Azure App Service Deployment Slots are a feature of Azure App Service that allow you to create multiple deployment environments for your web applications, your can refer this Set up staging environments - Azure App Service | Microsoft Learn documentation to learn the objects that can be cloned and the objects that cannot be cloned between the environments. Stage deployments are extremely useful for various scenarios, such as:
Development and Testing: You can have separate slots for development, staging, and testing your web app without affecting the production environment. This allows you to validate changes before making them live.
Blue-Green Deployments: You can set up a production slot and a staging slot. When you're ready to release a new version, you can swap the slots, making the staging slot the new production slot. This enables zero-downtime deployments.
A/B Testing: You can create multiple slots to test different versions of your application with a portion of your user base, allowing you to gather feedback and make informed decisions.
Rollback: If a new deployment causes issues, you can easily swap the slots back to the previous version, quickly rolling back changes
How do the Deployment slots works:
Production Slot: Every Azure App Service has a production slot, which is the main environment for your application accessible to users.
Staging Slots: You can create one or more staging slots that are exact copies of the production environment. These slots can be used for testing and validation.
Configurations: Each slot can have its own configurations, such as environment variables, connection strings, and app settings. This allows you to have different configurations for different environments.
Traffic Routing: You can route a percentage of traffic to a specific slot. This is helpful for A/B testing or gradual rollouts.
Leveraging the power of Stage deployments of App Service, we can easily manage the content updates, plugin modifications, version upgrades of WordPress sites without impacting the end users. As WordPress on App Service also has a Azure MySQL Flexible server database backend, we need to have a configuration for setting up production and stage databases aligning to your Web servers(App Service). Since Azure MySQL Flexible server do not have feature similar to App Service deployment slots, we need to follow certain customizations to maintain Product and Stage slots for WordPress sites.