docker save and load

usages

1. export and import image

   1. save

       $ docker save --help                                             ✱
      
       Usage:  docker save [OPTIONS] IMAGE [IMAGE...]
      
       Save one or more images to a tar archive (streamed to STDOUT by default)
      
       Options:
         -o, --output string   Write to a file, instead of STDOUT
      

   2. load

       $ docker load --help                                             ✱
      
       Usage:  docker load [OPTIONS]
      
       Load an image from a tar archive or STDIN
      
       Options:
         -i, --input string   Read from tar archive file, instead of STDIN
         -q, --quiet          Suppress the load output
      

2. export and import container

   1. export

       $ docker export --help                                           ✱
      
       Usage:  docker export [OPTIONS] CONTAINER
      
       Export a container's filesystem as a tar archive
      
       Options:
         -o, --output string   Write to a file, instead of STDOUT
      

   2. import

       $ docker import --help                                           ✱
      
       Usage:  docker import [OPTIONS] file|URL|- [REPOSITORY[:TAG]]
      
       Import the contents from a tarball to create a filesystem image
      
       Options:
         -c, --change list      Apply Dockerfile instruction to the created image
         -m, --message string   Set commit message for imported image
      

demo

1. how to copy docker images from one host to another without via repository

   1. install epel

       # RHEL/CentOS 6
       $ yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm
      
       # RHEL/CentOS 7
       $ yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
       # enable the optional & extras repos
       $ subscription-manager repos --enable "rhel-*-optional-rpms" --enable "rhel-*-extras-rpms"
      

   2. install pv

       $ yum install pv
      

   3. demo

       $ docker save centos:7.3.1611 | bzip2 | pv | ssh root@dc 'bunzip2 | docker load'
       $ docker save centos:7.2.1511 | bzip2 | pv | ssh root@dc 'bunzip2 | docker load'