Docker

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참고

1. docker 란

   • 애플리케이션을 신속하게 구축, 테스트 및 배포할 수 있는 소프트웨어 플랫폼
   • 소프트웨어를 컨테이너라는 표준화된 유닛으로 패키징하며, 이 컨테이너에는 라이브러리, 시스템 도구, 코드, 런타임 등 소프트웨어를 실행하는 데 필요한 모든 것이 포함되어 있다
   • Virtaul Machine vs Container
     • 
     • 컨테이너는 별도의 OS나 드라이버 없이 Host OS를 공유하는 형태로 실행 VM 의 경우 많은 시스템 리소스를 사용하게 된다
     • VM 은 서버, Host OS, Hypervisor 위에 올라가게 되고, 각 VM은 OS, 드라이버, 메모리 등 컴퓨터 환경이 구성되기 위해 필요한 요소들을 갖추게 된다
     • Container 의 문제점
       • Security
         • Libcontainers accesses five namespaces — Process, Network, Mount, Hostname, and Shared Memory — to work with Linux

2. ubuntu 환경에서 docker 설치하기

   • Set up the repository

       $ sudo apt-get -y install apt-transport-https  ca-certificates curl
       $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
       OK
       $ sudo apt-add-repository 'deb https://apt.dockerproject.org/repo ubuntu-xenial main'
       $ sudo apt-get update
       $ sudo apt-cache policy docker-engine
     

   • Get Docker

       $ sudo apt-get -y install docker-engine
     

3. docker 명령어 사용하기

   • docker [option] [command] [arguments]

4. docker 환경에서 tomcat server 설치 및 배포하기

   • tomcat image 확인

       docker@DockerClient:~$ docker search tomcat
       NAME                           DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
       tomcat                         Apache Tomcat is an open source implementa...   1346      [OK]
       dordoka/tomcat                 Ubuntu 14.04, Oracle JDK 8 and Tomcat 8 ba...   37                   [OK]
       davidcaste/alpine-tomcat       Apache Tomcat 7/8 using Oracle Java 7/8 wi...   18                   [OK]
       cloudesire/tomcat              Tomcat server, 6/7/8                            15                   [OK]
       andreptb/tomcat                Debian Jessie based image with Apache Tomc...   7                    [OK]
       openweb/oracle-tomcat          A fork off of Official tomcat image with O...   5                    [OK]
       fbrx/tomcat                    Minimal Tomcat image based on Alpine Linux      4                    [OK]
       bitnami/tomcat                 Bitnami Tomcat Docker Image                     2                    [OK]
       abzcoding/tomcat-redis         a tomcat container with redis as session m...   2                    [OK]
       picoded/tomcat                 tomcat 8 with java 8, and MANAGER_USER / M...   2                    [OK]
       antoineco/tomcat-mod_cluster   Apache Tomcat with JBoss mod_cluster            1                    [OK]
       camptocamp/tomcat-logback      Docker image for tomcat with logback integ...   1
     

   • docker image 저장

       docker@DockerClient:~$ docker image pull davidcaste/alpine-tomcat
     

   • docker image 저장 위치 확인

       root@DockerClient:/var/lib/docker/image/aufs# ls
       distribution  imagedb  layerdb  repositories.json
     
       root@DockerClient:/var/lib/docker/image/aufs# cat repositories.json
       {"Repositories":{"davidcaste/alpine-tomcat":{"davidcaste/alpine-tomcat:latest":"sha256:068917e56bf36062d3bfd6fe728b55b01b5ebd17406fda27cb2dca07acbfbfde","davidcaste/alpine-tomcat@sha256:5c9e43e76d66fc147bff8a9328d8369cb0d21505a5d0e055a24764cb39c439a0":"sha256:068917e56bf36062d3bfd6fe728b55b01b5ebd17406fda27cb2dca07acbfbfde"},"hello-world":{"hello-world:latest":"sha256:48b5124b2768d2b917edcb640435044a97967015485e812545546cbed5cf0233","hello-world@sha256:c5515758d4c5e1e838e9cd307f6c6a0d620b5e07e6f927b07d05f6d12a1ac8d7":"sha256:48b5124b2768d2b917edcb640435044a97967015485e812545546cbed5cf0233"}}}
     
       root@DockerClient:/var/lib/docker/image/aufs/imagedb/content/sha256# ls -al
       total 24
       drwx------ 2 root root 4096 Jun  7 08:37 .
       drwx------ 3 root root 4096 May 24 16:58 ..
       -rw------- 1 root root 8648 Jun  7 08:37 068917e56bf36062d3bfd6fe728b55b01b5ebd17406fda27cb2dca07acbfbfde
       -rw------- 1 root root 1478 May 24 17:21 48b5124b2768d2b917edcb640435044a97967015485e812545546cbed5cf0233
     

   • docker 실행

       docker@DockerClient:~$ docker run -it --rm davidcaste/alpine-tomcat /opt/tomcat/bin/catalina.sh run
       Using CATALINA_BASE:   /opt/tomcat
       Using CATALINA_HOME:   /opt/tomcat
       Using CATALINA_TMPDIR: /opt/tomcat/temp
       Using JRE_HOME:        /opt/jdk
       Using CLASSPATH:       /opt/tomcat/bin/bootstrap.jar:/opt/tomcat/bin/tomcat-juli.jar
     

   • docker 실행 확인

       docker@DockerClient:~$ docker ps
       CONTAINER ID        IMAGE                      COMMAND                  CREATED             STATUS              PORTS               NAMES
       381a87f75c84        davidcaste/alpine-tomcat   "/opt/tomcat/bin/c..."   4 minutes ago       Up 4 minutes        8080/tcp            inspiring_colden
       docker@DockerClient:~$ docker exec 381a87f75c84 ifconfig
       eth0      Link encap:Ethernet  HWaddr 02:42:AC:11:00:02
                 inet addr:172.17.0.2  Bcast:0.0.0.0  Mask:255.255.0.0
                 inet6 addr: fe80::42:acff:fe11:2%32650/64 Scope:Link
                 UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
                 RX packets:15 errors:0 dropped:0 overruns:0 frame:0
                 TX packets:15 errors:0 dropped:0 overruns:0 carrier:0
                 collisions:0 txqueuelen:0
                 RX bytes:1075 (1.0 KiB)  TX bytes:1176 (1.1 KiB)
     
       lo        Link encap:Local Loopback
                 inet addr:127.0.0.1  Mask:255.0.0.0
                 inet6 addr: ::1%32650/128 Scope:Host
                 UP LOOPBACK RUNNING  MTU:65536  Metric:1
                 RX packets:0 errors:0 dropped:0 overruns:0 frame:0
                 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
                 collisions:0 txqueuelen:1
                 RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
     
       docker@DockerClient:~$ telnet 172.17.0.2 8080
       Trying 172.17.0.2...
       Connected to 172.17.0.2.
       Escape character is '^]'.