CCNA Continuous Improvement for Existing Solutions Questions

Option C is correct because if there is an ongoing update or configuration change, Elastic Beanstalk prevents concurrent operations. Option A is wrong because CodePipeline does not require a specific instance type. Option B is wrong because insufficient capacity would cause a different error.

Option D is wrong because the environment URL being unavailable is a symptom, not cause.

Option D is correct because Fargate tasks require 'Task execution role' for pulling images and logging, but for S3 access they need 'Task role' with proper IAM permissions. The task role is set, but maybe the task definition is not using the correct role ARN. Option A is wrong because VPC endpoints for S3 are not required if the task can route to S3 via internet or NAT.

Option B is wrong because 'Task execution role' is for ECS agent, not for application. Option C is wrong because S3 Bucket Policy could block access, but the question states the task role has permissions.

Option A is correct because increasing the API Gateway throttling limits allows more requests to pass through to the backend. Option B is wrong because increasing Lambda concurrency may help but is more expensive than adjusting throttling limits. Option C is wrong because DynamoDB auto-scaling addresses database capacity, not API throttling.

Option D is wrong because API caching reduces backend calls for repeated requests but does not address throttling limits.

Option B is correct because if the Lambda function is processing larger files, it may exceed the 5-minute timeout. Option A is incorrect because increasing memory does not affect timeout. Option C is incorrect because reserved concurrency does not affect execution time.

Option D is incorrect because a new VPC configuration would not cause a timeout by itself.

Option B is correct because S3 event notifications for PUT and POST operations require the bucket to be configured to send events to CodePipeline. Option A is wrong because the bucket policy is not relevant for event notifications. Option C is wrong because CodePipeline can use S3 as a source without a webhook.

Option D is wrong because the pipeline execution role is not the cause.

Option A is correct because increasing reserved concurrency allows more simultaneous invocations, processing more messages in parallel. Option B is wrong because Lambda functions don't have a 'thread count' setting. Option C is wrong because batch size is already maxed at 10 for SQS.

Option D is wrong because adding more queues would require code changes and doesn't directly help.

Option B is correct because when a stack update fails and rollback fails, you must manually fix the resources that prevent rollback (e.g., delete a resource that is stuck) and then continue the rollback. Option A is wrong because you cannot update a stack in UPDATE_ROLLBACK_FAILED state without first completing the rollback. Option C is wrong because you cannot add resources while in failure state.

Option D is wrong because you cannot delete the stack without first fixing the rollback.

Option C is correct. The instance state is 'running', so it's not stopped or terminated. The issue is likely a security group or network ACL blocking SSH.

Option A is wrong because the instance is running. Option B is wrong because the instance ID is not shown but the query is correct. Option D is wrong because EBS optimization does not affect network connectivity.

Option C is correct because enabling stickiness (session affinity) ensures requests from the same user go to the same instance. Option A is incorrect because a Classic Load Balancer doesn't solve statefulness. Option B is incorrect because ElastiCache doesn't solve routing.

Option D is incorrect because cross-zone load balancing doesn't affect session persistence.

Option B is correct because a NAT Gateway in each AZ provides high availability; without it, a single NAT Gateway failure causes timeouts. Option A is wrong because it reduces security. Option C is wrong because it does not address NAT redundancy.

Option D is wrong because it adds complexity without directly fixing NAT issues.

Option B is correct because Amazon RDS Proxy manages connection pooling and can scale with application, reducing load on database. Option A is wrong because DynamoDB is a different database. Option C is wrong because scaling EC2 instances does not address database connections.

Option D is wrong because modifying RDS instance type is manual and not automatic.

Option C is correct because AWS Backup provides lifecycle policies and centralized snapshot management, making it easy to identify orphaned snapshots. Option A is wrong because it doesn't help identify unused snapshots. Option B is wrong because it's for storage class, not snapshot deletion.

Option D is wrong because it's for billing, not operations.

Options A, C, and D are correct. Checking AppSpec hooks ensures the validation scripts are correctly defined. Reviewing CodeDeploy agent logs helps identify script failures.

Testing the validation script manually on a healthy instance verifies its functionality. Option B is wrong because increasing the deployment timeout does not fix the script failure. Option E is wrong because CodeDeploy does not use Auto Scaling lifecycle hooks for instance health; it uses its own deployment lifecycle.

Option D is correct because AWS CodeDeploy supports automatic rollback based on CloudWatch alarm metrics, such as error rate, with minimal overhead. Option A is wrong because manual approval does not trigger automatic rollback. Option B is wrong because Lambda functions add complexity and are not the best practice for automatic rollback.

Option C is wrong because modifying ASG health checks does not directly monitor error rate for rollback.

Option C is correct because a NAT gateway with an Elastic IP can be placed in a single AZ, but if that AZ fails, the workload fails. A Network Load Balancer with EIPs and NAT instances provides a fixed IP and HA. Option A is wrong because multiple NAT gateways have different IPs.

Option B is wrong because it's not HA. Option D is wrong because a proxy fleet still uses multiple IPs.

Option B is correct because increasing the root volume size provides more space for temporary files without application changes. Option A is wrong because instance store is ephemeral and may not be available on t3 instances. Option C is wrong because mounting an EBS volume would require application changes to write to a different path.

Option D is wrong because reducing file size may not be feasible and requires code changes.

Option B is correct because a bucket policy that denies PutObject without x-amz-server-side-encryption header set to aws:kms will enforce encryption at upload time. Option A is not possible at the bucket level. Option C (default encryption) does not enforce on existing uploads if the header is omitted.

Option D (CloudTrail) is detective, not preventive.

Option B is correct because the query filters objects larger than 1000 bytes and returns only those keys. Option A is incorrect because the output shows two keys. Option C is incorrect because the command queries objects, not versions.

Option D is incorrect because size > 1000 bytes, not 1000 KB.

Option A is correct because an explicit deny in another statement would override the allow, but the question says users can access from outside the range, meaning the deny is not effective. The most likely reason is that the deny statement does not apply to the users (e.g., it applies to a different principal). Option B is incorrect because the policy is a bucket policy, not an IAM policy.

Option C is incorrect because the condition is correct syntax. Option D is incorrect because the bucket policy is applied to the bucket, not IAM users.

Option A is correct because CloudFormation stack updates have a 'Rollback on failure' option that defaults to 'Yes'. If an update fails, CloudFormation automatically rolls back to the previous state. Option B is wrong because a stack policy prevents updates to specific resources, not rollback behavior.

Option C is wrong because change sets allow you to preview changes but do not automate rollback. Option D is wrong because termination protection prevents stack deletion, not rollback on failed updates.

Option D is correct because ECS tasks should be launched in the same VPC and security group as the database, or use VPC peering/transit gateway. Option A is wrong because NAT gateway is for outbound. Option B is wrong because public subnet tasks cannot directly access private RDS without proper routing.

Option C is wrong because VPN is overkill.

Option A is correct because implementing an ElastiCache caching layer can reduce repeat database queries. Option D is correct because creating an Aurora read replica and directing read traffic to it offloads the primary instance. Option B is wrong because increasing the DB instance class may help but is not a best practice for immediate load reduction.

Option C is wrong because increasing Auto Scaling group size does not affect database load. Option E is wrong because enabling Performance Insights is for monitoring, not load reduction.

Option B is correct because AWS Config has managed rules to check S3 bucket encryption. Option A is wrong because Trusted Advisor checks only a subset of buckets. Option C is wrong because S3 Inventory provides object metadata, not encryption status.

Option D is wrong because CloudTrail logs API calls, not current state.

Option C is correct because enabling DynamoDB Accelerator (DAX) provides an in-memory cache that reduces read latency without increasing provisioned RCU. Option A is wrong because increasing RCU increases cost. Option B is wrong because switching to strongly consistent reads would double RCU consumption.

Option D is wrong because adding a global secondary index does not reduce read latency for the base table. Option E is wrong because using ElastiCache adds complexity and cost.

Options A and D are correct. A: Creating a read replica offloads read queries from the primary database. D: Using an RDS Proxy allows connection pooling, reducing overhead.

Option B is wrong because Multi-AZ is for high availability, not read scaling. Option C is wrong because increasing instance size can help but is often more expensive than read replicas. Option E is wrong because ElastiCache is for caching data, not for offloading database queries directly.

Option B is correct because blue/green deployment with a second Auto Scaling group and ALB switch allows instant rollback by switching back to the original environment. Option A is wrong because rolling updates with a single ASG can still cause partial downtime and slower rollback. Option C is wrong because it does not minimize downtime and requires manual intervention.

Option D is wrong because immutable deployments replace instances, but rollback requires redeployment.

Options A and D are correct. A: You need an IAM role for the approval action to allow the approver to review. D: The pipeline must be configured with a manual approval action.

Option B is wrong because SNS is optional for notification, not required. Option C is wrong because a Lambda function is not required for manual approval. Option E is wrong because CloudWatch Events can be used but not required.

Correct answers are A, B, and C. Option A catches vulnerabilities before deployment. Option B provides centralized control and enforcement.

Option C ensures only approved images are used. Option D is wrong because manual scanning slows down the pipeline. Option E is wrong because encryption alone doesn't address vulnerabilities.

Options B and D are correct because assigning an Elastic IP to the NLB provides static IPs, and using a Global Accelerator provides two static IPs. Option A is wrong because it doesn't provide static IPs. Option C is wrong because it's for ALB, not NLB.

Option E is wrong because EIPs cannot be attached to instances behind NLB directly.

Options B and D are correct. Service control policies (SCPs) can deny actions that do not meet encryption and public access conditions. Option A is wrong because resource-level policies are per bucket.

Option C is wrong because CloudTrail cannot enforce. Option E is wrong because Config rules only detect, not enforce.

Option B is correct because AWS Batch manages the compute environment, automatically scales, and handles long-running jobs without managing EC2 instances directly. Option A is wrong because Lambda has a 15-minute limit. Option C is wrong because it requires manual management of EC2 instances.

Option D is wrong because Fargate launch type for ECS can run long tasks but requires more setup than AWS Batch for batch jobs.

Option B is correct because if the function invocation rate exceeds the account-level concurrency limit (default 1000), throttling occurs. The code update may have increased execution time, causing more concurrent invocations to pile up. Option A is wrong because increasing S3 events would increase invocations, but the reserved concurrency of 100 might still be within account limits.

Option C is wrong because Lambda execution role permissions don't cause throttling errors. Option D is wrong because CloudWatch Logs throttling would cause logs to be dropped, not Lambda throttling.

CodeDeploy can be configured to automatically roll back a deployment when a CloudWatch alarm is triggered. This is a native feature. Option B is correct.

Options A, C, and D are not directly applicable: Lambda can be used but is not the primary feature; R53 health checks are not integrated with CodeDeploy; CodeBuild is for building, not deploying.

Option D is correct because using a bucket policy to deny uploads with SSE-KMS or without encryption ensures only SSE-S3 is allowed. Option A is incorrect because the bucket policy must be updated. Option B is incorrect because default encryption applies to new objects but does not prevent SSE-KMS.

Option C is incorrect because lifecycle rules do not change encryption of existing objects.

Option C is correct because S3 Lifecycle policies require proper permissions to execute actions. Option A is wrong because S3 Object Lock can prevent deletion if retention period is set. Option B is wrong because versioning does not prevent lifecycle expiration; expired delete markers are removed.

Option D is wrong because storage class transitions do not affect expiration.

Options A and D are correct. A: S3-Managed Keys (SSE-S3) is a server-side encryption option. D: AWS KMS (SSE-KMS) is another server-side encryption option.

Option B is wrong because client-side encryption is not managed by AWS. Option C is wrong because SSL/TLS encrypts data in transit, not at rest. Option E is wrong because S3 bucket policies do not encrypt data; they control access.

Option D is correct because the error message explicitly states that the runtime 'nodejs14.x' is not supported. Option A is wrong because the S3 bucket is not the issue. Option B is wrong because the role ARN is correct.

Option C is wrong because the timeout is within limits.

Option B is correct because the strangler fig pattern allows incremental replacement of functionality by routing specific requests to new microservices via API Gateway while keeping the monolithic application for the rest. Option A is incorrect because full migration at once risks downtime. Option C is incorrect because pattern does not require database changes initially.

Option D is incorrect because deployment pipeline is not a migration strategy.

Option D is correct because AWS Batch automatically provisions and terminates EC2 instances based on job queue, and can use spot instances for cost savings. Option A is wrong because Reserved Instances require 1-year commitment. Option B is wrong because keeping the instance running incurs costs even when idle.

Option C is wrong because Lambda has a 15-minute timeout limit.

Options A, B, and D are correct. CodeDeploy with blue/green deployment automates traffic shifting. An Application Load Balancer with a target group per task set routes traffic.

Multiple task definitions per environment allow updates without downtime. Option C is wrong because storing artifacts in ECR is for images, not deployment. Option E is wrong because an NLB does not support blue/green deployments with CodeDeploy for ECS.

Option A is correct because enabling Amazon RDS Proxy provides connection pooling and reduces failover time by keeping connections alive. Option B is wrong because read replicas are for read scaling, not for reducing failover time. Option C is wrong because increasing instance size doesn't directly affect failover time.

Option D is wrong because disabling Multi-AZ increases downtime.

Option C is correct because an AWS Config rule with an iam policy to deny non-compliant stacks is the most automated enforcement method. Option A is wrong because AWS Service Catalog does not enforce tags on existing stacks. Option B is wrong because Lambda can remediate but not prevent non-compliant stacks.

Option D is wrong because tagging at the resource level is not automated enforcement.

Option A is correct because DynamoDB Auto Scaling automatically adjusts write capacity based on utilization. Option B is wrong because Global Tables do not address throttling. Option C is wrong because DAX is a cache, not a scaling solution.

Option D is wrong because On-Demand mode is not automatic scaling based on traffic patterns.

Option A is correct because enabling sticky sessions on the ALB ensures that a user's requests are always routed to the same instance, preserving the local session files. Option B is wrong because ElastiCache still requires application code changes to use it. Option C is wrong because DynamoDB also requires code changes.

Option D is wrong because scaling down based on memory does not prevent session loss; it may cause more terminations.

Option D is correct. The Lambda function's resource-based policy must allow S3 to invoke it. The template does not add any resource-based policy.

Option A is wrong because the bucket notification is configured. Option B is wrong because the role allows CloudWatch Logs. Option C is wrong because the Lambda function code does not need to read S3 for the trigger to work.

Option D is correct because S3 Cross-Region Replication (CRR) automatically replicates objects to a destination bucket in a different AWS Region, providing disaster recovery with minimal operational overhead. Option A is wrong because S3 Versioning alone does not replicate data. Option B is wrong because S3 Lifecycle policies manage storage tiers, not replication.

Option C is wrong because S3 Transfer Acceleration speeds up uploads but does not replicate data.

A typical deployment pipeline includes: build the application, run automated tests in a staging environment, and then deploy to production after approval. Option A (build) is needed. Option C (test in staging) is needed.

Option D (deploy to production after staging tests pass) is needed. Option B (manual approval to production) is common but not required for automated testing. Option E (deploy to staging) is redundant if already included in test stage.

Option D is correct because AWS Config conformance packs can be deployed at the organization level using AWS Organizations, allowing centralized management of rules and automatic remediation with SSM Automation. Option A is wrong because manual deployment doesn't scale. Option B is wrong because CloudFormation StackSets require per-account management.

Option C is wrong because AWS Config aggregator only aggregates data, doesn't enforce rules.

Options B and D are correct. Using a DynamoDB table to track processed file IDs (B) allows the function to skip duplicates. Enabling S3 event notifications with a prefix and suffix filter (D) reduces the chance of multiple events for the same object.

Option A is wrong because increasing Lambda timeout doesn't prevent multiple invocations. Option C is wrong because SQS can help but needs deduplication logic as well. Option E is wrong because S3 Transfer Acceleration is for faster uploads, not idempotency.

Option B is correct. The Deny statement with StringNotEquals will match because the condition s3:x-amz-server-side-encryption is not set (or evaluates to a value not equal to AES256). Since the Deny statement applies, the request is denied.

Option A is wrong because the Allow statement requires the condition to be true; if not specified, the condition is not met. Option C is wrong because the Deny statement explicitly denies if encryption is not AES256. Option D is wrong because the condition is evaluated.

Option B is correct because using a warm pool allows instances to be pre-initialized and ready to serve traffic quickly when scaling out. Option A is wrong because increasing instance size does not address the replacement delay. Option C is wrong because purchasing Reserved Instances does not affect scaling speed.

Option D is wrong because lifecycle hooks can delay termination but do not speed up new instance readiness.

Option C is correct because reducing the batch size decreases the processing time per invocation, reducing the chance of timeout. Option A is wrong because increasing the timeout may not help if the issue is total processing time. Option B is wrong because increasing reserved concurrency does not help with timeout.

Option D is wrong because SQS queues do not send batches to Lambda as SQS batch size; the Lambda batch size is the relevant parameter.

Options B, D, and E are correct. Option B: Using a custom metric based on queue depth allows scaling on actual workload. Option D: Reducing the cooldown period allows faster scaling actions.

Option E: Using a step scaling policy provides more aggressive scaling when queue depth is high. Option A is wrong because increasing instance size does not improve scaling speed. Option C is wrong because decreasing the warm-up time for the metric is not a standard Auto Scaling feature.

Option B is correct because enabling default encryption on the bucket ensures all new objects are encrypted. Option A is wrong because bucket policy can be circumvented. Option C is wrong because CloudTrail only logs.

Option D is wrong because versioning does not enforce encryption.

Option B is correct because the CodePipeline deploy action uses CodeDeploy for blue/green deployments. The error indicates that the original target group (blue) is not healthy, possibly because the health check path is not valid for the original application version. Adjusting the health check to a common path like '/' allows both versions to pass.

Option A is incorrect because Fargate does not allow SSH. Option C is incorrect because redeploying the same version won't fix the underlying health check issue. Option D is incorrect because a new target group does not address the root cause.

Option A and Option C are correct. Option A (S3 Bucket Policy denying PutObject without the correct encryption header) enforces encryption at upload time. Option C (Default encryption with SSE-KMS) ensures that objects uploaded without encryption headers are encrypted with KMS.

Option B (Bucket policy allowing any encryption) does not enforce KMS. Option D (Disable SSE-S3) is not possible; you cannot disable SSE-S3, you can only set default encryption. Option E (CloudTrail logging) does not enforce encryption.

Option C is correct because SSE-KMS provides centralized key management and access control. Option A is wrong because SSE-S3 keys are managed by AWS, not the customer. Option B is wrong because client-side encryption does not use S3 server-side encryption.

Option D is wrong because bucket policies control access to objects, not encryption keys.

Option C (increase memory and timeout) directly addresses the issue of processing large images. Option A (Elastic Transcoder) is for video. Option B (EC2 with EBS) is overkill and not serverless.

Option D (API Gateway with larger payload) does not solve the Lambda processing limit.

Option B is correct because KCL distributes shard processing across workers; adding more workers allows parallel processing. Option A is wrong because it does not reduce per-shard load. Option C is wrong because it does not help shard distribution.

Option D is wrong because it may increase shard count but still requires more workers.

Option C is correct because using a custom JDBC URL with a timeout and retry logic allows the application to reconnect after failover. Option A is wrong because RDS proxy does not eliminate the need for application retry logic. Option B is wrong because increasing the TTL does not affect the connection timeout.

Option D is wrong because a Lambda function does not directly improve failover recovery.