How can I use a local image as the base image with

问题:

I'm working on a dockerfile. I just realised that I've been using FROM with indexed images all along.

So I wonder:

• How can I use one of my local (custom) images as my base (FROM) image without pushing it to the index?

回答1:

You can use it without doing anything special. If you have a local image called blah you can do FROM blah. If you do FROM blah in your Dockerfile, but don't have a local image called blah, then Docker will try to pull it from the registry.

In other words, if a Dockerfile does FROM ubuntu, but you have a local image called ubuntu different from the official one, your image will override it.

回答2:

Verified: it works well in Docker 1.7.0.

BTW, don't specify --pull=true when running the docker build command:

if you want use the local image as the base image, please without the option --pull=true, --pull=true will always attempt to pull a newer version of the image.

-https://github.com/docker/docker/issues/14943

回答3:

You can have - characters in your images. Assume you have a local image (not a local registry) named centos-base-image with tag 7.3.1611.

docker version 
      Client:
       Version:         1.12.6
       API version:     1.24
       Package version: docker-common-1.12.6-16.el7.centos.x86_64
       Go version:      go1.7.4

      Server:
       Version:         1.12.6
       API version:     1.24
       Package version: docker-common-1.12.6-16.el7.centos.x86_64
       Go version:      go1.7.4

docker images
 REPOSITORY            TAG
 centos-base-image     7.3.1611

Dockerfile

FROM centos-base-image:7.3.1611
RUN yum -y install epel-release libaio bc flex

Result

Sending build context to Docker daemon 315.9 MB
Step 1 : FROM centos-base-image:7.3.1611
  ---> c4d84e86782e
Step 2 : RUN yum -y install epel-release libaio bc flex
  ---> Running in 36d8abd0dad9
...

In the example above FROM is fetching your local image, you can provide additional instructions to fetch an image from your custom registry (e.g. FROM localhost:5000/my-image:with.tag). See https://docs.docker.com/engine/reference/commandline/pull/#pull-from-a-different-registry and https://docs.docker.com/registry/#tldr

Finally, if your image is not being resolved when providing a name, try adding a tag to the image when you create it

This GitHub thread describes a similar issue of not finding local images by name.

By omitting a specific tag, docker will look for an image tagged "latest", so either create an image with the :latest tag, or change your FROM

回答4:

Remember to put not only the tag but also the repository in which that tag is, this way:

docker images
REPOSITORY                                TAG                       IMAGE ID            CREATED             SIZE
elixir                                    1.7-centos7_3             e15e6bf57262        20 hours ago        925MB

You should reference it this way:

elixir:1.7-centos7_3