Windows azure platform (17) reboot and reimage

(To better explain this chapter, I changed the language of Windows azure portal to English at the beginning)

When we use the Windows azure portal, we will find the reboot and reimage buttons for the multi-instance (Multi-instance) site.

The translation of the two buttons in the azure portal in simplified Chinese is

So what does reboot mean?

Reboot is to restart the azure computing node (azure VM. During the restart, the computing node does not provide normal computing services.

• For azure hosting services on a single computing node (1-instance), the azure hosting service temporarily becomes abnormal.
• For azure hosting services with multiple computing nodes (Multi-instance), fabric controller (FC) automatically sends requests to other normal computing nodes (azure VM ).

For example, I have released an azure hosting service, which has three computing nodes. If I restart (reboot) Two of the computing nodes, such:

If a user needs to request this azure service at this time, fabric controller (FC) will send these requests to the first node (in_0) that runs normally. This is also why Windows azure recommends that you use at least two instances (2-instance) to improve the reliability of Windows azure.

 

In fact, we can also connect to Azure VM through remote desktop (for detailed steps, refer to Windows
Azure platform (18) deploy applications to the Windows azure platform using Visual Studio), and then restart the azure VM like restarting the computer. For example:

UseRestart through azure portal (reboot)AndRemote Desktop Connection restart Windows azure VMIs similar. The difference is:

• Restart using the azure portal, FC will fully recognize which VM is being restarted and displayed on the portal.
• When the Remote Desktop Connection is restarted, FC does not know what happened to the computing node (VM. FC can only passively send external requests to healthy computing nodes.

 

Finally, let's talk about resetting the image (reimage ):

• To use reimage for Web role and worker role, the azure hosting service is first offline, then azure guest operation is re-installed, and the service is started.
• (Web and worker role reimage-in this type of role, azure brings the role offline first and applies the fresh reinstallation of the azure guest operating system and make the role online again)

We still connect to Windows azure VM (in_0) through remote desktop.

• I create three folders on drive F.

 

Then I click reimage to restart the image. Wait until the image restart operation is complete, and then I connect to the azure VM through the Remote Desktop.

I will find that the content on the local storage of the azure VM is lost after reimage.

Therefore, the data stored on the local disk of the azure VM is non-persistent! To save data, you must use azure storage (blob, drive, table, and queue.