Installation fails on Digital Ocean Kubernetes (missing EnvironmentFile in kubelet.service)

Sysbox installation fails on Digital Ocean Kubernetes because the install script's $KUBELET_CRIO_ARGS are not applied (and the user will see FailedCreatePodSandBox Failed to create pod sandbox: rpc error: code = Unknown desc = failed to get sandbox runtime: no runtime for "sysbox-runc" is configured). This is happening because Digitial Ocean's (Debian Bookworm) nodes' kubelet.service doesn't include a EnvironmentFile directive, adding EnvironmentFile=-/etc/default/kubelet fixes the installation.

It looks like the install script searches for EnvironmentFile in kublet.service, it should add one if it doesn't find it.

On a side note, k8s troubleshooting doc might want to mention kubectl get node <node> -o jsonpath='{.status.nodeInfo.containerRuntimeVersion}' and the kublelet command line arguments to check for to verify the runtime is running, that would have helped me figure out this problem faster.

Start by inspecting the install script's handling of EnvironmentFile and the kubelet.service configuration on Debian Bookworm nodes. Check /etc/default/kubelet and verify the resulting kubelet arguments with kubectl; done means installation applies the CRI-O arguments and pods can start with sysbox-runc.