go-runner

Kubernetes go-runner image

The Kubernetes go-runner image wraps the gcr.io/distroless/static image and provides a go based binary that can run commands and wrap stdout/stderr etc.

Why do we need this? Some of our images like kube-apiserver currently use bash for collecting logs, so we are not able to switch to distroless images directly for these images. The klog's --log-file was supposed to fix this problem, but we ran into trouble in scalability CI jobs around log rotation and picked this option instead. we essentially publish a multi-arch manifest with support for various platforms. This can be used as a base for other kubernetes components.

For example instead of running kube-apiserver like this:

"/bin/sh",
  "-c",
  "exec /usr/local/bin/kube-apiserver {{params}} --allow-privileged={{pillar['allow_privileged']}} 1>>/var/log/kube-apiserver.log 2>&1"

we would use go-runner like so:

"/go-runner", "--log-file=/var/log/kube-apiserver.log", "--also-stdout=false", "--redirect-stderr=true",
  "/usr/local/bin/kube-apiserver",
  "--allow-privileged={{pillar['allow_privileged']}}",
  {{params}}

The go-runner would then ensure that we run the /usr/local/bin/kube-apiserver with the specified parameters and redirect stdout ONLY to the log file specified and ensure anything logged to stderr also ends up in the log file.