ICA Resilience And Fault Injection — 20 Questions

Question 1

Which THREE settings are part of the 'outlierDetection' configuration in a DestinationRule?

Accepted Answer

interval. The standard fields include consecutive5xxErrors, interval, and baseEjectionTime.

Answer

requestRetryCount

Answer

maxConnectionTimeout

Question 2

Which TWO fields are required when configuring an 'abort' fault injection in a VirtualService?

Accepted Answer

httpStatus. Abort requires both the percentage and the specific status code to be returned.

Answer

maxDuration

Answer

grpcStatus

Answer

delay

Question 3

To test how your application handles service unavailability, you want to return an HTTP 503 error for 20% of requests to the 'catalog' service. Which fault injection setting do you use?

Accepted Answer

abort. The abort fault injection allows specifying a status code and percentage.

Answer

circuitBreaker

Answer

outlierDetection

Answer

delay

Question 4

You want to limit the number of concurrent connections to the 'payment' service to 100. Where is this configuration set?

Accepted Answer

DestinationRule. Connection pool settings are configured under trafficPolicy in the DestinationRule.

Answer

EnvoyFilter

Answer

ServiceEntry

Answer

VirtualService

Question 5

You need to limit the number of concurrent connections to the 'order-service' to prevent cascading failures. Which Istio resource should you configure?

Accepted Answer

DestinationRule. The DestinationRule resource allows you to define traffic policies, including connection pool settings, which control concurrent connections and requests.

Answer

Sidecar

Answer

VirtualService

Answer

EnvoyFilter

Question 6

You have a DestinationRule with outlier detection enabled. If a host returns 5 consecutive 5xx errors and the 'interval' is set to 1s, what happens if 'baseEjectionTime' is 30s?

Accepted Answer

It is ejected for 30 seconds. The host is ejected from the load balancing pool for 30 seconds.

Answer

It is ejected for 1 second

Answer

It is removed permanently

Answer

It is ignored because the interval is too small

Question 7

Which field in the trafficPolicy of a DestinationRule controls the maximum number of pending requests in the connection pool?

Accepted Answer

maxPendingRequests. maxRequestsPerConnection is used for HTTP/1.1 and maxPendingRequests for total pending requests.

Answer

maxRequests

Answer

pendingLimit

Answer

connectionLimit

Question 8

You need to ensure that a request to the 'orders' service times out if it takes longer than 2 seconds. Which field in the VirtualService should you configure?

Accepted Answer

timeout. The timeout setting is defined within the route rule of a VirtualService.

Answer

deadline

Answer

maxRequestDuration

Answer

requestTimeout

Question 9

What is the default timeout for an HTTP request in Istio when no VirtualService is defined?

Accepted Answer

15 seconds. Istio defaults to 15 seconds for request timeouts if not explicitly configured.

Answer

5 seconds

Answer

10 seconds

Answer

30 seconds

Answer

60 seconds

Answer

0 (no timeout)

Question 10

To test the resilience of your microservice architecture, you want to introduce a 5-second delay to 50% of the requests directed to the 'catalog-service'. Where do you define this configuration?

Accepted Answer

VirtualService. Fault injection policies are defined within the 'http' routing rules of a VirtualService.

Answer

DestinationRule

Answer

Gateway

Answer

ServiceEntry

Question 11

You want to configure your microservice to be more resilient. Which THREE of the following are valid fields within an 'outlierDetection' policy in a DestinationRule?

Accepted Answer

consecutive5xxErrors. The outlierDetection object supports consecutive5xxErrors, interval, and baseEjectionTime.

Answer

http2MaxRequests

Answer

maxRequestsPerConnection

Question 12

Which TWO options are required to properly implement an abort fault injection in a VirtualService?

Accepted Answer

httpStatus. To implement an abort, you must specify the 'percentage' and the 'httpStatus' code within the 'fault' block.

Answer

headers

Answer

match

Answer

fixedDelay

Question 13

You want to simulate a 5-second network latency for 10% of requests to the 'cart' service. Which VirtualService configuration is correct?

Accepted Answer

fault: { delay: { percentage: { value: 10 }, fixedDelay: 5s } }. The fault injection delay policy requires both a percentage and a fixedDelay duration.

Answer

fault: { delay: { fixedDelay: 5s } }

Answer

fault: { delay: 5s, weight: 0.1 }

Answer

fault: { delay: { percentage: 10, latency: 5s } }

Answer

fault: { abort: { percentage: 10, duration: 5s } }

Question 14

An application is experiencing intermittent errors. You decide to use outlier detection to eject unhealthy pods. Which field in the DestinationRule controls the ejection of hosts after a certain number of 5xx errors?

Accepted Answer

consecutive5xxErrors. The 'consecutive5xxErrors' field in the 'outlierDetection' section of a DestinationRule is used to eject unhealthy hosts.

Answer

baseEjectionTime

Answer

interval

Answer

maxConnections

Question 15

You need to limit the number of concurrent connections to the 'orders' service. Which field in the DestinationRule do you configure?

Accepted Answer

trafficPolicy.connectionPool.tcp.maxConnections. The connectionPool settings within a DestinationRule allow you to control maxConnections for TCP or maxRequestsPerConnection for HTTP.

Answer

trafficPolicy.connectionPool.http.maxRequests

Answer

trafficPolicy.circuitBreaker.maxConnections

Answer

trafficPolicy.outlierDetection.maxConnections

Answer

trafficPolicy.loadBalancer.maxConnections

Question 16

A service is returning 5xx errors frequently. You want to eject instances that return 5 consecutive 5xx errors. Which OutlierDetection setting is required?

Accepted Answer

consecutive5xx: 5. consecutive5xx is the field used to trigger ejection based on the count of 5xx errors.

Answer

interval: 5s

Answer

maxEjectionPercent: 5

Answer

consecutiveErrors: 5

Answer

baseEjectionTime: 5s

Question 17

Where do you define the connection pool settings for a service?

Accepted Answer

DestinationRule. Connection pool settings are part of the trafficPolicy within a DestinationRule.

Answer

Gateway

Answer

VirtualService

Answer

ServiceEntry

Answer

Sidecar

Question 18

Which of the following is a valid method for performing fault injection?

Accepted Answer

Using a VirtualService to inject delays.. Istio supports both delay and abort faults via VirtualService.

Answer

Using a ServiceEntry to redirect traffic.

Answer

Using a DestinationRule to drop connections.

Answer

Using an EnvoyFilter to rewrite headers.

Answer

Using a Gateway to block traffic.

Question 19

You are testing resilience. You want to inject an HTTP 503 error for 20% of traffic to the 'catalog' service. Which fault setting is correct?

Accepted Answer

abort: { status: 503, percentage: { value: 20 } }. The fault injection abort policy requires an HTTP status code and a percentage.

Answer

abort: { code: 503, percent: 20 }

Answer

fault: { abort: 503, rate: 0.2 }

Answer

abort: { status: 503, ratio: 0.2 }

Answer

error: { status: 503, percentage: 20 }

Question 20

You notice that a pod is being ejected by Outlier Detection despite only having occasional errors. How do you increase the interval between ejection scans?

Accepted Answer

Set outlierDetection.interval to a higher value.. The interval field in OutlierDetection determines how often the health check is performed.

Answer

Disable outlierDetection.

Answer

Set outlierDetection.baseEjectionTime to a higher value.

Answer

Set outlierDetection.maxEjectionPercent to a higher value.

Answer

Set outlierDetection.consecutive5xx to a higher value.

Answer

Set connectionPool.tcp.maxConnections to a lower value.