Docker 使用带有 buildx 的本地镜像

Question

I am building an image for a docker container running on a different architecture. As I don't have internet access all the time, I usually just pull the image when I have internet and docker uses the local image instead of pulling a new one. After I started to build the image with buildx, this does not seem to work anymore. Is there any way to tell docker to only use the local image? When I have connection, docker seems to check wherever there is a new version available but uses the local (or cached) image as I would expect it without internet connection.

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

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

Example build command

$ 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

Below is a simple test. Images in buildx are not visible in docker. Images are managed separately (as a cache layer).

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)