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This guide explains how to use the helper scripts under utils/.

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Wipe a disk for thin‑pool provisioning

Script: utils/wipe-disk.sh
Destructive operation. This irreversibly erases all partitions, RAID metadata, filesystems, and attempts discards on the target device. Double‑check the device path.

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Usage

On dual-NVMe Hetzner boxes, wipe only the spare disk (the one that is not the OS root). After k7 install, leave k7_devmapper_disk / --disk unset so the playbook auto-detects that spare — NVMe names (nvme0n1 vs nvme1n1) swap across reboots. See Hetzner node setup. You will be prompted to type YES to proceed. The script will:
  • Remove filesystem signatures (wipefs -a)
  • Zap the partition table (sgdisk --zap-all)
  • Zero the beginning and end of the disk (dd)
  • Attempt block discard (blkdiscard) if supported
List disks to find the correct device:
Requirements: Linux with wipefs, sgdisk, and blkdiscard; run as root or via sudo.

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High‑density CPU/memory stress test

Script: utils/stress_test.sh This script launches many sandboxes to validate CPU limit enforcement and observe resource behavior.

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What it does

  • Creates namespace stress-test
  • Generates k7-stress-*.yaml files, each with:
    • before_script that installs stress-ng and htop via apk
    • CPU and memory limits per sandbox
  • Launches sandboxes in batches (default 50 total, batches of 10)
  • Sets up a cleanup trap on Ctrl+C to delete resources and namespace
Default parameters (edit inside the script if desired):
  • COUNT=50
  • NAMESPACE="stress-test"
  • CPU_LIMIT="300m"
  • MEM_LIMIT="2Gi"
  • STRESS_MEM="1500M"

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Run

Monitor during the test:
Cleanup when done (also done automatically on Ctrl+C):
Notes:
  • The generated YAML uses Alpine and installs packages in before_script. Ensure the container can run apk (i.e., not forced non‑root during setup). If you enforce strict non‑root, consider prebuilding an image with dependencies.
  • Ensure your node(s) have sufficient CPU/RAM to handle the configured load.