Check if Ceph CRUSH weight is zero for hosts

check-crush-weight.sh

#!/bin/bash
set -euo pipefail

HOST_FILE=""
HOSTS=()

usage() {
    echo "Usage: $0 [--file <hosts-file>] [hostname ...]"
    echo ""
    echo "Checks if CRUSH weight is zero for each specified host."
    exit 1
}

[[ $# -lt 1 ]] && usage
[[ "$1" == "--help" || "$1" == "-h" ]] && usage

while [[ $# -gt 0 ]]; do
    case "$1" in
        --file|-f) HOST_FILE="$2"; shift 2 ;;
        --help|-h) usage ;;
        *) HOSTS+=("$1"); shift ;;
    esac
done

if [[ -n "$HOST_FILE" ]]; then
    if [[ ! -f "$HOST_FILE" ]]; then
        echo "ERROR: file not found: $HOST_FILE"
        exit 1
    fi
    while IFS= read -r line; do
        line="${line%%#*}"
        line="$(echo "$line" | xargs)"
        [[ -n "$line" ]] && HOSTS+=("$line")
    done < "$HOST_FILE"
fi

if [[ ${#HOSTS[@]} -eq 0 ]]; then
    echo "ERROR: no hosts specified"
    usage
fi

crush_tree=$(ceph osd crush tree --format json)

failed=()
for host in "${HOSTS[@]}"; do
    weight=$(echo "$crush_tree" | jq --arg h "$host" '
        [.. | objects | select(.type == "host" and .name == $h) | .. | objects | select(.type == "osd") | .crush_weight] | add // 0
    ')
    if awk "BEGIN{exit !($weight > 0)}"; then
        echo "FAIL: $host — crush weight $weight"
        failed+=("$host")
    else
        echo "OK:   $host — crush weight 0"
    fi
done

if [[ ${#failed[@]} -gt 0 ]]; then
    echo ""
    echo "Hosts with non-zero weight: ${failed[*]}"
    exit 1
fi