sh: pg_isready: command not found

find / -name pg_isready
# it will show '/usr/pgsql-10/bin/pg_isready'

# see live environment for agent 2
cat /proc/$(ps -ef | grep "[z]abbix_agent2.conf" | awk '{print $2}')/environ | tr '\0' '\n'

# take existing PATH '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin'

# locate environment
grep EnvironmentFile /usr/lib/systemd/system/zabbix-agent2.service

# add new path to exsting PATH
cd /etc/sysconfig
cat << 'EOF' > zabbix-agent2 
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/usr/pgsql-10/bin
export PATH
EOF