1. 背景说明
openstack设计时的宗旨是能够为企业提供大规模的云计算服务，包括计算，存储，网络等资源，以服务的形式交付给用户，在一个非常大的环境中，需要将openstack的资源划分，openstack nova支持三种划分的方式:Region区域，Zone空间和Aggregate分组，其中Region是指一个地区或者地域，如可以将中国划分为:华南地区，华中地区，东北地区，西南地区；Zone则可以按照机房的形式来划分，如北京兆维机房为一个Zone，北京鲁谷机房为另外一个Zone；Aggreate粒度则更细，如按照同个机房中的不同机柜来划分。
概念说明：
1. Region，更像是一个地理上的概念，每个region有自己独立的endpoint，regions之间完全隔离，但是多个regions之间共享同一个keystone和dashboard，region的设计更多侧重地理位置的概念，用户可以选择离自己更近的region来部署自己的服务。
2. Zone，即 Availability Zone，AZ可以简单理解为一组节点的集合，这组节点具有独立的电力供应设备，比如一个个独立供电的机房，一个个独立供电的机架都可以被划分成AZ。所以，AZ主要是通过冗余来解决可用性问题，Zone的目的主要是，保障用户在创建instance的时候可以选择创建到哪些AZ中，以保证instance的可用性。
3. Host Aggregate， AZ是一个面向用户的概念和能力，而host aggregate是管理员用来根据硬件资源的某一属性来对硬件进行划分的功能，只对管理员可见，主要用来给nova-scheduler通过某一属性来进行instance的调度。其主要功能就是实现根据某一属性来划分物理机，比如按照地理位置，使用固态硬盘的机器，内存超过32G的机器，根据这些指标来构成一个host group。
2. 具体实现
因为规模的因素和设计的因素，此处只演示同个机房的Aggreate的划分，其中Aggreate需要配合Zone一起使用，否则没法实现
1. 创建Zone和Aggreate
[root@controller ~]# nova aggregate-create HappyLabZone1 HappyAggreate1 +----+---------------+-------------------+-------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+-------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | | 'availability_zone=HappyAggreate1' | +----+---------------+-------------------+-------+------------------------------------+
2. 查看aggreate列表
[root@controller ~]# nova aggregate-list +----+-------------------+-------------------+ | Id | Name | Availability Zone | +----+-------------------+-------------------+ | 5 | ChuangYiYuanZone1 | ChuangYiYuanZone1 | | 11 | HappyLabZone1 | HappyAggreate1 | #Zone和Aggreate关联一起了 +----+-------------------+-------------------+
3. 将compute节点加入到Aggreate内
[root@controller ~]# nova aggregate-add-host HappyLabZone1 ChuangYiYuan_10_16_2_19 #添加一台compute节点 Host ChuangYiYuan_10_16_2_19 has been successfully added for aggregate 11 +----+---------------+-------------------+---------------------------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+---------------------------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | 'ChuangYiYuan_10_16_2_19' | 'availability_zone=HappyAggreate1' | +----+---------------+-------------------+---------------------------+------------------------------------+ [root@controller ~]# nova aggregate-add-host HappyLabZone1 ChuangYiYuan_10_16_2_20 #添加另外一台compute节点 Host ChuangYiYuan_10_16_2_20 has been successfully added for aggregate 11 +----+---------------+-------------------+------------------------------------------------------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+------------------------------------------------------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | 'ChuangYiYuan_10_16_2_19', 'ChuangYiYuan_10_16_2_20' | 'availability_zone=HappyAggreate1' | +----+---------------+-------------------+------------------------------------------------------+------------------------------------+ [root@controller ~]# nova aggregate-add-host HappyLabZone1 ChuangYiYuan_10_16_2_21 #添加另外一台compute节点 Host ChuangYiYuan_10_16_2_21 has been successfully added for aggregate 11 +----+---------------+-------------------+---------------------------------------------------------------------------------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+---------------------------------------------------------------------------------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | 'ChuangYiYuan_10_16_2_19', 'ChuangYiYuan_10_16_2_20', 'ChuangYiYuan_10_16_2_21' | 'availability_zone=HappyAggreate1' | +----+---------------+-------------------+---------------------------------------------------------------------------------+------------------------------------+
4. 查看aggreate的详细信息
[root@controller ~]# nova aggregate-details HappyLabZone1 +----+---------------+-------------------+---------------------------------------------------------------------------------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+---------------------------------------------------------------------------------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | 'ChuangYiYuan_10_16_2_19', 'ChuangYiYuan_10_16_2_20', 'ChuangYiYuan_10_16_2_21' | 'availability_zone=HappyAggreate1' | +----+---------------+-------------------+---------------------------------------------------------------------------------+------------------------------------+ #已经添加了3台compute节点，在dashboard中，也能够正常显示
5.nova list查看划分情况
[root@controller ~]# nova service-list +------------------+-------------------------+-------------------+---------+-------+----------------------------+-----------------+ | Binary | Host | Zone | Status | State | Updated_at | Disabled Reason | +------------------+-------------------------+-------------------+---------+-------+----------------------------+-----------------+ | nova-conductor | ChuangYiYuan_10_16_2_8 | internal | enabled | up | 2016-01-27T06:06:05.000000 | - | | nova-cert | ChuangYiYuan_10_16_2_8 | internal | enabled | up | 2016-01-27T06:06:10.000000 | - | | nova-consoleauth | ChuangYiYuan_10_16_2_8 | internal | enabled | up | 2016-01-27T06:06:06.000000 | - | | nova-scheduler | ChuangYiYuan_10_16_2_8 | internal | enabled | up | 2016-01-27T06:06:09.000000 | - | | nova-compute | ChuangYiYuan_10_16_2_11 | ChuangYiYuanZone1 | enabled | up | 2016-01-27T06:06:11.000000 | - | | nova-compute | ChuangYiYuan_10_16_2_14 | ChuangYiYuanZone1 | enabled | up | 2016-01-27T06:06:12.000000 | - | | nova-compute | ChuangYiYuan_10_16_2_13 | ChuangYiYuanZone1 | enabled | up | 2016-01-27T06:06:13.000000 | - | | nova-compute | ChuangYiYuan_10_16_2_12 | ChuangYiYuanZone1 | enabled | up | 2016-01-27T06:06:05.000000 | - | #新添加的aggregate组 | nova-compute | ChuangYiYuan_10_16_2_19 | HappyAggreate1 | enabled | up | 2016-01-27T06:06:05.000000 | - | | nova-compute | ChuangYiYuan_10_16_2_20 | HappyAggreate1 | enabled | up | 2016-01-27T06:06:04.000000 | - | | nova-compute | ChuangYiYuan_10_16_2_21 | HappyAggreate1 | enabled | up | 2016-01-27T06:06:08.000000 | - | +------------------+-------------------------+-------------------+---------+-------+----------------------------+-----------------+ #至此，host aggregate配置完毕，后续扩容时，可以根据批次配置在不通的zone
3. 带来的好处
aggregate的分组带来的好处是，nova支持availablily zone级别的调度，即创建vm的时候，能够指定zone，指定zone之后，instance将会在指定的zone中选择合适的compute nodes来启动虚拟机，openstack默认安装完之后，只有一个nova的zone。效果如下:
[root@controller ~]# nova boot --name --flavor 1 --p_w_picpath db5fbfb7-bb14-4691-96dc-ba25531f4442 --key-name KEY --availability-zone HappyLabZone1 --security-groups 404af9b8-faa2-43df-aba8-24f17b40c17e --nic net-id=182d2632-4373-47ff-b3a6-d50f116b76a7 vm_test_for_zone_and_aggregate
页面效果:
创建VM的时候可以选择:
4.aggreate的删除
[root@controller ~]# nova aggregate-list #获取aggregate的ID号码 +----+-------------------+-------------------+ | Id | Name | Availability Zone | +----+-------------------+-------------------+ | 5 | ChuangYiYuanZone1 | ChuangYiYuanZone1 | | 11 | HappyLabZone1 | HappyAggreate1 | #id号是11 +----+-------------------+-------------------+ [root@controller ~]# nova aggregate-remove-host 11 ChuangYiYuan_10_16_2_21 #将主机从aggregate中删除，其他的compute节点，相同的方法执行 Host ChuangYiYuan_10_16_2_21 has been successfully removed from aggregate 11 +----+---------------+-------------------+------------------------------------------------------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+------------------------------------------------------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | 'ChuangYiYuan_10_16_2_19', 'ChuangYiYuan_10_16_2_20' | 'availability_zone=HappyAggreate1' | +----+---------------+-------------------+------------------------------------------------------+------------------------------------+ 查看详情: [root@controller ~]# nova aggregate-details 11 +----+---------------+-------------------+-------+------------------------------------+ | Id | Name | Availability Zone | Hosts | Metadata | +----+---------------+-------------------+-------+------------------------------------+ | 11 | HappyLabZone1 | HappyAggreate1 | | 'availability_zone=HappyAggreate1' | #已经没有compute节点 +----+---------------+-------------------+-------+------------------------------------+ 将aggregate删除 [root@controller ~]# nova aggregate-delete HappyLabZone1 Aggregate 11 has been successfully deleted.
5. 总结
openstack中的region，zone，host aggregate的实现里，其中region相对比较复杂，所有的的资源共享一个dashboard和keystone。关于具体实现，参考官方文档。
6. 附录
nova aggregate实现的几个命令
[root@controller ~]# nova -h |grep aggregate aggregate-add-host Add the host to the specified aggregate. #添加主机 aggregate-create Create a new aggregate with the specified details. #创建分组 aggregate-delete Delete the aggregate. #删除分组 aggregate-details Show details of the specified aggregate. #查看分组详情 aggregate-list Print a list of all aggregates. #查看分组列表 aggregate-remove-host aggregate. #从主机从分组删除 aggregate-set-metadata Update the metadata associated with the aggregate. #设置分组元数据信息 aggregate-update Update the aggregate's name and optionally #修改分组名字