This domain makes up 26% of the exam and includes the following 4 objectives:
1. Design a multi-tier architecture solution
2. Design highly available and/or fault-tolerant architectures
3. Design decoupling mechanisms using AWS services
4. Choose appropriate resilient storage
Understand the various block, file and object storage technologies such as Amazon EBS, Instance Store, Amazon EFS and Amazon S3, and know their use cases.
Be able to design multi-tier application architectures and know-how to decouple application components using technologies such as Amazon SQS and Amazon SWF.
Task Statement 1: Design scalable and loosely coupled architectures.
Knowledge of:
• API creation and management (for example, Amazon API Gateway, REST API)
• AWS managed services with appropriate use cases (for example, AWS Transfer Family, Amazon
Simple Queue Service [Amazon SQS], Secrets Manager)
• Caching strategies
• Design principles for microservices (for example, stateless workloads compared with stateful workloads)
• Event-driven architectures
• Horizontal scaling and vertical scaling
• How to appropriately use edge accelerators (for example, content delivery network [CDN])
• How to migrate applications into containers
• Load balancing concepts (for example, Application Load Balancer)
• Multi-tier architectures
• Queuing and messaging concepts (for example, publish/subscribe)
• Serverless technologies and patterns (for example, AWS Fargate, AWS Lambda)
• Storage types with associated characteristics (for example, object, file, block)
• The orchestration of containers (for example, Amazon Elastic Container Service [Amazon ECS],Amazon Elastic Kubernetes Service [Amazon EKS])
• When to use read replicas
• Workflow orchestration (for example, AWS Step Functions)
Skills in:
• Designing event-driven, microservice, and/or multi-tier architectures based on requirements
• Determining scaling strategies for components used in an architecture design
• Determining the AWS services required to achieve loose coupling based on requirements
• Determining when to use containers
• Determining when to use serverless technologies and patterns
• Recommending appropriate compute, storage, networking, and database technologies based on
• Using purpose-built AWS services for workloads Task Statement 2: Design highly available and/or fault-tolerant architectures.
Knowledge of:
• AWS global infrastructure (for example, Availability Zones, AWS Regions, Amazon Route 53)
• AWS managed services with appropriate use cases (for example, Amazon Comprehend, Amazon Polly)
• Basic networking concepts (for example, route tables)
• Disaster recovery (DR) strategies (for example, backup and restore, pilot light, warm standby,
active-active failover, recovery point objective [RPO], recovery time objective [RTO])
• Distributed design patterns
• Failover strategies
• Immutable infrastructure
• Load balancing concepts (for example, Application Load Balancer)
• Proxy concepts (for example, Amazon RDS Proxy)
• Service quotas and throttling (for example, how to configure the service quotas for a workload in a standby environment)
• Storage options and characteristics (for example, durability, replication)
• Workload visibility (for example, AWS X-Ray)
Skills in:
• Determining automation strategies to ensure infrastructure integrity
• Determining the AWS services required to provide a highly available and/or fault-tolerant architecture across AWS Regions or Availability Zones
• Identifying metrics based on business requirements to deliver a highly available solution
• Implementing designs to mitigate single points of failure
• Implementing strategies to ensure the durability and availability of data (for example, backups)
• Selecting an appropriate DR strategy to meet business requirements
• Using AWS services that improve the reliability of legacy applications and applications not built for the cloud (for example, when application changes are not possible)
• Using purpose-built AWS services for workloads
0
In designing an environment, what four main points should a Solutions Architect keep in mind?
- Cost-efficient,
- secure,
- Application session state,
- Undifferentiated heavy lifting: What means undifferentiated heavy lifting?
The reality, of course, today is that if you come up with a great idea you don't get to go quickly to a successful product. There's a lot of undifferentiated heavy lifting that stands between your idea and that success. The kinds of things that I'm talking about when I say undifferentiated heavy lifting are things like these: figuring out which servers to buy, how many of them to buy, what time line to buy them.
1
Pillar of AWS Well-Architected Framework
- Operational Excellence: The ability to support development and run
workloads effectively, gain insight into their
operations, and to continuously improve
supporting processes and procedures to deliver
business value.
- Security: The security pillar encompasses the ability
to protect data, systems, and assets to take
advantage of cloud technologies to improve your
security.
- Reliability: The reliability pillar encompasses the ability of
a workload to perform its intended function
correctly and consistently when it’s expected to.
This includes the ability to operate and test the
workload through its total lifecycle.
- Performance Efficiency: The ability to use computing resources efficiently
to meet system requirements, and to maintain
that efficiency as demand changes and
technologies evolve.
- Cost Optimization: The ability to run systems to deliver business
value at the lowest price point.
2
Placement Groups
Placement groups have the placement strategies of Cluster, Partition and Spread. With the Partition placement strategy, instances in one partition do not share the underlying hardware with other partitions. This strategy is suitable for distributed and replicated workloads such as Cassandra.
3
Elastic Network Adapter (ENA)
Enhanced networking has two mechanisms: Elastic Network Adapter (ENA) and Intel 82599Virtual Function (VF) interface. For ENA, users can enable it with --ena-support.
4
ENI Hot Attach, Cold Attach, warm Attach
Best practices for configuring network interfaces: You can attach a network interface to an instance when it's running (hot attach), when it's stopped (warm attach), or when the instance is being launched (cold attach). You can detach secondary network interfaces when the instance is running or stopped. However, you can't detach the primary network interface. You can move a network interface from one instance to another, if the instances are in the same Availability Zone and VPC but in different subnets. When launching an instance using the CLI, API, or an SDK, you can specify the primary network interface and additional network interfaces. Launching an Amazon Linux or Windows Server instance with multiple network interfaces automatically configures interfaces, private IPv4 addresses, and route tables on the operating system of the instance. A warm or hot attach of an additional network interface may require you to manually bring up the second interface, configure the private IPv4 address, and modify the route table accordingly. Instances running Amazon Linux or Windows Server automatically recognize the warm or hot attach and configure themselves. Attaching another network interface to an instance (for example, a NIC teaming configuration) cannot be used as a method to increase or double the network bandwidth to or from the dual-homed instance. If you attach two or more network interfaces from the same subnet to an instance, you may encounter networking issues such as asymmetric routing. If possible, use a secondary private IPv4 address on the primary network interface instead.
5
Route 53 Geolocation routing
Geolocation routing lets you choose the resources that serve your traffic based on the geographic location of your users, meaning the location that DNS queries originate from. For example, you might want all queries from Europe to be routed to an ELB in the Frankfurt region. When you use geolocation routing, you can localize your content and present some or all of your website in the language of your users. You can also use geolocation routing to restrict distribution of content to only the locations in which you have distribution rights. Another possible use is for balancing load across endpoints in a predictable, easy-to-manage way, so that each user location is consistently routed to the same endpoint.
6
EC2 Instances user data
When you launch an instance in Amazon EC2, you have the option of passing user data to the instance that can be used to perform common automated configuration tasks and even run scripts after the instance starts. You can pass two types of user data to Amazon EC2: shell scripts and cloud-init directives.
7
What happens during Multi-AZ failover and how long does it take?
Failover is automatically handled by Amazon RDS so that you can resume database operations as quickly as possible without administrative intervention. When failing over, Amazon RDS simply flips the canonical name record (CNAME) for your DB instance to point at the standby, which is in turn promoted to become the new primary. We encourage you to follow best practices and implement database connection retry at the application layer. Failovers, as defined by the interval between the detection of the failure on the primary and the resumption of transactions on the standby, typically complete within one to two minutes. Failover time can also be affected by whether large uncommitted transactions must be recovered; the use of adequately large instance types is recommended with Multi-AZ for best results. AWS also recommends the use of Provisioned IOPS with Multi-AZ instances for fast, predictable, and consistent throughput performance.
8
AWS Personal Health Dashboard
AWS Personal Health Dashboard provides alerts and remediation guidance when AWS is experiencing events that may impact you. While the Service Health Dashboard displays the general status of AWS services, Personal Health Dashboard gives you a personalized view of the performance and availability of the AWS services underlying your AWS resources. The dashboard displays relevant and timely information to help you manage events in progress, and provides proactive notification to help you plan for scheduled activities. With Personal Health Dashboard, alerts are triggered by changes in the health of AWS resources, giving you event visibility and guidance to help quickly diagnose and resolve issues.
9
Memory utilization in CloudWatch
Memory utilization is not available as an out of the box metric in CloudWatch. You can, however, collect memory metrics when you configure a custom metric for CloudWatch.
10
Amazon RDS Multi-AZ deployments
Amazon RDS Multi-AZ deployments provide enhanced availability and durability for RDS database (DB) instances, making them a natural fit for production database workloads. When you provision a Multi-AZ DB Instance, Amazon RDS automatically creates a primary DB Instance and synchronously replicates the data to a standby instance in a different Availability Zone (AZ). Each AZ runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable. In case of an infrastructure failure, Amazon RDS performs an automatic failover to the standby (or to a read replica in the case of Amazon Aurora), so that you can resume database operations as soon as the failover is complete. Since the endpoint for your DB Instance remains the same after a failover, your application can resume database operation without the need for manual administrative intervention.
11
What is NLB in AWS?
An NLB is a Network Load Balancer.
A Network Load Balancer functions at the fourth layer of the Open Systems Interconnection (OSI) model. It can handle millions of requests per second. After the load balancer receives a connection request, it selects a target from the target group for the default rule. It attempts to open a TCP connection to the selected target on the port specified in the listener configuration. When you enable an Availability Zone for the load balancer, Elastic Load Balancing creates a load balancer node in the Availability Zone. By default, each load balancer node distributes traffic across the registered targets in its Availability Zone only. If you enable cross-zone load balancing, each load balancer node distributes traffic across the registered targets in all enabled Availability Zones. It is designed to handle tens of millions of requests per second while maintaining high throughput at ultra low latency, with no effort on your part. The Network Load Balancer is API-compatible with the Application Load Balancer, including full programmatic control of Target Groups and Targets
12
How many types of VPC endpoints are available?
There are two types of VPC endpoints: (1) interface endpoints and (2) gateway endpoints. Interface endpoints enable connectivity to services over AWS PrivateLink.
13
What is an example of encryption at rest?
When a file(s) is encrypted and the stored data is not in transit it's known as encryption at rest.
14
When would vertical scaling be necessary?
When an application is built entirely into one source code, otherwise known as a monolithic application.
15
RPO vs RTO
RTO: Fault-Tolerance allows for continuous operation throughout a failure, which can lead to a low Recovery Time Objective.
RTO: High-Availability means automating tasks so that an instance will quickly recover, which can lead to a low Recovery Time Objective.
RPO: Frequent backups reduce the time between the last backup and recovery point, otherwise known as the Recovery Point Objective.
- High-Availability means the system will quickly recover from a failure event
- Fault-Tolerance means the system will maintain operations during a failure.
16
What are the characteristics of a tiered application?
In a tiered application, the presentation layer is separate from the logic layer; the logic layer is separate from the data layer. Since parts of the application are isolated, they can scale horizontally.
17
In which situation you will select provisioned IOPS over standard RDS storage?
- You should select provisioned IOPS storage over standard RDS storage if you want to perform
batch-related workloads.
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18
What are the different types of Load Balancer in AWS services?
- Application Load Balancer
- Classic Load Balancer
- Network Load Balancer
19
Do you need an internet gateway to use peering connections?
- Yes, the Internet gateway is needed to use VPC (virtual private cloud peering) connections.
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20
What are the advantages of auto-scaling?
- Offers fault tolerance
