When does an azure worker role report ready?

Question

I'm working on the deployment processes for a web application which runs inside an Azure cloud service.

I deploy to the staging slot, once all the instances report a status of RoleReady I then do a VIP swap into the production slot. The aim is that I can deploy a new version and my users won't have to wait while the site warms up.

I have added a certain amount of warmup into the RoleEntryPoint.OnStart, essentially this hits a number of the application's endpoints to allow the caches to spin up and and view compilation to run. What I'm seeing is that the instances all report ready, before this process has completed.

How can I tell if my application has warmed up before I swap staging into production? The deploy script I'm using is a derivative of https://gist.github.com/chartek/5265057.

Answer 1

The role instance does not report Ready until the OnStart method finishes and the Run method begins. You can validate this by looking at the guest agent logs on the VM itself (see http://blogs.msdn.com/b/kwill/archive/2013/08/09/windows-azure-paas-compute-diagnostics-data.aspx for more info about those logs).

When you access the endpoints are you waiting for response or just sending a request? See Azure Autoscale Restarts Running Instances for code which hits the endpoints and waits in OnStart for responses before moving the instance to the Ready state.