コンテナからの Docker イメージ作成

1. コンテナをシェルで実行する

   $ docker run -i -t centos /bin/bash
   Unable to find image 'centos:latest' locally
   latest: Pulling from library/centos
   aeb7866da422: Pull complete
   Digest: sha256:67dad89757a55bfdfabec8abd0e22f8c7c12a1856514726470228063ed86593b
   Status: Downloaded newer image for centos:latest
   [root@5aeee6cee1b1 /]#
   

2. コンテナ内でアプリケーションインストール

   • yum update

     [root@5aeee6cee1b1 /]# yum -y update
     

   • Apache HTTP Server install

     [root@5aeee6cee1b1 /]# yum -y install httpd
     

   • 抜ける

   • コンテナ確認

     $ docker ps -a
     CONTAINER ID        IMAGE                                      COMMAND                  CREATED             STATUS                     PORTS               NAMES
     5aeee6cee1b1        centos                                     "/bin/bash"              8 minutes ago       Exited (0) 3 seconds ago                       priceless_villani
     

3. コンテナから Docker イメージを作成する

   • 作成

     $ docker commit 5aeee6cee1b1 centos-apache-http
     sha256:c93287a7ebdf46eacd0035c23b5056450f34be3a7e12964597eb6b74dec4b798
     

   • Docker イメージ確認

     $ docker images
     REPOSITORY                                 TAG                 IMAGE ID            CREATED             SIZE
     centos-apache-http                         latest              c93287a7ebdf        47 seconds ago      334MB
     (snip)
     

   • 動作確認

     $ docker run centos-apache-http httpd -V
     AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
     Server version: Apache/2.4.6 (CentOS)
     Server built:   Jun 27 2018 13:48:59
     Server's Module Magic Number: 20120211:24
     Server loaded:  APR 1.4.8, APR-UTIL 1.5.2
     Compiled using: APR 1.4.8, APR-UTIL 1.5.2
     Architecture:   64-bit
     Server MPM:     prefork
       threaded:     no
         forked:     yes (variable process count)
     Server compiled with....
      -D APR_HAS_SENDFILE
      -D APR_HAS_MMAP
      -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
      -D APR_USE_SYSVSEM_SERIALIZE
      -D APR_USE_PTHREAD_SERIALIZE
      -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
      -D APR_HAS_OTHER_CHILD
      -D AP_HAVE_RELIABLE_PIPED_LOGS
      -D DYNAMIC_MODULE_LIMIT=256
      -D HTTPD_ROOT="/etc/httpd"
      -D SUEXEC_BIN="/usr/sbin/suexec"
      -D DEFAULT_PIDLOG="/run/httpd/httpd.pid"
      -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
      -D DEFAULT_ERRORLOG="logs/error_log"
      -D AP_TYPES_CONFIG_FILE="conf/mime.types"
      -D SERVER_CONFIG_FILE="conf/httpd.conf"