.NET8 not yet available on all instances running on Azure Functions Consumption plan?

Jens Pettersson 0

Haven't all instances for Consumption plans on Azure Function got the .net8 runtime installed? We get the following messages randomly when our instances spins up. Some are working, some are not working with the logs attached as an image here:

It's a Consumption plan, Windows, West Europe.

The Function App has the stack setting to .NET8 Isolated:

As it works on some instances we get when spinning up, it feels like the .net8 runtime hasn't been installed everywhere yet...

VenkateshDodda-MSFT 19,646 Reputation points Microsoft Employee

2023-11-17T07:06:38.42+00:00
@Jens Pettersson Thanks for reaching out to Microsoft Q&A, apologize for any inconvenience caused on this.

I am checking with the internal team on this and will update you here accordingly. Meanwhile can you help me with more information to check and assist you further.

Are you seeing the same behavior in different functions app which are running with same runtime in different regions as well. or only issue with this particular function app.

Also, help us with the last digits of subscription Id, impacted function app and Issue time stamp (UTC).
Jens Pettersson 0 Reputation points

2023-11-17T08:22:54.17+00:00

I've created a super simple Function App and deployed them on both a Windows Consumption plan and also a Linux Consumption plan in West Europe. The app is only one HttpTrigger and .net8 nothing more.

The one on the Windows Consumption plan behaves excatly like the one i showed above. It always starts with 502 for a couple of minutes and the logs shows that the .net8 version is not installed.

The one on the Linux Consumption plan starts cold and responds with 200 OK in 2 seconds. No missing .net8 version, everything works.

When we let the app idle out the behaviour is repeated, Windows a couple of failing requests and after a couple of minutes it works while Linux works right away.

So this seems to be related to Windows Consumption plan, and when reading the GA announcement from November 14th:

I get the feeling that what we're experiencing is this, but in this case, a "cold start" is also related to "...the instance needs to fetch and install the .net8 runtime on the fly". That's a pretty big task for a cold start...

Earlier today I created a support ticket with all relevant information: 2311170050000303
Jens Pettersson 0 Reputation points

2023-11-17T08:46:38.7266667+00:00

I've now also deployed the same Azure Function to a Windows Consumption Plan in EAST US instead of West Europe, and it worked immediately. Not sure if I got lucky or if .net8 is rolled out to more instances in that location and doesn't need to be "installed on the fly" as my theory was...
Jens Pettersson 0 Reputation points

2023-11-17T09:51:26.0833333+00:00

Sorry, false positive... After the East US instance had been idle for about 45 minutes, we got a new instance without .net8 installed:
VenkateshDodda-MSFT 19,646 Reputation points Microsoft Employee

2023-11-23T04:43:15.6066667+00:00

@Jens Pettersson Thanks for sharing more information apologize for the delay in my response.
I am still waiting to hear back from the internal team.

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.NET8 not yet available on all instances running on Azure Functions Consumption plan?