Symptom

There are rare cases, for some k3d versions and configurations, where users experience Functions failing to be built.

Your Function cannot be built:

kubectl get functions.serverless.kyma-project.io nyfun
NAME    CONFIGURED   BUILT   RUNNING   RUNTIME    VERSION   AGE
myfun   True         False             nodejs16   1         3h15m

and the Function build job shows the following error, meaning that your host k3d environment is likely to experience the problem:

kubectl logs myfun-build-zqhk8-7xl6h
kaniko should only be run inside of a container, run with the --force flag if you are sure you want to continue

Cause

This problem originates in kaniko - the container image build tool used in Kyma. kaniko is designed to be run in a container and this is how it is executed in Kyma (as build jobs). kaniko has a detection mechanism to verify whether the build is actually executed in a container and fails in case it is not. This detection mechanism has issues and in some circumstances (i.e. hosts with cgroups in version 2 or other, not yet clearly identified) it shows false positive result.

Related issues:

• https://github.com/kyma-project/kyma/issues/13051

• https://github.com/GoogleContainerTools/kaniko/issues/1592

Remedy

kaniko can be executed with a --force flag that skips the verification. To do so, please override the kaniko execution arguments by passing the --force flag.

Introduce a file with overrides, i.e. my-overrides.yaml

serverless:
  containers:
    manager:
      envs:
        functionBuildExecutorArgs:
          value: --insecure,--skip-tls-verify,--skip-unused-stages,--log-format=text,--cache=true,--force

Use the file to override the default configuration while deploying Kyma on your k3d instance:

kyma deploy --values-file my-overrides.yaml