openstack/nova
Code Issues Proposed changes
nova/doc/source/admin/configuration/resize.rst
Matt Riedemann 29100f9b5a FUP for docs nits in cross-cell-resize series 
Addresses review comments from:

* https://review.opendev.org/#/c/638269/63/doc/source/admin/configuration/resize.rst
* https://review.opendev.org/#/c/696212/6/doc/source/admin/configuration/cross-cell-resize.rst

Also updates contributor/resize-and-cold-migrate since that is relatively
new and biased toward same-cell resize and cold migrate. However, I chose
to link the same-cell resize glossary term to that contributor doc rather
than admin/configuration/resize because the admin doc is woefully bare.

Part of blueprint cross-cell-resize

Change-Id: I93b051252e34c8604cebea617c34e9299ac508d4
2019-12-23 10:10:57 -05:00

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Resize

Resize (or Server resize) is the ability to change the flavor of a server, thus allowing it to upscale or downscale according to user needs. For this feature to work properly, you might need to configure some underlying virt layers.

This document describes how to configure hosts for standard resize. For information on cross-cell resize <Cross-Cell Resize>, refer to /admin/configuration/cross-cell-resize.

Virt drivers

This section needs to be updated for other virt drivers, shared storage considerations, etc.

KVM

Resize on KVM is implemented currently by transferring the images between compute nodes over ssh. For KVM you need hostnames to resolve properly and passwordless ssh access between your compute hosts. Direct access from one compute host to another is needed to copy the VM file across.

Cloud end users can find out how to resize a server by reading /user/resize.

XenServer

To get resize to work with XenServer (and XCP), you need to establish a root trust between all hypervisor nodes and provide an /image mount point to your hypervisors dom0.

Automatic confirm

There is a periodic task configured by configuration option :oslo.configresize_confirm_window (in seconds). If this value is not 0, the nova-compute service will check whether servers are in a resized state longer than the value of :oslo.configresize_confirm_window and if so will automatically confirm the resize of the servers.