Deploying an EDB Postgres Distributed example cluster on Docker#

This quick start uses TPA to set up PGD with an Always On Single Location architecture using local Docker containers.

Introducing TPA and PGD#

We created TPA to make installing and managing various Postgres configurations easily repeatable. TPA orchestrates creating and deploying Postgres. In this quick start, you install TPA first. If you already have TPA installed, you can skip those steps. You can use TPA to deploy various configurations of Postgres clusters.

PGD is a multi-master replicating implementation of Postgres designed for high performance and availability. The installation of PGD is orchestrated by TPA. You will use TPA to generate a configuration file for a PGD demonstration cluster.

This cluster uses local Docker containers to host the cluster’s nodes: three replicating database nodes, three cohosted connection proxies, and one backup node. You can then use TPA to provision and deploy the required configuration and software to each node.

This configuration of PGD isn’t suitable for production use but can be valuable for testing the functionality and behavior of PGD clusters. You might also find it useful when familiarizing yourself with PGD commands and APIs to prepare for deployment on cloud, VM, or Linux hosts.

Note

This set of steps is specifically for Ubuntu 22.04 LTS on Intel/AMD processors. !!!

Prerequisites#

To complete this example, you need a system with enough RAM and free storage. You also need curl and Docker installed.

RAM requirements#

You need a minimum of 4GB of RAM on the system. You need this much RAM because you will be running four containers, three of which will be hosting Postgres databases.

Free disk space#

You need at least 5GB of free storage, accessible by Docker, to deploy the cluster described by this example. A bit more is probably wise.

The curl utility#

You will download and run scripts during this quick start using the curl utilty which might not be installed by default. To ensure that curl is installed, run:

sudo apt update
sudo apt install curl

Docker Engine#

You will use Docker containers as the target platform for this PGD deployment. Install Docker Engine:

sudo apt update
sudo apt install docker.io

sudo usermod -aG docker <username>
newgrp docker

Preparation#

EDB account#

To install both TPA and PGD, you’ll need an EDB account.

Sign up for a free EDB account if you don’t already have one. Signing up gives you a

trial subscription to EDB’s software repositories.

After you are registered, go to the EDB Repos 2.0 page, where you can obtain your repo token.

On your first visit to this page, select Request Access to generate your repo token. Copy the token using the Copy Token icon, and store it safely.

Setting environment variables#

First, set the EDB_SUBSCRIPTION_TOKEN environment variable to the value of your EDB repo token, obtained in the EDB account step.

export EDB_SUBSCRIPTION_TOKEN=<your-repo-token>

You can add this to your .bashrc script or similar shell profile to ensure it’s always set.

Configure the repository#

All the software needed for this example is available from the EDB Postgres Distributed package repository. The following command downloads and runs a script to configure the EDB Postgres Distributed repository. This repository also contains the TPA packages.

curl -1sLf "https://downloads.enterprisedb.com/$EDB_SUBSCRIPTION_TOKEN/postgres_distributed/setup.deb.sh" | sudo -E bash

edb_notranlate_5 If it produces no output or an error, double-check that you entered your token correctly. It the problem persists, contact Support for assistance.

Installing Trusted Postgres Architect (TPA)#

You’ll use TPA to provision and deploy PGD. If you previously installed TPA, you can move on to the Next Steps with PGD . You’ll find full instructions for installing TPA in the Trusted Postgres Architect documentation , which we’ve also included here.

Linux environment#

TPA supports several distributions of Linux as a host platform. These examples are written for Ubuntu

22.04, but steps are similar for other supported platforms.

Important

If the Linux host platform you're using is running cgroups v2, you need to disable it and enable cgroups v1 while using TPA to deploy to Docker. To check for cgroup v2, run:

mount | grep cgroup | head -1

If you do not see a line beginning: tmpfs on /sys/fs/cgroup type tmpfs

Then you need to to disable cgroup v2. To do this, run:

echo GRUB_CMDLINE_LINUX=systemd.unified_cgroup_hierarchy=false | sudo tee /etc/default/grub.d/cgroup.cfg

Then update the grub bootloader and reboot by running:

sudo update-grub
sudo reboot

Install the TPA package#

sudo apt install tpaexec

Configuring TPA#

You now need to configure TPA, which configures TPA’s Python environment. Call tpaexec with the command setup :

sudo /opt/EDB/TPA/bin/tpaexec setup
export PATH=$PATH:/opt/EDB/TPA/bin

You can add the export command to your shell’s profile.

Testing the TPA installation#

You can verify TPA is correctly installed by running selftest :

tpaexec selftest
```  TPA is now installed.

##  Installing PGD using TPA

###  Generating a configuration file

Run the  :ref:`tpaexec configure </tpa/latest/tpaexec-configure/>`  command to generate a configuration folder:

```shell-session
tpaexec configure democluster \
  --architecture PGD-Always-ON \
  --platform docker \
  --edb-postgres-advanced 15 \
  --redwood \
  --location-names dc1 \
  --pgd-proxy-routing local \
  --no-git \
  --hostnames-unsorted

You specify the PGD-Always-ON architecture (--architecture PGD-Always-ON ), which sets up the configuration for

PGD 5's Always On architectures . As part of the default architecture, it configures your

cluster with three data nodes, cohosting three Install a PGD proxy configuration on each host servers, along with a Barman

node for backup.

Specify that you’re using Docker (--platform docker ). By default, TPA configures Rocky Linux as the default image for all nodes.

Observe that you don’t have to deploy PGD to the same platform you’re using to run TPA!

Specify that the data nodes will be running EDB Postgres Advanced Server v15 (--edb-postgres-advanced 15 ) with Oracle compatibility (--redwood ).

You set the notional location of the nodes to dc1 using --location-names . You then set --pgd-proxy-routing to local so that proxy routing can route traffic to all nodes within each location.

By default, TPA commits configuration changes to a Git repository. For this example, you don’t need to do that, so pass the --no-git flag.

Finally, you ask TPA to generate repeatable hostnames for the nodes by passing --hostnames-unsorted . Otherwise, it selects hostnames at random from a predefined list of suitable words.

This command creates a subdirectory in the current working directory called democluster . It contains the config.yml configuration file TPA uses to create the cluster. You can view it using:

less democluster/config.yml

edb_notranlate_14 - More details on PGD-Always-ON configuration options in Deploying with TPA

-  :ref:`PGD-Always-ON </tpa/latest/architecture-PGD-Always-ON/>`  in the Trusted Postgres Architect documentation -  :ref:`tpaexec configure </tpa/latest/tpaexec-configure/>`  in the Trusted Postgres Architect documentation -  :ref:`Docker platform </tpa/latest/platform-docker/>`  in the Trusted Postgres Architect documentation

Provisioning the cluster#

Next, allocate the resources needed to run the configuration you just created using the tpaexec provision command:

tpaexec provision democluster

Since you specified Docker as the platform, TPA creates a Docker image, containers, networks, and so on.

Deploying the cluster#

With configuration in place and infrastructure provisioned, you can now: Deploying an EDB Postgres Distributed example cluster on AWS the distributed cluster:

tpaexec deploy democluster

TPA applies the configuration, installing the needed packages and setting up the actual EDB Postgres Distributed cluster.

You’re now ready to log into one of the nodes of the cluster with SSH and then connect to the database. Part of the configuration process set up SSH logins for all the nodes, complete with keys. To use the SSH configuration, you need to be in the democluster directory created by the tpaexec configure command earlier:

cd democluster

From there, you can run ssh -F ssh_config <hostname> to establish an SSH connection. You will connect to kaboom, the first database node in the cluster:

ssh -F ssh_config kaboom
__OUTPUT__
[root@kaboom ~]#

Notice that you’re logged in as root on kaboom .

You now need to adopt the identity of the enterprisedb user. This user is preconfigured and authorized to connect to the cluster’s nodes.

sudo -iu enterprisedb
__OUTPUT__
enterprisedb@kaboom:~ $

You can now run the psql command to access the bdrdb database:

psql bdrdb
__OUTPUT__
psql (15.2.0, server 15.2.0)
Type "help" for help.

bdrdb=#

You’re directly connected to the Postgres database running on the kaboom node and can start issuing SQL commands.

To leave the SQL client, enter exit .

Using PGD CLI#

The pgd utility, also known as the PGD CLI, lets you control and manage your EDB Postgres Distributed cluster. It’s already installed on the node.

You can use it to check the cluster’s health by running pgd check-health :

pgd check-health
__OUTPUT__
Check      Status Message
- ----      ------ -------
ClockSkew  Ok     All BDR node pairs have clockskew within permissible limit
Connection Ok     All BDR nodes are accessible
Raft       Ok     Raft Consensus is working correctly
Replslots  Ok     All BDR replication slots are working correctly
Version    Ok     All nodes are running same BDR versions
enterprisedb@kaboom:~ $

Or, you can use pgd show-nodes to ask PGD to show you the data-bearing nodes in the cluster:

pgd show-nodes
__OUTPUT__
Node   Node ID    Group        Type Current State Target State Status Seq ID
- ---   -------    -----        ---- ------------- ------------ ------ ------
kaboom 2710197610 dc1_subgroup data ACTIVE        ACTIVE       Up     1
kaftan 3490219809 dc1_subgroup data ACTIVE        ACTIVE       Up     3
kaolin 2111777360 dc1_subgroup data ACTIVE        ACTIVE       Up     2
enterprisedb@kaboom:~ $

Similarly, use pgd show-proxies to display the proxy connection nodes:

pgd show-proxies
__OUTPUT__
Proxy  Group        Listen Addresses Listen Port
- ----  -----        ---------------- -----------
kaboom dc1_subgroup [0.0.0.0]        6432
kaftan dc1_subgroup [0.0.0.0]        6432
kaolin dc1_subgroup [0.0.0.0]        6432

The proxies provide high-availability connections to the cluster of data nodes for applications. You can connect to the proxies and, in turn, to the database with the command psql -h kaboom,kaftan,kaolin -p 6432 bdrdb :

psql -h kaboom,kaftan,kaolin -p 6432 bdrdb
__OUTPUT__
psql (15.2.0, server 15.2.0)
SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, compression: off)
Type "help" for help.

bdrdb=#

Explore your cluster#

Connect to your database to applications
Explore failover with hands-on exercises
Understand conflicts by creating and monitoring them
Next Steps with PGD in working with your cluster

Deploying an EDB Postgres Distributed example cluster on Docker

Contents

Deploying an EDB Postgres Distributed example cluster on Docker#

Introducing TPA and PGD#

Prerequisites#

RAM requirements#

Free disk space#

The curl utility#

Docker Engine#

Preparation#

EDB account#

Setting environment variables#

Configure the repository#

Installing Trusted Postgres Architect (TPA)#

Linux environment#

Install the TPA package#

Configuring TPA#

Testing the TPA installation#

Provisioning the cluster#

Deploying the cluster#

Using PGD CLI#

Explore your cluster#