高速cachingdocker图像circleci
我正在使用circleci来运行testing并部署Docker镜像，但是我无法cachingDocker镜像，导致构build时间非常长。
这是一个不起作用的最小例子：
circle.yml
machine: services: - docker dependencies: cache_directories: - "~/docker" override: - if [[ -e ~/docker/image.tar ]]; then echo "cached files exists!" ; docker load -i ~/docker/image.tar; fi - docker images - docker build -t myorg/myapp:v1.1.1 . - mkdir -p ~/docker; docker save myorg/myapp:v1.1.1 > ~/docker/image.tar Dockerfile：
FROM debian:latest MAINTAINER My Name <myname@gmail.com> RUN apt-get update && apt-get install -y vim CMD ["sleep", "3"]
当推到github时，这个版本在circleci中运行良好。 但是docker映像每次运行时都会重build。 这在生产docker图像中非常耗时。
文件image.tar显然是加载的，这从docker docker images命令的输出中是清楚的，但是它仍然每次都构build整个映像，即使dockerfile没有改变。
以下是docker build -t myorg/myapp:v1.1.1 .的一些输出docker build -t myorg/myapp:v1.1.1 .
docker build -t myorg/myapp:v1.1.1 . Sending build context to Docker daemon 67.07 kB Step 1 : FROM debian:latest latest: Pulling from library/debian Digest: sha256:370807fef6f790d8519399026d26461bdf8360f94ab450da94c2350bea3cc66d Status: Downloaded newer image for debian:latest ---> ae85c48b369c Step 2 : MAINTAINER My Name <myname@gmail.com> ---> Running in 4ffd69c2a82d ---> 6029750ba0f3 Error removing intermediate container 4ffd69c2a82d: rmdriverfs: Driver btrfs failed to remove root filesystem 4ffd69c2a82d644ea7ee8576cc06e67ee412f651edecbc40932394c057aa931d: Failed to destroy btrfs snapshot /var/lib/docker/btrfs/subvolumes for 4ffd69c2a82d644ea7ee8576cc06e67ee412f651edecbc40932394c057aa931d: operation not permitted Step 3 : RUN apt-get update && apt-get install -y vim ---> Running in 544047b8c170 Ign http://httpredir.debian.org jessie InRelease Get:1 http://httpredir.debian.org jessie-updates InRelease [142 kB] Get:2 http://httpredir.debian.org jessie Release.gpg [2373 B] Get:3 http://httpredir.debian.org jessie Release [148 kB] Get:4 http://security.debian.org jessie/updates InRelease [63.1 kB] Get:5 http://httpredir.debian.org jessie-updates/main amd64 Packages [17.6 kB] Get:6 http://httpredir.debian.org jessie/main amd64 Packages [9064 kB] Get:7 http://security.debian.org jessie/updates/main amd64 Packages [390 kB] Fetched 9828 kB in 2s (4030 kB/s) Reading package lists... Reading package lists... Building dependency tree... The following extra packages will be installed: libgpm2 vim-common vim-runtime Suggested packages: gpm ctags vim-doc vim-scripts The following NEW packages will be installed: libgpm2 vim vim-common vim-runtime 0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded. Need to get 6218 kB of archives. After this operation, 28.9 MB of additional disk space will be used. Get:1 http://httpredir.debian.org/debian/ jessie/main libgpm2 amd64 1.20.4-6.1+b2 [34.0 kB] Get:2 http://httpredir.debian.org/debian/ jessie/main vim-common amd64 2:7.4.488-7 [184 kB] Get:3 http://httpredir.debian.org/debian/ jessie/main vim-runtime all 2:7.4.488-7 [5047 kB] Get:4 http://httpredir.debian.org/debian/ jessie/main vim amd64 2:7.4.488-7 [953 kB] debconf: delaying package configuration, since apt-utils is not installed Fetched 6218 kB in 0s (10.7 MB/s) Selecting previously unselected package libgpm2:amd64.
任何想法，为什么它每次重builddocker的形象？