maint_mode.sh

#!/bin/bash

# ---------------------------------------------------------
#                 Proxmox Maintenance Mode
#  -Darkhand81
#  https://github.com/Darkhand81/ProxmoxMaintenanceMode
#  Temporarily disable all VMs/CTs that are set to autoboot
#  at node startup to allow for node maintenance.
#
# ---------------------------------------------------------

# ---BEGIN---

# Require root
if [[ $EUID -ne 0 ]]; then
    echo "$0 is not running as root. Try using sudo."
    exit 2
fi

# Pathname of the lockfile that signals the script that we are in
# maintenance mode.  Contains the VMs/CTs that were disabled so they
# can be re-enabled later:
lockfile="/root/maintmode.lock"

# ---------
# Functions
# ---------

# Enable maintenance mode - Query all instances, check which are set to
# start at boot, record and disable them.
function enable_maintmode(){

  echo "Disabling (and saving) current onboot settings:"

  # List all VMs, filter only the first word, then filter only numerics (IDs):
  for vm in $(qm list | awk '{print $1}' | grep -Eo '[0-9]{1,5}')
  do
    # Of those, query each VMID and search for those with onboot: enabled:
    for vmstatus in $(qm config $vm | grep "onboot: 1" | awk '{print $2}')
    do
      #Save matching IDs to the lockfile, prepend with VM to identify as a VM:
      echo "VM$vm" >> $lockfile
      # Disable onboot for matching VMIDs:
      qm set $vm -onboot 0
    done
  done

  # Repeat for CTs as they use a different command to enable/disable:
  for ct in $(pct list | awk '{print $1}' | grep -Eo '[0-9]{1,5}')
  do
    for ctstatus in $(pct config $ct | grep "onboot: 1" | awk '{print $2}')
    do
      # Prepend with CT to identify as a container:
      echo "CT$ct" >> $lockfile
      # Disable onboot for matching containers:
      pct set $ct -onboot 0
      # pct currently doesn't provide an output like qm does, so simulate it here:
      echo "update CT $ct: -onboot 0"
    done
  done
}

# Disable maintenance mode - Parse the lockfile and re-enable onboot
# for those IDs:
function disable_maintmode(){

  file=$(cat $lockfile)
  echo -e "\nRe-enabling previous onboot settings:"

  for line in $file
  do
    # For each line starting with VM, run the qm command to enable VM onboot:
    for vm_on in $(echo -e "$line" | grep 'VM' | cut -c 3-)
    do
      qm set $vm_on -onboot 1
    done
  done

  for line in $file
  do
    # For each line starting with CT, run the pct command for CTs:
    for ct_on in $(echo -e "$line" | grep 'CT' | cut -c 3-)
    do
      pct set $ct_on -onboot 1
      # pct currently doesn't provide an output like qm does, so simulate it here:
      echo "update CT $ct_on: -onboot 1"
    done
  done

  # Remove the lockfile as we want to signal that we are out of maintenance mode:
  rm $lockfile
}

# -----
# Start
# -----

# If the lockfile doesn't exist, we want to enable maintenance mode (disable onboot).
# Otherwise we want to disable maintenance mode (enable onboot):
if [ ! -f "$lockfile" ]; then
  echo
  read -p "Enable maintenance mode and disable all current VM/CT bootup? (y/n) " CONT
    if [ "$CONT" = "y" ]; then
      enable_maintmode;
      echo -e "\nMaintenance mode is now enabled! VM autostart is disabled. Run this script again to re-enable."
    else
      echo "Exiting.";
      exit
    fi
else
  echo
  read -p "Maintenance mode is on! Re-enable previous VM/CT bootup? (y/n) " CONT
    if [ "$CONT" = "y" ]; then
      disable_maintmode
      echo -e "\nMaintenance mode is now disabled! All VMs/CTs that were previously set to autorun will do so at next bootup."
    else
      echo "Exiting.";
      exit
    fi
fi