该
--no-cache选项将重建图像，而无需使用本地缓存的图层。但是，该
FROM行将重用已经拉出的基础映像（如果它已存在于构建主机上）（from行本身可能不会被缓存，但是它拉出的映像是已缓存的）。如果要再次拉出基础映像，可以使用
--pullbuild命令的选项。例如
$ docker build --no-cache --pull -t new-image-name:latest .
要查看build命令采用的所有选项，可以运行
$ docker build --help
或参阅https://docs.docker.com/engine/reference/commandline/build/上的文档
这是一个示例，您可以自己测试此行为：
$ # very simple Dockerfile$ cat df.testFROM busybox:latestRUN echo hello >test.txt$ # pull an older version of busybox$ docker pull busybox:1.29.21.29.2: Pulling from library/busybox8c5a7da1afbc: Pull completeDigest: sha256:cb63aa0641a885f54de20f61d152187419e8f6b159ed11a251a09d115fdff9bdStatus: Downloaded newer image for busybox:1.29.2$ # retag that locally as latest$ docker tag busybox:1.29.2 busybox:latest$ # run the build, note the image id at the end of each build step$ DOCKER_BUILDKIT=0 docker build --no-cache -f df.test .Sending build context to Docker daemon 23.04kBStep 1/2 : FROM busybox:latest ---> e1ddd7948a1cStep 2/2 : RUN echo hello >test.txt ---> Running in dba83fef49f9Removing intermediate container dba83fef49f9 ---> 1f824ff05612Successfully built 1f824ff05612$ # rerun the build, note step 1 keeps the same id and never pulled a new latest$ DOCKER_BUILDKIT=0 docker build --no-cache -f df.test .Sending build context to Docker daemon 23.04kBStep 1/2 : FROM busybox:latest ---> e1ddd7948a1cStep 2/2 : RUN echo hello >test.txt ---> Running in 73df884b0f48Removing intermediate container 73df884b0f48 ---> e5870de6c24fSuccessfully built e5870de6c24f$ # run with --pull and see docker update the latest image, new container id from step 1$ DOCKER_BUILDKIT=0 docker build --no-cache --pull -f df.test .Sending build context to Docker daemon 23.04kBStep 1/2 : FROM busybox:latestlatest: Pulling from library/busyboxDigest: sha256:2a03a6059f21e150ae84b0973863609494aad70f0a80eaeb64bddd8d92465812Status: Downloaded newer image for busybox:latest ---> 59788edf1f3eStep 2/2 : RUN echo hello >test.txt ---> Running in 7204116ecbf4Removing intermediate container 7204116ecbf4 ---> 2c6d8c48661bSuccessfully built 2c6d8c48661b$ # one last run now that busybox:latest is updated shows the pull has nothing to do$ DOCKER_BUILDKIT=0 docker build --no-cache --pull -f df.test .Sending build context to Docker daemon 23.04kBStep 1/2 : FROM busybox:latestlatest: Pulling from library/busyboxDigest: sha256:2a03a6059f21e150ae84b0973863609494aad70f0a80eaeb64bddd8d92465812Status: Image is up to date for busybox:latest ---> 59788edf1f3eStep 2/2 : RUN echo hello >test.txt ---> Running in f37e19024e99Removing intermediate container f37e19024e99 ---> 044a5d4011c4Successfully built 044a5d4011c4
