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Amazon Web ServicesWeb Application Hosting in the AWS CloudAdditionally, any existing solutions for edge caching in your web applicationinfrastructure should work well in the AWS Cloud.Managing public DNSMoving a web application to the AWS Cloud requires some Domain Name System(DNS) changes. To help you manage DNS routing, AWS provides Amazon Route 53, ahighly available and scalable cloud DNS web service. Route 53 is designed to givedevelopers and businesses an extremely reliable and cost-effective way to route endusers to internet applications by translating names such as “www.example.com” intonumeric IP addresses such as 192.0.2.1, that computers use to connect to each other.Route 53 is fully compliant with IPv6 as well.Host securityIn addition to inbound network traffic filtering at the edge, AWS also recommends webapplications apply network traffic filtering at the host level. Amazon EC2 provides afeature named security groups. A security group is analogous to an inbound networkfirewall, for which you can specify the protocols, ports, and source IP ranges that areallowed to reach your EC2 instances.You can assign one or more security groups to each EC2 instance. Each security groupallows appropriate traffic in to each instance. Security groups can be configured so thatonly specific subnets, IP addresses, and resources have access to an EC2 instance.Alternatively, they can reference other security groups to limit access to EC2 instancesthat are in specific groups.In the AWS web hosting architecture in Figure 3, the security group for the web servercluster might allow access only from the web-layer Load Balancer and only over TCP onports 80 and 443 (HTTP and HTTPS). The application server security group, on theother hand, might allow access only from the application-layer Load Balancer. In thismodel, your support engineers would also need to access the EC2 instances, what canbe achieved with AWS Systems Manager Session Manager. For a deeper discussionon security, the AWS Cloud Security, which contains security bulletins, certificationinformation, and security whitepapers that explain the security capabilities of AWS.Page 8

Amazon Web ServicesWeb Application Hosting in the AWS CloudLoad balancing across clustersHardware load balancers are a common network appliance used in traditional webapplication architectures. AWS provides this capability through the Elastic LoadBalancing (ELB) service. ELB automatically distributes incoming application trafficacross multiple targets, such as Amazon EC2 instances, containers, IP addresses,AWS Lambda functions, and virtual appliances. It can handle the varying load of yourapplication traffic in a single Availability Zone or across multiple Availability Zones.Elastic Load Balancing offers four types of load balancers that all feature the highavailability, automatic scaling, and robust security necessary to make your applicationsfault tolerant.Finding other hosts and servicesIn the traditional web hosting architecture, most of your hosts have static IP addresses.In the AWS Cloud, most of your hosts have dynamic IP addresses. Although every EC2instance can have both public and private DNS entries and will be addressable over theinternet, the DNS entries and the IP addresses are assigned dynamically when youlaunch the instance. They cannot be manually assigned. Static IP addresses (Elastic IPaddresses in AWS terminology) can be assigned to running instances after they arelaunched. You should use Elastic IP addresses for instances and services that requireconsistent endpoints, such as primary databases, central file servers, and EC2-hostedload balancers.Caching within the web applicationIn-memory application caches can reduce load on services and improve performanceand scalability on the database tier by caching frequently used information. AmazonElastiCache is a web service that makes it easy to deploy, operate, and scale an inmemory cache in the cloud. You can configure the in-memory cache you create toautomatically scale with load and to automatically replace failed nodes. ElastiCache isprotocol-compliant with Memcached and Redis, which simplifies cloud migrations forcustomers running these services on-premises.Database configuration, backup, and failoverMany web applications contain some form of persistence, usually in the form of arelational or non-relational database. AWS offers both relational and non-relationalPage 9

Amazon Web ServicesWeb Application Hosting in the AWS Clouddatabase services. Alternatively, you can deploy your own database software on anEC2 instance. The following table summarizes these options, which are discussed ingreater detail in this section.Table 1 — Relational and non-relational database solutionsManageddatabaseserviceRelational database solutionsNon-relational database solutionsAmazon RDS for MySQLAmazon DynamoDBOracleAmazon KeyspacesSQL ServerAmazon NeptuneMariaDBAmazon QLDBPostgreSQLAmazon TimestreamAmazon AuroraSelf-managedHosting a relational databasemanagement system (DBMS)on an Amazon EC2 instanceHosting a non-relational databasesolution on an EC2 instanceAmazon RDSAmazon RDS gives you access to the capabilities of a familiar MySQL, PostgreSQL,Oracle, and Microsoft SQL Server database engine. The code, applications, and toolsthat you already use can be used with Amazon RDS. Amazon RDS automaticallypatches the database software and backs up your database, and it stores backups for auser-defined retention period. It also supports point-in-time recovery. You can benefitfrom the flexibility of being able to scale the compute resources or storage capacityassociated with your relational database instance by making a single API call.Amazon RDS Multi-AZ deployments increase your database availability and protectyour database against unplanned outages. Amazon RDS Read Replicas provide readonly replicas of your database, so you can scale out beyond the capacity of a singledatabase deployment for read-heavy database workloads. As with all AWS services, noupfront investments are required, and you pay only for the resources you use.Page 10

Amazon Web ServicesWeb Application Hosting in the AWS CloudHosting a relational database management system (RDBMS) on an Amazon EC2instanceIn addition to the managed Amazon RDS offering, you can install your choice ofRDBMS (such as MySQL, Oracle, SQL Server, or DB2) on an EC2 instance andmanage it yourself. AWS customers hosting a database on Amazon EC2 successfullyuse a variety of primary/standby and replication models, including mirroring for readonly copies and log shipping for always-ready passive standbys.When managing your own database software directly on Amazon EC2, you should alsoconsider the availability of fault-tolerant and persistent storage. For this purpose, werecommend that databases running on Amazon EC2 use Amazon Elastic Block Store(Amazon EBS) volumes, which are similar to network-attached storage.For EC2 instances running a database, you should place all database data and logs onEBS volumes. These will remain available even if the database host fails. Thisconfiguration allows for a simple failover scenario, in which a new EC2 instance can belaunched if a host fails, and the existing EBS volumes can be attached to the newinstance. The database can then pick up where it left off.EBS volumes automatically provide redundancy within the Availability Zone. If theperformance of a single EBS volume is not sufficient for your databases needs, volumescan be striped to increase input/output operations per second (IOPS) performance foryour database.For demanding workloads, you can also use EBS Provisioned IOPS, where you specifythe IOPS required. If you use Amazon RDS, the service manages its own storage soyou can focus on managing your data.Non-relational databasesIn addition to support for relational databases, AWS also offers a number of managednon-relational databases: Amazon DynamoDB is a fully managed NoSQL database service that providesfast and predictable performance with seamless scalability. Using the AWSManagement Console or the DynamoDB API, you can scale capacity up or downwithout downtime or performance degradation. Because DynamoDB handles theadministrative burdens of operating and scaling distributed databases to AWS,Page 11

Amazon Web ServicesWeb Application Hosting in the AWS Cloudyou don’t have to worry about hardware provisioning, setup and configuration,replication, software patching, or cluster scaling. Amazon DocumentDB (with MongoDB compatibility) is a database service thatis purpose-built for JSON data management at scale, fully managed and runs onAWS, and enterprise-ready with high durability. Amazon Keyspaces (for Apache Cassandra) is a scalable, highly available, andmanaged Apache Cassandra-compatible database service. With AmazonKeyspaces, you can run your Cassandra workloads on AWS using the sameCassandra application code and developer tools that you use today. Amazon Neptune is a fast, reliable, fully managed graph database service thatmakes it easy to build and run applications that work with highly connecteddatasets. The core of Amazon Neptune is a purpose-built, high-performancegraph database engine optimized for storing billions of relationships and queryingthe graph with milliseconds latency. Amazon Quantum Ledger Database (QLDB) is a fully managed ledgerdatabase that provides a transparent, immutable, and cryptographically verifiabletransaction log owned by a central trusted authority. Amazon QLDB can be usedto track each and every application data change and maintains a complete andverifiable history of changes over time. Amazon Timestream is a fast, scalable, and serverless time series databaseservice for IoT and operational applications that makes it easy to store andanalyze trillions of events per day up to 1,000 times faster and at as little as1/10th the cost of relational databases.Additionally, you can use Amazon EC2 to host other non-relational databasetechnologies you may be working with.Storage and backup of data and assetsThere are numerous options within the AWS Cloud for storing, accessing, and backingup your web application data and assets. Amazon S3 provides a highly available andredundant object store. S3 is a great storage solution for static objects, such as images,videos, and other static media. S3 also supports edge caching and streaming of theseassets by interacting with CloudFront.Page 12

Amazon Web ServicesWeb Application Hosting in the AWS CloudFor attached file system-like storage, EC2 instances can have EBS volumes attached.These act like mountable disks for running EC2 instances. Amazon EBS is great fordata that needs to be accessed as block storage and that requires persistence beyondthe life of the running instance, such as database partitions and application logs.In addition to having a lifetime that is independent of the EC2 instance, you can takesnapshots of EBS volumes and store them in S3. Because EBS snapshots only back upchanges since the previous snapshot, more frequent snapshots can reduce snapshottimes. You can also use an EBS snapshot as a baseline for replicating data acrossmultiple EBS volumes and attaching those volumes to other running instances.EBS volumes can be as large as 16TB, and multiple EBS volumes can be striped foreven larger volumes or for increased input/output (I/O) performance. To maximize theperformance of your I/O-intensive applications, you can use Provisioned IOPS volumes.Provisioned IOPS volumes are designed to meet the needs of I/O-intensive workloads,particularly database workloads that are sensitive to storage performance andconsistency in random access I/O throughput.You specify an IOPS rate when you create the volume and Amazon EBS provisions thatrate for the lifetime of the volume. Amazon EBS currently supports IOPS per volumeranging from maximum of 16000 (for all instance types) up to 64,000 (for instances builton Nitro System). You can stripe multiple volumes together to deliver thousands ofIOPS per instance to your application. Apart from this, for higher throughput andmission critical workloads requiring sub-millisecond latency, you can use io2 blockexpress volume type which can support up-to 256,000 IOPS with a maximum storagecapacity of 64TB.Automatically scaling the fleetOne of the key differences between the AWS Cloud architecture and the traditionalhosting model is that AWS can automatically scale the web application fleet on demandto handle changes in traffic. In the traditional hosting model, traffic forecasting modelsare generally used to provision hosts ahead of projected traffic. In AWS, instances canbe provisioned on the fly according to a set of triggers for scaling the fleet out and backin.The Auto Scaling service can create capacity groups of servers that can grow or shrinkon demand. Auto Scaling also works directly with Amazon CloudWatch for metrics dataPage 13

Amazon Web ServicesWeb Application Hosting in the AWS Cloudand with Elastic Load Balancing to add and remove hosts for load distribution. Forexample, if the web servers are reporting greater than 80 percent CPU utilization over aperiod of time, an additional web server could be quickly deployed and thenautomatically added to the load balancer for immediate inclusion in the load balancingrotation.As shown in the AWS web hosting architecture model, you can create multiple AutoScaling groups for different layers of the architecture, so that each layer can scaleindependently. For example, the web server Auto Scaling group might trigger scaling inand out in response to changes in network I/O, whereas the application server AutoScaling group might scale out and in according to CPU utilization. You can setminimums and maximums to help ensure 24/7 availability and to cap the usage within agroup.Auto Scaling triggers can be set both to grow and to shrink the total fleet at a given layerto match resource utilization to actual demand. In addition to the Auto Scaling service,you can scale Amazon EC2 fleets directly through the Amazon EC2 API, which allowsfor launching, terminating, and inspecting instances.Additional security featuresThe number and sophistication of Distributed Denial of Service (DDoS) attacks arerising. Traditionally, these attacks are difficult to fend off. They often end up being costlyin both mitigation time and power spent, as well as the opportunity cost from lost visitsto your website during the attack. There are a number of AWS factors and services thatcan help you defend against such attacks. One of them is the scale of the AWSnetwork. The AWS infrastructure is quite large, and enables you to leverage our scale tooptimize your defense. Several services, including Elastic Load Balancing, AmazonCloudFront, and Amazon Route 53, are effective at scaling your web application inresponse to a large increase in traffic.The infrastructure protection services in particular help with your defense strategy: AWS Shield is a managed DDoS protection service that helps safeguard againstvarious forms of DDoS attack vectors. The standard offering of AWS Shield isfree and automatically active throughout your account. This standard offeringhelps to defend against the most common network and transportation layerattacks. In addition to this level, the advanced offering grants higher levels ofPage 14

Amazon Web ServicesWeb Application Hosting in the AWS Cloudprotection against your web application by providing you with near real-timevisibility into an ongoing attack, as well as integrating at higher levels with theservices mentioned earlier. Additionally, you get access to the AWS DDoSResponse Team (DRT) to help mitigate large-scale and sophisticated attacksagainst your resources. AWS WAF (Web Application Firewall) is designed to protect your webapplications from attacks that can compromise availability or security, orotherwise consume excessive resources. AWS WAF works in line withCloudFront or Application Load Balancer, along with your custom rules, to defendagainst attacks such as cross-site scripting, SQL injection, and DDoS. As withmost AWS services, AWS WAF comes with a fully featured API that can helpautomate the creation and editing of rules for your AWS WAF instance as yoursecurity needs change. AWS Firewall Manager is a security management service which allows you tocentrally configure and manage firewall rules across your accounts andapplications in AWS Organizations. As new applications are created, FirewallManager makes it easy to bring new applications and resources into complianceby enforcing a common set of security rules.Failover with AWSAnother key advantage of AWS over traditional web hosting is the Availability Zonesthat give you easy access to redundant deployment locations. Availability Zones arephysically distinct locations that are engineered to be insulated from failures in otherAvailability Zones. They provide inexpensive, low-latency network connectivity to otherAvailability Zones in the same AWS Region. As the AWS web hosting architecturediagram shows, AWS recommends that you deploy EC2 hosts across multipleAvailability Zones to make your web application more fault tolerant.It’s important to ensure that there are provisions for migrating single points of accessacross Availability Zones in the case of failure. For example, you should set up adatabase standby in a second Availability Zone so that the persistence of data remainsconsistent and highly available, even during an unlikely failure scenario. You can do thison Amazon EC2 or Amazon RDS with the click of a button.Page 15

Amazon Web ServicesWeb Application Hosting in the AWS CloudWhile some architectural changes are often required when moving an existing webapplication to the AWS Cloud, there are significant improvements to scalability,reliability, and cost-effectiveness that make using the AWS Cloud well worth the effort.The next section discusses those improvements.Key considerations when using AWS for webhostingThere are some key differences between the AWS Cloud and a traditional webapplication hosting model. The previous section highlighted many of the key areas thatyou should consider when deploying a web application to the cloud. This section pointsout some of the key architectural shifts that you need to consider when you bring anyapp

Amazon Web Services Web Application Hosting in the AWS Cloud Page 1 An overview of traditional web hosting Scalable web hosting is a well-known problem space. The following image depicts a traditional web hosting architecture that implements a common three-tier web application model. In this model, the architecture is separated into presentation,File Size: 535KB