+#!/bin/bash
+
+#Postgres data directory
+postgres_datadir='/var/lib/postgresql/9.1/main'
+#Postgres configuration directory
+postgres_configdir='/etc/postgresql/9.1/main'
+#Postgres user ssh key
+postgres_user_key='/var/lib/postgresql/.ssh/id_rsa'
+#Pgpool configuration directory
+pgpool_configdir='/etc/pgpool2'
+
+if [ -f '/tmp/postgres_master' ]
+then
+ #Get current postgres master id
+ current_master_id=$(cat /tmp/postgres_master);
+else
+ echo "[ERROR] /tmp/postgres_master not found !";
+ exit 0;
+fi
+
+#Get postgres master name
+current_master_name=$(pcp_node_info 10 localhost 9898 postgres postgres $current_master_id | cut -d' ' -f1)
+#Get postgres slave id
+[ $current_master_id == 0 ] && current_slave_id=1 || current_slave_id=0
+#Get postgres slave name
+current_slave_name=$(pcp_node_info 10 localhost 9898 postgres postgres $current_slave_id | cut -d' ' -f1)
+
+#Test if pgpool is running
+CheckIfPgpoolIsRunning () {
+ #Send signal 0 to pgpool to check if it's running
+ if ! killall -0 pgpool; then echo "[ERROR] Pgpool is not running !"; exit 1; fi;
+}
+
+CheckPostgres () {
+
+}
+
+AttachNodeToPgpool () {
+ #pcp_attach_node is a command that permit to attach a specific postgres server (identified by 6th parameter) to pgpool.
+ #pcp_attach_node dont return a good error code when it fails so here if I catch "BackendError" message in stderr I presume
+ #that attachment failed.
+ #TODO:find a condition to break the folowing loop if attachment fails.
+ while [ "`pcp_attach_node 10 localhost 9898 postgres postgres $1`" == "BackendError" ]
+ do
+ pcp_attach_node 10 localhost 9898 postgres postgres $1;
+ #This sleep is recommanded to avoid stressing pgpool in this infinite loop.
+ sleep 5;
+ done
+}
+
+#Whether the slave node is down, start it and attach it to pgpool's backend pool.
+ReattachDegeneratedSlave () {
+ #Reboot slave node
+ echo "[INFO] Slave node '$current_slave_name' is down. Performing postgres server reboot..."
+ #Remote postgres reboot via ssh
+ ssh -i $postgres_user_key postgres@$current_slave_name "/etc/init.d/postgresql restart"
+ #Test if postgres is running
+ status=$(ssh -i $postgres_user_key postgres@$current_slave_name "if ! killall -0 postgres; then echo 'error'; else echo 'running'; fi;")
+ if [ $status == "error" ]
+ then
+ echo "[ERROR] Postgres slave still down !";
+ exit 0;
+ else
+ echo "[OK] Slave node successfully started.";
+ fi
+
+ #Do 'slave online recovery' to force slave sync if it has incoherent data relatevely to master.
+ #echo "[INFO] Starting online recovery for slave '$current_slave_name' ..."
+ #ssh -i /var/lib/postgresql/.ssh/id_rsa postgres@$current_slave_name "bash /var/lib/postgresql/streaming-replication.sh $current_master_name"
+ #Atttach slave (even master) to pgpool's backends pool
+ #Reattach the master node if you have performed an online recovery for slave node and not juste a simple reboot.
+ #Attempting to reatach master to pgpool's backend pool
+ #echo "[INFO] Attaching master node '$current_master_name' ..."
+ #AttachNodeToPgpool "$current_master_id"
+ #echo "[OK] Master node '$current_master_name' has been successfully reattached to pgpool."
+ #Attempting to reattach slave to pgpool's backend pool
+ echo "[INFO] Attaching slave node '$current_slave_name'..."
+ AttachNodeToPgpool "$current_slave_id"
+ echo "[OK] Slave node '$current_slave_name' has been successfully reattached to pgpool."
+}
+
+
+#Whether the master is down do the folowing operations :
+SwitchOldMasterToSlave () {
+
+ new_master_name=$current_slave_name
+ new_master_id=$current_slave_id
+ new_slave_name=$current_master_name
+ new_slave_id=$current_master_id
+ #Setup old master config to slave mode
+ echo "[INFO] Setting up configuration for the new slave node '$new_slave_name'..."
+ ssh -i $postgres_user_key postgres@$new_slave_name "/etc/init.d/postgresql stop"
+ ssh -i $postgres_user_key postgres@$new_slave_name "cp -p $postgres_configdir/postgresql.conf.slave $postgres_configdir/postgresql.conf"
+ ssh -i $postgres_user_key postgres@$new_slave_name "[ -f $postgres_datadir/recovery.done ] && mv $postgres_datadir/recovery.done $postgres_datadir/recovery.conf"
+ # Switch slave to new master
+ echo "[INFO] Setting up configuration for the new master '$new_master_name'..."
+ ssh -i $postgres_user_key postgres@$new_master_name "[ -f /tmp/trigger_file ] && rm /tmp/trigger_file"
+ ssh -i $postgres_user_key postgres@$new_master_name "[ -f $postgres_datadir/recovery.conf ] && mv $postgres_datadir/recovery.conf $postgres_datadir/recovery.done"
+ ssh -i $postgres_user_key postgres@$new_master_name "cp -p $postgres_configdir/postgresql.conf.master $postgres_configdir/postgresql.conf"
+ echo "[INFO] Restarting new master..."
+ ssh -i $postgres_user_key postgres@$new_master_name "/etc/init.d/postgresql restart"
+ status=$(ssh -i $postgres_user_key postgres@$new_master_name "if ! killall -0 postgres; then echo 'error'; else echo 'running'; fi;")
+ if [ $status == "error" ]
+ then
+ echo "[ERROR] New postgres master not running !";
+ exit 0;
+ else
+ echo "[OK] New master started.";
+ fi
+ # Start new slave/master with online recovery
+ echo "[INFO] Performing online slave recovery..."
+ ssh -i $postgres_user_key postgres@$new_slave_name "bash /var/lib/postgresql/streaming-replication.sh $new_master_name"
+ echo "[OK] Online recovery completed."
+
+ #Write changes to pgpool.conf file to keep the same current master and slave nodes even after pgpool reboot.
+ sed -i "s/^backend_hostname0.*/backend_hostname0='$new_master_name'/" $pgpool_configdir/pgpool.conf
+ sed -i "s/^backend_hostname1.*/backend_hostname1='$new_slave_name'/" $pgpool_configdir/pgpool.conf
+ echo "[OK] Pgpool configuration file updated."
+
+ #Attach new master to pgpool
+ echo "[INFO] Attaching new master node '$new_master_name'..."
+ AttachNodeToPgpool "$new_master_id"
+ echo "[OK] New master node '$new_master_name' has been successfully reattached to pgpool."
+
+ #Attach new slave to pgpool
+ echo "[INFO] Attaching new slave node '$new_slave_name'..."
+ AttachNodeToPgpool "$new_slave_id"
+ echo "[OK] New slave node '$new_slave_name' has been successfully reattached to pgpool."
+
+}
+
+CheckIfPgpoolIsRunning
+
+#Get master/slave state
+current_master_state=$(pcp_node_info 10 localhost 9898 postgres postgres $current_master_id | cut -d' ' -f3)
+current_slave_state=$(pcp_node_info 10 localhost 9898 postgres postgres $current_slave_id | cut -d' ' -f3)
+
+# state 1 => postgres server is attached but still not receiving connections
+# state 2 => postgres server is attached and managing clients connections
+# state 3 => postgres server is detached and probably is down.
+
+#If slave is down and master is up then perform an online slave backup.
+[ $current_slave_state == 3 ] && ([ $current_master_state == 1 ] || [ $current_master_state == 2 ]) && ReattachDegeneratedSlave
+#If master is down then switch roles between failed master(new server) and the slave(new master).
+[ $current_master_state == 3 ] && SwitchOldMasterToSlave
projects / pgpool-online-recovery / blobdiff