Enhancement: allow to filter what fields to return from the API about kubernetes HOT 10 CLOSED

Hi @ah8ad3,
Thanks for your reply. It's AKS, which, afaik, doesn't expose etcd - only via the k8s api. I think it's similar with EKS and GKE.

from kubernetes.

Joe Betz thanks. Could you elaborate that? deleteCollection sounds helpful, can't find details about it atm.

deleteCollection refers to the ability to perform a delete on a collection of resources, for example:

kubectl delete pods

In the API it would be of the form:

DELETE /api/v1/namespaces/{namespace}/pods

It's also possible to filter the list of resources to delete further using selectors. E.g. to delete only pods with a particular label:

kubectl delete pods -l app=my-app

It would still be helpful if I could use some sort of projection on lists. Let's say I only need the names of 100k items. It'd be silly to fetch gigs of data when all I need is perhaps 10kb. Now as I'm typing this, I wonder if this doesn't happen anyway. I have no knowledge of the internals, but I'd guess that the whole objects are stored in etcd, right? So at least from there the whole thing is retrieved anyway. We'd still not transfer everything along the (long) wire, though.

The Kubernetes API does not support arbitrary projections (it does get requested occasionally, but would be a HUGE project). However, it is possible to get back only the metadata of an object by using PartialObjectMetadata` which is requested via Accept headers. I don't know if kubectl provides any support for this though. It's primarily used by the garbage collector. It is easy to call from client-go.

from kubernetes.

/sig api-machinery
/sig cli

from kubernetes.

Thanks for raising this issue, did you consider using etcdctl directly?

from kubernetes.

/cc @jpbetz Thank you! :)

from kubernetes.

Could deleteCollection be used here?

Please reassign to sig-cli is this is purely a kubectl related request.

from kubernetes.

@jpbetz thanks. Could you elaborate that? deleteCollection sounds helpful, can't find details about it atm.

It would still be helpful if I could use some sort of projection on lists. Let's say I only need the names of 100k items. It'd be silly to fetch gigs of data when all I need is perhaps 10kb. Now as I'm typing this, I wonder if this doesn't happen anyway. I have no knowledge of the internals, but I'd guess that the whole objects are stored in etcd, right? So at least from there the whole thing is retrieved anyway. We'd still not transfer everything along the (long) wire, though.

from kubernetes.

Thanks a lot, really helpful!

So,

A) Next time I need to delete a bunch of stuff I can just delete on a collection level using selectors.
B) At least for metadata there is a workaround by using the API directly. If you don't mind, could you provide a very simple example? The only docs I find are from the go package.

It probably doesn't make sense to keep this issue open then. At least something as simple as counting would be nice. Afaik in order to just count the number of some object I have to fetch them all and count locally. But that's a thing for another issue, I guess.

from kubernetes.

/triage accepted
/close

from kubernetes.

@fedebongio: Closing this issue.

from kubernetes.