Wasb

What is HDFS?

The Hadoop Distributed File System (HDFS) is one of the core Hadoop components, it is how Hadoop manages data and storage. At a high level, when you load a file into Hadoop the "name node" uses HDFS to chunk the file into blocks and it spreads those blocks of data across the worker nodes within the cluster. Each chunk of data is stored on multiple nodes (assuming the replication factor is set to > 1) for higher availability. The name node knows where each chunk of data is stored and that information is used by the job manager to allocate tasks and resources appropriately across nodes.

Dockers Overview

Docker is an open-source project that automates the deployment of applications inside software containers

Measures for cost saving in the cloud

It is usually a better choice to select Paas (Platform as service) over Iaas (Infrastructure as service).If we spin off a VM in the cloud we need to start paying for it as soon as it is ready and running.

If we choose Paas we need to be smart for cost saving in the cloud.

• Scale down resource if we can
• Turn off or decommission resources
• Develop with cost in mind
• Measure the usage of the applications

Need for Azure File storage and Redis Cache

• We are used to In-memory cache for session state or used to store local files to serve as temp files.In azure we cannot rely on this, the reason ,when we use azure platform as a service we would not have single dedicated server. 
• Resources are abstracted using Azure service fabric.This would take care of the web application running. Even if one of the data center fails, it would magically move to a different data center. This would make sure that our web applications are always running

       In memory cache and local files has to be shifted to Azure local File Storage or Redis cache

Azure app services

 Azure App Service, a cloud service that bundles together several existing ones: Azure Websites,  Azure Mobile Services, and Azure BizTalk Services 

• Provides services that can be used to build many applications
• Offers these services as capabilities that can be used without having to worry about plumbing servers
• Enables us to focus on adding business values

Advantages of Microsoft Azure

• Ease of use 
• We do not need physical hardware
• Certain cloud services do not need servers
• Scalability. We can easily scale up or down based on the need
• Pay for what we use