AZ-204: Developing Solutions for Microsoft Azure

Exploring App Service Deployment Slots

Staging Environments

In this article, we explore the significance of staging environments within Azure App Service and how deployment slots can streamline your deployment process. Deployment slots allow you to test application updates in a production-like setting before they go live, ensuring a smooth and reliable experience for your users.

Deployment slots are available based on your App Service plan tier. Here’s a quick overview:

  • Standard Tier: Provides up to five deployment slots.
  • Premium Tier: Offers up to 20 deployment slots.
  • Isolated Tier: Supports up to 20 deployment slots and runs in a fully isolated, dedicated environment to ensure high performance and enhanced security.

The image shows three types of staging environments: Standard, Premium, and Isolated, each represented by a different colored icon.

Deployment slots offer several key benefits in your deployment process:

  1. Validation
    Validate app changes in a non-production slot before promoting them to production. This ensures that new versions function as expected without affecting your live environment.

  2. Warming Up
    Before swapping into production, deployment slots allow instances of your app to warm up. This proactive step helps minimize cold start issues and promotes a seamless transition for end users.

  3. Seamless Swap
    Slot swapping exchanges the contents of the staging and production slots. The previous production slot is retained as the new staging slot, making it easy to roll back if issues surface during deployment.

The image outlines the benefits of a non-production slot, highlighting validation of app changes, warming up instances before production, and maintaining previous production apps after a swap.

Note

Ensure that your App Service plan supports deployment slots. For more details on plan eligibility and pricing, refer to the Azure App Service Pricing documentation.

Summary

Deployment slots in Azure App Service are a powerful tool for enhancing the quality and reliability of your applications. By allowing thorough validation, facilitating instance warm-up, and enabling seamless slot swaps, they reduce risk and enable swift rollbacks if needed.

Now that we've covered the benefits of deployment slots, let's explore the concept of slot swapping in more detail.

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