openstack裸金属启用实例时会从可用资源池中，根据过滤策略随机分配一台主机来启用实例。
nova-scheduler 启动实例时的调度机制
#https://www.cnblogs.com/CloudMan6/p/5441782.html
#https://blog.csdn.net/u011692924/article/details/80578686
在一些特定的应用场景下，我们希望某个实例使用指定的一个或一批物理硬件。例如，希望Hadoop集群使用A批机器，k8s集群使用B批次的机器。通过摸索利用Placement_API打上资源特征的方法找到一条可行的路径。
环境
centos7.6
openstack queens + baremetal
过程：
1、安装placement client
yum install -y epel-release
yum install -y python-pip
pip install -U pip
pip install osc-placement
2、placement client 使用
#Queens版最高支持 1.17
#https://docs.openstack.org/placement/latest/placement-api-microversion-history.html#queens
#添加环境变量
export OS_PLACEMENT_API_VERSION=1.17
3、命令行使用
#参考https://docs.openstack.org/osc-placement/queens/cli/index.html
3.1 openstack resource class list
#资源类列表,
#Resource Class：资源种类，即资源的类型，Placement 为 Compute Node 缺省了下列几种类型，同时支持 Custom Resource Classes。
[[email protected] ~]# openstack resource class list
+-------------------+
| name |
+-------------------+
| VCPU |
| MEMORY_MB |
| DISK_GB |
| PCI_DEVICE |
| SRIOV_NET_VF |
| NUMA_SOCKET |
| NUMA_CORE |
| NUMA_THREAD |
| NUMA_MEMORY_MB |
| IPV4_ADDRESS |
| VGPU |
| VGPU_DISPLAY_HEAD |
+-------------------+
3.2 openstack resource provider list
#资源提供者列表
#裸金属可用节点将出现在资源提供者列表中
3.3 openstack resource provider inventory list
#资源提供者资源清单列表
#资源提供者，实际提供资源的实体，例如：Compute Node、Storage Pool、IP Pool 等
openstack resource provider inventory list 34a84cf3-4898-4d66-83cc-8f978d1349e6
[[email protected] ~]# openstack resource provider inventory list 34a84cf3-4898-4d66-83cc-8f978d1349e6
+----------------+------------------+----------+----------+-----------+----------+-------+
| resource_class | allocation_ratio | max_unit | reserved | step_size | min_unit | total |
+----------------+------------------+----------+----------+-----------+----------+-------+
| VCPU | 1.0 | 8 | 0 | 1 | 1 | 8 |
| MEMORY_MB | 1.0 | 24576 | 0 | 1 | 1 | 24576 |
| DISK_GB | 1.0 | 222 | 0 | 1 | 1 | 222 |
+----------------+------------------+----------+----------+-----------+----------+-------+
#裸金属资源的分配比率( allocation_ratio)为1:1,而普通虚拟机允许多分配
[[email protected] ~]# openstack resource provider inventory list e64c934c-cd5a-4991-8b64-2b83aad2405d
+----------------+------------------+----------+----------+-----------+----------+-------+
| resource_class | allocation_ratio | max_unit | reserved | step_size | min_unit | total |
+----------------+------------------+----------+----------+-----------+----------+-------+
| VCPU | 16.0 | 24 | 0 | 1 | 1 | 24 |
| MEMORY_MB | 1.5 | 18431 | 512 | 1 | 1 | 18431 |
| DISK_GB | 1.0 | 49 | 0 | 1 | 1 | 49 |
+----------------+------------------+----------+----------+-----------+----------+-------+
3.4 openstack resource provider usage show
#资源提供者的资源使用情况
openstack resource provider usage show 34a84cf3-4898-4d66-83cc-8f978d1349e6
[[email protected] ~]# openstack resource provider usage show 34a84cf3-4898-4d66-83cc-8f978d1349e6
+----------------+-------+
| resource_class | usage |
+----------------+-------+
| VCPU | 8 |
| MEMORY_MB | 24576 |
| DISK_GB | 222 |
+----------------+-------+
3.5 openstack trait create | list | show
#资源特征管理
#资源特征，不同资源提供者可能会具有不同的资源特征。Traits 作为资源提供者特征的描述，它不能够被消费，例如：标识可用#的 Disk 具有 SSD 特征，有助于 Scheduler 灵活匹配 Launch Instance 的请求。
#我们就是利用给资源打上特征，然后在分配时供我们使用。自定义特征以CUSTOM_开头，本例给几台机器打上CUSTOM_HADOOPNODE特征标记，以供启用hadoop集群时使用。
openstack trait create CUSTOM_HADOOPNODE
3.6 openstack resource provider trait set
#为资源提供者设置特征
openstack resource provider trait set --trait CUSTOM_HADOOPNODE 0623436c-816b-44c6-b741-01cc7c0b2fff
3.7 openstack allocation candidate list
#分配候选人列表
#列出满足当前条件的资源列表
openstack allocation candidate list --resource VCPU=8 --required CUSTOM_HADOOPNODE
[[email protected] ~]# openstack allocation candidate list --resource VCPU=16 --required CUSTOM_HADOOPNODE
+---+------------+--------------------------------------+-------------------------+-------------------+
| # | allocation | resource provider | inventory used/capacity | traits |
+---+------------+--------------------------------------+-------------------------+-------------------+
| 1 | VCPU=16 | e64c934c-cd5a-4991-8b64-2b83aad2405d | VCPU=12/384 | CUSTOM_HADOOPNODE |
| 2 | VCPU=16 | 0623436c-816b-44c6-b741-01cc7c0b2fff | VCPU=0/24 | CUSTOM_HADOOPNODE |
+---+------------+--------------------------------------+-------------------------+-------------------+
#指定节点上启动实例，根据allocation candidate --required trait 过滤出的provider id 即可以对应到相应的ironic node
#然后使用 --availability-zone nova:[ironic-node-name]启动实例
openstack server create \
--availability-zone nova:compute03 \
--image hadoop-master \
--flavor dell.bm \
--key-name mykey \
--nic net-id=b78a9fca-1e69-4668-91f5-0410998fbc5a \
allocation-candidate01
openstack server create \
--hypervisor-hostname compute01 \
--image hadoop-slaver \
--flavor r220.bm \
--key-name mykey \
--nic net-id=b78a9fca-1e69-4668-91f5-0410998fbc5a \
allocation-candidate02
即实现了根据特征trait启用相应的物理硬件。
参考文档：
https://blog.csdn.net/Jmilk/article/details/82980378
https://blog.csdn.net/weixin_34132768/article/details/93577066
https://blog.csdn.net/u011692924/article/details/80578686
https://blog.51cto.com/99cloud/2166339
https://docs.openstack.org/placement/latest/placement-api-microversion-history.html#queens
![openstack身份管理[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)