Tutorial / Cram Notes
DynamoDB is a fully managed NoSQL database service that supports key-value and document data structures. Auto-scaling in DynamoDB helps manage throughput capacity in response to dynamically changing traffic loads.
To enable auto-scaling on a DynamoDB table:
- Navigate to the DynamoDB console.
- Choose the table you want to configure.
- In the “Capacity” tab, switch to “On-demand” or “Provisioned” capacity mode as per your requirements.
- If “Provisioned” mode is selected, set the desired minimum and maximum capacity units for read and write operations.
- Enable auto scaling by setting the target utilization percentage. AWS will automatically adjust the provisioned throughput to maintain the target utilization.
“ScalableTargetAction”: {
“MaxCapacity”: 100,
“MinCapacity”: 10
},
“TargetTrackingScalingPolicyConfiguration”: {
“TargetValue”: 70.0
}
Amazon EC2 Auto Scaling Groups
EC2 Auto Scaling helps to ensure that you have the correct number of Amazon EC2 instances available to handle the load for your application.
To configure EC2 Auto Scaling:
- Define the minimum, maximum, and desired number of EC2 instances in your Auto Scaling group.
- Create a launch configuration or template that Auto Scaling can use to launch EC2 instances.
- Choose a scaling policy, such as target tracking scaling, step scaling, or simple scaling policies.
- Attach the scaling policy to your Auto Scaling group to determine when to scale in or out.
“TargetTrackingConfiguration”: {
“TargetValue”: 50.0,
“PredefinedMetricSpecification”: {
“PredefinedMetricType”: “ASGAverageCPUUtilization”
}
}
Amazon RDS Storage Auto Scaling
RDS storage auto-scaling automatically adjusts the amount of storage available to your RDS databases as needed, which means you only pay for the storage you use.
To enable storage auto-scaling on an RDS instance:
- Launch an RDS instance or modify an existing one.
- In the “Modify DB Instance” page, find the “Storage” section.
- Check the option “Enable storage autoscaling” and specify the maximum storage limit.
Amazon ECS Capacity Providers
ECS capacity providers are used to manage the infrastructure that the ECS tasks run on, whether using EC2 instances or Fargate.
To use a capacity provider with ECS:
- Define a capacity provider with the desired configuration for either Fargate or EC2.
- Associate the capacity provider with your ECS cluster.
- When running a task or creating a service, specify the capacity provider strategy (e.g., FARGATE, FARGATE_SPOT, or a defined EC2 capacity provider).
“capacityProviderStrategy”: [
{
“capacityProvider”: “FARGATE”,
“weight”: 1
},
{
“capacityProvider”: “FARGATE_SPOT”,
“weight”: 2
}
]
Comparison Table for Auto Scaling across AWS Services
Here’s a comparison table that highlights key aspects of auto-scaling for the AWS services discussed:
| Feature | DynamoDB | EC2 | RDS | ECS |
|---|---|---|---|---|
| Scaling Metric | Read/Write Capacity | CPU Utilization, Custom Metrics | Storage Utilization | CPU/Memory Utilization |
| Management Interface | AWS Console, CLI, SDK | AWS Console, CLI, SDK, Templates | AWS Console, CLI, SDK | AWS Console, CLI, SDK |
| Scaling Type | Horizontal | Horizontal | Vertical | Horizontal |
| Adjustment Types | Target Utilization | Target Tracking, Step, Simple | Automatic Adjustment | Capacity Provider Strategy |
| Supports Scheduled Scaling | No | Yes | No | No (However, ECS tasks or services can be scheduled) |
| Performance Impact | Minimal | Minimal | Minimal (may briefly impact connections during scaling) | Minimal |
| Billing | Pay per Capacity Unit | Pay per Instance Hour | Pay for Provisioned Storage | Pay per Task Running Time |
Auto-scaling ensures that your AWS resources adapt to the workload demands, maintaining performance levels and cost efficiency. By appropriately configuring each service, DevOps engineers can optimize infrastructure and eliminate manual intervention, thus reducing the risk of service disruptions or over-provisioning.
Practice Test with Explanation
True or False: Amazon DynamoDB can adjust its read and write capacity units automatically in response to the application’s actual workload.
- A) True
- B) False
Answer: A) True
Explanation: DynamoDB has an auto scaling feature that automatically adjusts the number of read and write capacity units to meet application demands.
Which service allows you to automatically adjust the number of EC2 instances in your application in response to demand?
- A) EC2 Auto Scaling
- B) AWS Lambda
- C) Amazon ECS
- D) Amazon RDS
Answer: A) EC2 Auto Scaling
Explanation: EC2 Auto Scaling helps you maintain application availability and allows you to automatically scale your Amazon EC2 capacity up or down.
True or False: RDS storage auto scaling requires manual intervention every time the database storage is nearing its capacity.
- A) True
- B) False
Answer: B) False
Explanation: Amazon RDS storage auto scaling monitors your database’s storage auto scaling and automatically scales it without requiring manual intervention.
Which AWS service does not directly provide a built-in auto scaling feature?
- A) Amazon DynamoDB
- B) Amazon EC2
- C) Amazon RDS
- D) Amazon S3
Answer: D) Amazon S3
Explanation: Amazon S3 does not have an auto scaling feature as it is designed to provide highly scalable object storage.
True or False: EC2 Auto Scaling Groups allow you to scale EC2 instances across multiple availability zones.
- A) True
- B) False
Answer: A) True
Explanation: EC2 Auto Scaling Groups support the distribution of instances across multiple availability zones for high availability.
What is the primary purpose of ECS capacity providers?
- A) To optimize the cost of ECS clusters
- B) To manage the scaling of tasks within ECS clusters
- C) To ensure compliance with AWS security policies
- D) To provide a persistent storage solution for ECS tasks
Answer: B) To manage the scaling of tasks within ECS clusters
Explanation: ECS capacity providers are used to manage the infrastructure the ECS tasks will run on and scale it in or out as necessary.
True or False: You can set a schedule for scaling actions with EC2 Auto Scaling.
- A) True
- B) False
Answer: A) True
Explanation: Scheduled scaling allows you to set specific start and end times for scaling actions in EC2 Auto Scaling.
In which of the following scenarios would you use DynamoDB auto scaling?
- A) To scale up the compute capacity of EC2 instances
- B) To manage the growth of Amazon EBS volumes
- C) To automatically adjust read and write capacity to maintain performance
- D) To control the versioning of Lambda functions
Answer: C) To automatically adjust read and write capacity to maintain performance
Explanation: DynamoDB auto scaling is used to dynamically adjust the provisioned throughput capacity on your tables and global secondary indexes in response to actual workload.
True or False: Auto Scaling groups can use a combination of policies based on schedules, metrics, or both.
- A) True
- B) False
Answer: A) True
Explanation: Auto Scaling groups can use a variety of policies, including target tracking scaling policies, step scaling policies, and simple scaling policies, which can be based on schedules, specific metrics, or a combination of both.
Which AWS feature automatically adjusts the number of Amazon EC2 instances within an Auto Scaling group based on network traffic?
- A) Elastic Load Balancing
- B) AWS Trusted Advisor
- C) AWS Auto Scaling
- D) Amazon CloudWatch
Answer: D) Amazon CloudWatch
Explanation: Amazon CloudWatch metrics can be used by EC2 Auto Scaling to adjust the number of instances in your Auto Scaling group when certain thresholds are met, such as high network traffic.
True or False: ECS capacity providers only support Amazon EC2 launch types and not AWS Fargate.
- A) True
- B) False
Answer: B) False
Explanation: ECS capacity providers are applicable to both Amazon EC2 launch types and AWS Fargate for managing the scaling of the ECS services.
What is the main advantage of using RDS storage auto scaling over manual storage scaling?
- A) Reduces storage costs
- B) Automates the storage scaling process
- C) Improves database performance
- D) Decreases backup times
Answer: B) Automates the storage scaling process
Explanation: The main advantage of RDS storage auto scaling is that it automates the scaling of the storage, which removes the need for manual intervention to increase the storage size as data grows.
Interview Questions
Can you describe how you would configure auto-scaling for an application running on EC2 instances to handle unexpected traffic spikes?
To configure auto-scaling for EC2, you would create an Auto Scaling group and define the desired, minimum, and maximum number of instances. You would then set up scaling policies based on CloudWatch metrics such as CPU utilization or network I/O to automatically adjust the number of EC2 instances in response to the demand.
Explain the difference between dynamic scaling and predictive scaling in EC2 Auto Scaling.
Dynamic scaling responds to changing demand by using CloudWatch alarms to trigger scaling actions, adjusting the capacity in real-time. Predictive scaling, on the other hand, uses machine learning algorithms to analyze historical load metrics and schedule scaling actions in anticipation of predictable demand patterns.
When using DynamoDB, how can you manage table scaling in response to changes in workload?
With DynamoDB, you can enable auto-scaling by setting a target utilization percentage for read and write capacity units. DynamoDB will then automatically adjust the provisioned capacity based on the actual usage patterns to maintain the target utilization level, thus handling changes in workload.
What strategies could you take to optimize costs while configuring auto-scaling for DynamoDB?
To optimize costs for DynamoDB auto-scaling, you can set conservative auto-scaling policies that closely align with your workload patterns, use DynamoDB’s on-demand capacity mode for unpredictable workloads, and monitor the scaling activities to adjust the policies as needed to better suit your cost-performance balance.
How does RDS storage auto-scaling work, and what are the considerations you need to make when enabling it?
RDS storage auto-scaling automatically adjusts the amount of allocated storage for your database when space is running low. You need to set a maximum storage threshold and be aware of the storage types and associated costs. Also, note that once scaled, the storage can’t shrink even if the used space decreases later.
Can you explain the purpose of ECS capacity providers and how they facilitate auto-scaling?
ECS capacity providers are used to manage the infrastructure that tasks run on. They define the Auto Scaling policies for an ECS cluster, allowing tasks to scale in and out based on defined requirements, ensuring that there is always sufficient capacity for ECS tasks without over-provisioning resources.
What metrics would you monitor to determine if your auto-scaling configuration is effective?
To determine the effectiveness of auto-scaling configuration, monitor metrics such as CPU utilization, memory usage, network in/out, latency, error rates, and request counts. These metrics provide insights into system performance and whether the auto-scaling policies are responding appropriately to workload changes.
How can you ensure high availability of your application when configuring EC2 Auto Scaling groups across multiple Availability Zones?
For high availability, configure the EC2 Auto Scaling group to distribute instances evenly across multiple Availability Zones within the same region. You would also ensure that the load balancing is set up to distribute traffic across all healthy instances regardless of the zone.
What are the best practices for setting up scaling policies for an EC2 Auto Scaling group in a production environment?
Best practices for scaling policies include using a combination of target tracking, step scaling, and simple scaling policies; scaling out quickly but scaling in slowly to avoid premature termination; and using scheduled scaling actions to anticipate known traffic patterns, all to ensure performance stability while optimizing cost.
How do you secure the data within an auto-scaled environment, ensuring that all newly launched instances comply with your security standards?
To secure data within an auto-scaled environment, use AMIs that are pre-configured with necessary security measures, apply security groups and IAM roles to your instances through the launch configuration/template, enforce resource tagging, regularly update your AMIs, and use automation tools like AWS Config or custom scripts to validate security compliance post-scaling.
Great post on configuring auto scaling solutions for AWS services like DynamoDB, EC2, and RDS!
I appreciate the clear explanation of DynamoDB auto-scaling. Very helpful for my exam preparation.
Don’t forget to set up the right CloudWatch alarms for your EC2 Auto Scaling groups.
Is there a way to estimate the cost implications for using RDS storage auto scaling?
Thanks for the information on ECS capacity provider. Just what I needed!
A bit long-winded, but still helpful.
For DynamoDB, do we need to manually adjust the write and read throughput?
Appreciate the detailed steps for setting up EC2 Auto Scaling groups. Very easy to follow.