Flat qingcloud: Windows azure (1)

This series will systematically introduce windows Azure, including basic terms, programming, and Windows azure applications, and explore the changes that Windows azure may bring to our current model.

Let's put the obscure concept of cloud computing aside and look at some of our situations before "moving forward.

1. When a large amount of data is processed and computed in real time, users have to wait. We have to consider whether to use caching and pass performance tests in encoding. At the same time, we also need to write someCodeEnsure cache update and erasure;
2. Asynchronous programming is used to solve the user waiting problem;
3. Various ApplicationsProgramThe unified web service integration platform and a wide variety of interaction methods make every release a headache;
4. Massive Data storage problems;
5. Public modules such as logging.

Then I will tell you that Windows azure provides us with the solution to the above five problems, and you may be interested in learning about it.

This is a typical application of Windows azure: it runs on a machine in Windows data center and provides users with commercial applications and data access through services.

What Can Windows azure do?

1. Software service providers can create applications for specific commercial companies on Windows azure and then provide them to commercial companies as SAAS.
2. Software service providers can create applications for specific users. If you need to expand the market to create commercial sites for customers, Windows azure supports them.
3. Windows Azure is also a good choice for enterprises to create applications for internal employees.

Next, let's take a look at the composition of Windows azure:

The compute Service is responsible for running applications, and the storage service provides data storage. The third component, fabric, is a tool for managing and monitoring applications on the cloud platform. This article describes the first component.

Compute Service)

Compute Service supports a variety of applications. Its primary task is to solve the bottleneck problem of a large number of concurrent requests: We used the hardware upgrade method, now, compute Service supports applications running on multiple servers with the same code version, and supports virtual machines, we can manage each virtual machine through the hyper-V operation interface. When you need to run a program, the developer logs on from the browser using the Windows Live ID, and then customizes the managed account and data storage account of the application. Developers with managed accounts can upload their programs and define their configurations on the Windows azure platform.

Windows azure provides two ways to run application instances: Web role instances and worker role instances.

As shown in the name, the Web role instance can receive HTTP and HTTPS requests. It must run in IIS 7. Developers can create ASP.. net, WCF, or other.. NET application. You can also create a non.. NET applications, such as PHP and Java programs deployed on Tomcat. In Figure 3, we can see that Windows azure has built-in Hardware load balancing to allocate Web requests to the same application instance on each server and manage the lifecycle of these instances. Because Windows azure does not establish an association for each instance of the application, it cannot ensure that a series of requests of the same user are sent only to a unique instance. Therefore, the Web role instance is stateless, and all client-specific statuses are written to Windows azure storage and returned to the client when the request is complete.

The difference between a worker role instance and a web role instance is that it does not need to be configured or run in IIS. Most of the time, it runs in the form of background work. We can also run Web server in worker role, such as Apache Web server.

Developers can use only one web role instance and one worker role instance, or combine the two. If the performance of an application declines, you can add a web role instance or a worker role instance through windows Azure, or both. If the performance exceeds the required standard, it can reduce the number of these instances, and developers can stop the application running by disabling all instances. Windows azure also provides APIs that allow you to dynamically change the number of web role and worker role instances by programming, but cannot automatically close the application.

During windows azure development, developers do not need to run the cloud platform on their own machines, but upload, configure, and debug their own programs to the running cloud platform, you can use the log API to debug applications on the platform, or use configuration tools to monitor applications, such as performance counters, CPU usage, and storage errors. These applications run in user mode. Windows azure manages its own system updates, so you don't have to worry about system level damages caused by applications, this occurs frequently on the current enterprise platform: after some applications are integrated, it affects many other programs and even causes damage to the platform.

Running the code is obviously not all about Windows azure. In the next article, we will talk about storage service ).