AWS Professional Knowledge Base

Amazon ElastiCache is a web service that makes it easy to deploy and run Memcached or Redis protocol-compliant server nodes in  the cloud . Amazon ElastiCache improves the performance of web applications by allowing you to retrieve information from a fast, managed, in-memory system, instead of relying entirely on slower disk-based databases. Once a cluster is provisioned, Amazon ElastiCache automatically detects and replaces failed nodes. The in-memory caching provided by Amazon ElastiCache can be used to significantly improve latency and throughput for many read-heavy application workloads (such as social networking, gaming, media sharing and Q&A portals) or compute-intensive workloads (such as a recommendation engine). Each node runs an instance of the Memcached or Redis protocol-compliant service and has its own DNS name and port.  Reserved Nodes or Reserved Instance (RI) is an offering that provides you with a significant discount over on-demand usage when you commit t...

Resolver Conditional forward rules R53 Resolver - single endpoint which can represent multiple VPC in multiple accounts in the same region. Made of 1 or more ENI.  Available in each AZ. Resolver checks if its Private Hosted zone (higher priority) followed by VPC DNS and then to Public DNS. Inbound endpoints - Traffic from on-premise will reach R53 resolver through the inbound endpoint. The IEP will be in the central VPC. Need not be in all other VPCs. Individual VPC will have R53 PHZ and Associate all those Private hosted zone to central VPC. Outbound endpoints We may have zones in On-premises which our EC2 instance may have to resolve. On-prem has its DNS server. OEP - R53 resolver to query your on-premise DNS resolvers. We need to create resolver rules to tell how to resolve Forward and System - 2 types of rule Forward has precedence over System rules. Create OEP in central and just share the rules with all the individual VPC (dont need to have OEP in each VPC). For VPC in other ...

Types of ELB Classic - Works along with Classic VPC.    Classic Load Balancer does not support SNI. For EC2 instances, always use a Type A Record without an Alias. For ELB, Cloudfront and S3, always use a Type A Record with an Alias and finally, for RDS, always use the CNAME Record with no Alias. Application Works on Layer 4 and 7  Supports SNI - multiple domains can be mapped to the ALB and ALB would serve them by automatically tagging the write certificates for those domains When the domain is resolved in Route53 it is mapped to the IP provided by ALB. uses ENI. When the traffic load increase ELB automatically allows more connections by scaling. The IP connections are held for a period of time to ensure if there are subsequent requests which hit that IP. When the IP is not available, the R53 tries the second IP. Even if that is not working then DNS refresh is required so R53 can get access to new set of IPs from ALB. ALB can support path and text based routing base...

Infrastructure Services   AWS CloudFormation    AWS CloudFormation provides several built-in functions that help you manage your stacks. Use intrinsic functions in your templates to assign values to properties that are not available until runtime. Currently, you can use intrinsic functions in resource properties, outputs, metadata attributes, and update policy attributes. You can also use intrinsic functions to conditionally create stack resources. Examples - Fn::Base64, GetAtt, GetAZ, Select, Join, Sub, Transform, Ref The  Fn::GetAtt  intrinsic function returns the value of an attribute from a resource in the template.  The intrinsic function  Fn::Transform  specifies a macro to perform custom processing on part of a stack template. Macros enable you to perform custom processing on templates, from simple actions like find-and-replace operations to extensive transformations of entire templates.  The intrinsic function  Ref  returns ...

 Config Manager Use AWS Config to evaluate the configuration settings of your AWS resources. You do this by creating AWS Config rules, which represent your ideal configuration settings. AWS Config provides customizable, predefined rules called managed rules. While AWS Config continuously tracks the configuration changes that occur among your resources, it checks whether these changes violate any of the conditions in your rules. If a resource violates a rule, AWS Config flags the resource and the rule as  noncompliant . When you add a rule to your account, you can specify when you want AWS Config to run the rule; this is called a  trigger .  AWS Config runs evaluations for the rule when certain types of resources are created, changed, or deleted. AWS Config runs evaluations for the rule at a frequency that you choose . AWS Config allows you to remediate noncompliant resources that are evaluated by AWS Config Rules. AWS Config applies remediation using  AWS System...

AWS IoT Core  is a managed cloud service that enables connected devices to securely interact with cloud applications and other devices.  AWS IoT provides device software that can help you integrate your IoT devices into AWS IoT-based solutions.  AWS IoT Core supports these protocols: MQTT MQTT WSS - Secure Web Sockets HTTPS Long range WAN - LoRaWAN AWS IoT Greengrass  extends AWS IoT to edge devices so they can act locally on the data they generate and use the cloud for management, analytics, and durable storage.  FreeRTOS  is an open source, real-time operating system for microcontrollers that lets you include small, low-power edge devices in your IoT solution. FreeRTOS includes a kernel and a growing set of software libraries that support many applications. FreeRTOS systems can securely connect your small, low-power devices to  AWS IoT  and support more powerful edge devices running  AWS IoT Greengrass .    AWS IoT Things Graph pr...

  AWS Glue is a serverless, fully managed ETL (extract, transform, and load) service that makes it simple and cost-effective to categorize your data, clean it, enrich it, and move it reliably between various data stores and data streams.   AWS Glue consists of a central metadata repository known as the AWS Glue Data Catalog. AWS Glue is designed to work with semi-structured data. You can use AWS Glue to organize, cleanse, validate, and format data for storage in a data warehouse or data lake.  Glue  discovers and catalogs metadata about your data stores into a central catalog.  Populates the AWS Glue Data Catalog with table definitions from scheduled crawler programs. AWS Glue can catalog your Amazon Simple Storage Service (Amazon S3) data, making it available for querying with Amazon Athena and Amazon Redshift Spectrum. You can run your ETL jobs as soon as new data becomes available in Amazon S3 by invoking your AWS Glue ETL jobs from an AWS Lambda function. Gl...