[Drbd-dev] drbd.ocf Split-Brain detection patch

[Uwe Grawert]

Hello,

the following is a patch for the OCF Agent script, to detect a  
Split-Brain and turn the resource into unmanaged mode if a Split-Brain  
has been detected. This is not meant as a substitution for a fencing  
mechanism but as a help to discover a Split-Brain when setting up a  
cluster.


--- /usr/lib/ocf/resource.d/linbit/drbd	2010-10-28 14:58:05.000000000 +0200
+++ drbd.split-brain.patch	2010-11-15 14:28:46.000000000 +0100
@@ -405,6 +405,9 @@
  	case "${DRBD_ROLE_LOCAL}" in
  	Primary)
  		rc=$OCF_RUNNING_MASTER
+		# This Node is Primary but StandAlone, there must be a Split-Brain
+		[[ $OCF_RESKEY_CRM_meta_master_max = 2 && $DRBD_CSTATE = "StandAlone" ]] \
+		&& rc=$OCF_ERR_CONFIGURED
  		;;
  	Secondary)
  		rc=$OCF_SUCCESS
@@ -518,6 +521,11 @@
  		$OCF_RUNNING_MASTER)
  			ocf_log warn "$DRBD_RESOURCE already Primary, demoting."
  			do_drbdadm secondary $DRBD_RESOURCE
+			;;
+		$OCF_ERR_CONFIGURED)
+			ocf_log warn "Split-Brain detected! See DRBD logging output."
+			rc=$status
+			break
  		esac
  		$first_try || sleep 1
  		first_try=false
@@ -560,6 +568,11 @@
  		$OCF_RUNNING_MASTER)
  			rc=$OCF_SUCCESS
  			break
+			;;
+		$OCF_ERR_CONFIGURED)
+			ocf_log warn "Split-Brain detected! See DRBD logging output."
+			rc=$status
+			break
  		esac
  		$first_try || sleep 1
  		first_try=false
@@ -591,6 +604,11 @@
  			;;
  		$OCF_RUNNING_MASTER)
  			do_drbdadm secondary $DRBD_RESOURCE
+			;;
+			$OCF_ERR_CONFIGURED)
+			ocf_log warn "Split-Brain detected! See DRBD logging output."
+			rc=$status
+			break
  		esac
  		$first_try || sleep 1
  		first_try=false
@@ -619,6 +637,11 @@
  		$OCF_RUNNING_MASTER)
  			ocf_log warn "$DRBD_RESOURCE still Primary, demoting."
  			do_drbdadm secondary  $DRBD_RESOURCE
+			;;
+		$OCF_ERR_CONFIGURED)
+			ocf_log warn "Split-Brain detected! See DRBD logging output."
+			rc=$status
+			break
  		esac
  		$first_try || sleep 1
  		first_try=false

-- 
Uwe Grawert
Linux / Unix Consultant & Trainer
Tel.: +49 151 12051100
Mail: grawert at b1-systems.de

B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de
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