PGD Lightweight

PGD Lightweight#

Note

This architecture is for Postgres Distributed 5 only. If you require PGD 4 or 3.7 please use BDR-Always-ON .

EDB Postgres Distributed 5 in a Lightweight configuration, suitable for use in test and production.

This architecture requires an EDB subscription. All software will be sourced from Configuring EDB Repos 2.0 repositories .

Cluster configuration#

Overview of configuration options#

An example invocation of tpaexec configure for this architecture is shown below.

tpaexec configure ~/clusters/pgd-lw \
    --architecture Lightweight \
    --edb-postgres-extended 15 \
    --platform aws --instance-type t3.micro \
    --distribution Debian \
    --location-names main dr \

You can list all available options using the help command.

tpaexec configure --architecture Lightweight --help

The table below describes the mandatory options for PGD-Always-ON and additional important options. More detail on the options is provided in the following section.

Mandatory Options#

Options

Description

--architecture (-a)

Must be set to Lightweight

Postgres flavour and version (e.g. --postgresql 15)

A valid Postgres flavour and version .

Additional Options#

Options

Description

Behaviour if omitted

--platform

One of aws, docker, bare.

Defaults to aws.

--location-names

A space-separated list of location names. The number of locations is equal to the number of names supplied.

TPA will configure a single location with three data nodes.

--add-proxy-nodes-per-location

The number of proxy nodes in each location.

PGD-proxy will be installed on each data node.

--bdr-database

The name of the database to be used for replication.

Defaults to bdrdb.

--enable-pgd-probes

Enable http(s) api endpoints for pgd-proxy such as health/is-ready to allow probing proxy's health.

Disabled by default.

--proxy-listen-port

The port on which proxy nodes will route traffic to the write leader.

Defaults to 6432

--proxy-read-only-port

The port on which proxy nodes will route read-only traffic to shadow nodes.

Defaults to 6433

More detail about Lightweight configuration#

A PGD Lightweight cluster comprises 2 locations, with a primary active location containing 2 nodes and a disaster recovery (dr) location with a single node.

Location names for the cluster are specified as --location-names primary dr . A location represents an independent data centre that provides a level of redundancy, in whatever way this definition makes sense to your use case. For example, AWS regions, your own data centres, or any other designation to identify where your servers are hosted.

By default, every data node (in every location) will also run PGD-Proxy for connection routing. To create separate PGD-Proxy instances instead, use --add-proxy-nodes-per-location 3 (or however many proxies you want to add).

Global routing will make every proxy route to a single write leader, elected amongst all available data nodes across all locations.

You may optionally specify --bdr-database dbname to set the name of the database with BDR enabled (default: bdrdb).

You may optionally specify --enable-pgd-probes [{http, https}] to enable http(s) api endpoints that will allow to easily probe proxy’s health.

You may also specify any of the options described by Cluster configuration .

Contents