docker 本地保存镜像方法--docker export 和docker save 使用介绍

在很多环境中，由于网络问题，无法docker pull 镜像，就需要tar包方式获取镜像，以下就制作tar包的方式和区别加以介绍：

一、docker commit && docker save && docker load 保存容器内容为镜像

docker run -itd redis:6.0.16 /bin/bash
721156a2acb38fc8391c36c409c9cb6ab8942fcda78a828af2e32b9c5b842612

docker commit 721156a2acb38fc8391c3 redis_use
sha256:6044d3a75a1706d67b5e49650ca749aa1dfc3ed95bc8f44043d9d0d0c2bdc971


docker save -o redis_use.tar redis_use

docker save -o redis_test.tar redis_use

ll
total 112676
-rw------- 1 root root 115378688 Nov  7 11:18 redis_test.tar

# 把tar 包发送到其他机器加载

docker load -i redis_test.tar 
3070f050ae24: Loading layer [==================================================>]  4.096kB/4.096kB
Loaded image: redis_use:latest


docker images | grep redis
redis_use       latest     6044d3a75a17        16 minutes ago      112MB
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如果要定义tag，如下操作

docker run -itd redis:6.0.16 /bin/bash
acd739e8fead16c20e553dc916440054c03c3e44ad40b020db1391aaa94e7a99

docker commit acd739e8fead16c20e553 redis_use:v1
sha256:46e1e86e2562b227c3ced13c7c5e97af0d0321d6b4a10a224a416f753515d1cf

docker save -o redis_use_v1.tar redis_use:v1
 
# 把tar 包发送到其他机器加载
 
docker load -i redis_use_v1.tar 
1d2d823b0f8c: Loading layer [==================================================>]  4.096kB/4.096kB
Loaded image: redis_use:v1

docker images | grep redis
redis_use       v1         46e1e86e2562        10 minutes ago      112MB
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二、docker export && docker import 保存容器内容为镜像

docker run -itd redis:6.0.16 /bin/bash
7cbed6522d8a0e7f4d0b85b069cd199c70401d3d4a650347e7d6b51280503a02

docker export -o redis_use_v2.tar 7cbed6522d8a0e7f4d0b85


docker import redis_use_v2.tar redis:v2
sha256:a78a9f22b085edae03eb1248a6e84d82ff6ed0ed353446e3af4cd2fe182b5b79

docker images | grep redis
redis           v2         a78a9f22b085        5 seconds ago       108MB
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三、异常情况

3.1、docker import docker save的包

docker import redis_use_v1.tar redis:v1
sha256:f079d70bb557518c9f7215f80720c4a9b13a48fe728c86dfb6800c015f7b9389

docker images | grep redis
redis           v1         f079d70bb557        4 seconds ago        115MB

#可以加载，但是没有办法使用
docker run -itd redis:v1 /bin/bash
d48784a1618cc7c03c6571bec6c1ecb1cd9905adcfec18ff105a8da63a9512aa
docker: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"/bin/bash\": stat /bin/bash: no such file or directory": unknown.


docker inspect redis:v1
[
    {
        "Id": "sha256:f079d70bb557518c9f7215f80720c4a9b13a48fe728c86dfb6800c015f7b9389",
        "RepoTags": [
            "redis:v1"
        ],
        "RepoDigests": [],
        "Parent": "",
        "Comment": "Imported from -",
        "Created": "2022-11-07T07:06:39.683003465Z",
        "Container": "",
        "ContainerConfig": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": null,
            "Cmd": null,
            "Image": "",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": null
        },
        "DockerVersion": "18.09.9",
        "Author": "",
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": null,
            "Cmd": null,
            "Image": "",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": null
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 115356256,
        "VirtualSize": 115356256,
        "GraphDriver": {
            "Data": {
                "MergedDir": "/iso2/root/var/lib/docker/overlay2/ac95e2b15114808fa46c93855f1edbd8d7dc1972421482f2f7e392993ce25604/merged",
                "UpperDir": "/iso2/root/var/lib/docker/overlay2/ac95e2b15114808fa46c93855f1edbd8d7dc1972421482f2f7e392993ce25604/diff",
                "WorkDir": "/iso2/root/var/lib/docker/overlay2/ac95e2b15114808fa46c93855f1edbd8d7dc1972421482f2f7e392993ce25604/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:9df4129a40789ea469a97ec538470791e9c9a531c514f02f9188ec3ac145ef93"
            ]
        },
        "Metadata": {
            "LastTagTime": "2022-11-07T15:06:39.695859731+08:00"
        }
    }
]

# 可以看到没有镜像元信息，无法使用
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3.2、docker load docker export 的包

docker load -i redis_use_v2.tar 
open /iso2/root/var/lib/docker/tmp/docker-import-109823248/bin/json: no such file or directory

# 报错
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四、docker save 和docker export 区别总结

docker save 保存镜像为镜像文件，使用docker load 加载，docker export 保存容器为镜像文件，使用docker import 加载
docker commit 与docker save结合，也可实现导出容器为镜像文件
docker export 导出的镜像是不带历史记录的，导入后镜像变为一层，docker commit 会保留原有镜像层，经过commit后增加一层
docker export 比 docker save的包要小，原因是save的是一个分层的文件系统，export导出的只是一层文件系统
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五、docker load 和docker import 区别总结

docker load 加载docker save 保存的镜像，docker import 加载docker export保存的镜像
docker load不能对载入的镜像重命名，而docker import可以为镜像指定新名称
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六、参考文档

1、https://blog.csdn.net/Wqr_18390921824/article/details/123083151

2、https://blog.csdn.net/JineD/article/details/118761569

3、https://m.php.cn/article/452245.html