drbd-utils 8.9.6-1 / usr / lib / ocf / resource.d / linbit / drbd

#!/bin/bash
#
#
#		OCF Resource Agent compliant drbd resource script.
#
# Copyright (c) 2009 LINBIT HA-Solutions GmbH,
# Copyright (c) 2009 Florian Haas, Lars Ellenberg
# Based on the Heartbeat drbd OCF Resource Agent by Lars Marowsky-Bree
# (though it turned out to be an almost complete rewrite)
#
#					 All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# Further, this software is distributed without any warranty that it is
# free of the rightful claim of any third person regarding infringement
# or the like.	Any license provided herein, whether implied or
# otherwise, applies only to this software file.  Patent licenses, if
# any, provided herein do not apply to combinations of this program with
# other software, or any other product whatsoever.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
#
#

# OCF instance parameters
#	OCF_RESKEY_drbd_resource
#	OCF_RESKEY_drbdconf
#	OCF_RESKEY_stop_outdates_secondary
#	OCF_RESKEY_adjust_master_score
#
# meta stuff this agent looks at:
#	OCF_RESKEY_CRM_meta_clone_max
#	OCF_RESKEY_CRM_meta_clone_node_max
#	OCF_RESKEY_CRM_meta_master_max
#	OCF_RESKEY_CRM_meta_master_node_max
#
#	OCF_RESKEY_CRM_meta_interval
#
#	OCF_RESKEY_CRM_meta_notify
#	OCF_RESKEY_CRM_meta_notify_active_uname
#	OCF_RESKEY_CRM_meta_notify_demote_uname
#	OCF_RESKEY_CRM_meta_notify_master_uname
#	OCF_RESKEY_CRM_meta_notify_operation
#	OCF_RESKEY_CRM_meta_notify_promote_uname
#	OCF_RESKEY_CRM_meta_notify_slave_uname
#	OCF_RESKEY_CRM_meta_notify_start_uname
#	OCF_RESKEY_CRM_meta_notify_stop_uname
#	OCF_RESKEY_CRM_meta_notify_type
#

#######################################################################
# Initialization:

# Resource-agents have moved their ocf-shellfuncs file around.
# There are supposed to be symlinks or wrapper files in the old location,
# pointing to the new one, but people seem to get it wrong all the time.
# Try several locations.

if test -n "${OCF_FUNCTIONS_DIR}" ; then
	if test -e "${OCF_FUNCTIONS_DIR}/ocf-shellfuncs" ; then
		. "${OCF_FUNCTIONS_DIR}/ocf-shellfuncs"
	elif test -e "${OCF_FUNCTIONS_DIR}/.ocf-shellfuncs" ; then
		. "${OCF_FUNCTIONS_DIR}/.ocf-shellfuncs"
	fi
else
	if test -e "${OCF_ROOT}/lib/heartbeat/ocf-shellfuncs" ; then
		. "${OCF_ROOT}/lib/heartbeat/ocf-shellfuncs"
	elif test -e "${OCF_ROOT}/resource.d/heartbeat/.ocf-shellfuncs"; then
		. "${OCF_ROOT}/resource.d/heartbeat/.ocf-shellfuncs"
	fi
fi

# Defaults
OCF_RESKEY_drbdconf_default="/etc/drbd.conf"
OCF_RESKEY_unfence_extra_args_default="--quiet --flock-required --flock-timeout 0 --unfence-only-if-owner-match"

if ocf_is_true ${OCF_RESKEY_unfence_if_all_uptodate:=false}; then
	unfence_if_all_uptodate=true
else
	unfence_if_all_uptodate=false
fi

# The passed in OCF_CRM_meta_notify_* environment
# is not reliably with pacemaker up to at least
# 1.0.10 and 1.1.4. It should be fixed later.
# Until that is fixed, the "self-outdating feature" would base its actions on
# wrong information, and possibly not outdate when it should, or, even worse,
# outdate the last remaining valid copy.
# Disable.
OCF_RESKEY_stop_outdates_secondary_default="false"

  OCF_RESKEY_adjust_master_score_default="5 10 1000 10000"
#   ignored  |  Consistent    |  Unknown -'  |   |     |
#   ignored  |  NOT UpToDate  |  UpToDate ---'   |     |
# Secondary  |  UpToDate      |  unknown --------'     |
#   ignored  |  UpToDate      |  known   --------------+
#   Primary  |  UpToDate      |  ignored --------------'

: ${OCF_RESKEY_drbdconf:=${OCF_RESKEY_drbdconf_default}}
: ${OCF_RESKEY_stop_outdates_secondary:=${OCF_RESKEY_stop_outdates_secondary_default}}
: ${OCF_RESKEY_adjust_master_score:=${OCF_RESKEY_adjust_master_score_default}}

# Defaults according to "Configuration 1.0 Explained",
# "Multi-state resource configuration options"
: ${OCF_RESKEY_CRM_meta_clone_node_max=1}
: ${OCF_RESKEY_CRM_meta_master_max=1}
: ${OCF_RESKEY_CRM_meta_master_node_max=1}
#######################################################################
# for debugging this RA
DEBUG_LOG_DIR=/tmp/drbd.ocf.ra.debug
DEBUG_LOG=$DEBUG_LOG_DIR/log
USE_DEBUG_LOG=false
ls_stat_is_dir_0700_root() {
	set -- $(command ls -ldn "$1" 2>/dev/null);
	case "$1/$3" in
	drwx?-??-?/0|\
	drwx?-??-?./0)	true ;;
	*)	false ;;
	esac
}
# try to avoid symlink vuln.
if ls_stat_is_dir_0700_root $DEBUG_LOG_DIR &&
   [[ -w "$DEBUG_LOG" && ! -L "$DEBUG_LOG" ]]
then
	USE_DEBUG_LOG=true
	# PS4='+[`date +%F\ %T.%3N`] '
	exec 9>>"$DEBUG_LOG"
	date >&9
	echo "$*" >&9
	env | grep OCF_ | sort >&9
else
	exec 9>/dev/null
fi
# end of debugging aid
#######################################################################

meta_data() {
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="drbd">
<version>1.3</version>

<longdesc lang="en">
This resource agent manages a DRBD resource as a master/slave resource.
DRBD is a shared-nothing replicated storage device.
Note that you should configure resource level fencing in DRBD,
this cannot be done from this resource agent.
See the DRBD User's Guide for more information.
http://www.drbd.org/docs/applications/
</longdesc>

<shortdesc lang="en">Manages a DRBD device as a Master/Slave resource</shortdesc>

<parameters>
<parameter name="drbd_resource" unique="1" required="1">
<longdesc lang="en">
The name of the drbd resource from the drbd.conf file.
</longdesc>
<shortdesc lang="en">drbd resource name</shortdesc>
<content type="string"/>
</parameter>

<parameter name="drbdconf">
<longdesc lang="en">
Full path to the drbd.conf file.
</longdesc>
<shortdesc lang="en">Path to drbd.conf</shortdesc>
<content type="string" default="${OCF_RESKEY_drbdconf_default}"/>
</parameter>

<parameter name="adjust_master_score">
<longdesc lang="en">
Space separated list of four master score adjustments for different scenarios:
 - only access to 'consistent' data
 - only remote access to 'uptodate' data
 - currently Secondary, local access to 'uptodate' data, but remote is unknown
 - local access to 'uptodate' data, and currently Primary or remote is known

Numeric values are expected to be non-decreasing.

Default are the previously hardcoded values.

Set the first value to 0 (and configure proper fencing methods)
to prevent pacemaker from trying to promote while it is unclear
whether the data is really the most recent copy.
(DRBD knows it is "consistent", but is unsure about "uptodate"ness).

Advanced use: Adjust the other values to better fit into complex
dependency score calculations.
</longdesc>
<shortdesc lang="en">master score adjustments</shortdesc>
<content type="string" default="${OCF_RESKEY_adjust_master_score_default}"/>
</parameter>

<parameter name="stop_outdates_secondary">
<longdesc lang="en">
Recommended setting: leave at default (disabled).

Note that this feature depends on the passed in information in
OCF_RESKEY_CRM_meta_notify_master_uname to be correct, which unfortunately is
not reliable for pacemaker versions up to at least 1.0.10 / 1.1.4.

If a Secondary is stopped (unconfigured), it may be marked as outdated in the
drbd meta data, if we know there is still a Primary running in the cluster.
Note that this does not affect fencing policies set in drbd config,
but is an additional safety feature of this resource agent only.
You can enable this behaviour by setting the parameter to true.

If this feature seems to not do what you expect, make sure you have defined
fencing policies in the drbd configuration as well.
</longdesc>
<shortdesc lang="en">outdate a secondary on stop</shortdesc>
<content type="boolean" default="${OCF_RESKEY_stop_outdates_secondary_default}"/>
</parameter>

<parameter name="ignore_missing_notifications">
<longdesc lang="en">
Some setups do not benefit from notifications.
Allow to disable notifications without patching this resource agent.
</longdesc>
<shortdesc lang="en">ignore missing notify=true</shortdesc>
<content type="boolean" default="false"/>
</parameter>

<parameter name="unfence_if_all_uptodate">
<longdesc lang="en">
If all volumes of this resource report to be UpToDate,
call an unfence script hook, just in case some stale fencing constraint
or similar is still around.
<![CDATA[
- With DRBD utils version <= 8.9.4, this is hardcoded to
  /usr/lib/drbd/crm-unfence-peer.sh -r \$DRBD_RESOURCE
- With DRBD utils version >= 8.9.5, this is dispatched to
   \$DRBDADM unfence-peer \$DRBD_RESOURCE

In any case, the hook itself is responsible to fetch
\$OCF_RESKEY_unfence_extra_args from its environment.
]]>
</longdesc>
<shortdesc lang="en">call unfence hook once fully UpToDate</shortdesc>
<content type="boolean" default="false"/>
</parameter>

<parameter name="unfence_extra_args">
<longdesc lang="en">
This may be used to pass extra hints to the unfence hook.
See description of unfence_if_all_uptodate.
</longdesc>
<shortdesc lang="en">Extra arguments for the unfence hook.</shortdesc>
<content type="boolean" default="$OCF_RESKEY_unfence_extra_args_default"/>
</parameter>
</parameters>

<actions>
<action name="start"   timeout="240" />
<action name="promote"	 timeout="90" />
<action name="demote"	timeout="90" />
<action name="notify"	timeout="90" />
<action name="stop"    timeout="100" />
<action name="monitor" depth="0"  timeout="20" interval="20" role="Slave" />
<action name="monitor" depth="0"  timeout="20" interval="10" role="Master" />
<action name="meta-data"  timeout="5" />
<action name="validate-all"  timeout="30" />
</actions>
</resource-agent>
END
}

do_cmd() {
	# Run a command, return its exit code, capture any output, and log
	# everything if appropriate.
	local cmd="$*" cmd_out ret
	ocf_log debug "$DRBD_RESOURCE: Calling $cmd"
	cmd_out=$( "$@" )
	ret=$?

	if [ $ret != 0 ]; then
		ocf_log err "$DRBD_RESOURCE: Called $cmd"
		ocf_log err "$DRBD_RESOURCE: Exit code $ret"
		ocf_log err "$DRBD_RESOURCE: Command output: $cmd_out"
	else
		ocf_log debug "$DRBD_RESOURCE: Exit code $ret"
		ocf_log debug "$DRBD_RESOURCE: Command output: $cmd_out"
	fi

	echo "$cmd_out"

	return $ret
}

do_drbdadm() {
	local ret
	# Run drbdadm with appropriate command line options, and capture
	# its output.
	# $DRBDADM is defined during drbd_validate as "drbdadm" plus
	# appropriate command line options
	do_cmd $DRBDADM "$@"
	ret=$?

	# having the version mismatch warning once per RA invokation
	# should be enough.
	export DRBD_DONT_WARN_ON_VERSION_MISMATCH=

	return $ret
}

set_master_score() {
	# Use quiet mode (-Q) to quench logging. Actual score updates
	# will get logged by attrd anyway
	if [[ $1 -le 0 ]]; then
		remove_master_score
	else
		do_cmd ${HA_SBIN_DIR}/crm_master -Q -l reboot -v $1
	fi
}

remove_master_score() {
	do_cmd ${HA_SBIN_DIR}/crm_master -l reboot -D
}

_sh_status_process() {
	# _volume not present should not happen,
	# but may help make this agent work even if it talks to drbd 8.3.
	: ${_volume:=0}
	# not-yet-created volumes are reported as -1
	(( _volume >= 0 )) || _volume=$[1 << 16]
	DRBD_ROLE_LOCAL[$_volume]=${_role:-Unconfigured}
	DRBD_ROLE_REMOTE[$_volume]=${_peer:-Unknown}
	DRBD_CSTATE[$_volume]=$_cstate
	DRBD_DSTATE_LOCAL[$_volume]=${_disk:-Unconfigured}
	DRBD_DSTATE_REMOTE[$_volume]=${_pdsk:-DUnknown}
}
drbd_set_status_variables() {
	# drbdsetup sh-status prints these values to stdout,
	# and then prints _sh_status_process.
	#
	# if we eval that, we do not need several drbdadm/drbdsetup commands
	# to figure out the various aspects of the state.
	local _minor _res_name _known _cstate _role _peer _disk _pdsk
	local _volume
	local _flags_susp _flags_aftr_isp _flags_peer_isp _flags_user_isp
	local _resynced_percent
	local out

	DRBD_ROLE_LOCAL=()
	DRBD_ROLE_REMOTE=()
	DRBD_CSTATE=()
	DRBD_DSTATE_LOCAL=()
	DRBD_DSTATE_REMOTE=()

	if $DRBD_HAS_MULTI_VOLUME ; then
		out="$($DRBDSETUP sh-status "$DRBD_RESOURCE")" && eval "$out"
	else
		# without "MULTI_VOLUME", the DRBD_DEVICES array
		# should contain exactly one value
		out="$($DRBDSETUP "$DRBD_DEVICES" sh-status)" && eval "$out"
	fi

	# if there was no output at all, or a weird output
	# make sure the status arrays won't be empty.
	[[ ${#DRBD_ROLE_LOCAL[@]}    != 0 ]] || DRBD_ROLE_LOCAL=(Unconfigured)
	[[ ${#DRBD_ROLE_REMOTE[@]}   != 0 ]] || DRBD_ROLE_REMOTE=(Unknown)
	[[ ${#DRBD_CSTATE[@]}        != 0 ]] || DRBD_CSTATE=(Unconfigured)
	[[ ${#DRBD_DSTATE_LOCAL[@]}  != 0 ]] || DRBD_DSTATE_LOCAL=(Unconfigured)
	[[ ${#DRBD_DSTATE_REMOTE[@]} != 0 ]] || DRBD_DSTATE_REMOTE=(DUnknown)


	: == DEBUG == DRBD_ROLE_LOCAL    == ${DRBD_ROLE_LOCAL[@]} ==
	: == DEBUG == DRBD_ROLE_REMOTE   == ${DRBD_ROLE_REMOTE[@]} ==
	: == DEBUG == DRBD_CSTATE        == ${DRBD_CSTATE[@]} ==
	: == DEBUG == DRBD_DSTATE_LOCAL  == ${DRBD_DSTATE_LOCAL[@]} ==
	: == DEBUG == DRBD_DSTATE_REMOTE == ${DRBD_DSTATE_REMOTE[@]} ==
}

call_unfence()
{
	# It is easier to just call the crm-unfence-peer script, without
	# duplicating part of its code here.  Also adding cibadmin calls to
	# first check if such constraint does even exist would needlessly add
	# even more load on the cib.

	export OCF_RESKEY_unfence_extra_args
	: ${OCF_RESKEY_unfence_extra_args:=$OCF_RESKEY_unfence_extra_args_default}

	# The unfence-peer handler was introduced only in 8.9.5.
	if (( DRBDADM_VERSION_CODE >= 0x080905 )) ; then
		$DRBDADM unfence-peer $DRBD_RESOURCE
	else
		/usr/lib/drbd/crm-unfence-peer.sh -r $DRBD_RESOURCE
	fi
	: "unfence exit code: $?"
}

# This is not the only fencing mechanism.
# But in addition to the drbd "fence-peer" handler, which should be configured,
# and is expected to place some appropriate constraints, this is used to
# actually store the Outdated information in DRBD on-disk meta data.
#
# called after stop, and from post notification events.
maybe_outdate_self()
{
	# if you claim your right to go online with stale data,
	# there you are.
	ocf_is_true $OCF_RESKEY_stop_outdates_secondary || return 1

	local host stop_uname
	# We ignore $OCF_RESKEY_CRM_meta_notify_promote_uname here
	# because: if demote and promote for a _stacked_ resource
	# (or a "floating" one, where DRBD sits on top of some SAN)
	# happen in the same transition, demote will see the promote
	# hostname here, and voluntarily outdate itself. Which would
	# result in promote failure, as it is using the same meta
	# data, which would then be outdated.
	# If that is not sufficient for you, you probably need to
	# configure fencing policies in the drbd configuration.
	host=$(printf "%s\n" $OCF_RESKEY_CRM_meta_notify_master_uname |
		grep -vix -m1 -e "$HOSTNAME" )
	if [[ -z $host ]] ; then
		# no current master host found, do not outdate myself
		return 1
	fi
	for stop_uname in $OCF_RESKEY_CRM_meta_notify_stop_uname; do
		[[ $host == "$stop_uname" ]] || continue
		# post notification for stop on that host.
		# hrmpf. crm passed in stale master_uname :(
		# ignore
		return 1
	done

	# e.g. post/promote of some other peer.
	# Should not happen, fencing constraints should take care of that.
	# But in case it does, scream out loud.
	case "${DRBD_ROLE_LOCAL[*]}" in
	*Primary*)
		# I am Primary.
		# The other one is Primary (according to OCF_RESKEY_CRM_meta_notify_master_uname).
		# But we cannot talk to each other :( (otherwise this function was not called)
		# One of us has to die.
		# Which one, however, is not ours to decide.

		ocf_log crit "resource internal SPLIT BRAIN: both $HOSTNAME and $host are Primary for $DRBD_RESOURCE, but the replication link is down!"
		return 1
	esac

	# OK, I am not Primary, but there is an other node Primary
	# Outdate myself
	ocf_log notice "outdating $DRBD_RESOURCE: according to OCF_RESKEY_CRM_meta_notify_master_uname, '$host' is still master"
	do_drbdadm outdate $DRBD_RESOURCE

	# on some pacemaker versions, -INFINITY may cause resource instance stop/start.
	# But in this case that is ok, it may even clear the replication link
	# problem.
	set_master_score -INFINITY

	return 0
}

drbd_update_master_score() {
	set -- $OCF_RESKEY_adjust_master_score
	local only_consistent=$1 only_remote=$2 local_ok=$3 as_good_as_it_gets=$4
	# NOTE
	# there may be constraint scores from rules on role=Master,
	# that in some ways can add to the node attribute based master score we
	# specify below. If you think you want to add personal preferences,
	# in case the scores given by this RA do not suffice, this is the
	# value space you can work with:
	# -INFINITY: Do not promote. Really. Won't work anyways.
		# Too bad, at least with current (Oktober 2009) Pacemaker,
		# negative master scores cause instance stop; restart cycle :(
	# missing, zero: Do not promote.
	#        I think my data is not good enough.
	#        Though, of course, you may try, and it might even work.
	#     5: please, do not promote, unless this is your only option.
	#    10: promotion is probably a bad idea, our local data is no good,
	#        you'd probably run into severe performance problems, and risk
	#        application crashes or blocking IO in case you lose the
	#        replication connection.
	#  1000: Ok to be promoted, we have good data locally (though we don't
	#        know about the peer, so possibly it has even better data?).
	#        You sould use the crm-fence-peer.sh handler or similar
	#        mechanism to avoid data divergence.
	# 10000: Please promote me/keep me Primary.
	#        I'm confident that my data is as good as it gets.
	#
	# For multi volume, we need to compare who is "better" a bit more sophisticated.
	# The ${XXX[*]//UpToDate}, without being in double quotes, results in a single space,
	# if all are UpToDate.
	: == DEBUG == ${DRBD_ROLE_LOCAL[*]}/${DRBD_DSTATE_LOCAL[*]//UpToDate/ }/${DRBD_DSTATE_REMOTE[*]//UpToDate/ }/ ==
	case ${DRBD_ROLE_LOCAL[*]}/${DRBD_DSTATE_LOCAL[*]//UpToDate/ }/${DRBD_DSTATE_REMOTE[*]//UpToDate/ }/ in
	*Primary*/\ /\ /)
		# I am Primary, all local disks are UpToDate,
		# AND all peer disks are UpToDate
		set_master_score $as_good_as_it_gets
		: == DEBUG == unfence_if_all_uptodate=$unfence_if_all_uptodate
		$unfence_if_all_uptodate && call_unfence
		;;
	*Primary*/\ /*/)
		# I am Primary, all local disks are UpToDate,
		# not so sure about the peer's disks
		set_master_score $as_good_as_it_gets
		;;
	*/\ /*DUnknown*/)
		# all local disks are UpToDate,
		# but I'm not Primary,
		# and I'm not sure about the peer's disk state(s).
		# We may need to outdate ourselves?
		# But if we outdate in a MONITOR, and are disconnected
		# secondary because of a hard primary crash, before CRM noticed
		# that there is no more master, we'd make us utterly useless!
		# Trust that the primary will also notice the disconnect,
		# and will place an appropriate fencing constraint via
		# its fence-peer handler callback.
		set_master_score  $local_ok
		;;
	*/\ /*/)
		# We know something about our peer, which means that either the
		# replication link is established, or it was not even
		# consistent last time we talked to each other.
		# Also all our local disks are UpToDate, which means even if we are
		# currently synchronizing, we do so as SyncSource.
		set_master_score $as_good_as_it_gets
		;;

	*/*/\ /)
		# At least one of our local disks is not up to date.
		# But our peer is ALL OK.
		# We can expect to have access to useful
		# data, but must expect degraded performance.
		set_master_score $only_remote
		;;

	*/*Attaching*/*/|\
	*/*Negotiating*/*/)
		# some transitional state.
		# just don't do anything
		: ;;

	Unconfigured*|\
	*/*Diskless*/*/|\
	*/*Failed*/*/|\
	*/*Inconsistent*/*/|\
	*/*Outdated*/*/)
		# ALWAYS put the cluster in MAINTENANCE MODE
		# if you add a volume to a live replication group,
		# because the new volume will typically come up as Inconsistent
		# the first time, which would cause a monitor to revoke the
		# master score!
		#
		# At least some of our local disks are not really useable.
		# Our peer is not all good either (or some previous case block
		# would have matched).  We have no access to useful data.
		# DRBD would refuse to be promoted, anyways.
		#
		# set_master_score -INFINITY
		# Too bad, at least with current (Oktober 2009) Pacemaker,
		# negative master scores cause instance stop; restart cycle :(
		# Hope that this will suffice.
		remove_master_score
		;;
	*)
		# All local disks seem to be Consistent.
		# They _may_ be up to date, or not.
		# We hope that fencing mechanisms have put constraints in
		# place, so we won't be promoted with stale data.
		# But in case this was a cluster crash,
		# at least allow _someone_ to be promoted.
		set_master_score $only_consistent
		;;
	esac

	: "$OCF_SUCCESS = OCF_SUCCESS"
	return $OCF_SUCCESS
}

is_drbd_enabled() {
	test -f /proc/drbd
}

#######################################################################

drbd_usage() {
	echo "\
usage: $0 {start|stop|monitor|validate-all|promote|demote|notify|meta-data}

Expects to have a fully populated OCF RA-compliant environment set."
}

drbd_status() {
	local rc
	local dev
	rc=$OCF_NOT_RUNNING

	# NOT local! but "return values"
	# since 8.4 supports multi volumes per resource,
	# these are shell arrays.
	#
	# Initialize to "Unconfigured", in case this returns early.
	# They will be re-initialized and properly populated in drbd_set_status_variables.
	DRBD_ROLE_LOCAL=(Unconfigured)
	DRBD_ROLE_REMOTE=(Unknown)
	DRBD_CSTATE=(Unconfigured)
	DRBD_DSTATE_LOCAL=(Unconfigured)
	DRBD_DSTATE_REMOTE=(DUnknown)

	is_drbd_enabled || return $rc

	# Not running, if no block devices exist.
	#
	# FIXME what if some do, and some do not exist?
	# Adding/removing volumes to/from existing resources should only be
	# done with maintenance-mode enabled.
	# If someone does manually kill/remove only some of the volumes,
	# we tolerate that here.
	for dev in ${DRBD_DEVICES[@]} ""; do
		test -b $dev && break
	done
	[[ $dev ]] || return $rc

	# ok, module is loaded, block device nodes exist.
	# lets see the status
	drbd_set_status_variables
	case "${DRBD_ROLE_LOCAL[*]}" in
	*Primary*)
		rc=$OCF_RUNNING_MASTER
		;;
	*Secondary*)
		rc=$OCF_SUCCESS
		;;
	*Unconfigured*)
		rc=$OCF_NOT_RUNNING
		;;
	*)
		ocf_log err "Unexpected role(s) >>${DRBD_ROLE_LOCAL[*]}<<"
		rc=$OCF_ERR_GENERIC
	esac

	return $rc
}

# I'm sorry, but there is no $OCF_DEGRADED_MASTER or similar yet.
drbd_monitor() {
	local status
	drbd_status
	status=$?

	if [[ $status = $OCF_NOT_RUNNING ]] && ocf_is_probe ; then
		# see also linux-ha mailing list archives,
		# From: Andrew Beekhof
		# Subject: Re: pacemaker+drbd promotion delay
		# Date: 2012-04-13 01:47:37 GMT
		# e.g.: http://thread.gmane.org/gmane.linux.highavailability.user/37089/focus=37163
		# ---
		: "do nothing" ;
	else
		drbd_update_master_score
	fi

	case $status in
	(0) : "OCF_SUCCESS" ;;
	(1) : "OCF_ERR_GENERIC" ;;
	(2) : "OCF_ERR_ARGS" ;;
	(3) : "OCF_ERR_UNIMPLEMENTED" ;;
	(4) : "OCF_ERR_PERM" ;;
	(5) : "OCF_ERR_INSTALLED" ;;
	(6) : "OCF_ERR_CONFIGURED" ;;
	(7) : "OCF_NOT_RUNNING" ;;
	(8) : "OCF_RUNNING_MASTER" ;;
	(9) : "OCF_FAILED_MASTER" ;;
	(*) : " WTF? $status " ;;
	esac

	return $status
}

figure_out_drbd_peer_uname()
{
	# depending on whether or not the peer is currently
	# configured, slave, master, or about to be started,
	# it may be mentioned in various variables (or not at all)
	local x
	# intentionally not cared for stop_uname
	x=$(printf "%s\n" \
		$OCF_RESKEY_CRM_meta_notify_start_uname \
		$OCF_RESKEY_CRM_meta_notify_promote_uname \
		$OCF_RESKEY_CRM_meta_notify_master_uname \
		$OCF_RESKEY_CRM_meta_notify_slave_uname \
		$OCF_RESKEY_CRM_meta_notify_demote_uname |
		grep -vix -m1 -e "$HOSTNAME" )
	DRBD_TO_PEER=${x:+ --peer $x}
}

my_udevsettle()
{
	for dev in ${DRBD_DEVICES[@]}; do
		while ! test -b $dev; do
			sleep 1;
		done
	done
	return 0
}
create_device_udev_settle() {
	local dev
	if $DRBD_HAS_MULTI_VOLUME; then
		if do_drbdadm new-resource $DRBD_RESOURCE &&
		   do_drbdadm new-minor $DRBD_RESOURCE; then
			my_udevsettle
		else
			return 1
		fi
	elif do_drbdadm syncer $DRBD_RESOURCE ; then
		my_udevsettle
	else
		return 1
	fi
}

drbd_start() {
	local rc
	local status
	local first_try=true

	rc=$OCF_ERR_GENERIC

	if ! is_drbd_enabled; then
		do_cmd modprobe -s drbd `$DRBDADM sh-mod-parms` || {
			ocf_log err "Cannot load the drbd module.";
			: "$OCF_ERR_INSTALLED = OCF_ERR_INSTALLED"
			return $OCF_ERR_INSTALLED
		}
		ocf_log debug "$DRBD_RESOURCE start: Module loaded."
	fi

	# Keep trying to bring up the resource;
	# wait for the CRM to time us out if this fails
	while :; do
		drbd_status
		status=$?
		case "$status" in
		$OCF_SUCCESS)
			# Just in case we have to adjust something, this is a
			# good place to do it.  Actually, we don't expect to be
			# called to "start" an already "running" resource, so
			# this is probably dead code.
			# Also, ignore the exit code of adjust, as we are
			# "running" already, anyways, right?
			figure_out_drbd_peer_uname
			do_drbdadm $DRBD_TO_PEER adjust $DRBD_RESOURCE
			rc=$OCF_SUCCESS
			break
			;;
		$OCF_NOT_RUNNING)
			# Check for offline resize. If using internal meta data,
			# we may need to move it first to its expected location.
			$first_try && do_drbdadm check-resize $DRBD_RESOURCE
			figure_out_drbd_peer_uname
			if ! create_device_udev_settle; then
				# We cannot even create the objects
				exit $OCF_ERR_GENERIC
			fi
			if ! do_drbdadm $DRBD_TO_PEER attach $DRBD_RESOURCE ; then
				# If we cannot up it, even on the second try,
				# it is unlikely to get better.  Don't wait for
				# this operation to timeout, but short circuit
				# exit with generic error.
				$first_try || exit $OCF_ERR_GENERIC
				sleep 1
			fi
			;;
		$OCF_RUNNING_MASTER)
			ocf_log warn "$DRBD_RESOURCE already Primary, demoting."
			do_drbdadm secondary $DRBD_RESOURCE
		esac
		$first_try || sleep 1
		first_try=false
	done
	# in case someone does not configure monitor,
	# we must at least call it once after start.
	drbd_update_master_score

	return $rc
}

drbd_promote() {
	local rc
	local status
	local first_try=true

	rc=$OCF_ERR_GENERIC

	# Keep trying to promote the resource;
	# wait for the CRM to time us out if this fails
	while :; do
		drbd_status
		status=$?
		case "$status" in
		$OCF_SUCCESS)
			do_drbdadm primary $DRBD_RESOURCE
			if [[ $? = 17 ]]; then
				# All available disks are inconsistent,
				# or I am consistent, but failed to fence the peer.
				# Cannot become primary.
				# No need to retry indefinitely.
				ocf_log crit "Refusing to be promoted to Primary without UpToDate data"
				break
			fi
			;;
		$OCF_NOT_RUNNING)
			ocf_log error "Trying to promote a resource that was not started"
			break
			;;
		$OCF_RUNNING_MASTER)
			rc=$OCF_SUCCESS
			break
		esac
		$first_try || sleep 1
		first_try=false
	done

	# avoid too tight pacemaker driven "recovery" loop,
	# if promotion keeps failing for some reason
	if [[ $rc != 0 ]] && (( $SECONDS < 15 )) ; then
		delay=$(( 15 - SECONDS ))
		ocf_log warn "promotion failed; sleep $delay # to prevent tight recovery loop"
		sleep $delay
	fi
	return $rc
}

drbd_demote() {
	local rc
	local status
	local first_try=true

	rc=$OCF_ERR_GENERIC

	# Keep trying to demote the resource;
	# wait for the CRM to time us out if this fails
	while :; do
		drbd_status
		status=$?
		case "$status" in
		$OCF_SUCCESS)
			rc=$OCF_SUCCESS
			break
			;;
		$OCF_NOT_RUNNING)
			ocf_log error "Trying to promote a resource that was not started"
			break
			;;
		$OCF_RUNNING_MASTER)
			do_drbdadm secondary $DRBD_RESOURCE
		esac
		$first_try || sleep 1
		first_try=false
	done

	return $rc
}

drbd_stop() {
	local rc=$OCF_ERR_GENERIC
	local first_try=true

	# Keep trying to bring down the resource;
	# wait for the CRM to time us out if this fails
	while :; do
		drbd_status
		status=$?
		case "$status" in
		$OCF_SUCCESS)
			do_drbdadm down $DRBD_RESOURCE
			;;
		$OCF_NOT_RUNNING)
			# Just in case, down it anyways, in case it has been
			# deconfigured but not yet removed.
			# Relevant for >= 8.4.
			do_drbdadm down $DRBD_RESOURCE
			# But ignore any return codes,
			# we are not running, so stop is successfull.
			rc=$OCF_SUCCESS
			break
			;;
		$OCF_RUNNING_MASTER)
			ocf_log warn "$DRBD_RESOURCE still Primary, demoting."
			do_drbdadm secondary  $DRBD_RESOURCE
		esac
		$first_try || sleep 1
		first_try=false
	done

	# if there is some Master (Primary) still around,
	# outdate myself in drbd on-disk meta data.
	maybe_outdate_self

	# do not let old master scores laying around.
	# they may confuse crm if this node was set to standby.
	remove_master_score

	return $rc
}


drbd_notify() {
	local n_type=$OCF_RESKEY_CRM_meta_notify_type
	local n_op=$OCF_RESKEY_CRM_meta_notify_operation

	# active_* and *_resource not really interessting
	# : "== DEBUG == active  = $OCF_RESKEY_CRM_meta_notify_active_uname"
	: "== DEBUG == slave   = $OCF_RESKEY_CRM_meta_notify_slave_uname"
	: "== DEBUG == master  = $OCF_RESKEY_CRM_meta_notify_master_uname"
	: "== DEBUG == start   = $OCF_RESKEY_CRM_meta_notify_start_uname"
	: "== DEBUG == promote = $OCF_RESKEY_CRM_meta_notify_promote_uname"
	: "== DEBUG == stop    = $OCF_RESKEY_CRM_meta_notify_stop_uname"
	: "== DEBUG == demote  = $OCF_RESKEY_CRM_meta_notify_demote_uname"

	case $n_type/$n_op in
	*/start)
		# We do not get a /pre/ start notification for ourself.
		# but we get a /pre/ start notification for the other side, unless both
		# are started from the same transition graph.  If there are only two
		# peers (the "classic" two-node DRBD), this adjust is usually a no-op.
		#
		# In case of more than one _possible_ peer, we may still be StandAlone,
		# or configured for a meanwhile failed peer, and should now adjust our
		# network settings during pre-notification of start of the other node.
		#
		# We usually get /post/ notification for ourself and the peer.
		# In both cases adjust should be a no-op.
		drbd_set_status_variables
		figure_out_drbd_peer_uname
		do_drbdadm $DRBD_TO_PEER -v adjust $DRBD_RESOURCE
		;;
	post/*)
		# After something has been done is a good time to
		# recheck our status:
		drbd_set_status_variables
		drbd_update_master_score

		: == DEBUG == ${DRBD_DSTATE_REMOTE[*]} ==
		case ${DRBD_DSTATE_REMOTE[*]} in
		*DUnknown*)
			# Still not communicating.
			# Maybe someone else is primary (too)?
			maybe_outdate_self
		esac
	esac

	: "$OCF_SUCCESS = OCF_SUCCESS"
	return $OCF_SUCCESS
}

# "macro" to be able to give useful error messages
# on clone resource configuration error.
meta_expect()
{
	local what=$1 whatvar=OCF_RESKEY_CRM_meta_${1//-/_} op=$2 expect=$3
	local val=${!whatvar}
	if [[ -n $val ]]; then
		# [, not [[, or it won't work ;)
		[ $val $op $expect ] && return
	fi
	ocf_log err "meta parameter misconfigured, expected $what $op $expect, but found ${val:-unset}."
	exit $OCF_ERR_CONFIGURED
}

ls_stat_is_block_maj_147() {
	set -- $(command ls -L -l "$1" 2>/dev/null)
	[[ $1 = b* ]] && [[ $5 == 147,* ]]
}

check_crm_feature_set()
{
	set -- ${OCF_RESKEY_crm_feature_set//[!0-9]/ }
	local a=${1:-0} b=${2:-0} c=${3:-0}
	
	(( a > 3 )) ||
	(( a == 3 && b > 0 )) ||
	(( a == 3 && b == 0 && c > 0 )) ||
	ocf_log warn "You may be disappointed: This RA is intended for pacemaker 1.0 or better!"
}

drbd_validate_all () {
	DRBDADM="drbdadm"
	DRBDSETUP="drbdsetup"
	DRBD_HAS_MULTI_VOLUME=false

	# these will _exit_ if they don't find the binaries
	check_binary $DRBDADM
	check_binary $DRBDSETUP
	# XXX I really take cibadmin, sed, grep, etc. for granted.

	local VERSION DRBD_KERNEL_VERSION_CODE=0 DRBDADM_VERSION_CODE=0
	if VERSION="$($DRBDADM --version 2>/dev/null)"; then
		eval $VERSION
	fi
	if (( $DRBD_KERNEL_VERSION_CODE == 0x0 )) ; then
		# Maybe the DRBD module was not loaded (yet).
		# I don't want to load the module here,
		# maybe this is just a probe or stop.
		# It will be loaded on "start", though.
		# Instead, look at modinfo output.
		# Newer drbdadm does this implicitly, but may reexec older
		# drbdadm versions for compatibility reasons.
		DRBD_KERNEL_VERSION_CODE=$(printf "0x%02x%02x%02x" $(
			modinfo -F version drbd |
			sed -ne 's/^\([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\).*$/\1 \2 \3/p'))
	fi
	if (( $DRBD_KERNEL_VERSION_CODE >= 0x080400 )); then
		DRBD_HAS_MULTI_VOLUME=true
	elif (( $DRBD_KERNEL_VERSION_CODE >= 0x090000 )) ; then
		ocf_log err "This resource agent does (still) only support DRBD version 8.x"
		exit $OCF_ERR_INSTALLED
	fi
	check_crm_feature_set

	# Check clone and M/S options.
	meta_expect clone-max -le 2
	meta_expect clone-node-max = 1
	meta_expect master-node-max = 1
	meta_expect master-max -le 2

	# Rather than returning $OCF_ERR_CONFIGURED, we sometimes return
	# $OCF_ERR_INSTALLED here: the local config may be broken, but some
	# other node may have a valid config.

	# check drbdconf plausibility
	case "$OCF_RESKEY_drbdconf" in
	"")
		# this is actually ok. drbdadm has its own builtin defaults.
		# but as long as we assign an explicit default above,
		# this cannot happen anyways.
		: ;;
	*[!-%+./0-9:=@A-Z_a-z]*)
		# no, I do not trust the configurable cib parameters.
		ocf_log err "drbdconf name must only contain [-%+./0-9:=@A-Z_a-z]"
		: "$OCF_ERR_CONFIGURED = OCF_ERR_CONFIGURED"
		return $OCF_ERR_CONFIGURED
		;;
	*)
		# Check if we can read the configuration file.
		if [ ! -r "${OCF_RESKEY_drbdconf}" ]; then
			ocf_log err "Configuration file ${OCF_RESKEY_drbdconf} does not exist or is not readable!"
			: "$OCF_ERR_INSTALLED = OCF_ERR_INSTALLED"
			return $OCF_ERR_INSTALLED
		fi
		DRBDADM="$DRBDADM -c $OCF_RESKEY_drbdconf"
	esac

	# check drbd_resource plausibility
	case "$OCF_RESKEY_drbd_resource" in
	"")
		ocf_log err "No resource name specified!"
		: "$OCF_ERR_CONFIGURED = OCF_ERR_CONFIGURED"
		return $OCF_ERR_CONFIGURED
		;;
	*[!-%+./0-9:=@A-Z_a-z]*)
		# no, I do not trust the configurable cib parameters.
		ocf_log err "Resource name must only contain [-%+./0-9:=@A-Z_a-z]"
		: "$OCF_ERR_CONFIGURED = OCF_ERR_CONFIGURED"
		return $OCF_ERR_CONFIGURED
	esac
	# exporting this is useful for "drbdsetup show".
	# and it makes it all a little bit more readable.
	export DRBD_RESOURCE=$OCF_RESKEY_drbd_resource

	# The resource should appear in the config file,
	# otherwise something's fishy
	# NOTE
	# since 8.4 has multi volume support,
	# DRBD_DEVICES will be a shell array!
	# FIXME we should double check that we explicitly restrict the set of
	# valid characters in device names...
	if DRBD_DEVICES=($($DRBDADM --stacked sh-dev $DRBD_RESOURCE 2>/dev/null)); then
		# apparently a "stacked" resource. Remember for future DRBDADM calls.
		DRBDADM="$DRBDADM -S"
	elif DRBD_DEVICES=($($DRBDADM sh-dev $DRBD_RESOURCE 2>/dev/null)); then
		: # nothing to do.
	else
		if [[ $__OCF_ACTION = "monitor" && $OCF_RESKEY_CRM_meta_interval = 0 ]]; then
			# ok, this was a probe. That may happen on any node,
			# to enforce configuration.
			: "$OCF_NOT_RUNNING = OCF_NOT_RUNNING"
			return $OCF_NOT_RUNNING
		else
			# hm. probably misconfigured constraint somewhere.
			# sorry. don't retry anywhere.
			ocf_log err "DRBD resource ${DRBD_RESOURCE} not found in configuration file ${OCF_RESKEY_drbdconf}."
			remove_master_score
			: "$OCF_ERR_INSTALLED = OCF_ERR_INSTALLED"
			return $OCF_ERR_INSTALLED
		fi
	fi

	# check for master-max and allow-two-primaries on start|promote only,
	# so it could be stopped still, if someone re-configured while running.
	case $__OCF_ACTION:$OCF_RESKEY_CRM_meta_master_max in
	start:2|promote:2)
		if ! $DRBDADM -d -v dump $DRBD_RESOURCE 2>/dev/null |
			grep -q -Ee '^[[:space:]]*allow-two-primaries([[:space:]]+yes)?;$'
		then
			ocf_log err "master-max = 2, but DRBD resource $DRBD_RESOURCE does not allow-two-primaries."
			: "$OCF_ERR_CONFIGURED = OCF_ERR_CONFIGURED"
			return $OCF_ERR_CONFIGURED
		fi
	esac

	# detect whether notify is configured or not.
	# for probes, the meta_notify* namespace is not exported.
	case $__OCF_ACTION in
	monitor|validate-all)
		:;;
	*)
		# Test if the environment variables for either the notify
		# enabled, or one of its effects, are set.
		# If both are unset, we complain.
		if ocf_is_true ${OCF_RESKEY_ignore_missing_notifications:=false} ; then
			: "ignore" ;
		elif ! ocf_is_true ${OCF_RESKEY_CRM_meta_notify} &&
		   [[ ${OCF_RESKEY_CRM_meta_notify_start_uname- NOT SET } = " NOT SET " ]]; then
			ocf_log err "you really should enable notify when using this RA (or set ignore_missing_notifications=true)"
			: "$OCF_ERR_CONFIGURED = OCF_ERR_CONFIGURED"
			return $OCF_ERR_CONFIGURED
		fi
	esac

	local i j n=0 fallback=false
	for i in $OCF_RESKEY_adjust_master_score; do
		[[ $i = *[!0-9]* ]]   && fallback=true && ocf_log err "BAD adjust_master_score value $i ; falling back to default"
		[[ $j && $i -lt $j ]] && fallback=true && ocf_log err "BAD adjust_master_score value $j > $i ; falling back to default"
		j=$i
		n=$(( n+1 ))
	done
	[[ $n != 4 ]] && fallback=true && ocf_log err "Not enough adjust_master_score values ($n != 4); falling back to default"
	$fallback && OCF_RESKEY_adjust_master_score=$OCF_RESKEY_adjust_master_score_default

	# we use it in various places,
	# just make sure it contains what we expect.
	HOSTNAME=`uname -n`

	: "$OCF_SUCCESS = OCF_SUCCESS"
	return $OCF_SUCCESS
}

#######################################################################

if [ $# != 1 ]; then
	drbd_usage
	exit $OCF_ERR_ARGS
fi

# if $__OCF_ACTION = monitor, but meta_interval not set,
# this is a "probe". we could change behaviour.
: ${OCF_RESKEY_CRM_meta_interval=0}

case $__OCF_ACTION in
meta-data)
	meta_data
	exit $OCF_SUCCESS
	;;
usage)
	drbd_usage
	exit $OCF_SUCCESS
esac

if $USE_DEBUG_LOG ; then
	exec 2>&9
	set -x
fi

# Everything except usage and meta-data must pass the validate test
drbd_validate_all || exit

case $__OCF_ACTION in
start)
	drbd_start
	;;
stop)
	drbd_stop
	;;
notify)
	drbd_notify
	;;
promote)
	drbd_promote
	;;
demote)
	drbd_demote
	;;
status)
	drbd_status
	;;
monitor)
	drbd_monitor
	;;
validate-all)
	;;
*)
	drbd_usage
	exit $OCF_ERR_UNIMPLEMENTED
esac
# exit code is the exit code (return code) of the last command (shell function)