6.7. 使用镜像流

流程

• 获取有关镜像流的常规信息及其指向的所有标签的详细信息：

  $ oc describe is/<image-name>

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  例如：

  $ oc describe is/python

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  输出示例

  Name:			python
  Namespace:		default
  Created:		About a minute ago
  Labels:			<none>
  Annotations:		openshift.io/image.dockerRepositoryCheck=2017-10-02T17:05:11Z
  Docker Pull Spec:	docker-registry.default.svc:5000/default/python
  Image Lookup:		local=false
  Unique Images:		1
  Tags:			1
  
  3.5
    tagged from centos/python-35-centos7
  
    * centos/python-35-centos7@sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
        About a minute ago

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• 获取有关特定镜像流标签的所有可用信息：

  $ oc describe istag/<image-stream>:<tag-name>

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  例如：

  $ oc describe istag/python:latest

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  输出示例

  Image Name:	sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
  Docker Image:	centos/python-35-centos7@sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
  Name:		sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
  Created:	2 minutes ago
  Image Size:	251.2 MB (first layer 2.898 MB, last binary layer 72.26 MB)
  Image Created:	2 weeks ago
  Author:		<none>
  Arch:		amd64
  Entrypoint:	container-entrypoint
  Command:	/bin/sh -c $STI_SCRIPTS_PATH/usage
  Working Dir:	/opt/app-root/src
  User:		1001
  Exposes Ports:	8080/tcp
  Docker Labels:	build-date=20170801

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流程

• 使用 `oc tag` 命令添加指向其中一个现有标签的标签：

  $ oc tag <image-name:tag1> <image-name:tag2>

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  例如：

  $ oc tag python:3.5 python:latest

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  输出示例

  Tag python:latest set to python@sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25.

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• 确认镜像流有两个标签，3.5 指向外部容器镜像，latest 指向同一镜像，因为它基于第一个标签创建而成。

  $ oc describe is/python

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  输出示例

  Name:			python
  Namespace:		default
  Created:		5 minutes ago
  Labels:			<none>
  Annotations:		openshift.io/image.dockerRepositoryCheck=2017-10-02T17:05:11Z
  Docker Pull Spec:	docker-registry.default.svc:5000/default/python
  Image Lookup:		local=false
  Unique Images:		1
  Tags:			2
  
  latest
    tagged from python@sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
  
    * centos/python-35-centos7@sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
        About a minute ago
  
  3.5
    tagged from centos/python-35-centos7
  
    * centos/python-35-centos7@sha256:49c18358df82f4577386404991c51a9559f243e0b1bdc366df25
        5 minutes ago

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流程

• 通过使用 oc tag 命令执行所有标签相关操作，添加指向内部或外部镜像的标签：

  $ oc tag <repository/image> <image-name:tag>

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  例如，该命令可将 docker.io/python:3.6.0 镜像映射到 python 镜像流中的 3.6 标签。

  $ oc tag docker.io/python:3.6.0 python:3.6

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  输出示例

  Tag python:3.6 set to docker.io/python:3.6.0.

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  如果外部镜像安全，则您必须创建带有凭证的 secret 以访问该 registry。

流程

• 更新标签：

  $ oc tag <image-name:tag> <image-name:latest>

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  例如，以下命令更新了 latest 标签，以反映镜像流中的 3.6 标签：

  $ oc tag python:3.6 python:latest

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  输出示例

  Tag python:latest set to python@sha256:438208801c4806548460b27bd1fbcb7bb188273d13871ab43f.

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流程

• 从镜像流中删除旧标签：

  $ oc tag -d <image-name:tag>

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  例如：

  $ oc tag -d python:3.5

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  输出示例

  Deleted tag default/python:3.5.

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