Multi-OS images via manifest property

[Koubek]

I would like to present a proposal to provide multi-OS images via manifest. We had a chat regarding this but I would like to register this request here, on the place where it should be.

Expected Behavior

It would be nice to be able to reference images without having to specify OS relationship in the tag. That would dramatically simplify the usage of the images for us, partners, customers, and end-users.

We would be able to run the following commands independently on OS host (let's say WinServer 2016 or WinServer 2019 etc.):

docker pull mcr.microsoft.com/businesscentral/onprem:2004-w1
docker pull mcr.microsoft.com/businesscentral/onprem:2004-dk
docker pull mcr.microsoft.com/businesscentral/onprem:2004-cu1-dk

Actual Behavior

Today we have to consider what OS we are going to use (which might be uncertain if we run some sort of orchestrated environment - e. g. Docker Swarm cluster with multiple nodes on different versions of OS):

• WinServer 2016:

docker pull mcr.microsoft.com/businesscentral/onprem:2004-w1-ltsc2016
docker pull mcr.microsoft.com/businesscentral/onprem:2004-dk-ltsc2016
docker pull mcr.microsoft.com/businesscentral/onprem:2004-cu1-dk-ltsc2016

• WinServer 2016 alternative (which isn't very OK from my perspective - the tag should be mandatory if the image is for a specific OS version only):

  docker pull mcr.microsoft.com/businesscentral/onprem:2004-w1
  docker pull mcr.microsoft.com/businesscentral/onprem:2004-dk
  docker pull mcr.microsoft.com/businesscentral/onprem:2004-cu1-dk

• WinServer 2019:

docker pull mcr.microsoft.com/businesscentral/onprem:2004-w1-ltsc2019
docker pull mcr.microsoft.com/businesscentral/onprem:2004-dk-ltsc2019
docker pull mcr.microsoft.com/businesscentral/onprem:2004-cu1-dk-ltsc2019

Motivations

• Generally, a radical simplification when working with images (tags). We might focus only on relevant aspects related to NAV/BC releases (major, cu, country etc.).
• This is especially needed in order to be able to work properly with multiple OS without any additional logic being added (which isn't necessary IMO).

Details

• My suggestion is based on multi-arch approach existing for a long time in Docker.
• There is a possibility to use it also to distinguish between OS versions, not only to identify platforms. More can be found e. g. here - multi-win-version-aspnet.
• A demonstration of how do the image tags look like can be seen here - multi-win-version-aspnet/tags.
• The best is that the cost is very low (almost nothing).
• It's easy to create a manifest. The only problem is that the command itself is still hidden in experimental features:
  • https://docs.docker.com/engine/reference/commandline/manifest/
  • Drop experimental tag for manifest commands docker/cli#1355
  • I was able to create manifest in a few seconds but I can't (of course) upload it to your repo :):

docker manifest create mcr.microsoft.com/businesscentral/onprem:1910-es-multi mcr.microsoft.com/businesscentral/onprem:1910-es-ltsc2016 mcr.microsoft.com/businesscentral/onprem:1910-es-ltsc2019

And the content is:

{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 8342,
         "digest": "sha256:c11670cea7a9263b706a2bc0869a992c1e15cbb37b7526e6dd9792aa3742c75f",
         "platform": {
            "architecture": "amd64",
            "os": "windows",
            "os.version": "10.0.14393.3443"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 8342,
         "digest": "sha256:ea5ad7a924d90ea51f94bc87721ac9e01201943cebef029e307a8b9589474722",
         "platform": {
            "architecture": "amd64",
            "os": "windows",
            "os.version": "10.0.17763.973"
         }
      }
   ]
}

• The downside I can see is the fact we can't use no-ltsc tag as this means to use LTSC2016 today. We would need to use e. g. -multi postfix instead to use automatic assignation.

  docker pull mcr.microsoft.com/businesscentral/onprem:2004-w1-multi
  docker pull mcr.microsoft.com/businesscentral/onprem:2004-dk-multi
  docker pull mcr.microsoft.com/businesscentral/onprem:2004-cu1-dk-multi

[freddydk]

Thanks for this suggestion - I will definitely have a look at this.

[Koubek]

Hello @freddydk, please, have you been able to check this issue?

[freddydk]

Not yet - within the next 1-2 weeks hopefully

[Koubek]

OK, thanks.

[Koubek]

An example

• I tag MS images as our internal images and push to the registries (acr). This is where experimental features features must be enabled for Docker CLI.
• Then I create manifest and push it to the registries.
• Since then I can reference only the manifest (it's like a tag) from different OS versions (used process isolation only).

• One "common image", scheduled two replicas. The first one created on DockerHost01 which is hosted by WinServer2016 and the second one on DockerHost03 which is running on WinServer2019:
  

[Koubek]

Hello @freddydk. Please, do you have any plans for this topic? We use this approach very successfully (OS version transparent) so I could tell it's a very nice and important improvement (at least for us but I believe anyone could benefit from it).

As I mentioned somewhere above, for us the biggest "trouble" here is the fact we need to re-tag your images and push them to our repo (registries) in order to be able to create multi-os manifest (it's not possible for foreign images).

I believe, for you (Microsoft) it will be very easy to add this multi-os manifest and this would save us a lot of data (or anyone else willing to use the same approach). And also for you, there is no harm, it's just an additional piece of info so it shouldn't break down the existing stuff.

[Koubek]

Closing the case as it's been there for a very long time and no activity.