Docker 使用带有 buildx 的本地镜像

Question

我正在为在不同架构上运行的 docker 容器构建镜像。由于我无法一直访问互联网，因此我通常只在有互联网的情况下拉取镜像，而 docker 使用本地镜像而不是拉取新镜像。在我开始使用 buildx 构建镜像后，这似乎不再起作用了。有什么办法可以告诉 docker 只使用本地镜像吗？当我有连接时，docker 似乎会检查任何有新版本可用的地方，但使用本地(或缓存)图像，正如我在没有互联网连接的情况下所期望的那样。

$ docker image ls
ros                     galactic          bac817d14f26   5 weeks ago    626MB

$ docker image inspect ros:galactic
...
"Architecture": "arm64",
 "Variant": "v8",
 "Os": "linux",
...

示例构建命令

$ docker buildx build . --platform linux/arm64
WARN[0000] No output specified for docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load 
[+] Building 0.3s (3/3) FINISHED                                                                                                  
 => [internal] load build definition from Dockerfile                                                                         0.0s
 => => transferring dockerfile: 72B                                                                                          0.0s
 => [internal] load .dockerignore                                                                                            0.0s
 => => transferring context: 2B                                                                                              0.0s
 => ERROR [internal] load metadata for docker.io/library/ros:galactic                                                        0.0s
------
 > [internal] load metadata for docker.io/library/ros:galactic:
------
Dockerfile:1
--------------------
   1 | >>> FROM ros:galactic
   2 |     RUN "echo hello"
   3 |     
--------------------
error: failed to solve: failed to fetch anonymous token: Get "https://auth.docker.io/token?scope=repository%3Alibrary%2Fros%3Apull&service=registry.docker.io": proxyconnect tcp: dial tcp 127.0.0.1:3333: connect: connection refused

Answer 1

下面是一个简单的测试。
buildx 中的图像在 docker 中不可见。图像单独管理(作为缓存层)。
Dockerfile:

FROM alpine:3.14
RUN echo "HELLO WORLD"

$ docker image ls | grep alpine | grep "3\.14"
(EMPTY)

$ docker buildx build .
[+] Building 4.4s (6/6) FINISHED                                                                                                                      
 => [internal] load build definition from Dockerfile                                                                                             0.0s
 => => transferring dockerfile: 79B                                                                                                              0.0s
 => [internal] load .dockerignore                                                                                                                0.0s
 => => transferring context: 2B                                                                                                                  0.0s
 => [internal] load metadata for docker.io/library/alpine:3.14                                                                                   3.5s
 => [1/2] FROM docker.io/library/alpine:3.14@sha256:e1c082e3d3c45cccac829840a25941e679c25d438cc8412c2fa221cf1a824e6a                             0.0s
 => => resolve docker.io/library/alpine:3.14@sha256:e1c082e3d3c45cccac829840a25941e679c25d438cc8412c2fa221cf1a824e6a                             0.0s
 => => sha256:e1c082e3d3c45cccac829840a25941e679c25d438cc8412c2fa221cf1a824e6a 1.64kB / 1.64kB                                                   0.0s
 => => sha256:69704ef328d05a9f806b6b8502915e6a0a4faa4d72018dc42343f511490daf8a 528B / 528B                                                       0.0s
 => => sha256:14119a10abf4669e8cdbdff324a9f9605d99697215a0d21c360fe8dfa8471bab 1.47kB / 1.47kB                                                   0.0s
 => [2/2] RUN echo "HELLO WORLD"                                                                                                                 0.4s
 => exporting to image                                                                                                                           0.0s
 => => exporting layers                                                                                                                          0.0s
 => => writing image sha256:9c2f6f3712c2dc2c2e4684821eddea260a444b76c2017f197e30d0f4c4542bd9                                                     0.0s



$ docker buildx build .
[+] Building 1.4s (6/6) FINISHED                                                                                                                      
 => [internal] load build definition from Dockerfile                                                                                             0.0s
 => => transferring dockerfile: 31B                                                                                                              0.0s
 => [internal] load .dockerignore                                                                                                                0.0s
 => => transferring context: 2B                                                                                                                  0.0s
 => [internal] load metadata for docker.io/library/alpine:3.14                                                                                   1.1s
 => [1/2] FROM docker.io/library/alpine:3.14@sha256:e1c082e3d3c45cccac829840a25941e679c25d438cc8412c2fa221cf1a824e6a                             0.0s
 => CACHED [2/2] RUN echo "HELLO WORLD"                                                                                                          0.0s
 => exporting to image                                                                                                                           0.0s
 => => exporting layers                                                                                                                          0.0s
 => => writing image sha256:9c2f6f3712c2dc2c2e4684821eddea260a444b76c2017f197e30d0f4c4542bd9                                                     0.0s

$ docker image ls | grep alpine | grep "3\.14"
(EMPTY)