README.multiple-servers.rst

Multiple server configuration

It’s best to run PostgreSQL on a separate server, as PostgreSQL doesn’t like memory pressure.

Example

Let’s deploy PostgreSQL to 198.51.100.111. We’ll deploy everything else to 198.51.100.222. We’ll manage the configuration of both servers from our local computer. You’ll need SSH access to a remote user with sudo permissions.

Prepare Ansible

Install Ansible on your local computer and clone this repository.

$ git clone https://github.com/jamielinux/ansible-discourse
$ cd ansible-discourse

Configure hosts

The inventory file tells Ansible about your remote hosts and puts them into groups. Each section is a group of one or more servers. The deploy-local.sh script uses inventory/local.

Create inventory/remote with these contents:

[postgres]
198.51.100.111

[redis]
198.51.100.222

[discourse]
198.51.100.222

Configure options

Get started with vars_example.yml:

$ cp vars_example.yml group_vars/all/main.yml

Edit the options in group_vars/all/main.yml, and also append these additional options:

# By default, Discourse connects to the database on localhost.
# Point Discourse to the database server:
discourse_db_host:            "198.51.100.111"
discourse_db_port:            "5432"

# By default, postgres only listens for connections on localhost.
# Tell postgres to listen on all interfaces:
postgres_listen:              ["*"]
postgres_port:                "5432"

# By default, only localhost is allowed to connect to the postgres.
# Tell postgres to allow connections from the Discourse server:
postgres_hosts_allow:         ["198.51.100.222/32"]

Deploy

Replace USERNAME with the remote user on your servers.

$ ansible-playbook -i inventory/remote \
      -s -K -u USERNAME master.yml

You should configure a firewall on your postgres host that allows connections to port 5432 only from 198.51.100.222.