#!/bin/bash
# wait-for-host.sh - polls SSH until host is back, then runs verification.
# Usage: bash wait-for-host.sh <host>
set -uo pipefail
HOST="$1"
SSH_OPTS=(-o BatchMode=yes -o ConnectTimeout=5 -o ServerAliveInterval=5 -o StrictHostKeyChecking=accept-new)

DEADLINE=$(( $(date +%s) + 600 ))
echo "Polling $HOST for SSH return (max 10 min)..."
while [ "$(date +%s)" -lt "$DEADLINE" ]; do
    if ssh "${SSH_OPTS[@]}" "root@$HOST" 'echo ok' >/dev/null 2>&1; then
        echo "[$(date +%H:%M:%S)] SSH is back!"
        break
    fi
    sleep 10
    echo "  [$(date +%H:%M:%S)] still down..."
done

if ! ssh "${SSH_OPTS[@]}" "root@$HOST" 'echo ok' >/dev/null 2>&1; then
    echo "FAILED: $HOST not back after 10 minutes"
    exit 1
fi

echo "Waiting 30s for services to settle..."
sleep 30

echo ""
echo "================================================================"
echo "[$HOST] POST-REBOOT VERIFICATION"
echo "================================================================"
echo "--- Uptime (should be < 5 min) ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'uptime'
echo ""
echo "--- TCP congestion control (expect bbr) ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'sysctl net.ipv4.tcp_congestion_control net.core.default_qdisc'
echo ""
echo "--- vm.swappiness ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'sysctl vm.swappiness'
echo ""
echo "--- scaling_governor ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor 2>/dev/null || echo "(no cpufreq driver)"'
echo ""
echo "--- NFS mount options (looking for nconnect=4 + noatime) ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'nfsstat -m 2>/dev/null | head -16'
echo ""
echo "--- NFS TCP connection count to :2049 (expect ~8 = 4 per server × 2 servers) ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'ss -tn state established "( dport = :2049 )" 2>/dev/null'
ssh "${SSH_OPTS[@]}" "root@$HOST" 'ss -tn state established "( dport = :2049 )" 2>/dev/null | tail -n +2 | wc -l'
echo ""
echo "--- Running VMs ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'qm list 2>/dev/null'
echo ""
echo "--- Failed services ---"
ssh "${SSH_OPTS[@]}" "root@$HOST" 'systemctl --failed --no-legend 2>/dev/null | head -10'
echo ""
echo "================================================================"
echo "[$HOST] DONE"
echo "================================================================"
