Docker&Kubernetes ❀ Docker save load export import 容器镜像的导入与导出方法

Posted 2022-08-02 无糖可乐没有灵魂

文章目录

• 1、构建镜像
• 2、docker save&load
• • 2.1 save
  • 2.2 load
• 3、docker export&import
• • 3.1 export
  • 3.2 import
• 4、梳理与总结

1、构建镜像

---

为了完成save与load，需要首先构建一个新的镜像，区别其他镜像；

#爬取centos最新版本镜像文件，若已经本地存在，则忽略此步骤
[root@localhost ~]# docker pull centos
[root@localhost ~]# docker images
REPOSITORY    TAG       IMAGE ID       CREATED         SIZE
centos        latest    5d0da3dc9764   2 months ago    231MB

#使用DockerFile构建新镜像文件，区分与新爬取的镜像
[root@localhost ~]# cat /tmp/docker_test 
FROM centos
RUN yum install -y vim
RUN yum install -y net-tools
CMD /bin/bash

#创建新镜像，镜像版本自定义
[root@localhost ~]# docker build -f /tmp/docker_test -t mycentos:1.1 .
Sending build context to Docker daemon  10.67MB
Step 1/4 : FROM centos
 ---> 5d0da3dc9764
Step 2/4 : RUN yum install -y vim
 ---> Running in fd8ea201e781
Complete!
Removing intermediate container fd8ea201e781
 ---> 705f34782fe8
Step 3/4 : RUN yum install -y net-tools
 ---> Running in 2b55f92b2400
Transaction Summary
Complete!
Removing intermediate container 2b55f92b2400
 ---> 3cf9004e05db
Step 4/4 : CMD /bin/bash
 ---> Running in 6f5051dd5df6
Removing intermediate container 6f5051dd5df6
 ---> a57146ea148c
Successfully built a57146ea148c
Successfully tagged mycentos:1.1

#查看自定义镜像是否与源镜像存在区别
[root@localhost ~]# docker images
REPOSITORY    TAG       IMAGE ID       CREATED         SIZE
mycentos      1.1       a57146ea148c   6 seconds ago   322MB
centos        latest    5d0da3dc9764   2 months ago    231MB

2、docker save&load

---

2.1 save

#查看save帮助信息
[root@localhost ~]# docker save --help

Usage:  docker save [OPTIONS] IMAGE [IMAGE...]

Save one or more images to a tar archive (streamed to STDOUT by default)

Options:
  -o, --output string   Write to a file, instead of STDOUT

#保存新镜像为压缩文件（镜像保存的方式为tar文件）
[root@localhost ~]# docker save mycentos:1.1 -o /tmp/docker_test.tar

#查看保存后的文件
[root@localhost ~]# ll -dh /tmp/docker_test.tar 
-rw-------. 1 root root 316M Nov 25 23:45 /tmp/docker_test.tar

#为了区分导入效果，删除已经存在的新镜像
[root@localhost ~]# docker rmi mycentos:1.1 
Untagged: mycentos:1.1
Deleted: sha256:a57146ea148c22072e0d38f0a54f1f6980a41a635569e0bd0cbe0ca20a16056a
Deleted: sha256:3cf9004e05db213e83d5d2a07437aefdc027ea5a6231975442c53965697e81e8
Deleted: sha256:567a09c801ae815e0f77d51d5a53b199d63dff41a7018507403cb20a7c1719c2
Deleted: sha256:705f34782fe83875c7b93ff02b355a3d1a0f1254e1999c4473e1060be1c45a8e
Deleted: sha256:ea725633ca1e7902c20ad8f8955108e2ce1159f3a74be4cc3918206a5f5fb3d4

2.2 load

#查看load帮助信息
[root@localhost ~]# docker load --help

Usage:  docker load [OPTIONS]

Load an image from a tar archive or STDIN

Options:
  -i, --input string   Read from tar archive file, instead of STDIN
  -q, --quiet          Suppress the load output

#使用load导入相关tar文件
[root@localhost ~]# docker load -i /tmp/docker_test.tar 
df73d6b025a6: Loading layer [==================================================>]  65.34MB/65.34MB
53aeac00a22a: Loading layer [==================================================>]  27.04MB/27.04MB
Loaded image: mycentos:1.1

#查看导入结果
[root@localhost ~]# docker images | grep centos
mycentos      1.1       a57146ea148c   8 minutes ago   322MB
centos        latest    5d0da3dc9764   2 months ago    231MB

3、docker export&import

---

3.1 export

#查看export帮助信息
[root@localhost ~]# docker export --help

Usage:  docker export [OPTIONS] CONTAINER

Export a container's filesystem as a tar archive

Options:
  -o, --output string   Write to a file, instead of STDOUT

#使用新镜像创建新容器
[root@localhost ~]# docker run -it --name docker_test_001 -d mycentos:1.1
4f0bddcc627d85e1d1e94ae4b7fb42afcc5cb937f8760ff10b53887122503366

#查看新创建的容器信息
[root@localhost ~]# docker ps 
CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS     NAMES
4f0bddcc627d   mycentos:1.1   "/bin/sh -c /bin/bash"   3 seconds ago   Up 2 seconds             docker_test_001

#使用export导出新创建的容器
[root@localhost ~]# docker export docker_test_001 -o /tmp/docker_test2.tar

#查看导出文件
[root@localhost ~]# ll -hd /tmp/docker_test2.tar 
-rw-------. 1 root root 280M Nov 25 23:55 /tmp/docker_test2.tar

3.2 import

#查看import帮助信息
[root@localhost ~]# docker import --help

Usage:  docker import [OPTIONS] file|URL|- [REPOSITORY[:TAG]]

Import the contents from a tarball to create a filesystem image

Options:
  -c, --change list       Apply Dockerfile instruction to the created image
  -m, --message string    Set commit message for imported image
      --platform string   Set platform if server is multi-platform capable

#使用import导入tar文件，并修改名称（将容器文件导入为镜像文件）
[root@localhost ~]# cat /tmp/docker_test2.tar | docker import - mycentos:1.1
sha256:9ec265f446a211c7f3518aa927ffbc436ee20f12d00352ed8bb02b23bb79902e
#此命令同上条命令，功能一致
[root@localhost ~]# docker import /tmp/docker_test2.tar mycentos:1.1

#查看导入结果
[root@localhost ~]# docker images
REPOSITORY      TAG       IMAGE ID       CREATED          SIZE
mycentos        1.1       c05c5045a5c1   3 seconds ago    231MB

4、梳理与总结

---

export和import 导出的内容是一个容器的快照，并不是镜像本身，没有layer，快照文件会导致容器丢失所有的历史记录与元数据信息，而使用save和load保存的镜像文件则可以保留此两种内容，但是其体积更大；

• docker load 加载镜像包、 docker import 加载容器包，两者都将其恢复为镜像；
• docker load不能对镜像重命名、docker import可以为镜像指定新名称；