AWS CloudWatch provides resource-level metrics that provide visibility into resource utilization, system performance, operational health, and application performance, such as CPU usage, disk operations, and network operations.
For example, key metrics for EC2 instances include:
- CPU utilization: The percentage of total CPU time that the instance spent on processing, excluding the idle process.
- Network packets: The number of packets received on all network interfaces by the instance. This metric identifies the volume of incoming traffic in terms of the number of packets on each network interface.
- Disk operations: The number and type of read and write operations performed on the instance volumes.
Understanding and monitoring these metrics can inform you about the instances’ performance and necessary compute resources.
Choosing the right compute resources
When it comes to AWS, some commonly used compute resources are EC2 (Elastic Compute Cloud) instances, ECS (Elastic Container Service), AWS Lambda, etc. The choice of these resources depends on various factors like workload, latency tolerance, and cost optimization.
Here’s a summary of these resources and their strengths:
| Compute Resources | Best Used For | Strengths |
|---|---|---|
| EC2 Instances | Long-running, steady state applications | Customizable, large variety of configurations, block-level storage access |
| ECS | Containerized applications | Managed service, supports Docker, integrates with ELB and ECR |
| AWS Lambda | Event-triggered or infrequent workloads | Auto-scaling, high concurrency, no server to manage |
Consider you have a web application that experiences unexpected traffic spikes during certain times of the day. In this case, you can use an EC2 instance with Auto Scaling enabled. CloudWatch metrics can monitor the CPU Utilization of your EC2 instance and increase or decrease the instance count based on the load. Thus, you can ensure high availability even during traffic spikes, while also cost-optimizing during the periods of low traffic.
Here’s a basic example of how you can configure an Auto Scaling policy based on CloudWatch metrics:
aws autoscaling put-scaling-policy --policy-name my-scaledown-policy --auto-scaling-group-name my-asg --scaling-adjustment -1 --adjustment-type ChangeInCapacity
In this example, the Auto Scaling policy removes one instance from ‘my-asg’ when the associated alarm is triggered.
Implementing cost optimization
To balance performance with cost, it’s important to match your workloads with the right compute resource. For predictable workloads, it is often more cost-effective to use Reserved Instances or Savings Plans. For variable workloads, On-Demand Instances or Spot Instances might be a better choice.
Using AWS Compute Optimizer can also help recommend optimal AWS compute resources for your workloads by analyzing historical utilization metrics.
Overall, the key requisite is understanding performance metrics and having a well-articulated resource strategy that aligns with your application or service requirements. Engage with AWS Well-Architected Framework, Trusted Advisor, and Cost Explorer to ensure continual refinement and optimization of your resource strategy.
Practice Test
True or False: Amazon CloudWatch is not able to monitor AWS resources and the applications you run on AWS in real time.
• True
• False
Answer: False
Explanation: Amazon CloudWatch is a monitoring service for AWS resources and the applications. It collects and track metrics, collect and monitor log files, and respond to system events.
What is CloudWatch’s metric granularity for custom metrics?
• A. Between 1 second and 2 days
• B. 1 minute
• C. It can’t track custom metrics
• D. 1 second
Answer: B. 1 minute
Explanation: For detailed monitoring, EC2 instances send metric data to CloudWatch in periods as frequent as one minute.
What can be a possible reason if CloudWatch metrics show consistently high CPU usage?
• A. You need to reduce the number of EC2 instances.
• B. You need to increase the number of EC2 instances.
• C. You need to reduce the load on the EC2 instances.
• D. You need to update the AMIs on the EC2 instances.
Answer: C. You need to reduce the load on the EC2 instances.
Explanation: Constant high CPU usage may indicate that there is too much load on your EC2 instances. Offloading tasks, optimizing your application, or upgrading to a larger instance type can help reduce the load.
True or False: CloudWatch alarms once set cannot be edited.
• True
• False
Answer: False
Explanation: CloudWatch alarms can be set, edited and deleted as per requirements.
What should you consider if your EBS volume’s queue length is consistently high?
• A. Increase the IOPS
• B. Decrease the IOPS
• C. Decrease the size of the EBS volume
• D. Update the EBS volume type
Answer: A. Increase the IOPS
Explanation: If the EBS volume’s queue length is consistently high, you need to increase the IOPS to improve system responsiveness and performance.
In Amazon RDS, what metric would you look at to determine if your DB instance is CPU bound?
• A. WriteIOPS
• B. ReadIOPS
• C. CPUUtilization
• D. NetworkTransmitThroughput
Answer: C. CPUUtilization
Explanation: The CPUUtilization metric gives you the amount of CPU your DB instance is using. If this metric is high, it could indicate that your DB instance is CPU bound.
True or False: Amazon CloudWatch only allows collecting metrics for resources within the same region
• True
• False
Answer: True
Explanation: By default, metrics are separate between regions, CloudWatch does not automatically aggregate metrics across regions.
What does a metric represent in AWS CloudWatch?
• A. A collection of data points over a specific period of time
• B. The status of the AWS account
• C. The configuration details of a service
• D. A service’s current performance status
Answer: A. A collection of data points over a specific period of time
Explanation: In AWS CloudWatch, a metric represents a time-ordered set of data points that are published to the service.
True or False: AWS Trusted Advisor does not provide recommendations for optimizing AWS resources.
• True
• False
Answer: False
Explanation: AWS Trusted Advisor is a tool that provides real time guidance to help you provision your resources following AWS best practices.
What does the NetworkPacketsOut metric represent in Amazon EC2?
• A. Total network packet count.
• B. Number of network packets sent out by the instance.
• C. Number of error packets sent out by the instance.
• D. Number of packets that failed to reach their destination.
Answer: B. Number of network packets sent out by the instance.
Explanation: The NetworkPacketsOut metric represents the number of network packets sent out by the instance. It’s a common metric for monitoring network activity.
Interview Questions
What does Amazon CloudWatch provide in regards to performance metrics and computing resources?
Amazon CloudWatch provides centralized collection of logs and metrics that allows administrators to review and analyze performance metrics, set alarms, and react accordingly towards changing performance in order to optimize computing resources.
How can you forecast future needs for your AWS resources using performance metrics?
AWS includes tools such as AWS Trusted Advisor and Amazon CloudWatch, that allow you to analyze and forecast future resource needs based on past utilisation and performance metrics.
What is the function of AWS Auto Scaling with regard to compute resources?
AWS Auto Scaling allows you to automatically adjust compute resources based on changes in demand patterns and predetermined performance metrics, helping to ensure application availability and cost effectiveness.
How can you use Amazon CloudWatch to trigger scaling activities?
Amazon CloudWatch can observe Amazon EC2 CPU utilization, network traffic, and other metrics. If these metrics exceed or fall below certain thresholds, Amazon CloudWatch can send a signal to AWS Auto Scaling to adjust the amount of compute resources being used.
What is the AWS Trusted Advisor; and how does it help in managing compute resources?
AWS Trusted Advisor is an online resource that helps you reduce cost, increase performance, and improve security by optimizing your AWS environment. It provides real-time guidance to help provision your resources following AWS best practices.
What is AWS Compute Optimizer?
AWS Compute Optimizer is a service that analyzes the configuration and utilization metrics of your AWS resources, then recommends opportunities to reduce costs and improve performance.
What performance metrics are generally recommended to review for EC2 instances?
CPU utilization, Disk read/write operations, Network packets in/out, Discard Packets, Status Check Failed (Any, Instance, System), and Amazon EBS volumes metrics are generally recommended to review for EC2 instances.
How does the AWS Well-Architected Framework help in better compute resources management?
It provides a consistent approach for customers and partners to evaluate architectures and implement designs that can scale over time. It provides a set of questions that allows you to understand the pros and cons of decisions you make while building systems on AWS.
Name a service that can be used for automated actions on underutilized Amazon EC2 instances.
AWS Instance Scheduler can be used for automated start-stop actions on underutilized Amazon EC2 instances.
What is the purpose of Amazon EC2 right sizing?
Right sizing involves matching instance types and sizes to workload performance requirements and is a key component of cost optimization on Amazon EC2.
How can AWS Cost Explorer help in managing compute resources?
AWS Cost Explorer has an easy-to-use interface that lets you visualize, understand, and manage your AWS costs and usage over time. This can help you understand the cost implications of your resource usage.
What role does Amazon Elastic Load Balancing play in managing compute resources?
Elastic Load Balancing automatically distributes incoming application traffic across multiple targets, such as Amazon EC2 instances. This ensures that the workload is efficiently distributed across resources.
What does AWS Auto Scaling plan consist of?
AWS Auto Scaling plan includes information such as the minimum and maximum number of instances, and the desired capacity which based on requirements can increase or decrease compute resources automatically.
What tool can be used to automate the management of Amazon EC2 instance life cycles?
AWS Systems Manager, specifically the Maintenance Window feature, can automate the lifecycle management of Amazon EC2 instances.
How can you create alarms for RDS DB instances based on performance metrics?
Alarms for RDS DB instances can be created by using Amazon CloudWatch, you can create an alarm that sends an Amazon SNS message when the CPU Utilization metric exceeds a specified threshold.
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