master-postgres-9.6-hot-standby.sh

MASTER_IP=
SLAVE_IP=

# service postgresql stop
su - postgres
psql -c "CREATE ROLE replica WITH PASSWORD 'myreplpassword' LOGIN REPLICATION;"

#Security for master allow standby access
echo "host replication replica $SLAVE_IP/32 md5" >> /etc/postgresql/9.6/main/pg_hba.conf 

# Postgres Master config
cat <<EOT >> /etc/postgresql/9.6/main/postgresql.conf
listen_addresses = '*'
wal_level = replica
max_wal_senders = 5
wal_keep_segments = 32
archive_mode = on
archive_command = 'cp %p /var/lib/postgresql/9.6/main/archive/%f'
EOT

mkdir -p /var/lib/postgresql/9.6/main/archive/
chmod 700 /var/lib/postgresql/9.6/main/archive/
chown -R postgres:postgres /var/lib/postgresql/9.6/main/archive/

# service postgresql start

#########################
# Standby server config
su - postgres
echo "$MASTER_IP:*:*:replica:myreplpassword" > ~/.pgpass
chmod 600 ~/.pgpass

# service postgresql stop

# clear old db by rename
mv /var/lib/postgresql/9.6/main /var/lib/postgresql/9.6/main.bak

#inital download database from master
pg_basebackup -h $MASTER_IP -D /var/lib/postgresql/9.6/main -P -U replica --xlog-method=stream

echo "hot_standby = on" >> /etc/postgresql/9.6/main/postgresql.conf

cat <<EOT >> /var/lib/postgresql/9.6/main/recovery.conf
standby_mode = 'on'
primary_conninfo = 'host=$MASTER_IP port=5432 user=replica application_name=db2-standby'
trigger_file = '/tmp/postgresql.trigger.5432'
restore_command = 'cp /var/lib/postgresql/9.6/main/archive/%f %p'
archive_cleanup_command = 'pg_archivecleanup /var/lib/postgresql/9.6/main/archive %r'
recovery_target_timeline = 'latest'
EOT

# service postgresql start

# check standby server for standby mode
# tail -f /var/log/postgresql/postgresql-9.6-main.log

# references
# https://dba.stackexchange.com/questions/158901/creating-a-hot-standby-with-postgres-9-6/159035
# https://blog.2ndquadrant.com/evolution-of-fault-tolerance-in-postgresql-replication-phase/
# https://www.howtoforge.com/tutorial/how-to-set-up-master-slave-replication-for-postgresql-96-on-ubuntu-1604/