Kind: determine and document resource requirements

[BenTheElder]

What would you like to be documented: A more accurate lower bound on resources when using kind with docker desktop. Currently we suggest 4GB / 4 CPU which while probably accurate for building kubernetes should be more than we need to run a node.

https://kind.sigs.k8s.io/docs/user/quick-start/#creating-a-cluster

Why is this needed: We don't want to overstate requirements dramatically and scare off potential users :-)

We'll need to do some testing to determine the threshold. It should be reduced at HEAD, it might also be interesting to check if that is true 🙃

[BenTheElder]

/assign

[nickolaev]

I am trying kind in the CircleCI machine executor which seems to be perfectly fine with its 2 CPU cores. Hope this helps.

[BenTheElder]

thanks!

can confirm that at HEAD even the smallest settings docker desktop offers currently work fine for kind create cluster:

$ kind create cluster
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.14.1) 🖼
 ✓ Preparing nodes 📦 
 ✓ Creating kubeadm config 📜 
 ✓ Starting control-plane 🕹️ 
 ✓ Installing CNI 🔌 
 ✓ Installing StorageClass 💾 
Cluster creation complete. You can now use the cluster with:

export KUBECONFIG="$(kind get kubeconfig-path --name="kind")"
kubectl cluster-info

$ kubectl get no
NAME                 STATUS   ROLES    AGE   VERSION
kind-control-plane   Ready    master   20s   v1.14.1

$ kubectl get po --all-namespaces
NAMESPACE     NAME                      READY   STATUS    RESTARTS   AGE
kube-system   coredns-fb8b8dccf-qhm47   1/1     Running   0          23s
kube-system   coredns-fb8b8dccf-rc56v   1/1     Running   0          23s
kube-system   kube-proxy-ksw7d          1/1     Running   0          23s
kube-system   weave-net-dqz4p           2/2     Running   0          23s

[BenTheElder]

will actually have to follow up and sample the usage over time, the lowest settings on docker desktop / macOS appear to be above our lower bound 🙃

[costinm]

We are using both CircleCI machine and remote_docker environments, which are 2 CPU, to test Istio - it seems to be working quite well. Since Circle doesn't allow higher CPU, it would be good to keep this as a baseline.

[costinm]

Besides - if the ARM64 bugs are fixed, I would hope Kind will run on Raspberry Pi - k8s can run just fine.

[BenTheElder]

We are using both CircleCI machine and remote_docker environments, which are 2 CPU, to test Istio - it seems to be working quite well. Since Circle doesn't allow higher CPU, it would be good to keep this as a baseline.

A single node should work with considerably less than this, however the rest of what we can do performance wise is mostly bound by Kubernetes / CRI / ... CNI is probably the last place we have room for squeezing this lower and we're working on that.

It may regress some in the future due to the components we don't control, but keeping everything as low as we can is a high priority 👍

Besides - if the ARM64 bugs are fixed, I would hope Kind will run on Raspberry Pi - k8s can run just fine.

As far as I know ARM64 works but requires building images yourself. Currently it will be painful to cross-build those because of getting kubernetes loaded, but that is being worked on in low priority.

There is some limited ARM64 CI working now from the openlab folks.

[BenTheElder]

these will shift a bit with the updated CNI configuration (should be lower), but will remeasure.

still need to document as well

[BenTheElder]

since we've approached the limits of what we can reduce from kind's end alone, some experimentation with making upstream Kubernetes lighter: https://github.com/BenTheElder/kubernetes/tree/experiment

if we go forward with this change upstream then kind will support leveraging it immediately.

[BenTheElder]

I've improved that prototype with the goals of:

• being able to test / use out of tree cloud providers without in-tree code well ahead of the in-tree removal
• being able to ship kind with lighter node images

So far that more or less works and I've created a provisional PR upstream.

At this point I think the next step is a KEP, expect more on this in the near future :-)

We may need to slightly adjust what else we ship though (EG currently we are missing the metrics APIs) but will continue to push for light weight clusters overall. I think we can lighten some other things at the same time to make room without adding much overhead.

[BenTheElder]

https://github.com/kubernetes-sigs/kind/pull/932 + recent containerd build infra and upgrades should reduce the memory overhead per pod.

[BenTheElder]

/help

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[shreyasbapat]

Hi @BenTheElder
I wish to work on this issue and get started, can you confirm if only the image of the docker desktop interface needs to be changed with the one you posted above?

[BenTheElder]

the image can be left actually, as the image is talking about building kubernetes image which takes more resources.

it would be helpful to determine exactly how much resources a typical kind cluster uses in a repeatable fashion and keep this documented.

[shreyasbapat]

it would be helpful to determine exactly how much resources a typical kind cluster uses in a repeatable fashion and keep this documented.

And for that, I will have to perform some experiments and report back right? Do you suggest me to check multiple times?

[BenTheElder]

that's a good idea, I think the most important thing is that we write down how we determined this somewhere so we can come back and verify what it's currently at :-)

[shreyasbapat]

that's a good idea, I think the most important thing is that we write down how we determined this somewhere so we can come back and verify what it's currently at :-)

On it. Will notify once I am done

[shekhar-rajak]

it would be helpful to determine exactly how much resources a typical kind cluster uses in a repeatable fashion and keep this documented.

Different hardware system and system config can behave differently, not sure where to benchmark memory & time .