From 9752012c439a151d38a72d774b4d82ebec80f67b Mon Sep 17 00:00:00 2001 From: Stephen Gordon Date: Thu, 21 May 2015 17:01:03 -0700 Subject: [PATCH] Correct host aggregate and availability zone info The documentation around the creation of host aggregates and availability zones. In particular indicating that a host could be in multiple availability zones. Change-Id: I56ea99cfe004b58ed903702b20896c479fa43644 Closes-Bug: #1433673 --- .../section_cli_nova_host_aggregates.xml | 58 +++++++++++-------- 1 file changed, 35 insertions(+), 23 deletions(-) diff --git a/doc/common/section_cli_nova_host_aggregates.xml b/doc/common/section_cli_nova_host_aggregates.xml index 06531d84b7..e25b8182ea 100644 --- a/doc/common/section_cli_nova_host_aggregates.xml +++ b/doc/common/section_cli_nova_host_aggregates.xml @@ -8,18 +8,31 @@ xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="host-aggregates"> - Host aggregates - Host aggregates are a mechanism to further partition an - availability zone; while availability zones are visible to - users, host aggregates are only visible to administrators. - Host Aggregates provide a mechanism to allow administrators to - assign key-value pairs to groups of machines. Each node can - have multiple aggregates, each aggregate can have multiple - key-value pairs, and the same key-value pair can be assigned - to multiple aggregates. This information can be used in the - scheduler to enable advanced scheduling, to set up hypervisor - resource pools or to define logical groups for - migration. + Host aggregates and availability zones + + Host aggregates are a mechanism for partitioning hosts in an OpenStack + cloud, or a region of an OpenStack cloud, based on arbitrary + characteristics. Examples where an administrator may want to do this + include where a group of hosts have additional hardware or performance + characteristics. + + + Host aggregates are not explicitly exposed to users. + Instead administrators map flavors to host aggregates. Administrators + do this by setting metadata on a host aggregate, and matching flavor + extra specifications. The scheduler then endeavors to match user + requests for instance of the given flavor to a host aggregate with the + same key-value pair in its metadata. Compute nodes can be in more than + one host aggregate. + + + Administrators are able to optionally expose a host aggregate as an + availability zone. Availability zones are different to host aggregates + in that they are explicitly exposed to the user, and hosts can only be + in a single availability zone. Administrators can configure a default + availability zone where instances will be scheduled when the user + fails to specify one. + Command-line interface The nova command-line tool supports @@ -34,19 +47,18 @@ nova aggregate-create <name> - <availability-zone> + [availability-zone] Create a new aggregate named - <name> - in availability zone - <availability-zone>. - Returns the ID of the newly created - aggregate. Hosts can be made available to - multiple availability zones, but - administrators should be careful when - adding the host to a different host - aggregate within the same availability - zone and pay attention when using the + <name>, and + optionally in availability zone + [availability-zone] + if specified. The command returns the ID of the + newly created aggregate. Hosts can be made + available to multiple host aggregates. Be careful + when adding a host to an additional host + aggregate when the host is also in an availability + zone. Pay attention when using the aggregate-set-metadata and aggregate-update commands to avoid user confusion when they