PostgreSQL server failed to start, could not create lock file: permission denied

Question

Change the owner of /var/run/postgresql and set it to postgres:

sudo chown -R postgres:postgres /var/run/postgresql

If the user you are running as does not have sudo privilege, then

Change to root:
```
su -
```
Change ownership of /var/run/postgresql to user postgres and group postgres:
```
chown -R postgres:postgres /var/run/postgresql
```

I had the same problem when installing postgres on Ubuntu 14.04 and changing the ownership fixed the problem for me.