placement服务提供一个HTTP API，用于跟踪资源提供者清单和使用情况。placement作为数据模型上的web服务进行操作。安装包括创建必要的数据库以及安装和配置web服务。这是一个简单的过程，但是要将placement与OpenStack云的其余部分集成起来，有相当多的步骤。
  其他一些OpenStack服务(尤其是nova)需要安装placement，因此应该在其他服务之前安装placement，而在Identity (keystone)之后安装placement。

安装准备

安装配置placement服务之前，建库等。

1. 建立数据库

   1. 完成下列建库操作:
       ○ 使用root用户登录:
           $ mysql -u root -p root123 
       ○ 建立placement database:
           MariaDB [(none)]> CREATE DATABASE placement;
       ○ Grant proper access to the database:
           MariaDB [(none)]> GRANT ALL PRIVILEGES ON placement.* TO 'placement'@'%'  IDENTIFIED BY 'placement123';
   
   2. Configure User and Endpoints
       1. Source the admin credentials to gain access to admin-only CLI commands:
           $ . admin-openrc
       2. Create a Placement service user using your chosen PLACEMENT_PASS:
           $ openstack user create --domain default --password-prompt placement
   
           User Password:placement123
           Repeat User Password:placement123
           +---------------------+----------------------------------+
           | Field               | Value                            |
           +---------------------+----------------------------------+
           | domain_id           | default                          |
           | enabled             | True                             |
           | id                  | fa742015a6494a949f67629884fc7ec8 |
           | name                | placement                        |
           | options             | {}                               |
           | password_expires_at | None                             |
           +---------------------+----------------------------------+
       3. Add the Placement user to the service project with the admin role:
           $ openstack role add --project service --user placement admin
    
       4. Create the Placement API entry in the service catalog:
           $ openstack service create --name placement \
             --description "Placement API" placement
   
           +-------------+----------------------------------+
           | Field       | Value                            |
           +-------------+----------------------------------+
           | description | Placement API                    |
           | enabled     | True                             |
           | id          | 2d1a27022e6e4185b86adac4444c495f |
           | name        | placement                        |
           | type        | placement                        |
           +-------------+----------------------------------+
       5. Create the Placement API service endpoints:
           注意:域名为你规划好url, 必须能够解析.
           $ openstack endpoint create --region RegionOne placement public http://stack.flex.net:8778
           +--------------+----------------------------------+
           | Field        | Value                            |
           +--------------+----------------------------------+
           | enabled      | True                             |
           | id           | 2b1b2637908b4137a9c2e0470487cbc0 |
           | interface    | public                           |
           | region       | RegionOne                        |
           | region_id    | RegionOne                        |
           | service_id   | 2d1a27022e6e4185b86adac4444c495f |
           | service_name | placement                        |
           | service_type | placement                        |
           | url          | http://controller:8778           |
           +--------------+----------------------------------+
   
           $ openstack endpoint create --region RegionOne placement internal http://stack.flex.net:8778
           +--------------+----------------------------------+
           | Field        | Value                            |
           +--------------+----------------------------------+
           | enabled      | True                             |
           | id           | 02bcda9a150a4bd7993ff4879df971ab |
           | interface    | internal                         |
           | region       | RegionOne                        |
           | region_id    | RegionOne                        |
           | service_id   | 2d1a27022e6e4185b86adac4444c495f |
           | service_name | placement                        |
           | service_type | placement                        |
           | url          | http://controller:8778           |
           +--------------+----------------------------------+
   
           $ openstack endpoint create --region RegionOne placement admin http://stack.flex.net:8778
           +--------------+----------------------------------+
           | Field        | Value                            |
           +--------------+----------------------------------+
           | enabled      | True                             |
           | id           | 3d71177b9e0f406f98cbff198d74b182 |
           | interface    | admin                            |
           | region       | RegionOne                        |
           | region_id    | RegionOne                        |
           | service_id   | 2d1a27022e6e4185b86adac4444c495f |
           | service_name | placement                        |
           | service_type | placement                        |
           | url          | http://controller:8778           |
           +--------------+----------------------------------+

   安装配置组件

2. Install the packages:

   # yum install openstack-placement-api

3. Edit the /etc/placement/placement.conf file and complete the following actions:

   ○ In the [placement_database] section, configure database access:
       [placement_database]
       # ...
       connection = mysql+pymysql://placement:placement123@dbs.flex.net/placement
   ○ In the [api] and [keystone_authtoken] sections, configure Identity service access:
       [api]
       # ...
       auth_strategy = keystone
   
       [keystone_authtoken]
       # ...
       auth_url = http://stack.flex.net:5000/v3
       memcached_servers = dbs.flex.net:11211
       auth_type = password
       project_domain_name = default
       user_domain_name = default
       project_name = service
       username = placement
       password = placement123
   
       注意: 注释或移除在掉在[keystone_authtoken]区域中的其它的选项

4. Populate the placement database:

   # su -s /bin/sh -c "placement-manage db sync" placement

   完成完装

   ○ Restart the httpd service:
       # systemctl restart httpd

   校验安装

   你需要admin的权限验证

5. 加载admin的访问凭据，执行管理员命令:

   $ . admin-openrc

6. 执行状态检查命令:

   $ placement-status upgrade check
   +----------------------------------+
   | Upgrade Check Results            |
   +----------------------------------+
   | Check: Missing Root Provider IDs |
   | Result: Success                  |
   | Details: None                    |
   +----------------------------------+
   | Check: Incomplete Consumers      |
   | Result: Success                  |
   | Details: None                    |
   +----------------------------------+

7. 运行对placement API的命令（这个步骤我没有成功，但不影响）:

   ○ Install the osc-placement plugin:
       $ pip install osc-placement
   ○ List available resource classes and traits:
       $ openstack --os-placement-api-version 1.2 resource class list --sort-column name
       +----------------------------+
       | name                       |
       +----------------------------+
       | DISK_GB                    |
       | IPV4_ADDRESS               |
       | ...                        |
   
       $ openstack --os-placement-api-version 1.6 trait list --sort-column name
       +---------------------------------------+
       | name                                  |
       +---------------------------------------+
       | COMPUTE_DEVICE_TAGGING                |
       | COMPUTE_NET_ATTACH_INTERFACE          |
       | ...                                   |