No valid host was found. There are not enough hosts available-----openstack建虚拟机直接报错

No valid host was found. There are not enough hosts available-----openstack建虚拟机直接报错
一、问题现象：
二、解决思路：

一、问题现象：

本次环境中只有一个计算节点，创建虚拟机直接报错，使用nova show 看到报错如下图：

"message": "No valid host was found. There are not enough hosts available.", "code": 500

二、解决思路：

1、查看计算节点的nova-compute 日志,发现如下日志：

2019-11-21 19:47:09.484 8 ERROR nova.scheduler.client.report [req-cbc37e88-16be-4b5b-be98-d889cd1b01dc - - - - -] [req-a5a6d438-3f63-49aa-9dd2-98d061b122b4] Failed to create resource provider record in placement API for UUID d878a164-6499-43d4-9772-b77107a1bb8c. Got 409: {"errors": [
{"status": 409, "request_id": "req-a5a6d438-3f63-49aa-9dd2-98d061b122b4", "detail": "There was a conflict when trying to complete your request.\n\n Conflicting resource provider name: compute1 already exists. ", "title": "Conflict"}
2019-11-21 19:47:09.485 8 ERROR nova.compute.manager [req-cbc37e88-16be-4b5b-be98-d889cd1b01dc - - - - -] Error updating resources for node compute1.: ResourceProviderCreationFailed: Failed to create resource provider compute1

发现ResourceProviderCreationFailed: Failed to create resource provider compute1 ，发现resource Provider 创建失败。怀疑数据库resource provider 表没有建出来，继续查看nova-nova-scheduler.log。

2、查看nova-scheduler.log

2019-11-21 20:18:43.360 29 INFO nova.filters [req-448bd5fa-ddc8-45d9-9b8b-a63bdb691335 e0111848d3904a7288df61cac5163f4f 9be97009f556459cb1814232dbedb4a3 - default default] Filter RetryFilter returned 0 hosts
2019-11-21 20:18:43.362 29 INFO nova.filters [req-448bd5fa-ddc8-45d9-9b8b-a63bdb691335 e0111848d3904a7288df61cac5163f4f 9be97009f556459cb1814232dbedb4a3 - default default] Filtering removed all hosts for the request with instance ID 'c9542c1c-191e-49f2-815a-fdcacc081af6'. Filter results: ['RetryFilter: (start: 0, end: 0)']

3、进数据查看数据库表

mysql> use nova_api;
mysql[nova_api] >  select * from resource_providers;
+---------------------+---------------------+----+--------------------------------------+----------+------------+----------+------------------+--------------------+
| created_at          | updated_at          | id | uuid                                 | name     | generation | can_host | root_provider_id | parent_provider_id |
+---------------------+---------------------+----+--------------------------------------+----------+------------+----------+------------------+--------------------+
| 2019-11-21 06:17:39 | 2019-11-21 06:17:41 |  3 | 16d1bd53-7919-4fef-9a11-a0e98c149823 | compute1 |          1 |     NULL |                3 |               NULL |
+---------------------+---------------------+----+--------------------------------------+----------+------------+----------+------------------+--------------------+
1 row in set (0.00 sec)

发现有数据。重新创建虚拟机，依然会发生报错，

4、尝试将compute节点从nova service-list中删除，并重新加入到集群中

# 停掉compute节点的nova-compute 服务
nova service-delete <计算节点的uuid>
# 开启计算节点的nova-compute服务，让计算节点重新注册

尝试创建虚拟机，发现还是报错。返回去，查看nova-compute的日志发现 There was a conflict when trying to complete your request.\n\n Conflicting resource provider name: compute1 already exists. 。提示矛盾。

5、再次进入数据库，执行 `select * from resource_providers;`

mysql> use nova_api;
mysql[nova_api] >  select * from resource_providers;
+---------------------+---------------------+----+--------------------------------------+----------+------------+----------+------------------+--------------------+
| created_at          | updated_at          | id | uuid                                 | name     | generation | can_host | root_provider_id | parent_provider_id |
+---------------------+---------------------+----+--------------------------------------+----------+------------+----------+------------------+--------------------+
| 2019-11-21 06:17:39 | 2019-11-21 06:17:41 |  3 | 16d1bd53-7919-4fef-9a11-a0e98c149823 | compute1 |          1 |     NULL |                3 |               NULL |
+---------------------+---------------------+----+--------------------------------------+----------+------------+----------+------------------+--------------------+
1 row in set (0.00 sec)

发现新注册的计算节点，但是resource_providers的uuid 没有发生变化，怀疑是注册compute节点的时候，并没有更新resource_providers，尝试删除resource_providers;

6、查找官网，找到了操作 `resource_providers`的openstack命令,执行如下操作。

# 安装osc-placement 软件包，生成命令行工具
# 执行如下命令：
export OS_PLACEMENT_API_VERSION=1.10
openstack allocation candidate list --resource VCPU=1
# 查看当前resource provider
[root@control1 ~]# openstack resource provider  list
+--------------------------------------+----------+------------+
| uuid                                 | name     | generation |
+--------------------------------------+----------+------------+
| 16d1bd53-7919-4fef-9a11-a0e98c149823 | compute1 |          2 |
+--------------------------------------+----------+------------+
# 停止计算节点nova-compute服务
# 从service 中删除compute1
nova service-delete  <uuid>
# 删除当前resource provider
openstack resource provider  delete 16d1bd53-7919-4fef-9a11-a0e98c149823
# 重启nova-compute服务，让其自动注册
# 查看当前resource provider
[root@control1 ~]# openstack resource provider  list
+--------------------------------------+----------+------------+
| uuid                                 | name     | generation |
+--------------------------------------+----------+------------+
| b32cd7b5-26c6-4998-97f1-79fa2315871b | compute1 |          2 |
+--------------------------------------+----------+------------+
# # 执行如下命令，验证是否更新了数据
export OS_PLACEMENT_API_VERSION=1.10
openstack allocation candidate list --resource VCPU=1

执行创建云主机，云主机成功创建。