[StackOverflow/kubernetes] Are Kubernetes kernel-dependent features fully supported on Rocky Linux 9’s 5.14 kernel?

### ROOT CAUSE The issue arises from uncertainty about whether Kubernetes' kernel-dependent features (e.g., cgroups, overlay2, specific kernel modules) are fully supported on Rocky Linux 9's 5.14 kernel. While Rocky Linux 9 (based on RHEL 8.5) uses a kernel compatible with Red Hat, Kubernetes' support depends on the specific kernel version and configuration, not just the distribution. The 5.14 kernel is generally supported, but certain features may require additional configuration or patches. ### CODE FIX 1. **Verify Kernel Features**: Check if required kernel modules are loaded: ```bash lsmod | grep -E 'overlay|br_netfilter|xt_MASQUERADE' ``` If missing, load them: ```bash sudo modprobe overlay sudo modprobe br_netfilter sudo modprobe xt_MASQUERADE ``` 2. **Enable sysctl Parameters**: Ensure kernel parameters are set: ```bash echo "1" | sudo tee /sys/module/overlay/parameters/overlay_max_dir_items sudo sysctl -w net.bridge.bridge-nf-call-iptables=1 sudo sysctl -w fs.protected_regular=0 ``` Add these to `/etc/sysctl.conf` to persist. 3. **Test Kubernetes Compatibility**: Use the official Kubernetes release notes to confirm the minimum kernel version for your Kubernetes version (e.g., Kubernetes 1.25+ requires ≥4.15). For Rocky Linux, install the `kubernetes` package from the official repositories or use the `containerd` runtime. 4. **Check for Patches**: Rocky Linux 9's kernel may require patches for specific Kubernetes features. Check the [Rocky Linux kernel repositories](https://github.com/rocky-linux/rocky-id) or apply patches for cgroups v2 if needed. 5. **Validate with a Pod**: Deploy a pod with a `sysctl` check to ensure features are active: ```yaml apiVersion: v1 kind: Pod metadata: name: kernel-check spec: containers: - name: check image: alpine command: ["sh", "-c", "cat /proc/filesystems | grep overlay && cat /proc/self/cgroup"] ``` If issues persist, consult the [Kubernetes documentation](https://kubernetes.io/docs/setup/production-environment/) or the [Rocky Linux forums](https://rockylinux.org/community/).