some details on it.
https://vsupalov.com/docker-latest-tag/

Moving tag is not possible.

Understood. Thanks for the answer.

[djmaze]

Yes, but using the "latest" tag in deployment scripts means that your deployments are not deterministic.

That's why most docker images are being semantically versioned and you should make use of that. As @martadinata666 said, you can then use mariadb:10.6 and you will get the patch releases (10.6.1, 10.6.2, ...) but no more.

For doing minor and major releases, I recommend managing your stacks via git and using something like renovate (or some Github action thingy) in order to get notified of new releases, and then do those updates manually.