AZ-104
The 3am Production Crash
It is 3:14am. PagerDuty wakes you up. The production e-commerce web application is down. The app runs on two VMs (web-vm-01 and web-vm-02) placed in an Availability Set. Monitoring shows web-vm-01 is offline. An Azure platform health notification in the portal says: "Planned maintenance — your VM was moved to a new host." web-vm-02 is running but under extreme load (CPU 98%). The development team is reporting that temp disk data they use for session caching is missing on web-vm-02 after a recent resize.
STEP 1 OF 5 — FREE PREVIEW
Explain why, despite having an Availability Set, web-vm-01 is down during planned maintenance. Should the Availability Set have prevented this? What configuration was likely missing that would have guaranteed the maintenance took the VMs offline sequentially, never both at once?
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Steps 2–5 require purchase
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