CODEWITHSUNDEEP
azureazure-functionsazureservicebusservicebus
Mori
Mori

Reputation: 2574

Limit number of instances of Azure Function Apps v2

I need to have only one instance of an Azure Function App in place and put the following json code in host.json.

But when a function gets triggered by a servicebus queue, I can clearly see in Live Metrics Stream in Application Insights that several servers get provisioned to serve the load. What am I missing to limit the running servers to only one?

{
  "version": "2.0",
  "WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT": 1,
  "maxConcurrentCalls": 2,
  "extensions": {
        "serviceBus": {
            "prefetchCount": 1,
            "messageHandlerOptions": {
                "maxConcurrentCalls": 2
            }
        }
    }
}

Upvotes: 1

Views: 3098

Answers (2)

Carlos Garcia
Carlos Garcia

Reputation: 2970

Why do you want to do that? Remember that each instance can process multiple messages at the same time, so 1 instance does not means one message at at time

Anyways, you can go to your app settings and add the following: WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT = 1

Azure Functions settings

Upvotes: 4

MarkXA
MarkXA

Reputation: 4384

WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT is an application setting, not a host.json setting. I would also point out that it's somewhat less than 100% reliable, so if you need a hard guarantee of only 1 instance then you should use either a Premium plan or a standard App Service plan rather than a Consumption plan.

Upvotes: 1

Related Questions