Configuring the cluster v6.0.0

Configuring the cluster

The next step in the process is to configure the database and the cluster.

This involves logging into each host and running the pgd command to create the cluster as the database user.

These steps will vary according to which platform you are using and which version of Postgres you are using.

Cluster names

You will need to choose a name for your cluster. This is the name that will be used to identify the cluster in the PGD CLI and in the database. It will be referred to as <cluster-name> in the examples.

Group names

You will also need to choose a name for the group. This is the name that will be used to identify the group in the PGD CLI and in the database. It will be referred to as <group-name> in the examples. The group name must be unique within the cluster.

Node names

You will also need to choose a name for each node. This is the name that will be used to identify the node in the PGD CLI and in the database. It will be referred to as <node-name> in the examples. This is separate from the host name, which is the name of the machine on which the node is running.

The node name must be unique within the group and within the cluster.

Paths and users

The paths and users used in the examples will vary according to which version of Postgres you are using and which platform you are using.

For EDB Postgres Advanced Server

You will use the system's enterprisedb user to run the pgd command. The database port is 5444.

On CentOS/RHEL

Postgres executable files are installed in /usr/edb/as$PG_VERSION/bin/ and the data directory is in /var/lib/edb/as$PG_VERSION/data/.

On Debian/Ubuntu

Postgres executable files are installed in /usr/lib/edb-as/$PG_VERSION/bin/ and the data directory is in /var/lib/edb-as/$PG_VERSION/main/.

For EDB Postgres Extended

You will use the system's postgres user to run the pgd command. The database port is 5432

On CentOS/RHEL

Postgres Extended executable files are installed in /usr/edb/pge$PG_VERSION/bin/ and the data directory is in /var/lib/edb-pge/$PG_VERSION/data/.

On Debian/Ubuntu

Postgres Extended executable files are installed in /usr/lib/edb-pge/$PG_VERSION/bin/ and the data directory is in /var/lib/edb-pge/$PG_VERSION/main/.

For Community PostgreSQL

You will use the system's postgres user to run the pgd command. The database port is 5432.

On CentOS/RHEL

Postgres executable files are installed in /usr/pgsql-$PG_VERSION/bin/ and the data directory is in /var/lib/pgsql/$PG_VERSION/data/.

On Debian/Ubuntu

Postgres executable files are installed in /usr/lib/postgresql/$PG_VERSION/bin/ and the data directory is in /var/lib/postgresql/$PG_VERSION/main/.

On each host

1. Log in as the database user.

sudo su - <db-user>

2. Add the Postgres executable files to your path.

export PATH=$PATH:<executable-path>

3. Run the pgd node setup command

On the first host

On the first host, run the following command to create the cluster:

pgd node <first-node-name> setup "host=<first-host> user=<db-user> port=<db-port> dbname=bdrdb" --pgdata <data-path>  --group-name <group-name> --cluster-name <cluster-name> --create-group 

This command will create the cluster and the group on the first host. It will also create the data directory and initialize the database.

On the second host

On the second host, run the following command to create the cluster:

pgd node <second-node-name> setup "host=<second-host> user=<db-user> port=<db-port> dbname=bdrdb" --pgdata <data-path> --cluster-dsn "host=<first-host> user=pos<db-user> tgres port=<db-port> dbname=bdrdb"

This command will create the node on the second host, and then join the cluster using the cluster-dsn setting to connect to the first host.

On the third host

On the third host, run the following command to create the cluster:

pgd node <third-node-name> setup "host=<third-host> user=<db-user> port=<db-port> dbname=bdrdb" --pgdata <data-path> --cluster-dsn "host=<first-host> user=<db-user> port=<db-port> dbname=bdrdb"

This command will create the node on the third host, and then join the cluster using the cluster-dsn setting to connect to the first host.

Worked example

In this example, we will configure the PGD Essential cluster with EDB Postgres Extended Server 17 on a CentOS/RHEL system using an enterprise subscription that we installed in the previous worked example.

We will now create a cluster called pgd with three nodes called node1, node2, and node3.

• The group name will be group1. The hosts are host-1, host-2, and host-3.
• The Postgres version is 17.
• The database user is postgres.
• The database port is 5432.
• The Postgres executable files are in /usr/edb/pge17/bin/.
• The Postgres data directory is in /var/lib/edb-pge/17/main/.

On the first host

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

On the second host

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

On the third host

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