Function jobs shouldn't request resources by default

[dbadura]

Description
In current implementation by default we enforce build profile.

Expected result
By default the build profiles are not applied.

Actual result
Having those values set as default, that:

• function deployment request 500m cpu
• function build job request 1000m cpu
  let's consider following situation:
  User creates 3 function on node with 2000cpu available:
• first job requires 1000m, the available left is 1000m
• job finished and then we deploy the function which requires 500m, the available cpu is 1500m
• user deploy second function and at the end available cpu is 1000m
• user deploy third function. The job can fit, because we have 1000m cpu available and at the end we deploy function and cluster have available 500m cpu.
• the user want to upgrade one of those three functions and the upgrade stuck, because the job doesn't have enough space.

By default we shouldn't apply any build profiles or at least not enforce minimum request for build jobs.
I would consider to also remove the default profile for functions if the user didn't specify.

Steps to reproduce

Troubleshooting
Settings for minimum requests: https://github.com/kyma-project/kyma/blob/main/components/function-controller/pkg/apis/serverless/v1alpha1/function_validation.go#L28=

[kwiatekus]

function build job cannot start in an over-commited CPU environment.
The following shows the scenario: CPU utilisation is really low ( ~14%) but CPU commitment is ~100%

We should lower the overcommitment of CPU for kyma components

[dbadura]

The code which check minimum values requested:

kyma/components/function-controller/pkg/apis/serverless/v1alpha1/function_validation.go

Lines 24 to 32 in cc7cbc4

	type MinFunctionResourcesValues struct {
	MinRequestCpu string `envconfig:"default=10m"`
	MinRequestMemory string `envconfig:"default=16Mi"`
	}
	type MinBuildJobResourcesValues struct {
	MinRequestCpu string `envconfig:"default=200m"`
	MinRequestMemory string `envconfig:"default=200Mi"`
	}

Also look here in charts, for example:

kyma/resources/serverless/charts/webhook/values.yaml

Lines 101 to 102 in 30c0da1

	minRequestCpu: "10m"
	minRequestMemory: "16Mi"

[kwiatekus]

We should

• check if we can allow to set any value for requested CPU time and CPU limits for function builds (even empty)
• analyse the actual CPU utilisation (% of the requested CPU time ) for kyma components that sit on most of the requested CPU
• propose a PR with adjusted requested CPU time for kyma components

[kwiatekus]

Thanks
We have reduced the cpu overcommitment across kyma components - saving cpu cycles for build jobs.
Additionally, we removed the requested cpu and memory for the build jobs by default - allowing for more flexible job scheduling in scenarios where cpu is limited on the worker nodes