Initial BDR failover documentation

scripts/bdr-pgbouncer.sh

@@ -0,0 +1,101 @@
+#!/usr/bin/env bash
+set -u
+set -e
+
+# Process parameters passed to script
+# -----------------------------------
+#
+# This assumes the repmgr "event_notification_command" is defined like this:
+#
+#   event_notification_command='/path/to/bdr-pgbouncer.sh %n %e %s "%c" "%a" >> /tmp/bdr-failover.log 2>&1'
+#
+# Adjust as appropriate.
+
+NODE_ID=$1
+EVENT_TYPE=$2
+SUCCESS=$3
+NEXT_CONNINFO=$4
+NEXT_NODE_NAME=$5
+
+if [ "$EVENT_TYPE" != "bdr_failover" ]; then
+    echo "unable to handle event type '$EVENT_TYPE'"
+    exit
+fi
+
+# Define database name here
+# -------------------------
+#
+# Note: this assumes the BDR-enabled database has the same name on
+# both hosts
+
+BDR_DBNAME=bdr_db
+
+# Define PgBouncer hosts here
+# ---------------------------
+
+PGBOUNCER_HOSTS="host1 host2"
+PGBOUNCER_PORTS=(6432 6432)
+PGBOUNCER_DATABASE_INI=(/path/to/pgbouncer.database.ini /path/to/pgbouncer.database.ini)
+
+
+# Define local host info here
+# ---------------------------
+
+THIS_HOST="host1"
+THIS_PGBOUNCER_PORT="6432"
+THIS_DB_PORT="5432"
+
+# Pause all pgbouncer nodes to minimize impact on clients
+# -------------------------------------------------------
+
+i=0
+for HOST in $PGBOUNCER_HOSTS
+do
+    PORT="${PGBOUNCER_PORTS[$i]}"
+
+    psql -tc "pause" -h $HOST -p $PORT -U postgres pgbouncer
+
+    i=$((i+1))
+done
+
+# Copy pgbouncer database ini file to all nodes and restart pgbouncer
+# -------------------------------------------------------------------
+
+i=0
+THIS_HOSTPORT="$THIS_HOST$THIS_PGBOUNCER_PORT"
+PGBOUNCER_DATABASE_INI_NEW="/tmp/pgbouncer.database.ini.new"
+
+for HOST in $PGBOUNCER_HOSTS
+do
+    PORT="${PGBOUNCER_PORTS[$i]}"
+
+    # Recreate the pgbouncer config file
+    # ----------------------------------
+    echo -e "[databases]\n" > $PGBOUNCER_DATABASE_INI_NEW
+
+    echo -e "$BDR_DBNAME= $NEXT_CONNINFO application_name=pgbouncer_$PORT" >> $PGBOUNCER_DATABASE_INI_NEW
+
+    # Copy file to host
+    # -----------------
+    CONFIG="${PGBOUNCER_DATABASE_INI[$i]}"
+
+    if [ "$HOST$PORT" != "$THIS_HOSTPORT" ]; then
+      rsync $PGBOUNCER_DATABASE_INI_NEW $HOST:$CONFIG
+    else
+      cp $PGBOUNCER_DATABASE_INI_NEW $CONFIG
+    fi
+
+    # Reload and resume PgBouncer
+    # ---------------------------
+
+    psql -tc "reload" -h $HOST -p $PORT -U postgres pgbouncer
+    psql -tc "resume" -h $HOST -p $PORT -U postgres pgbouncer
+
+    i=$((i+1))
+done
+
+
+# Clean up generated file
+rm $PGBOUNCER_DATABASE_INI_NEW
+
+echo "Reconfiguration of pgbouncer complete"