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OpenStack4j简洁易用，项目中一直使用方便，构造OS如下：

OSClientV2 os = OSFactory    .builderV2()    .endpoint(cred.getCloudURI())    .credentials(cred.getUsername(), cred.getPassword())    .tenantName(cred.getProject())    .withConfig(        Config.newConfig()            .withConnectionTimeout(1000 * 60)            .withReadTimeout(1000 * 60 * 5))    .authenticate();

近期用于访问OpenStack却发生如下异常：

2018-09-28 11:30:02 DEBUG HttpExecutor:50 - Executing Request: https://my-openstack-cloud:5000/v2.0 -> /tokensException in thread "main" ClientResponseException{message=Not Found, status=404, status-code=NOT_FOUND}	at org.openstack4j.core.transport.HttpExceptionHandler.mapException(HttpExceptionHandler.java:38)	at org.openstack4j.core.transport.HttpExceptionHandler.mapException(HttpExceptionHandler.java:23)	at org.openstack4j.openstack.internal.OSAuthenticator.authenticateV2(OSAuthenticator.java:125)	at org.openstack4j.openstack.internal.OSAuthenticator.invoke(OSAuthenticator.java:52)	at org.openstack4j.openstack.client.OSClientBuilder$ClientV2.authenticate(OSClientBuilder.java:117)	at org.openstack4j.openstack.client.OSClientBuilder$ClientV2.authenticate(OSClientBuilder.java:79)

在调试过程中，执行如下命令，得到熟悉的响应（从OpenStack M版本开始）：

> curl https://my-openstack-cloud:5000/{	"versions": {		"values": [{			"status": "stable",			"updated": "2018-02-28T00:00:00Z",			"media-types": [{				"base": "application/json",				"type": "application/vnd.openstack.identity-v3+json"			}],			"id": "v3.10",			"links": [{				"href": "https://my-openstack-cloud:5000/v3/",				"rel": "self"			}]		}, {			"status": "deprecated",			"updated": "2016-08-04T00:00:00Z",			"media-types": [{				"base": "application/json",				"type": "application/vnd.openstack.identity-v2.0+json"			}],			"id": "v2.0",			"links": [{				"href": "https://my-openstack-cloud:5000/v2.0/",				"rel": "self"			}, {				"href": "https://docs.openstack.org/",				"type": "text/html",				"rel": "describedby"			}]		}]	}}

在确定OpenStack4j访问已有Cloud正常的情况下，怀疑是OpenStack的问题。

查看部署的OpenStack采用了OpenStack Q版本，恍然大悟。

通过OpenStack Q版本文档可知，对于OpenStack Queens及其之后版本：

• 只有Keystone /v3有效
• Keystone /v2.0的主要功能已经被移除
• 仅保留Keystone /v2.0的ec2tokens API到OpenStack T版本

截图如下：

使用Keystone v3运行通过，代码如下：

OSClientV3 os = OSFactory    .builderV3()    .endpoint(cred.getCloudURI())    .credentials(cred.getUsername(), cred.getPassword(), Identifier.byName(cred.getDomain()))    .scopeToProject(Identifier.byName(cred.getProject()), Identifier.byName(cred.getDomain()))    .withConfig(        Config.newConfig()            .withConnectionTimeout(1000 * 60)            .withReadTimeout(1000 * 60 * 5))    .authenticate();

参考链接：