Windows Azure Virtual Machine (1) Related technologies

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Does 1.Microsoft Azure consist of System Center and Hyper-V?

While Microsoft Azure supports Hyper-V-enabled VHDs to be uploaded directly to the Azure cloud for management, Azure's underlying technology is a proprietary technology developed by Microsoft and is not available externally. If customers want to build their own private cloud platform, they can use azure Pack to build their own private cloud platform using Microsoft's system Center + Windows server products.

2. Can I create virtual machines in Microsoft Azure virtual machine?

The Microsoft Azure Datacenter is comprised of thousands of rack, each of which has a Windows Server 2012 operating system, which we call the host OS, which is the physical server's operating system.
These windows Server 2012 uses a special version of Hyper-V virtualization technology, virtual out of several virtual machines, called the guest OS.
Host OS contains a fabric agent in-control software to monitor the current virtual machine information to the fabric Controller.
End users of Microsoft Azure are only exposed to the guest OS and cannot access the host OS. The user cannot create the virtual machine in the guest OS again.

3. How does Azure Virtual machine recover if the server on which Microsoft Azure resides is down?

In traditional IDC room hosting, if the physical server is down, all virtual machines will be down and need manual or monitoring software for redeployment.
From high-availability files, Microsoft Azure virtual machines are saved in VHD format and are triple-redundant in the same datacenter (supporting geo-redundancy across datacenters), guaranteeing the 99.9% SLA for Azure virtual machine underlying VHD files.

From the data Center architecture, Microsoft Azure has self-managed capabilities. Azure Fabric Controller is the central management system that manages the azure datacenter, and you can think of him as the brain of the Azure data center. Azure Fabric Controller itself is an assembly that incorporates many Microsoft Systems management technologies, including management of virtual machines (System Center Virtual Machine Manager), management of the job Environment (System Center Operation Manager), and so on, is played in the fabric controller.

Azure Fabric Controller is responsible for automating the management of all entity servers in the datacenter, including deployment of user-requested Microsoft Azure Guest OS, timed hotfix patching, machine state monitoring, and managing different versions of VM mirroring, among other important core tasks. The Fabric controller itself is also highly available

The fabric controller also handles the health management work of the virtual machine (Management), which occurs when the Microsoft Azure Guest OS crashes, and is created by the fabric The controller automatically chooses different physical machines to redeploy and start.

In the case of a single guest OS, when the guest OS goes down, redeploying and starting the guest OS can take a while, causing the customer app to be short-lived, so Microsoft Azure does not have a single instance SLA.

4. Does Microsoft have an SLA for a single instance?

Microsoft does not have an SLA for a single instance. For example, a customer has an application deployed in a traditional IDC room, an ad server, a Web server, and a SQL Server.

In Microsoft Azure virtual machine, users can also choose to deploy AD Server with one azure virtual machines, and one Azure Vsan deployment Web application. Deploy SQL Server using another virtual machine. However, there is no SLA guarantee for this scenario.

Microsoft Azure Virtual Machine promises a 99.95% SLA that requires 2 or more than 2 Azure virtual machines to run concurrently, and all of the virtual machine needs to be in the same availability set. For the above instance, if you want to implement a 99.95% SLA in Azure, you need to deploy simultaneously:

-Two ad servers, placed in the same availability set a.

-Two virtual machines deploy Web application, and the virtual machine where Web application resides needs to be placed in another availability set B.

-Two virtual machine deployed SQL Server, using the always-on features provided by SQL Server, to achieve high availability. and the virtual machine where SQL Server resides needs to be in a different availability set, C.

To add, Microsoft does not have a single instance of the SLA for the following two main reasons:

-From an infrastructure perspective, it is not possible to predict when the hardware of a single physical server has failed, i.e. CPU failure, network failure, power failure, etc. of a single physical server.

-From the maintenance of the physical server. Microsoft upgrades and maintains Azure Virtual machine every month, usually in the early Friday and early Saturday (the Beijing and Shanghai data centers are maintained separately). Maintenance Period window is generally about 6-8 hours, in the maintenance period of the virtual machine instance will be restarted, restart time generally in about 10 minutes.

That is, the maintenance period is defined by Microsoft, the user has no way to reject the maintenance process, the user can not specify at what point of time Microsoft, the maintenance of which virtual machines. Any azure Virtual machine will be restarted during the Maintenance Period window. However, Azure Virtual machine will only affect a single instance.

Azure Virtual machine that affects a single instance during the Azure maintenance period.

5. Will Microsoft affect my business when maintaining azure Virtual machine? How is Microsoft going to guarantee the 99.95% SLA?

　　

If you use Azure Virtual machine with a single instance, you cannot guarantee a 99.95% SLA.
Microsoft Azure Virtual Machine promises a 99.95% SLA that requires 2 or more than 2 Azure virtual machines to run concurrently, and all of the virtual machine needs to be in the same availability set.

In this case, from an infrastructure perspective, Microsoft has a mechanism to ensure that 2 Azure Virtual machines running concurrently will not go down at the same time.
From the maintenance of the service server. When Microsoft maintains the Azure virtual machine, it monitors the 2 azure virtual machines in the same availability set and knows that customers need these 2 azure virtual machines to be highly available. When Microsoft restarts Azure Virtual machine, it does not restart at the same time. Instead, restart one of them and restart the other when the virtual machine restarts. This ensures that at least one virtual machine is online at the same time within the Maintenance window.

If the customer deploys 2 azure Virtual machines but does not set the availability set. When Microsoft was doing maintenance for azure virtual machine, it found that the 2 Azure virtual machines were not associated and would restart the 2 Azure virtual machines at the same time, resulting in a service off-line.

6. What is an availability set?

Please refer to: http://www.cnblogs.com/threestone/archive/2012/01/06/2382322.html

7.Microsoft How does Azure guarantee CPU, memory, hard disk performance?

Answer: Traditional hyper-V technology, the CPU is shared. For example, the author of ThinkPad T430s is 4CORE/8GB, installs the Windows Server R2 operating system, and uses Hyper-V virtual out of 3 virtual machines. The notebook's physical operating system + 3 virtual machine operating systems are essentially shared 4Core CPUs.

The types of virtual machines available in Microsoft Azure are as follows:

Virtual machine Type	Cpu	Ram	Number of external disks	IOPS
A0	Shares	768MB	1	500
A1	1	1.75GB	2	2 * 500
A2	2	3.5GB	4	4 * 500
A3	4	7GB	8	8 * 500
A4	8	14GB	16	16 *500
A5	2	14GB	4	4 * 500
A6	4	28GB	8	8 * 500
A7	8	56GB	16	16 * 500

　　

In addition to the A0 virtual machine type, its CPU is shared with other users. Other types of virtual machines, such as A1-a7, whose CPUs are exclusive, are not shared with other users. For example, the physical server is 20Core, the physical server can only virtual out of 2 A7 Azure virtual Machine (8CORE/56GB), and the additional 4Core to be reserved for the physical server.

With regard to the performance assurance of hard drives, Microsoft is guaranteeing disk IOPS.