suggest a --replace flag for play kube

[chenzhiwei]

/kind feature

Description

• podman kube create -f k8s-manifests.yaml
• podman kube apply -f k8s-manifests.yaml
• podman kube delete -f k8s-manifests.yaml

[rhatdan]

Please further explain or open PRs to examine.
@haircommander @mrunalp WDYT?

[haircommander]

the create and apply commands are done with podman play kube, and delete was just recently added with podman play kube --down

are you just looking for an alias between the two sets of commands?

[chenzhiwei]

@haircommander something similar.

• create just creates the manifests, return error if already exist
• apply pulls the images in the manifests, if new images or containers detected, apply the new images to the manifests
• delete means deleting the manifests

[haircommander]

Ah so you'd like podman behaving like api server/etcd, rather than kubelet/runtime which is closer to how it's behaving now. What use case are you looking to fill? I can't think of a use of keeping track of the underlying manifest if the pod/containers is what podman typically thinks about

[chenzhiwei]

one of the container use latest tag image, can podman now support update the image to the real latest one?

[flouthoc]

@chenzhiwei I dont think that even k8s supports that, you can have a image pull policy as always on deployment and k8s will only update image if pod is restarted. You can have similar pull policy on podman pods but afaik they need to be restarted as well.

[chenzhiwei]

@flouthoc Thank you.

What about introducing a new flag --replace to play kube?

I think my core requirement is apply the new changes from both my manifest file and the images inside it.

If the pod already exists, delete and re-create it, this can trigger the image refresh if the pull policy is always or image tag is latest. If no pod found, create one.

[rhatdan]

That makes some sense to me. @baude @mheon WDYT?

[mheon]

A --replace flag SGTM