ICA Resilience And Fault Injection Practice Test 4 — 15 Questions

Question 1

When configuring circuit breaking, what does 'maxRequestsPerConnection' control?

Accepted Answer

The number of requests per individual connection.. It limits the number of requests that can be sent over a single keep-alive connection, useful to prevent connection starvation.

Answer

The number of concurrent requests.

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The total number of requests sent to a service.

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The latency of each request.

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The size of the request body.

Question 2

Which resource is used to configure circuit breaking for a service?

Accepted Answer

DestinationRule. DestinationRule is the resource where circuit breaking settings are defined within the trafficPolicy.

Answer

PeerAuthentication

Answer

Gateway

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VirtualService

Answer

EnvoyFilter

Question 3

What happens when a circuit breaker trips?

Accepted Answer

Traffic is no longer sent to the instance.. The circuit breaker stops sending traffic to the unhealthy host, protecting the system from overload.

Answer

The service is deleted.

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All traffic is redirected to a static page.

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The entire mesh is shut down.

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The pod is restarted.

Question 4

What is the primary purpose of adding a timeout to a service call?

Accepted Answer

To prevent resource exhaustion from hanging requests.. A timeout on a service call ensures that if a downstream service does not respond within a specified period, the call is aborted. This prevents the calling service from indefinitely waiting, which can lead to thread pool exhaustion, memory buildup, and cascading failures. Thus, the primary purpose is to prevent resource exhaustion from hanging requests.

Answer

To hide errors from the user.

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To load balance more effectively.

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To increase throughput.

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To encrypt traffic.

Question 5

Which field defines how long an ejected pod remains out of the rotation?

Accepted Answer

baseEjectionTime. baseEjectionTime determines the duration an instance is excluded from the load balancing pool.

Answer

maxEjectionPercent

Answer

interval

Answer

minHealthPercent

Answer

consecutive5xx

Question 6

Can you configure fault injection for specific traffic patterns, such as user headers?

Accepted Answer

Yes, by adding a 'match' criteria in the VirtualService.. Yes, fault injection can be scoped to specific route matches in a VirtualService.

Answer

No, fault injection is global for the service.

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No, it must be applied via global EnvoyFilter.

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Yes, but only via DestinationRule.

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Yes, but only for egress traffic.

Question 7

In OutlierDetection, what is the effect of setting 'maxEjectionPercent' to 0?

Accepted Answer

It disables outlier detection.. Setting this to 0 effectively disables outlier detection, as no hosts can be ejected.

Answer

It makes the ejection time infinite.

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It forces all hosts to be healthy.

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It ejects hosts immediately.

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It ejects all hosts.

Question 8

How do you specify the percentage of traffic that should experience a fault?

Accepted Answer

Using a 'percentage' object with a 'value' field.. In Istio's fault injection API, the percentage of requests affected by a fault is specified using a 'percentage' object containing a 'value' field (an integer 0–100), nested under the delay or abort fault. For example, an HTTPAbort fault uses 'percentage: {value: 50}' to abort half of matching requests. This is the documented schema for controlling fault scope in a VirtualService.

Answer

Using a 'weight' field.

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Using a 'threshold' field.

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Using the 'ratio' field.

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Using a 'rate' field in the VirtualService.

Question 9

Which component is responsible for the actual enforcement of circuit breaking and fault injection?

Accepted Answer

Envoy proxy. The Envoy proxy (sidecar) performs the enforcement based on the configuration pushed by Istiod.

Answer

Kubernetes API Server

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Istiod

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Prometheus

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Ingress Gateway

Question 10

What is the consequence of having a timeout that is shorter than the average latency of the service?

Accepted Answer

Increased 504 Gateway Timeout errors.. If the timeout is too short, requests will be terminated prematurely, causing valid requests to fail.

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Faster response times.

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Increased throughput.

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Automatic retries.

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Better connection pooling.

Question 11

What happens if a request times out in Istio?

Accepted Answer

The proxy returns a 504 Gateway Timeout.. If a request exceeds the timeout, the proxy terminates the request and returns a 504 Gateway Timeout.

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The request is retried automatically.

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The proxy returns a 408 Request Timeout.

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The request is passed to another healthy host.

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The connection is closed without an error.

Question 12

What is the recommended way to test fault injection in a production environment?

Accepted Answer

Using header-based matches in a VirtualService.. Using header-based matching allows you to target faults to specific test traffic without impacting all users.

Answer

Injecting faults in the code.

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Using a separate mesh for testing.

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Enabling it for 1% of traffic using weight.

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Applying it globally to all users.

Question 13

Which of the following describes the difference between Circuit Breaking and Outlier Detection?

Accepted Answer

Circuit Breaking monitors request load, Outlier Detection monitors host health.. Circuit Breaking monitors request load (e.g., connection pool saturation, pending requests, retries) and trips when thresholds are exceeded, preventing cascading failures by rejecting new requests. Outlier Detection monitors host health by passively tracking errors (e.g., 5xx responses) and ejecting unhealthy hosts from the load balancing pool. Thus, the correct distinction is that Circuit Breaking focuses on request load, while Outlier Detection focuses on host health.

Answer

Circuit Breaking is for ingress, Outlier Detection is for egress.

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Circuit Breaking is proactive, Outlier Detection is reactive.

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Outlier Detection is for connection pooling.

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Circuit Breaking only works on TCP.

Question 14

How do you define a circuit breaker that limits the number of pending requests?

Accepted Answer

http1MaxPendingRequests. The 'http1MaxPendingRequests' field is used to limit the number of pending requests in the connection pool.

Answer

maxRequestsInQueue

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maxPending

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pendingRequestsLimit

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maxPendingRequests

Question 15

What is the default value for 'consecutive5xx' in OutlierDetection?

Accepted Answer

5. The default value for consecutive5xx in Istio/Envoy is 5.

Answer

10

Answer

20

Answer

0

Answer

1