Category: Cloud

AWS edge computing services provide infrastructure and software that move data processing and analysis as close to the endpoint as necessary. This includes deploying AWS managed hardware and software to locations outside AWS data centers, and even onto customer-owned devices. 

You can extend the cloud for a consistent hybrid experience using these AWS edge services related to locations:

• AWS edge locations – Edge locations are connected to the AWS Regions through the AWS network backbone. Amazon CloudFront, AWS WAF, and AWS Shield are services you use here.
• AWS Local Zones – Local Zones are an extension of the AWS Cloud located close to large population and industry centers. You learned about Local Zones in Module 1: Architecting Fundamentals.
• AWS Outposts – With AWS Outposts, you can run some AWS services on premises or at your own data center.
• AWS Snow Family – The Snow Family of products provides offline storage at the edge, which is used to deliver data back to AWS Regions.

Edge services architecture

Review the edge services architecture. A user sends a request to an application partly hosted on premises. The user’s request interacts with Amazon Route 53, AWS WAF, Amazon CloudFront and AWS Outposts. The AWS services hosted in the cloud are protected with AWS Shield.

Amazon Route 53

Amazon Route 53 provides a DNS, domain name registration, and health-checks. Route 53 was designed to give developers and businesses a reliable and cost-effective way to route end users to internet applications. It translates names like example.com into the numeric IP addresses that computers use to connect to each other. 

Route 53 effectively connects user requests to infrastructure running in AWS—such as EC2 instances, ELB load balancers, or Amazon S3 buckets—and can also be used to route users to infrastructure outside of AWS.

You can configure a Amazon CloudWatch alarm to check on the state of your endpoints. Combine your DNS with Health Check Metrics to monitor and route traffic to healthy endpoints.

Amazon Route 53 public and private DNS

A hosted zone is a container for records. Records contain information about how you want to route traffic for a specific domain, such as example.com, and its subdomains such as dev.example.com or mail.example.com. A hosted zone and the corresponding domain have the same name. 

PUBLIC HOSTED ZONE

Public hosted zones contain records that specify how you want to route traffic on the internet.

• For internet name resolution
• Delegation set – for authoritative name servers to be provided to the registrar or parent domain
• Route to internet-facing resources
• Resolve from the internet
• Global routing policies

PRIVATE HOSTED ZONE

Private hosted zones contain records that specify how you want to route traffic in your Amazon VPC.

• For name resolution inside a VPC
• Can be associated with multiple VPCs and across accounts
• Route to VPC resources
• Resolve from inside the VPC
• Integrate with on-premises private zones using forwarding rules and endpoints

Routing policies

When you create a record, you choose a routing policy, which determines how Amazon Route 53 responds to queries.

Failover routing

Amazon Route 53 health checks monitor the health and performance of your web applications, web servers, and other resources. 

Each health check that you create can monitor one of the following:

• The health of a specified resource, such as a web server
• The status of other health checks
• The status of an Amazon CloudWatch alarm

After you create a health check, you can get the status of the health check, get notifications when the status changes, and configure DNS failover.

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 load balancer in the Frankfurt Region.

Geoproximity routing

Geoproximity routing lets Amazon Route 53 route traffic to your resources based on the geographic location of your users and your resources. You can also optionally choose to route more traffic or less to a given resource by specifying a value, known as a bias. A bias expands or shrinks the size of the geographic Region from which traffic is routed to a resource.

Latency-based routing

If your application is hosted in multiple AWS Regions, you can improve performance for your users by serving their requests from the AWS Region that provides the lowest latency.

Data about the latency between users and your resources is based entirely on traffic between users and AWS data centers. If you aren’t using resources in an AWS Region, the actual latency between your users and your resources can vary significantly from AWS latency data. This is true even if your resources are located in the same city as an AWS Region.

Multivalue answer routing

Multivalue answer routing lets you configure Route 53 to return multiple values, such as IP addresses for your web servers, in response to DNS queries. You can specify multiple values for almost any record, but multivalue answer routing also lets you check the health of each resource. Route 53 returns only values for healthy resources.

The ability to return multiple health-checkable IP addresses is a way for you to use DNS to improve availability and load balancing. However, it is not a substitute for a load balancer.

Weighted routing

Weighted routing enables you to assign weights to a resource record set to specify the frequency with which different responses are served.

In this example of a blue/green deployment, a weighted routing policy is used to send a small amount of traffic to a new production environment. If the new environment is operating as intended, the amount of weighted traffic can be increased to confirm it can handle the increased load. If the test is successful, all traffic can be sent to the new environment.

Amazon CloudFront

Content delivery networks 

It’s not always possible to replicate your entire infrastructure across the globe when your web traffic is geo-dispersed. It is also not cost effective. With a content delivery network (CDN), you can use its global network of edge locations to deliver a cached copy of your web content to your customers. 

To reduce response time, the CDN uses the nearest edge location to the customer or the originating request location. Using the nearest edge location dramatically increases throughput because the web assets are delivered from cache. For dynamic data, you can configure many CDNs to retrieve data from the origin servers.

Use Regional edge caches when you have content that is not accessed frequently enough to remain in an edge location. Regional edge caches absorb this content and provide an alternative to having to retrieve that content from the origin server.

Edge caching 

Edge caching helps applications perform dramatically faster and cost significantly less at scale. Review the content below to learn the benefits of edge caching.

WITHOUT EDGE CACHING

As an example, let’s say you are serving an image from a traditional web server, not from Amazon CloudFront. You might serve an image named sunsetphoto.png using the URL:

 http://example.com/sunsetphoto.png

Your users can easily navigate to this URL and see the image. They don’t realize that their request was routed from one network to another (through the complex collection of interconnected networks that comprise the internet) until the image was found.

WITH EDGE CACHING

Amazon CloudFront speeds up the distribution of your content by routing each user request through the AWS backbone network to the edge location that can best serve your content. Typically, this is a CloudFront edge server that provides the fastest delivery to the viewer. 

Using the AWS network can dramatically reduce the number of networks your users’ requests must pass through, which improves performance. Users get lower latency (the time it takes to load the first byte of the file) and higher data transfer rates.

You also get increased reliability and availability because copies of your files (also called objects) are now held (or cached) in multiple edge locations around the world.

Amazon CloudFront

Amazon CloudFront is a global CDN service that accelerates delivery of your websites, APIs, video content, or other web assets. It integrates with other AWS products to give developers and businesses a straightforward way to accelerate content to end users. There are no minimum usage commitments. 

Amazon CloudFront provides extensive flexibility for optimizing cache behavior, coupled with network-layer optimizations for latency and throughput. The CDN offers a multi-tier cache by default, with regional edge caches that improve latency and lower the load on your origin servers when the object is not already cached at the edge.

Amazon CloudFront supports real-time, bidirectional communication over the WebSocket protocol. This persistent connection permits clients and servers to send real-time data to one another without the overhead of repeatedly opening connections. This is especially useful for communications applications such as chat, collaboration, gaming, and financial trading.

Support for WebSockets in Amazon CloudFront makes it possible for customers to manage WebSocket traffic through the same avenues as any other dynamic and static content. With CloudFront, customers can take advantage of distributed denial of service (DDoS) protection using the built-in CloudFront integrations with Shield and AWS WAF.

Amazon CloudFront caching

When a user requests content that you are serving with Amazon CloudFront, the user is routed to the edge location that provides the lowest latency. Content is delivered with the best possible performance. To review the steps for CloudFront caching, select each hotspot in the image below.

Improving CloudFront performance

WHAT AWS DOES

AWS provides features that improve the performance of your content delivery:

• TCP optimization – CloudFront uses TCP optimization to observe how fast a network is already delivering your traffic and the latency of your current round trips. It then uses that data as input to automatically improve performance.
• TLS 1.3 support – CloudFront supports TLS 1.3, which provides better performance with a simpler handshake process that requires fewer round trips. It also adds improved security features.
• Dynamic content placement – Serve dynamic content, such as web applications or APIs from ELB load balancers or Amazon EC2 instances, by using CloudFront. You can improve the performance, availability, and security of your content.

You can also adjust the configuration of your CloudFront distribution to accommodate for better performance:

• Define your caching strategy – Choosing an appropriate TTL is important. In addition, consider caching based on things like query string parameters, cookies, or request headers.
• Improve your cache hit ratio – You can view the percentage of viewer requests that are hits, misses, and errors in the CloudFront console. Make changes to your distribution based on statistics collected in the CloudFront cache statistics report.
• Use Origin Shield – Get an additional layer of caching between the regional edge caches and your origin. It is not always a best fit for your use case, but it can be beneficial for viewers that are spread across geographic regions or on-premises origins with capacity or bandwidth constraints.

DDoS Protection

A DDoS attack is an attack in which multiple compromised systems attempt to flood a target, such as a network or web application, with traffic. A DDoS attack can prevent legitimate users from accessing a service and can cause the system to crash due to the overwhelming traffic volume.

OSI layer attacks

In general, DDoS attacks can be segregated by which layer of the OSI model they attack. They are most common at the Network (layer 3), Transport (Layer 4), Presentation (Layer 6) and Application (Layer 7) Layers.

Infrastructure Layer Attacks – Attacks at Layer 3 and 4, are typically categorized as Infrastructure layer attacks. These are also the most common type of DDoS attack and include vectors like synchronized (SYN) floods and other reflection attacks like User Datagram Packet (UDP) floods. These attacks are usually large in volume and aim to overload the capacity of the network or the application servers. But fortunately, these are also the type of attacks that have clear signatures and are easier to detect.

Application Layer Attacks – An attacker may target the application itself by using a layer 7 or application layer attack. In these attacks, similar to SYN flood infrastructure attacks, the attacker attempts to overload specific functions of an application to make the application unavailable or extremely unresponsive to legitimate users. 

AWS Solutions

AWS Shield Standard, AWS Web Application Firewall (WAF), and AWS Firewall Manager are AWS services that protect architectures against web-based attacks. Review the section below to learn more about each of these AWS services.

AWS Shield

AWS Shield is a managed DDoS protection service that safeguards your applications running on AWS. It provides you with dynamic detection and automatic inline mitigations that minimize application downtime and latency. There are two tiers of AWS Shield: Shield Standard and Shield Advanced.

AWS Shield Standard provides you protection against some of the most common and frequently occurring infrastructure (Layer 3 and 4) attacks. This includes SYN/UDP floods and reflection attacks. Shield Standard improves availability of your applications on AWS. The service applies a combination of traffic signatures, anomaly algorithms, and other analysis techniques. Shield Standard detects malicious traffic and it provides real-time issue mitigation. You are protected by Shield Standard at no additional charge.

If you need even more protection from DDoS attacks on your applications, consider using Shield Advanced. You get additional detection and mitigation against large and sophisticated DDoS attacks, near real-time visibility, and integration with AWS WAF, a web application firewall.

AWS Web Application Firewall (WAF)

AWS WAF is a web application firewall that helps protect your web applications or APIs against common web exploits and bots. AWS WAF gives you control over how traffic reaches your applications. Create security rules that control bot traffic and block common attack patterns, such as SQL injection (SQLi) or cross-site scripting (XSS). You can also monitor HTTP(S) requests that are forwarded to your compatible AWS services.

AWS WAF: Components of access control

Before configuring AWS WAF, you should understand the components used to control access to your AWS resources.

• Web ACLs – You use a web ACL to protect a set of AWS resources. You create a web ACL and define its protection strategy by adding rules. 
• Rules – Each rule contains a statement that defines the inspection criteria and an action to take if a web request meets the criteria.
• Rules groups – You can use rules individually or in reusable rule groups. 
• Rule statements – This is the part of a rule that tells AWS WAF how to inspect a web request.
•  IP set – This is a collection of IP addresses and IP address ranges that you want to use together in a rule statement. 
• Regex pattern set – This is a collection of regular expressions that you want to use together in a rule statement.

AWS Firewall Manager

AWS Firewall Manager simplifies your AWS WAF and Amazon VPC security groups administration and maintenance tasks. Set up your AWS WAF firewall rules, Shield protections, and Amazon VPC security groups once. 

The service automatically applies the rules and protections across your accounts and resources, even as you add new resources. Firewall Manager helps you to:

• Simplify management of rules across accounts and application.
• Automatically discover new accounts and remediate noncompliant events.
• Deploy AWS WAF rules from AWS Marketplace.
• Enable rapid response to attacks across all accounts.

As new applications are created, Firewall Manager also facilitates bringing new applications and resources into compliance with a common set of security rules from day one. Now you have a single service to build firewall rules, create security policies, and enforce them in a consistent, hierarchical manner across your entire AWS infrastructure.

AWS Outposts solutions

These applications might need to generate near-real-time responses to end-user applications, or they might need to communicate with other on-premises systems or control on-site equipment. Examples include workloads running on factory floors for automated operations in manufacturing, real-time patient diagnosis or medical imaging, and content and media streaming. 

You need a solution to securely store and process customer data that must remain on premises or in countries outside an AWS Region. You need to run data-intensive workloads and process data locally, or when you want closer controls on data analysis, backup, and restore.

With Outposts, you can extend the AWS Cloud to an on-premises data center. Outposts come in different form factors, each with separate requirements. Verify that your site meets the requirements for the form factor that you’re ordering.

The AWS Outposts family is made up of two types of Outposts: Outposts racks and Outposts servers. Choose each tab to learn more about the Outposts family products.

OUTPOSTS RACKS

When you order an Outposts rack, you can choose from a variety of Outposts configurations. Each configuration provides a mix of EC2 instance types and Amazon Elastic Block Store (Amazon EBS) volumes.

The benefits of Outposts racks include the following:

• Scale up to 96 42U–standard racks.
• Pool compute and storage capacity between multiple Outposts racks.
• Get more service options than Outposts servers.

To fulfill the Outposts rack order, AWS will schedule a date and time with you. You will also receive a checklist of items to verify or provide before the installation. The team will roll the rack to the identified position, and your electrician can power the rack. The team will establish network connectivity for the rack over the uplink that you provide, and they will configure the rack’s capacity.

The installation is complete when you confirm that the Amazon EC2 and Amazon EBS capacity for your AWS Outpost is available from your AWS account.

OUTPOSTS SERVERS

With Outposts servers, you can order hardware at a smaller scale while still providing you AWS services on premises. You can choose from Arm-based or Intel-based options. Not all services available in Outposts racks are supported in Outposts servers.

Outposts servers are delivered directly to you and installed by either your own onsite personnel or a third-party vendor. Once connected to your network, AWS will remotely provision compute and storage resources.

Benefits of Outposts servers include the following:

• Place in your own rack
• Choose from:
  • 1U Graviton-based processor
  • 2U Intel Xeon Scalable processor

Outposts extend your VPC

A virtual private cloud (VPC) spans all Availability Zones in its AWS Region. You can extend any VPC in the Region to your Outpost by adding an Outpost subnet.

Outposts support multiple subnets. You choose the EC2 instance subnet when you launch the EC2 instance in your Outpost. You cannot choose the underlying hardware where the instance is deployed, because the Outpost is a pool of AWS compute and storage capacity.

Each Outpost can support multiple VPCs that can have one or more Outpost subnets.

You create Outpost subnets from the VPC CIDR range where you created the Outpost. You can use the Outpost address ranges for resources, such as EC2 instances that reside in the Outpost subnet. AWS does not directly advertise the VPC CIDR, or the Outpost subnet range to your on-premises location.

Regards

Osama