About seamless function deployment

Question

hello. If you 'publish' from an Azure project or 'swap' from a 'deployment slot', the following error will occur if you make a request to an already deployed function before the function app is fully deployed.

///
Invocation of cloud script function FunctionRequest failed with HTTP status ServiceUnavailable and response body The service is unavailable.
///

If your production environment requires critical updates, you don't want a temporary outage during deployment. Is there a way around this?

Answer 1

Hello @mrym - Welcome & thanks for posting on MS Q&A! Could you clarify the order of steps described in your statement below?

If you 'publish' from an Azure project or 'swap' from a 'deployment slot', the following error will occur if you make a request to an already deployed function before the function app is fully deployed.

Blue/green deployment pattern for Functions is indeed achieved through the use of deployment slots, and once configured correctly & between swaps, there shouldn't be any outage though.

Referencing the following resources as they may be helpful:

• Azure Functions deployment slots
• Azure Durable Functions: Blue Green Deployment