For local k8s clusters with kubeadm, Debian offers stability and simplicity, while Ubuntu provides newer packages and better hardware support, depending on your needs.

Why It Matters

Local Kubernetes clusters demand minimal overhead and predictable behavior. Both Ubuntu and Debian work, but the choice hinges on hardware compatibility, maintenance preferences, and tolerance for bloat.

Actionable Workflow

1. Assess Hardware Requirements
   • Use lshw or dmidecode to check hardware specs.
   • If using cutting-edge NICs or GPUs, Ubuntu’s newer kernel (6.1+ in 24.04) may be necessary.
2. Evaluate Maintenance Strategy
   • Prefer Debian if you want long-term stability and minimal updates.
   • Choose Ubuntu if you need newer container-runtime versions or pre-built snap packages.
3. Test Both in Isolation
   • Spin up single-node clusters with both OSes using kubeadm init.
   • Validate CNI plugins (Calico, Cilium) and storage classes function as expected.

Policy Example

# OS Selection for Local Kubernetes Clusters  
**Default Choice**: Debian 12 (Bookworm)  
**Rationale**:  
- Avoids snapd overhead (reduces attack surface and resource usage).  
- Stable kernel (6.1) sufficient for most local dev workflows.  
**Exceptions**:  
- Use Ubuntu 24.04 if hardware requires newer drivers (e.g., NVIDIA GPUs).  

Tooling

• Cluster Bootstrap: kubeadm (same workflow for both OSes).
• Configuration Management: Ansible playbooks to enforce OS-specific tuning (e.g., sysctl settings).
• Monitoring: Prometheus + Node Exporter to compare resource usage between OSes.

Tradeoffs

• Debian:
  • Pros: No snapd, smaller default footprint, community-driven security patches.
  • Cons: Older kernel (6.1 in Bookworm) may lack drivers for newer hardware.
• Ubuntu:
  • Pros: Newer packages (e.g., containerd 1.6+), better hardware support.
  • Cons: snapd consumes ~200MB RAM idle; Canonical telemetry enabled by default.

Troubleshooting

• Kernel Module Issues:
  • Debian: modprobe -a to load missing drivers; check /var/log/syslog for errors.
  • Ubuntu: Use ubuntu-drivers devices to auto-install hardware-specific packages.
• Systemd Conflicts:
  • Disable snapd on Ubuntu:

    systemctl stop snapd && systemctl disable snapd && snap list --all  
    

• Network Plugin Failures:
  • Verify conntrack and ip_vs modules are loaded:

    lsmod | grep conntrack  
    lsmod | grep ip_vs  
    

Conclusion

Neither OS is universally better. For most local clusters, Debian’s simplicity wins unless hardware demands otherwise. Disable snapd on Ubuntu, and always validate with a throwaway node before scaling.

Source thread: Ubuntu server or Debian for a local k8s cluster with kubeadm ?