Shulou(Shulou.com)06/01 Report--

This article will explain in detail how to understand the operation of Unshelve Instance, the content of the article is of high quality, so the editor will share it with you for reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

How to restore the instance through a unshelve operation.

Because the process of saving instance's image,unshelve in Glance is actually through that image launch a new instance,nova-scheduler will also schedule the appropriate compute node to create the instance.

After instance unshelve, it may run on a different compute node than before shelve, but other properties of instance (such as flavor,IP, etc.) will not change.

Send a request to nova-api

Customers (either OpenStack end users or other programs) send a request to API (nova-api): "help me Unshelve this Instance"

View log / opt/stack/logs/n-api.log

Nova-api sends messages

Nova-api sends a message to Messaging (RabbitMQ): "unshelve this Instance" looks at the source code / opt/stack/nova/nova/compute/api.py, using unshelve.

Nova-scheduler execution scheduling

When nova-scheduler receives the message, it selects the appropriate compute node for instance. View log / opt/stack/logs/n-sch.log

After filtering, devstack-controller is finally selected as launch instance.

Nova-scheduler sends messages

Nova-scheduler sends a message telling the selected compute node to launch instance the source code on line 95 of / opt/stack/nova/nova/scheduler/filter_scheduler.py, the method is select_destinations

Nova-compute executes the operation

The process by which nova-compute executes unshelve is very similar to launch instance. Will also go through the following steps: 1. Prepare CPU, memory, and disk resources for instance 2. Create an instance image file 3. Create the XML definition file for instance 4. Create a virtual network and start instance

Log is recorded in / opt/stack/logs/n-cpu.log.

On how to understand the operation of Unshelve Instance to share here, I hope that the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.