Configure PostgreSQL for remote connections

This guide covers how to configure PostgreSQL for remote connections. This is useful when deploying MAAS on a separate machine to the database.

Requirements

You will need two machines with the following already in place:

• MAAS machine: The MAAS snap is installed. See Install the MAAS snap if you have not done this yet.

• Database machine: The PostgreSQL snap is installed and a MAAS database role and database have been created. See Install PostgreSQL if you have not done this yet.

• Network connectivity between the two machines.

Configure PostgreSQL

On the database machine, ensure the following environment variables are set to the same values used to set up the PostgreSQL database. After following the Install PostgreSQL guide, these variables will be:

export DBUSER=maas
export DBNAME=maas

Configure remote access authentication:

echo "host    $DBNAME    $DBUSER    0/0    scram-sha-256" | sudo tee -a /var/snap/postgresql/common/etc/postgresql/16/main/pg_hba.conf

Set the listen address to all available IP interfaces using the * wildcard, or specify specific IP addresses for improved security:

echo "listen_addresses = '*'" | sudo tee -a /var/snap/postgresql/common/etc/postgresql/16/main/postgresql.conf

Restart PostgreSQL to apply the changes:

sudo snap restart postgresql

You can verify the changes by checking the listen address:

sudo postgresql.psql -U postgres -c "SHOW listen_addresses;"

An example output of the process is shown below:

ubuntu@host-system:~$

echo "host    $DBNAME    $DBUSER    0/0    scram-sha-256" | sudo tee -a /var/snap/postgresql/common/etc/postgresql/16/main/pg_hba.conf

host    maas    maas    0/0    scram-sha-256

ubuntu@host-system:~$

sudo postgresql.psql -U postgres -c "SHOW listen_addresses;"

 listen_addresses
------------------
 localhost
(1 row)

ubuntu@host-system:~$

echo "listen_addresses = '*'" | sudo tee -a /var/snap/postgresql/common/etc/postgresql/16/main/postgresql.conf

listen_addresses = '*'

ubuntu@host-system:~$

sudo snap restart postgresql

Restarted.

ubuntu@host-system:~$

sudo postgresql.psql -U postgres -c "SHOW listen_addresses;"

 listen_addresses
------------------
 *
(1 row)

Initialize MAAS

You can now initialize MAAS on your other machine with the remote database credentials, specifying the IP address of the database machine and the database user password:

sudo maas init region+rack --database-uri "postgres://$DBUSER:<password>@<database-machine-ip>/$DBNAME"

Press Enter when prompted to accept the default MAAS URL, or specify your own.