openstack-nova源码分析(五）flavor extra_specs 扩展属性

喜欢ヅ旅行 2022-02-24 03:54 459阅读 0赞

Flavors extra-specs (flavors, os-flavor-extra-specs)  
Flavor 扩展属性设置， 扩展属性可以用来对虚拟机做一些额外的限制设置，具体的参数，将在后面的博客中做统一列出，这里暂时不做列出

openstack api 定义如下：  
Lists, creates, deletes, and updates the extra-specs or keys for a flavor.  
Refer to Compute Flavors for available built-in extra specs.

##### 一. url及命令行 #####

1.  url  
    API为标准的restful API 风格 支持GET , POST, PUT, DELETE 方法:  
    /flavors/\{flavor\_id\}/os-extra\_specs  
    /flavors/\{flavor\_id\}/os-extra\_specs/\{flavor\_extra\_spec\_key\}
2.  命令行  
    nova flavor-key

#### 二. 源码分析 ####

对应的方法在： flavors\_extraspecs = nova.api.openstack.compute.flavors\_extraspecs:FlavorsExtraSpecs

FlavorsExtraSpecs定义如下：

class FlavorsExtraSpecs(extensions.V21APIExtensionBase):
        """Flavors extra specs support."""
        name = 'FlavorExtraSpecs'
        alias = ALIAS
        version = 1
    
        def get_resources(self):
            extra_specs = extensions.ResourceExtension(
                    'os-extra_specs',
                    FlavorExtraSpecsController(),
                    parent=dict(member_name='flavor', collection_name='flavors'))
    
            return [extra_specs]

get\_resources 将os-extra\_specs 注册到collection flavors 下， 处理方法映射到FlavorExtraSpecsController

查看FlavorExtraSpecsController 为标准的restful api处理方法

def index(self, req, flavor_id):
            """Returns the list of extra specs for a given flavor."""
            context = req.environ['nova.context']
            context.can(fes_policies.POLICY_ROOT % 'index')
            return self._get_extra_specs(context, flavor_id)

index实际处理\_get\_extra\_specs函数

def _get_extra_specs(self, context, flavor_id):
            flavor = common.get_flavor(context, flavor_id)
            return dict(extra_specs=flavor.extra_specs)

flavor.extra\_specs获取扩展属性，并转换为dict  
get\_flavor 实际调用的是Flavor show一样的方法，这里不做重复分析

**1. 创建接口：**

@extensions.expected_errors((400, 404, 409))
        @validation.schema(flavors_extraspecs.create)
        def create(self, req, flavor_id, body):
            context = req.environ['nova.context']
            context.can(fes_policies.POLICY_ROOT % 'create')
    
            specs = body['extra_specs']
            self._check_extra_specs_value(specs)
            flavor = common.get_flavor(context, flavor_id)
            try:
                flavor.extra_specs = dict(flavor.extra_specs, **specs)
                flavor.save()
            except exception.FlavorExtraSpecUpdateCreateFailed as e:
                raise webob.exc.HTTPConflict(explanation=e.format_message())
            except exception.FlavorNotFound as e:
                raise webob.exc.HTTPNotFound(explanation=e.format_message())
            return body

注： 创建接口只对参数的长度及字符合法性做了校验，没有做是否允许key与合法value的校验

create方法，仍然先查询flavorid 并返回Flavor  
通过Flavor 调用save函数  
**save实际是检查对象的改变项并将其更新，或创建, 或删除**

**2. update 更新操作：**

@extensions.expected_errors((400, 404, 409))
        @validation.schema(flavors_extraspecs.update)
        def update(self, req, flavor_id, id, body):
            context = req.environ['nova.context']
            context.can(fes_policies.POLICY_ROOT % 'update')
    
            self._check_extra_specs_value(body)
            if id not in body:
                expl = _('Request body and URI mismatch')
                raise webob.exc.HTTPBadRequest(explanation=expl)
            flavor = common.get_flavor(context, flavor_id)
            try:
                flavor.extra_specs = dict(flavor.extra_specs, **body)
                flavor.save()
            except exception.FlavorExtraSpecUpdateCreateFailed as e:
                raise webob.exc.HTTPConflict(explanation=e.format_message())
            except exception.FlavorNotFound as e:
                raise webob.exc.HTTPNotFound(explanation=e.format_message())
            return body

这里与create大同小异， 需要注意的是： 这里是全量更新，不修改的key也需要将原来的值传入，否则将会被删除

**3 delete 删除操作：**

@extensions.expected_errors(404)
        def delete(self, req, flavor_id, id):
            """Deletes an existing extra spec."""
            context = req.environ['nova.context']
            context.can(fes_policies.POLICY_ROOT % 'delete')
            flavor = common.get_flavor(context, flavor_id)
            try:
                del flavor.extra_specs[id]
                flavor.save()
            except (exception.FlavorExtraSpecsNotFound,
                    exception.FlavorNotFound) as e:
                raise webob.exc.HTTPNotFound(explanation=e.format_message())
            except KeyError:
                msg = _("Flavor %(flavor_id)s has no extra specs with "
                        "key %(key)s.") % dict(flavor_id=flavor_id,
                                               key=id)
                raise webob.exc.HTTPNotFound(explanation=msg)

这里直接通过del flavor.extra\_specs\[id\] 将Flavor对象的extra\_specs中的id key删除  
save函数，对比属性的更新，自动清除不存在的key，并在数据库删除对应的数据

**注： novaclient中对应 Flavor操作额外属性时，不能调用delete函数，因为delete将直接删除Flavor，应该调用unset\_keys 将key一个一个清除**， 这里踩了个小坑

def delete(self):
            """
            Delete this flavor.
    
            :returns: An instance of novaclient.base.TupleWithMeta
            """
            return self.manager.delete(self)

**三. 测试：**  
可以通过命令功能： flavor-key 进行测试

[root@nova ~]# nova help flavor-key
    usage: nova flavor-key <flavor> <action> <key=value> [<key=value> ...]
    
    Set or unset extra_spec for a flavor.
    
    Positional arguments:
      <flavor>     Name or ID of flavor.
      <action>     Actions: 'set' or 'unset'.
      <key=value>  Extra_specs to set/unset (only key is necessary on unset).

首先创建一个flavor： nova flavor-create ‘1-2-50’ ‘auto’ 2 50 1

[root@nova ~]# nova flavor-create '1-2-50' 'auto' 2 50 1 
    +--------------------------------------+--------+-----------+------+-----------+------+-------+-------------+-----------+
    | ID                                   | Name   | Memory_MB | Disk | Ephemeral | Swap | VCPUs | RXTX_Factor | Is_Public |
    +--------------------------------------+--------+-----------+------+-----------+------+-------+-------------+-----------+
    | 92c4d107-6926-4adb-9e79-cd101e4fa588 | 1-2-50 | 2         | 50   | 0         |      | 1     | 1.0         | True      |
    +--------------------------------------+--------+-----------+------+-----------+------+-------+-------------+-----------+

设置testkey

[root@nova ~]# nova flavor-key 92c4d107-6926-4adb-9e79-cd101e4fa588 set testkey='123456'

查看是否设置成功

[root@nova ~]# nova flavor-show 92c4d107-6926-4adb-9e79-cd101e4fa588
    +----------------------------+--------------------------------------+
    | Property                   | Value                                |
    +----------------------------+--------------------------------------+
    | OS-FLV-DISABLED:disabled   | False                                |
    | OS-FLV-EXT-DATA:ephemeral  | 0                                    |
    | disk                       | 50                                   |
    | extra_specs                | {"testkey": "123456"}                |
    | id                         | 92c4d107-6926-4adb-9e79-cd101e4fa588 |
    | name                       | 1-2-50                               |
    | os-flavor-access:is_public | True                                 |
    | ram                        | 2                                    |
    | rxtx_factor                | 1.0                                  |
    | swap                       |                                      |
    | vcpus                      | 1                                    |
    +----------------------------+--------------------------------------+

更新key  
更新操作，直接调用与create一样的命令，修改value值即可

[root@nova ~]# nova flavor-key 92c4d107-6926-4adb-9e79-cd101e4fa588 set testkey='12345678'

查看是否更新成功

[root@nova ~]# nova flavor-show 92c4d107-6926-4adb-9e79-cd101e4fa588                      
    +----------------------------+--------------------------------------+
    | Property                   | Value                                |
    +----------------------------+--------------------------------------+
    | OS-FLV-DISABLED:disabled   | False                                |
    | OS-FLV-EXT-DATA:ephemeral  | 0                                    |
    | disk                       | 50                                   |
    | extra_specs                | {"testkey": "12345678"}              |
    | id                         | 92c4d107-6926-4adb-9e79-cd101e4fa588 |
    | name                       | 1-2-50                               |
    | os-flavor-access:is_public | True                                 |
    | ram                        | 2                                    |
    | rxtx_factor                | 1.0                                  |
    | swap                       |                                      |
    | vcpus                      | 1                                    |
    +----------------------------+--------------------------------------+

删除testkey

[root@nova ~]# nova flavor-key 92c4d107-6926-4adb-9e79-cd101e4fa588 unset testkey

查看是否删除成功

[root@nova ~]# nova flavor-show 92c4d107-6926-4adb-9e79-cd101e4fa588             
    +----------------------------+--------------------------------------+
    | Property                   | Value                                |
    +----------------------------+--------------------------------------+
    | OS-FLV-DISABLED:disabled   | False                                |
    | OS-FLV-EXT-DATA:ephemeral  | 0                                    |
    | disk                       | 50                                   |
    | extra_specs                | {}                                   |
    | id                         | 92c4d107-6926-4adb-9e79-cd101e4fa588 |
    | name                       | 1-2-50                               |
    | os-flavor-access:is_public | True                                 |
    | ram                        | 2                                    |
    | rxtx_factor                | 1.0                                  |
    | swap                       |                                      |
    | vcpus                      | 1                                    |
    +----------------------------+--------------------------------------+