add net.ipv4.ip_unprivileged_port_start sysctl

[pacoxu]

kubernetes/kubernetes#103326 marked it as safe sysctl since Kubernetes v1.22.

Kernel 4.11 add this: torvalds/linux@4548b68 which is per namespaced.

xref coredns/coredns#6716 and kubernetes/kubernetes#125226.

[pacoxu]

CI failure is golang install failure.
I sent a PR #299 to fix the CI seperately.

[pacoxu]

/assign @chrisohaver

[pacoxu]

BTW, this needs kernel 4.11+

Or coredns pod will fail with below error:

Warning FailedCreatePodSandBox 2s (x13 over 43s) kubelet Failed to create pod sandbox: rpc error: code = Unknown desc = failed to create containerd task: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: open /proc/sys/net/ipv4/ip_unprivileged_port_start: no such file or directory: unknown

For more context, see kubernetes/kubernetes#105309 (comment).

[pacoxu]

/hold
for kernel version 4.11 requirement

[Tej-Singh-Rana]

Thanks, Pacoxu. 👍