Why Consider the Cloud?As mentioned in my previous set of notes, I explained there are three main areas which benefit through Cloud Computing; speed, scale and economics.However, constant innovation in Cloud Computing poses challenges to IT which may lead to organisations asking themselves:How do I integrate with my existing IT investments?What about my heterogenous, complex IT landscape?What about security and compliance?Every enterprise needs integration, heterogeneity and security within their IT department, so it's vital new innovations do not damage these factors.
Enterprise and CloudThere are many viable reasons why a business may or may not look into the Cloud as a viable alternative to their onsite IT structure. Some organisations may be concerned about data privacy, law and security.Other companies may adopt a hybrid approach in which some services are onsite while others are in the Cloud. Many Universities around the UK use this approach.Meanwhile, small businesses might not see an advantage in using the Cloud due to cost and aligning it with their actual IT requirements. Large businesses, on the other hand, may see it as cost effective in terms of required expertise, hardware, software, as well as uptime guarantees.
RedundancyThere are lots of Storage Redundancy Options. These include: Database Local and Geo-Replication Caching with high availability option Load-Balanced Service Apps, Cloud Services and Virtual Machines Built-in redundancy across Virtual Network gateways Failover with Traffic Manager
PaaS Cloud ServicesWhen using Platform as a Service (PaaS), you the user will simply manage the Applications and the Data. The vendor, on the other hand, will have to manage: Runtime Middleware O/S Virtualisation Servers Storage Networking The first benefit of implementing a PaaS solution is speed. This is because there is less work for developers to do and applications can go from idea to availability in a shorter space of time.The second benefit of implementing a PaaS solution is cost. There's less admin and management work to do, meaning organisations spend less supporting application.The third benefit of implementing a PaaS solution is lower risk. The platform does the heavy lifting, leaving fewer opportunities for error. This means creating and running applications gets more reliable.In short, you build it and PaaS will run it. Most cloud providers offer PaaS such as Google, Heroku and Amazon.
How do PaaS Cloud Services Communicate?PaaS cloud services communicate through three forms of endpoint; public, internal and instance input. Public endpoints are publicly accessible and load balanced whilst internal endpoints are private to the cloud service and not load balanced.Each cloud service which is running is called an instance. An instance of any given cloud service deployment is actually a fully-managed virtual machine. All traffic will reach the same public endpoint, the load balancer then distributes requests to the three instances dependent upon their load at the time.
What can a PaaS Cloud Service Run?The general rule is if a cloud service runs in Microsoft Windows, then it runs in Azure. There are a wide variety of languages available including: C# Visual Basic C++ Java PHP Node.js Python There are also a choice of frameworks available, including: .NET ExpressJS Rails Zend
Cloud Service Roles and InstancesA role is the definition file for the service. This specifies the: VM size (CPU, RAM etc.) Communication Endpoints (Port 80, SSL) Local Storage Resources (Database Endpoints) At runtime each role will execute on one or more instances. A role instance is a set of code, configuration, and local data, deployed in a virtual machine.