Deploying an EDB Postgres Distributed example cluster on Docker v5
This quick start uses TPA to set up PGD with an Always On Single Location architecture using local Docker containers.
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.
This set of steps is specifically for Ubuntu 22.04 LTS on Intel/AMD processors.
To complete this example, you need a system with enough RAM and free storage. You also need
curl and Docker installed.
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.
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.
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:
You will use Docker containers as the target platform for this PGD deployment. Install Docker Engine:
Running as a non-root user
Once Docker Engine is installed, be sure to add your user to the Docker group:
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.
First, set the
EDB_SUBSCRIPTION_TOKEN environment variable to the value of your EDB repo token, obtained in the EDB account step.
You can add this to your
.bashrc script or similar shell profile to ensure it's always set.
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.
Troubleshooting repo access
The script should produce output starting with:
If it produces no output or an error, double-check that you entered your token correctly. It the problem persists, contact Support for assistance.
You'll use TPA to provision and deploy PGD. If you previously installed TPA, you can move on to the next step. You'll find full instructions for installing TPA in the Trusted Postgres Architect documentation, which we've also included here.
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.
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:
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:
Then update the grub bootloader and reboot by running:
You now need to configure TPA, which configures TPA's Python environment. Call
tpaexec with the command
You can add the
export command to your shell's profile.
You can verify TPA is correctly installed by running
TPA is now installed.
tpaexec configure command to generate a configuration folder:
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 PGD
Proxy 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.
Other Linux platforms are supported as deployment targets for PGD. See the EDB Postgres Distributed compatibility table for details.
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 (
You set the notional location of the nodes to
--location-names. You then set
global so that proxy routing can route traffic to all nodes in the cluster.
By default, TPA commits configuration changes to a Git repository. For this example, you don't need to do that, so pass the
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:
- View the full set of available options by running:
- More details on PGD-Always-ON configuration options in Deploying with TPA
- PGD-Always-ON in the Trusted Postgres Architect documentation
tpaexec configurein the Trusted Postgres Architect documentation
- Docker platform in the Trusted Postgres Architect documentation
Next, allocate the resources needed to run the configuration you just created using the
tpaexec provision command:
Since you specified Docker as the platform, TPA creates a Docker image, containers, networks, and so on.
tpaexec provisionin the Trusted Postgres Architect documentation
With configuration in place and infrastructure provisioned, you can now deploy the distributed cluster:
TPA applies the configuration, installing the needed packages and setting up the actual EDB Postgres Distributed cluster.
tpaexec deployin the Trusted Postgres Architect documentation
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:
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:
Notice that you're logged in as
You now need to adopt the identity of the enterprisedb user. This user is preconfigured and authorized to connect to the cluster's nodes.
You can now run the
psql command to access the
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
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
Or, you can use
pgd show-nodes to ask PGD to show you the data-bearing nodes in the cluster:
pgd show-proxies to display the proxy connection nodes:
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: