feat(env): Add automatic memory limit handling

[dongjiang1989]

add auto GOMEMLIMIT setting

[dongjiang1989]

cc @EItanya PTAL

[EItanya]

So I've been thinking about this PR and your previous one a little more, and I think they may be overkill tbh. I've used the following approach before which has been super simple and worked well.

         - name: GOMEMLIMIT
            valueFrom:
              resourceFieldRef:
                resource: limits.memory
                divisor: "1"
          - name: GOMAXPROCS
            valueFrom:
              resourceFieldRef:
                resource: limits.cpu
                divisor: "1"

Here it is in Istio: https://github.com/istio/istio/blob/b6df261b7c9f66c10b0d17b02f9c9b9ebb546033/manifests/charts/istio-control/istio-discovery/templates/deployment.yaml#L209-L218

[dongjiang1989]

thanks @EItanya

This method is also effective. However, there is a drawback: under VPA adjustment, the Go runtime configuration cannot be dynamically adjusted. Just start it once for the first time.

[dongjiang1989]

thanks @EItanya

This method is also effective. However, there is a drawback: under VPA adjustment, the Go runtime configuration cannot be dynamically adjusted. Just start it once for the first time.

[howardjohn]

thanks @EItanya

This method is also effective. However, there is a drawback: under VPA adjustment, the Go runtime configuration cannot be dynamically adjusted. Just start it once for the first time.

I don't think thats true. a VPA change triggers a new pod, which will have a freshly computed value.

I agree with @EItanya on the approach

[dongjiang1989]

thanks @EItanya
This method is also effective. However, there is a drawback: under VPA adjustment, the Go runtime configuration cannot be dynamically adjusted. Just start it once for the first time.

I don't think thats true. a VPA change triggers a new pod, which will have a freshly computed value.

I agree with @EItanya on the approach

@howardjohn

It might be that my description wasn't clear enough. When a VPA change with in place pod resize.

[howardjohn]

you are referring to https://kubernetes.io/blog/2025/05/16/kubernetes-v1-33-in-place-pod-resize-beta/ yeah?

Given we are only calling SetMemLimit, if the memory limit actually does change during the pod lifetime, this change won't handle it either...?