PiFence.sh

#!/bin/bash

# Written by Brian Jenkins
# 4 August 2022

# Send a UDP packet to the homemade power supply to cycle power to any one
# of the individual power supplies. This will serve to fence a Raspberry Pi
# that is powered by this supply. This script is used in conjuction with
# a pacemaker cluster setup with Raspberry Pis.

# This script is based on the fence_ssh script written by Steve Bissaker
# See credits and GPL below
# https://github.com/nannafudge/fence_ssh/blob/alternate_version/fence_ssh

# Copyright (C) 2017  Steve Bissaker
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# Initialization
if [[ -z $OCF_ROOT ]]; then
  # Set default OCF_ROOT directory
  export OCF_ROOT=/usr/lib/ocf
fi

: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/resource.d/heartbeat}
. ${OCF_FUNCTIONS_DIR}/.ocf-shellfuncs

if [[ -z $__SCRIPT_NAME ]]; then
  __SCRIPT_NAME=$(basename $0)
fi

# Default action
action=$__OCF_ACTION
# Current node name
current_node_name=$(crm_node -n)
description="${__SCRIPT_NAME} is a fencing agent for homemade USB power supply."

function usage() {
  cat <<EOF
$__SCRIPT_NAME - $description
Usage: $__SCRIPT_NAME -a|--action [action] -n|--nodename [nodename] [options]
Options:
 --help            This text
Commands:
 -a, --action      Action to perform: on|off/shutdown|reboot|monitor|metadata, defaults to reboot
 -n, --nodename    Node to fence
Options:
 -i, --fence-ip    IP address of the fence device, default to 10.0.1.77
 -P, --fence-port  Port of the fence device, default to 11089
EOF
  exit $OCF_SUCCESS
}

function metadata() {
  cat <<EOF
<?xml version="1.0" ?>
<resource-agent name="${__SCRIPT_NAME}" shortdesc="Fencing agent for homemade USB power supply"> 
  <longdesc>
    $description
  </longdesc>
  <vendor-url>
    https://tnthr.dev
  </vendor-url>
  <parameters>
    <parameter name="action" unique="0" required="0">
      <getopt mixed="-a, --action"/>
      <content type="string" default="reboot"/>
      <shortdesc lang="en">Action to perform: on|off/shutdown|reboot|monitor|metadata</shortdesc>
    </parameter>
    <parameter name="nodename" unique="0" required="0">
      <getopt mixed="-n, --nodename"/>
      <content type="string"/>
      <shortdesc lang="en">The nodename of the remote machine to fence</shortdesc>
    </parameter>
    <parameter name="fence-ip" unique="0" required="1">
      <getopt mixed="-i, --fence-ip"/>
      <content type="string" default="10.0.1.77"/>
      <shortdesc lang="en">The IP address of the fence device</shortdesc>
    </parameter>
    <parameter name="fence-port" unique="0" required="1">
      <getopt mixed="-P, --fence-port"/>
      <content type="string" default="11089"/>
      <shortdesc lang="en">The port of the fence device</shortdesc>
    </parameter>
  </parameters>
  <actions>
    <action name="on" />
    <action name="off" />
    <action name="reboot" />
    <action name="monitor" />
    <action name="metadata" />
  </actions>
</resource-agent>
EOF
  exit 0
}

# Function to monitor the status of the fence and report back to pacemaker
function monitor() {
  # Check to see if the fence device is online
  ps_output=$(ping -c 1 10.0.1.77 >/dev/null 2>&1) # TODO change this hardcoded ip port

  if [[ $? != 0 ]]; then
    ocf_Log err "${__SCRIPT_NAME}: Fence device is NOT running ${current_node_name}: ${ps_output}"
    return $OCF_NOT_RUNNING
  fi

  ocf_log debug "${__SCRIPT_NAME}: Fence device is running, ${current_node_name} is available for fencing if need be."
  return $OCF_SUCCESS
}

# Function to send a UDP packet to the power supply and perform the fencing
# $1 is the command to perform (RP | RK | RR)
function perform_action() {
  command="nc -u -w2"
  action_code=$1

  if [[ -z $host ]]; then
    ocf_log err "Error, no nodename specified! Run '${__SCRIPT_NAME} --help' for usage."
    return $OCF_ERR_ARGS
  fi

  # add the destination ip to the end of the command
  if [[ -n $fence_ip ]]; then
    command="${command} ${fence_ip}"
  else
    command="${command} 10.0.1.77"
  fi
  # add the destination port to the end of the command
  if [[ -n $fence_port ]]; then
    command="${command} ${fence_port}"
  else
    command="${command} 11089"
  fi

  ocf_log debug "${__SCRIPT_NAME}: About to execute STONITH command ${action_code}${host} | ${command}"
  #echo "${__SCRIPT_NAME}: About to execute STONITH command ${action_code}${host} | ${command}"

  err_output=$(eval "echo '${action_code}${host}' | ${command}" 2>&1)
  exit_code=$?

  if [[ $exit_code != 0 ]]; then
    ocf_log err "Error fencing machine: ${err_output}"
    return $OCF_ERR_GENERIC
  fi

  ocf_log debug "Machine ${host} successfully fenced"
  #echo "Machine ${host} successfully fenced"
  return $OCF_SUCCESS
}

# Data being piped in from stonith-ng
if [[ -p /dev/stdin ]]; then
  while read line; do
    raw_input+="${line} "
  done
  # Suffix args with double dash so it can be parsed by the case statement below
  args=$(echo $raw_input | awk '{ $0="--"$0; gsub(/ /, " --", $0); gsub(/=/, " ", $0); print $0 }')
  ocf_log debug "${__SCRIPT_NAME}: ARGS ARE $args"
  #echo "${__SCRIPT_NAME}: ARGS ARE $args"
  eval set -- "$args"
fi

while [[ $# -gt 0 ]]; do
  case $1 in
    -a | --action)
      action=$2
      shift
      shift
      ;;
    -n | --nodename)
      host=$2
      shift
      shift
      ;;
    -i | --fence-ip)
      fence_ip=$2
      shift
      shift
      ;;
    -P | --fence-port)
      fence_port=$2
      shift
      shift
      ;;
    --help)
      usage
      ;;
    --port)
      shift
      shift
      ;;
    *)
      unknown_args+=($1)
      shift
      shift
      ;;
  esac
done

if [[ -z $action ]]; then
  ocf_log err "Error, no action specified! Run '${__SCRIPT_NAME} --help' for usage."
  exit $OCF_ERR_ARGS
fi

for unknown_arg in ${unknown_args[@]}; do
  ocf_log err "Argument '${unknown_arg}' is not a valid argument!"
done

# Change the node name to the powered port number for use at the arduino
# TODO: add pcmk host map or something
case $host in
  node1)
    host='1'
    ;;
  node2)
    host='2'
    ;;
  node3)
    host='3'
    ;;
  node4)
    host='4'
    ;;
  node5)
    host='5'
    ;;
esac

# Decide which action was requested and call the action function
case $action in
  on)
    perform_action 'RP'
    ;;
  off | shutdown)
    perform_action 'RK'
    ;;
  reboot)
    perform_action 'RR'
    ;;
  monitor)
    monitor
    ;;
  metadata | meta_data | metadata)
    metadata
    ;;
  *)
    ocf_log info "Action ${action} is not a valid action, run '${__SCRIPT_NAME} --help' for usage."
    exit $OCF_ERR_UNIMPLEMENTED
    ;;
esac

exit $?