Starting postgresql service and specifying data directory

I have recently installed pg 8.4 on Ubuntu 10.0.4 using apt-get install.

It installed pg as a service which starts ehenever the machine starts. However I have created a db cluster in a specific location that I want postgres to use.

This is the command line output of how I created the cluster:

username@jupiter:~$ sudo /usr/lib/postgresql/8.4/bin/initdb --encoding=UTF8 --pgdata=/mydata/pgdbdata/
initdb: cannot be run as root
Please log in (using, e.g., "su") as the (unprivileged) user that will
own the server process.
username@jupiter:~$ /usr/lib/postgresql/8.4/bin/initdb --encoding=UTF8 --pgdata=/mydata/pgdbdata/
The files belonging to this database system will be owned by user "username".
This user must also own the server process.

The database cluster will be initialized with locale en_US.utf8.
The default text search configuration will be set to "english".

fixing permissions on existing directory /mydata/pgdbdata ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 24MB
creating configuration files ... ok
creating template1 database in /mydata/pgdbdata/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating conversions ... ok
creating dictionaries ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the -A option the
next time you run initdb.

Success. You can now start the database server using:

    /usr/lib/postgresql/8.4/bin/postgres -D /mydata/pgdbdata
or
    /usr/lib/postgresql/8.4/bin/pg_ctl -D /mydata/pgdbdata -l logfile start

username@jupiter:~$

Now, I try to start the postgresql service:

Here is the command line outpu

There error is telling ... The problem is that you ran initdb as your local login, but I'm pretty that your login (username) doesn't have access to /var/run/postgresql. If you have a clean install, may I recommend that you remove the data directory and start all over, this time by su-ing into the postgres account:

username@jupiter:~$ sudo su - postgres

Then you can initdb

postgres@jupiter:~$ /usr/lib/postgresql/8.4/bin/initdb --encoding=UTF8 --pgdata=/mydata/pgdbdata/

Also, as Catcall mentioned, make sure you're using the correct location for your data.

StackExchange Database Administrators Q#19557, answer score: 7