Project Overview

Kube-Ready-Box provides the operating-system baseline required before Kubernetes is installed on local VMs.

It deliberately does not include Kubernetes itself. Instead, it standardizes the repetitive work around kernel modules, networking, storage prerequisites, filesystem choices, diagnostics, time synchronization, and disk expansion so projects such as Narwhal and Beluga can focus on cluster bootstrap.

The project publishes Ubuntu 24.04 LTS and 26.04 LTS variants for ext4 and XFS, with ARM64 and AMD64 support and common local hypervisors such as VirtualBox and VMware Fusion.

Why the Layer Exists

Ubuntu Cloud Image
      ↓
filesystem / disk setup
      ↓
kernel modules / sysctl
      ↓
network / conntrack / buffers
      ↓
CSI / iSCSI / NFS prerequisites
      ↓
time synchronization / diagnostics
      ↓
Kubernetes bootstrap

Kube-Ready-Box standardizes the left side of this boundary and leaves Kubernetes version and runtime selection to the consuming project.

Published Variants

Vagrant Cloud names include:

dasomel/ubuntu-24.04-ext4
dasomel/ubuntu-24.04-xfs
dasomel/ubuntu-26.04-ext4
dasomel/ubuntu-26.04-xfs

Kubernetes Readiness Baseline

The boxes include OS-level preparation such as:

• disabled swap
• Kubernetes kernel modules (br_netfilter, overlay, iscsi_tcp)
• IP forwarding and bridge networking
• conntrack and network buffer tuning
• persistent /sys/fs/bpf mount (keeps Cilium eBPF resources across reboots)
• open-iscsi (with iscsid enabled), cryptsetup, dmsetup for Longhorn V1 · nfs-common
• chrony time synchronization — replaces the systemd-timesyncd default on Ubuntu 25.10+/26.04, with Korean NTP servers preconfigured (/etc/chrony/sources.d/kr-ntp.sources) for etcd's clock-skew sensitivity
• security hardening: needrestart removed (addresses 5 Qualys local-privilege-escalation CVEs), unattended-upgrades fully purged (avoids conflicting with kubelet Graceful Node Shutdown), auditd installed but disabled by default (CIS-ready, bounded I/O), apparmor-utils added
• Kubernetes/network/performance CLI utilities
• automatic disk/partition/LVM/filesystem expansion (1TB thin-provisioned disk; box size is ~2.2GB for ext4 and ~3.4GB for XFS)

Container runtimes and Kubernetes packages are intentionally left to the consumer project.

24.04 vs 26.04

Ubuntu 26.04 is a cgroup v2-only environment. Kubernetes installations using it should explicitly configure systemd cgroup integration for the chosen runtime. Ubuntu 24.04 remains the more conservative default when stability is the priority.

Build and Release Model

Ubuntu Cloud Image
       ↓
     Packer
       ↓
OS configuration + filesystem tuning
       ↓
provider / architecture validation
       ↓
Vagrant Box
       ↓
Vagrant Cloud
       ↓
Narwhal / Beluga / local Kubernetes

Packer defines the image construction process, while CI validates and publishes the provider/architecture combinations.

Filesystem Choice

ext4

A broad default for general Kubernetes development, with familiar Linux tooling and online operations appropriate to common workloads.

XFS

Useful for large files and filesystem quota scenarios. It is also the natural companion for NFS Quota Agent when XFS project quotas are required.

Getting Started

# Stable default
vagrant init dasomel/ubuntu-24.04-ext4
vagrant up --provider=vmware_desktop
 
# XFS / quota-oriented environment
vagrant init dasomel/ubuntu-24.04-xfs
vagrant up --provider=vmware_desktop
 
# Ubuntu 26.04
vagrant init dasomel/ubuntu-26.04-ext4
vagrant up --provider=vmware_desktop

After boot, install the Kubernetes/runtime versions required by the consuming project.

Verification

vagrant ssh -c "cat /etc/vagrant-box/info.json"
vagrant ssh -c "/bin/bash /etc/vagrant-box/check-tuning.sh"

The goal is to verify OS readiness, not merely whether the VM starts.

Current Status

The latest release is v1.1.0 (2026-07-19). It is the first tagged release to ship Ubuntu 26.04 LTS (Resolute Raccoon, kernel 7.0) alongside 24.04 LTS (Noble Numbat, the default), and it introduced the security hardening, chrony migration, CSI/Longhorn prerequisites, and persistent bpffs mount described above.

• A declarative NixOS variant, dasomel/nixos-kube-ready, is published separately (libvirt/arm64; usable on Apple Silicon via vagrant-qemu).
• Building from source requires Packer 1.10+ (CI pins 1.15.4); build timeouts are ssh_timeout 1h (2h for vmware-arm64), with a 90-minute CI job timeout.

Documentation Index

Project Relationship