The principle of virtual machine mirroring deployment in the cloud

Starting and stopping virtual machines is a routine use of cloud computing resources. There are two basic options for deploying virtual machines in the cloud: Customers can copy a pre-configured virtual machine image (also known as the final version), or they can assemble a custom virtual machine image as required.

To enable a virtual machine, first select a machine image from the Cloud directory. When you deploy an application related to http://www.aliyun.com/zixun/aggregation/14417.html ">apache Web or JBoss application server," It is a good idea to choose a Linux image that is preloaded with these components. If you're a. NET programmer, it is a good idea to choose a Windows operating system that is pre-installed and configured with development tools. In addition to selecting a virtual machine image to install the prerequisite software, you must also confirm that the software is up to date and patched. Once you have selected the mirror, the next step is to deploy the image in the cloud.

Complete version mirroring: Minimal effort but limited choice

There are several advantages to using the final version of mirroring. The most important thing is that it can ensure the consistency of the virtual machine. In addition, starting with an existing mirror can save a lot of effort and time. End-Customers do not have to care about installing libraries or attaching packages; they can rely on cloud administrators to maintain a final version of the image.

Limited options owned by end users are a flaw in this approach; A mirrored directory typically contains a common mirror rather than some infrequently used collection of components. For a professional virtual machine image, you can select a final version and install the required components. If an end-user often deploys a custom mirror, he must keep a copy of the mirror, but that means that the user has to patch themselves in order to lose the advantage of using the final version.

It is not important to consider a professional cloud instance: Your Web application has been running for several weeks after you have configured a load-balanced environment, and if your application suddenly breaks, you may consider adding several servers to the load-balanced cluster. In this case, you need to run identical mirrors in the cluster to maintain consistency. If you've ever done this before, there may be different versions of the components in the system. This situation also occurs when a component releases a new version during a two deployment.

Latest components and on-demand assembly

Creating a custom mirror each time a new mirror is deployed enables end users to install the required components themselves. Cloud users like to start with an underlying system image and then install application components (databases, application servers, and Web servers). However, without the help of tools, creating the required cloud is impractical for regular deployments. In this case, consider using configuration management tools such as Chef or puppet, which allow you to specify which components you want to include in the mirror. If the latest versions of applications and patches are critical to mirroring, assembling them on demand is the best option. For example, if you have a standard database server configuration, create a chef or puppet script to create a mirror to ensure you have the latest version of the component.

On-demand Assembly also helps maintain consistency in multiple servers because database administrators do not like point-to-point patches for an outdated final version of the image.

The virtual machine methods in both of these deployment clouds (creating final mirrors and creating on-demand iterative mirroring) are not independent of each other. When you need to create a server cluster, for example, you should build a script to assemble a custom mirror and make it the final version. You first create multiple virtual machine images through the configuration management tool and then use this image to create multiple virtual machine instances. In this scenario, as long as you need to add a new virtual server to the cluster, keep the final version of the image.

There is no single way to assemble and deploy mirrors in a cloud environment. The final version of mirroring works well in a consistent case, while assembling an on-demand version ensures that the latest components are running in your environment.

(Responsible editor: The good of the Legacy)