The Network Operations Center reports that an application had an outage last night during an Avi upgrade. The Service Engine Group assigned to this Virtual Service is using the default…

Question

Options

• AFirewall rules were not configured for failover SE.
• BThis is by design since Service Engine upgrades are disruptive.
• CThere was a global internet outage.
• DThe Virtual Service was not scaled out.

• A
  11% (5)
• B
  83% (39)
• C
  4% (2)
• D
  2% (1)

Explanation

During an Avi (NSX Advanced Load Balancer) upgrade, Service Engines must restart to apply the new software - and when only a single SE is serving a Virtual Service, that restart causes a complete traffic outage. The Basic Virtual Service wizard and the default Service Engine Group both provision just one active SE, meaning there is no secondary SE to absorb traffic during the upgrade; this behavior is by design and documented, not a bug or misconfiguration error.

Why the distractors are wrong:

• A - Firewall rules for a failover SE are irrelevant here; the problem is architectural (single SE), not a connectivity/policy issue.
• C - A global internet outage is implausible and doesn't explain why the timing coincided precisely with the Avi upgrade.
• D - While "not scaled out" accurately describes the configuration gap, it states a contributing condition rather than the reason for the outage; the outage occurred because SE upgrades are inherently disruptive on a single-SE deployment, which is the designed behavior B describes.

Memory tip: Think "Basic = Bare minimum = 1 SE = Disruptive upgrade." To survive an upgrade without downtime, you need N+1 SEs so one can serve traffic while the other reboots - that requires scaling out beyond the Basic wizard defaults.

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