High CPU spike on app service plan after swapping to Production, causing down time

Marcel Croes 1 Reputation point
2020-06-13T08:26:50.52+00:00

Hello,

We have 5 Web App's under 1 plan and we use Azure Pipelines to deploy them. We deploy them to one Warmup slot and than swap them with Production.

Right now with every deployment, right after swapping or during the swap the app plan will spike to 100% causing down time for several minutes on all the sites.
We've reached a point where we halted deployments until this can get resolved.

Some more info:

  • Views are compiled.
  • I've checked that configurations are the same on de Warmup slot and the Production slot.
  • App settings are on both slots the same
  • I've tried adding WEBSITE_ADD_SITENAME_BINDINGS_IN_APPHOST_CONFIG=1 according to the swap troubleshoot docstroubleshoot docs
  • Proactive CPU monitoring does not seem to be helpful, since this mostly happen during swapping/restart
  • I also tried applicationInitialization in web.config with no dice

I would like some assistance in debugging this problem.

Azure App Service
Azure App Service
Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
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  1. Malleswara Reddy, G 1,631 Reputation points
    2020-06-13T13:09:22.427+00:00

    Hi,

    If you are using Basic or standard plan of App services, Tyr upgrading to premium and also try increasing DTUs.

    Regards,
    Eshwar

  2. Wolf, Lorenz 1 Reputation point
    2021-11-19T08:23:14.593+00:00

    We are facing exactly the same issue. Swapping a slot on App Service P1V2 leads to high CPU peaks (nearly 100%) which affects the production slot and also leads to a failing deployment sometimes. During normal load we are on a way lower CPU usage which is why it would not make sense to further increase the SKU.

    @Anonymous did you managed to work around this issue?

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