install CentOS 6
yum update
yum upgrade
check the server time. sync the time to a time server if needed (service 'ntpd')
download and install Postgresql Server v9.1 rpm package:
rpm -Uvh http://yum.pgrpms.org/9.1/redhat/rhel-6-x86_64/pgdg-centos91-9.1-4.noarch.rpm
This should have installed the necessary server package: postgresql91-server.x86_64.
Install the package:
yum install postgresql91-server.x86_64
This will install even the postgresql91.x86_64 and the postgresql91-libs.x86_64 packages. Create a user (e.g. "postgres") to run the server instance, and change its password:
adduser postgres
passwd postgres
Create any database clusters as needed. The installation creates an empty data directory in /var/lib/pgsql/9.1/data/. Make sure that the data directory is owned by the Postgresql user ("postgres" in this example). Initialize the cluster (as Postgresql user "postgres"):
whoami
#=> "postgres"
#initialize the cluster with admin user "postgres" (-U postgres), prompting to enter a password (-W), setting the password to md5 (-A md5):
/path/to/initdb -D /path/to/data/directory -W -A md5 -U postgres
Open the server for external connections:
vi /path/to/data/directory/postgresql.conf
# find the line with listen_addresses and edit as follows
listen_addresses = '*'
Edit the /path/to/data/directory/pg_hba.conf file to set which hosts/user are allowed to establish connections.
The install process creates a startup script in /etc/rc.d/init/postgresql-9.1. Edit the script as required (or create a custom script). Turn on the automatic startup:
chkconfig --level 345 postgresql-9.1 on
Try establishing an external connection. If you get a "Connection refused...accepting TCP/IP connections on port 5432?" error then the port is probably closed. Check that the firewall allows external TCP/IP connections (netstat -nap). You can open a port with lokkit or by configuring the iptables.
also this is bad:
chkconfig postgresql-9.1 on
It needs to be far more selective:
chkconfig --level 345 postgresql on