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

This article is about how to understand the operation of Snapshot Instance, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

We discuss the snapshot operation of instance in detail through the log.

Sometimes the operating system is so damaged that it cannot be repaired by Rescue, so we have to consider restoring it through backup. Of course, only if we have made a backup of instance before.

The operation of Nova backup is called Snapshot, which works by fully backing up the image file (system disk) of instance, generating an image of type snapshot, and then saving it to Glance.

The operation to restore from a backup is called Rebuild.

Send a request to nova-api

The customer (either an OpenStack end user or another program) sends a request to API (nova-api): "take a snapshot of this Instance"

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

Nova-api sends messages

Nova-api sends a message to Messaging (RabbitMQ): "take a snapshot of this Instance." the source code is in / opt/stack/nova/nova/compute/api.py and the method is snapshot.

Nova-compute executes the operation

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

Pause instance

Take a snapshot of the mirror file of instance

Restore instance

Upload a snapshot to Glance

Snapshot is successfully saved in Glance

The instance backup was successful.

The above is how to understand the operation of Snapshot Instance, the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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