1. Put check_pgreplication.py to /etc/zabbix/scripts

2. Install psycopg2 python module

3. Write down to zabbix_agentd.conf
   UserParameter=check_pgreplication,/etc/zabbix/scripts/check_pgreplication.py --master_ip=<ip> --standby_ip=<ip> --master_user=<user> --master_passwd=<pass>

4. Write down to master and standby pg_hba.conf
   host postgres replmon 0.0.0.0/0 md5

5. Execute such sql statements on master server:
   postgres=# CREATE ROLE replmon NOSUPERUSER LOGIN password 'passW00rd';

6. Import postgresql_template.xml into zabbix.