Automating Azure HorizonDB Labs with ARM Templates

HorizonDB preview: automate a reproducible lab with ARM

Azure HorizonDB is a new PostgreSQL-compatible database service featuring a specialized storage layer for high availability. It allows for rapid deployment via Azure Resource Manager (ARM) to test application compatibility.

Why This Matters

Traditional PostgreSQL deployments rely on both buffer cache and OS filesystem cache, often leading to double buffering. HorizonDB utilizes disaggregated storage to align shared_buffers and effective_cache_size, while disabling full_page_writes because the underlying storage layer prevents torn pages, significantly increasing performance over standard configurations.

Key Insights

• PostgreSQL 17.9 compatibility provided by HorizonDB (2026), enabling developers to use standard psql clients.
• Disaggregated storage architecture allowing shared_buffers to exceed typical recommendations, such as allocating ~11GB on a 16GiB RAM instance.
• Infrastructure as Code (IaC) using ARM templates to automate firewall rules and cluster configuration for reproducibility.
• Optimization of data consistency where full_page_writes is set to ‘off’ due to storage layer guarantees.

Working Examples

Commands to create a resource group and deploy the HorizonDB cluster using an ARM template.

az group create --name franckpachot-rg --location swedencentral

az deployment group create --resource-group franckpachot-rg --template-file hdb-template.json --parameters @hdb-parameters.json --parameters administratorLoginPassword=PostgreSQL@Azure

CLI command to retrieve the fully qualified domain name of the deployed cluster.

az resource show --resource-type Microsoft.HorizonDB/clusters --name franckpachot-hdb --resource-group franckpachot-rg --query properties.fullyQualifiedDomainName -o tsv

Practical Applications

• …Use case: Developers testing PostgreSQL application compatibility on Azure by deploying ephemeral labs that can be dismantled via ‘az group delete’.
• …Pitfall: Manually configuring network access via UI, which leads to non-reproducible environments; solved by embedding firewall rules in the ARM template loop.

References:

• https://dev.to/franckpachot/horizondb-preview-automate-a-reproducible-lab-with-arm-2515

https://learn.microsoft.com/en-us/azure/horizondb/overview#azure-regions