Module 10: Monitoring, elasticity and high availability Flashcards
What is Amazon CloudWatch?
A monitoring and observability service that collects data from AWS resources, applications, and services in real-time.
What are the primary components of CloudWatch?
Metrics, Alarms, Logs, Events, and Dashboards.
What is a CloudWatch metric?
A data point representing a specific performance characteristic of a resource, such as CPU utilization or network traffic.
How often are metrics collected by default for EC2 instances?
Every 5 minutes for basic monitoring, every 1 minute for detailed monitoring.
: How can you analyze log data in CloudWatch?
Use CloudWatch Logs Insights to query and analyze log data interactively.
What is a CloudWatch Alarm?
A feature that monitors a specific metric and performs an action (e.g., sending notifications) when the metric crosses a defined threshold.
What are the three alarm states in CloudWatch?
OK, ALARM, and INSUFFICIENT_DATA.
What action can a CloudWatch Alarm trigger?
Send notifications via SNS, perform an EC2 Auto Scaling action, or execute an AWS Lambda function for example.
What is a CloudWatch Dashboard?
A customizable, visual interface for monitoring metrics and alarms across multiple AWS resources.
How can you share a CloudWatch Dashboard?
Dashboards can be shared with team members or made public for specific viewers.
What is Amazon EventBridge?
A serverless event bus service that makes it easy to connect applications using event-driven architecture.
What is an EventBridge Event Bus?
A logical grouping of events that applications can subscribe to and process. AWS services send events to the default event bus.
What is AWS Cost Explorer used for?
To visualize and analyze AWS costs and usage over time, identifying spending patterns and anomalies.
What is the AWS Budget tool used for?
To set custom cost, usage, or savings plans thresholds and receive alerts when those thresholds are breached.
What is AWS Cost and Usage Report for?
contains the most comprehensive set of AWS cost and usage data available, including additional metadata about AWS services, pricing, and reservations.AWS
What is vertical scaling?
Replacing a resource with a larger or smaller one (e.g., upgrading an EC2 instance for more RAM or CPU). It may involve downtime.
What is horizontal scaling?
Adding or removing instances or resources (e.g., increasing the number of EC2 instances). This enables building internet-scale applications.
Why is horizontal scaling preferred for high availability?
It distributes traffic across multiple instances, reducing the impact of failures and improving cost efficiency.
What is an Amazon EC2 Auto Scaling group?
A logical collection of EC2 instances managed across multiple Availability Zones.
What does a launch template specify in an Auto Scaling group?
Configuration details for EC2 instances, including AMI ID, instance type, and network settings.
What triggers Amazon EC2 Auto Scaling?
Scaling policies, schedule actions, and health checks from ELB or Auto Scaling.
What is the role of Elastic Load Balancing (ELB) in Auto Scaling?
ELB distributes incoming traffic to instances in the Auto Scaling group and reports unhealthy instances.
What are the benefits of EC2 Auto Scaling?
Better fault tolerance: Replaces unhealthy instances.
Better availability: Matches traffic demand dynamically.
Better cost management: Avoids overprovisioning.
What are the three capacity settings of an Auto Scaling group?
A:
Minimum capacity: Smallest number of instances needed.
Maximum capacity: Largest number of instances permitted.
Desired capacity: Optimal number of instances under normal conditions.
What is the significance of scaling in multiple Availability Zones?
Ensures high availability by distributing instances across zones, reducing the impact of a zone failure.
How does EC2 Auto Scaling handle Spot Instances?
It provisions Spot Instances if they are available, based on cost preferences in the launch template.
What are the types of scaling mechanisms for EC2 Auto Scaling?
Manual scaling: User adjusts capacity manually.
Scheduled scaling: Based on predefined times.
Dynamic scaling: Responds to real-time metrics.
Predictive scaling: Uses historical data for capacity forecasts.
What is target tracking scaling?
Adjusting capacity to maintain a specific metric (e.g., keeping CPU utilization at 50%).
How does step scaling differ from simple scaling?
Step scaling adjusts capacity based on the size of the alarm breach, while simple scaling waits for scaling to finish before responding to new alarms.
What is predictive scaling?
Uses machine learning to forecast traffic patterns and scale resources in advance.
What workloads are ideal for predictive scaling?
Cyclical traffic, batch processing, or applications with long initialization times.
Can dynamic and predictive scaling work together?
Yes, combining them ensures both proactive and reactive scaling for optimal efficiency.
What is an example of a target tracking policy?
Keeping average CPU utilization at 50%, scaling out when the metric exceeds the target and scaling in when it drops below.
What is a step adjustment in step scaling?
Defines how much capacity to add or remove based on the metric’s deviation from thresholds.
What is a scheduled scaling policy?
Automates scaling actions based on a specific date and time (e.g., scaling up every Wednesday morning).
Why is scaling out important during traffic spikes?
Prevents performance degradation by provisioning additional resources to meet demand.
What happens if a load balancer reports an unhealthy instance?
EC2 Auto Scaling terminates the unhealthy instance and replaces it with a new one.
How does an Auto Scaling group handle minimum capacity?
Ensures at least the minimum number of instances are running, even during low demand periods.
What metric does an Auto Scaling group commonly track for scaling?
CPU utilization, but it can track other metrics like SQS queue length or network traffic.
What is AWS Auto Scaling?
A service to configure scaling plans across multiple AWS services, such as Aurora, ECS, and DynamoDB.
What is Application Auto Scaling?
A service for scaling individual AWS resources like Lambda functions, SageMaker, or ElastiCache
How does Application Auto Scaling support target tracking?
Automatically adjusts resources to maintain a predefined target metric.
What is the main difference between AWS Auto Scaling and Application Auto Scaling?
AWS Auto Scaling manages scaling for groups of resources, while Application Auto Scaling focuses on individual scalable resources.
What are the two primary types of scaling for databases?
Vertical scaling (increasing instance size) and horizontal scaling (adding resources, such as read replicas).
What does “service-managed storage scaling” mean?
AWS automatically manages storage growth for databases like Aurora and DynamoDB.
Why is database scaling not instantaneous?
Scaling typically involves background processes that can take time to complete.
How can Aurora be scaled vertically?
By changing the DB instance class size.
How can Aurora be scaled horizontally?
By adding up to 15 read replicas.