Infrastructure Advanced Quiz
Related Document: Infrastructure Advanced
Multiple Choice Questions
1. What is the primary purpose of NLB weighted target groups in a blue/green deployment?
- A) To reduce costs by using fewer load balancers
- B) To control traffic distribution between cluster versions
- C) To improve SSL termination performance
- D) To eliminate the need for health checks
Show Answer
Answer: B) To control traffic distribution between cluster versions
Explanation: NLB weighted target groups allow gradual traffic shifting between blue (current) and green (new) clusters. By adjusting weights (e.g., 90:10, 50:50, 0:100), operators can perform controlled rollouts and quickly rollback if issues are detected.
2. In a single-zone EKS cluster strategy, why might you deploy data nodes to only one Availability Zone?
- A) To reduce cross-AZ data transfer costs
- B) To simplify DNS configuration
- C) To avoid using multiple subnets
- D) To eliminate the need for persistent volumes
Show Answer
Answer: A) To reduce cross-AZ data transfer costs
Explanation: Cross-AZ data transfer incurs costs in AWS. For data-intensive workloads with local storage (like databases), keeping all replicas in a single AZ eliminates these costs while relying on application-level replication for durability.
3. What Kubernetes feature ensures pods are distributed across different zones or nodes?
- A) PodAffinity
- B) TopologySpreadConstraints
- C) ResourceQuota
- D) LimitRange
Show Answer
Answer: B) TopologySpreadConstraints
Explanation: TopologySpreadConstraints control how pods are spread across topology domains (zones, nodes, regions). They ensure even distribution for high availability and can be configured with maxSkew, topologyKey, and whenUnsatisfiable parameters.
4. How does Route53 weighted routing differ from NLB weighted target groups?
- A) Route53 works at DNS level, NLB works at connection level
- B) Route53 only supports equal weights
- C) NLB doesn't support health checks
- D) Route53 requires VPC peering
Show Answer
Answer: A) Route53 works at DNS level, NLB works at connection level
Explanation: Route53 weighted routing distributes traffic at DNS resolution time, while NLB weighted target groups distribute at the connection level. DNS-based routing has TTL considerations, while NLB provides more immediate traffic shifting.
5. What is the recommended maxSkew value for TopologySpreadConstraints in a 3-AZ deployment?
- A) 0
- B) 1
- C) 3
- D) 10
Show Answer
Answer: B) 1
Explanation: A maxSkew of 1 ensures pods are evenly distributed with at most one pod difference between topology domains. This provides good balance while still allowing scheduling flexibility when nodes have resource constraints.
6. In blue/green cluster architecture, what should be shared between clusters?
- A) Worker nodes
- B) External DNS and load balancer
- C) etcd storage
- D) Kubernetes API server
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Answer: B) External DNS and load balancer
Explanation: Blue/green clusters are separate EKS clusters that share external infrastructure like DNS records and load balancers. This allows traffic to be shifted between clusters without changing client-facing endpoints.
7. What happens when whenUnsatisfiable: DoNotSchedule is set in TopologySpreadConstraints?
- A) Pods are scheduled anywhere regardless of constraints
- B) Pods remain pending if constraints cannot be satisfied
- C) Pods are automatically deleted
- D) The constraint is ignored
Show Answer
Answer: B) Pods remain pending if constraints cannot be satisfied
Explanation:DoNotSchedule prevents pod scheduling when the spread constraint would be violated. This ensures strict adherence to topology requirements but may result in pending pods if cluster topology doesn't support the constraint.
8. For automated failover between blue/green clusters, what AWS service can be used with health checks?
- A) AWS Config
- B) Route53 health checks with failover routing
- C) AWS Inspector
- D) AWS Trusted Advisor
Show Answer
Answer: B) Route53 health checks with failover routing
Explanation: Route53 health checks continuously monitor endpoint availability and can automatically switch traffic to a healthy cluster using failover routing policy. This enables automated disaster recovery without manual intervention.
9. What is a key consideration when using NLB cross-zone load balancing?
- A) It's always free
- B) It may incur additional data transfer charges
- C) It requires VPC peering
- D) It only works with TCP protocol
Show Answer
Answer: B) It may incur additional data transfer charges
Explanation: When cross-zone load balancing is enabled, NLB distributes traffic evenly across all registered targets in all enabled AZs, which can result in cross-AZ data transfer charges. Consider this cost when architecting multi-AZ deployments.
10. In a zonal cluster deployment (a-zone blue, c-zone green), what is the primary benefit?
- A) Reduced networking complexity
- B) Failure isolation and independent upgrade paths
- C) Lower compute costs
- D) Automatic data replication
Show Answer
Answer: B) Failure isolation and independent upgrade paths
Explanation: Zonal clusters provide failure domain isolation - an issue in one zone doesn't affect the other cluster. This also enables independent upgrade testing and gradual rollouts, reducing risk during Kubernetes version upgrades.