Manually deploying PGD Essential standard architecture
======================================================

Manually deploying the PGD Essential standard architecture is a
straightforward process. This architecture is designed for a single
location that needs to be highly available and can recover from a
disaster. It does this by having three data nodes in a multi-master
replication configuration, with one node acting as the write leader.

PGD configuration
-----------------

Install PGD on each of the three nodes using the instructions in the
Essentials install guide. Specifically:

- `Configure repositories <https://www.enterprisedb.com/docs/pgd/latest/essential-how-to/install/02-configure-repositories/>`_  to enable installation of the PGD packages.

- :ref:`Install PGD and Postgres <Step 3 - Installing the database and pgd>`  to install the PGD packages.

- :ref:`Configure the PGD cluster <Step 4 - Configuring the cluster>`  to configure the PGD cluster.

Worked example
--------------

This example create a three-node RHEL cluster with EDB Postgres Extended
Server, using the PGD Essential Standard architecture and the following
parameters:

- The first node is called ``node1`` and is located on ``host-1`` .

- The second node is called ``node2`` and is located on ``host-2`` .

- The third node is called ``node3`` and is located on ``host-3`` .

- the cluster name is ``pgd`` (the default name).

- The group name is ``group1`` .

- The Postgres version is ``17`` .

- The Postgres data directory is ``/var/lib/edb-pge/17/main/`` .

- The Postgres executable files are in ``/usr/edb/pge17/bin/`` .

- The Postgres database user is ``postgres`` .

- The Postgres database port is ``5432`` .

- The Postgres database name is ``pgddb`` .

For the first node
^^^^^^^^^^^^^^^^^^

This is the common setup for all three nodes, installing the software:

.. code:: bash

   export EDB_SUBSCRIPTION_TOKEN=XXXXXXXXXXXXXX
   export EDB_SUBSCRIPTION_PLAN=enterprise
   export EDB_REPO_TYPE=rpm
   curl -1sSLf " https://downloads.enterprisedb.com/$EDB_SUBSCRIPTION_TOKEN/$EDB_SUBSCRIPTION_PLAN/setup.$EDB_REPO_TYPE.sh" | sudo -E bash
   export PG_VERSION=17
   export PGD_EDITION=essential
   export EDB_PACKAGES="edb-as$PG_VERSION-server edb-pgd6-$PGD_EDITION-epas$PG_VERSION"
   sudo dnf install -y $EDB_PACKAGES

On the first node, the following command creates the cluster and the
group. It also creates the data directory and initializes the database.

.. code:: bash

   sudo su - postgres
   export PATH=$PATH:/usr/edb/pge17/bin/
   pgd node node1 setup "host=host-1 user=postgres port=5432 dbname=pgddb" --pgdata /var/lib/edb-pge/17/main/ --group-name group1 --cluster-name pgd --create-group --initial-node-count 3

For the second node
^^^^^^^^^^^^^^^^^^^

Repeat the software installation steps on the second node.

Then run the following command to initialize the node and join the
cluster and group:

.. code:: bash

   sudo su - postgres
   export PATH=$PATH:/usr/edb/pge17/bin/
   pgd node node2 setup "host=host-2 user=postgres port=5432 dbname=pgddb" --pgdata /var/lib/edb-pge/17/main/ --cluster-dsn "host=host-1 user=postgres port=5432 dbname=pgddb"

For the third node
^^^^^^^^^^^^^^^^^^

Repeat the software installation steps on the third node.

The command to initialize the node and join the cluster and group is
similar to the second node but with a different host and node name:

.. code:: bash

   sudo su - postgres
   export PATH=$PATH:/usr/edb/pge17/bin/
   pgd node node3 setup "host=host-3 user=postgres port=5432 dbname=pgddb" --pgdata /var/lib/edb-pge/17/main/ --cluster-dsn "host=host-1 user=postgres port=5432 dbname=pgddb"