Archive for CentOS

PostgreSQL 9.4 on CentOS 6.6

As usual there are many guides out there on installing something on some OS, but with Linux I never got a guide that could bring me straight through (every environment, every version requires different setup). So here’s my very own steps for installing PostgresSQL 9.4 on CentOS 6.6. (also for my future self-reference)

Prerequisites: Ensure DNS and HTTP(S) working for yum, otherwise you may encounter Host not found, etc. (This is out of scope as it may be nameservers or firewall settings)

1. Configure yum repo
Ref: http://tecadmin.net/install-postgresql-on-centos-rhel-and-fedora/

sudo rpm -Uvh http://yum.postgresql.org/9.4/redhat/rhel-6-x86_64/pgdg-redhat94-9.4-1.noarch.rpm
sudo yum install postgresql94-server postgresql94 postgresql94-contrib

2. Initialize the database
Ref: https://wiki.postgresql.org/wiki/YUM_Installation

sudo service postgresql-9.4 initdb
sudo service postgresql-9.4 start

3. Connect and create the database
Ref: http://serverfault.com/questions/110154/whats-the-default-superuser-username-password-for-postgres-after-a-new-install
After default installation, only the “postgres” user can access the database, but it has no password.
Create the database and grant a user access, which you will use to manage the database subsequently (don’t use “postgres” user)

sudo -u postgres psql postgres
    CREATE DATABASE devdb;
    CREATE USER devuser WITH PASSWORD 'devpass';
    GRANT ALL ON DATABASE devdb TO devuser;

4. Allow remote connections
Ref: http://www.thegeekstuff.com/2014/02/enable-remote-postgresql-connection/
pg_hba.conf allows any IP to connect (0.0.0.0) and authenticate using md5. You can also restrict this to your webserver IP only.
postgresql.conf will let the server listen on all attached IPs.

sudo vi /var/lib/pgsql/9.4/data/pg_hba.conf
	host    all     all     0.0.0.0/0       md5

sudo vi /var/lib/pgsql/9.4/data/postgresql.conf
	listen_addresses = '*'

sudo service postgresql-9.4 restart

5. Move the data to another disk
Ref: http://stackoverflow.com/questions/28414558/moving-postgresql-main-folder-out-of-var-lib-postgresql-9-4
My main disk was a default 10GB, enough for OS and programs but not for the database data. I have a spanking new 300GB disk attached, and I want to move the table space to the new disk.
There were several methods involving specifying the data directory but I found it was easier to just link it.

sudo service postgresql-9.4 stop
sudo mv /var/lib/pgsql/9.4/data /media/xvdb1/pgsql/9.4/
sudo ln -s /media/xvdb1/pgsql/9.4/data/ /var/lib/pgsql/9.4/data
sudo chown postgres:postgres /var/lib/pgsql/9.4/data
sudo service postgresql-9.4 start

6. Autostart
Finally, configure PostgreSQL to start itself on boot.

sudo chkconfig postgresql-9.4 on

Ready-to-use PostgreSQL.

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