docker新手入门(3)之镜像使用

blacsheep

2018-01-28

web篇

运行容器的时候如果镜像本地不存在,docker就会从docker镜像仓库里面去下载,默认docker hub公共镜像源这一篇主要是怎么管理使用本地镜像以及创建镜像

列出镜像列表

命令:docker images

root@blacsheep-myubuntu:/home/blacsheep# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
ubuntu              16.10               7d3f705d307c        6 months ago        107MB
training/webapp     latest              6fae60ef3446        2 years ago         349MB
root@blacsheep-myubuntu:/home/blacsheep#

其中 repository:镜像的仓库源 tag:镜像的标签 image id:镜像id created:创建时间 size:大小一个仓库源可以有多个tag,比如一个ubuntu的仓库源里面可以有14.04,15.10等等版本,我们可以用repository:tag来定义不同的镜像,比如我们要用16.10的ubuntu来运行容器的时候,就是使用

1 2	root@blacsheep-myubuntu:/home/blacsheep# docker run -t -i ubuntu:16.10 /bin/bash root@68cc92ce5dee:/#

如果不去指定镜像的标签的话,比如只用ubuntu,docker就会默认使用ubuntu:latest的镜像

获取镜像

使用docker pull,同时说明不带标签的话使用的是latest的标签

root@blacsheep-myubuntu:/home/blacsheep# docker pull ubuntu
Using default tag: latest
latest: Pulling from library/ubuntu
1be7f2b886e8: Pull complete 
6fbc4a21b806: Pull complete 
c71a6f8e1378: Pull complete 
4be3072e5a37: Pull complete 
06c6d2f59700: Pull complete 
Digest: sha256:e46251ecd3548065ca203df31bdcf25e53b530b9b39bd3a86ac8147b347bb7ac
Status: Downloaded newer image for ubuntu:latest
root@blacsheep-myubuntu:/home/blacsheep#

下载完成之后docker images查看

root@blacsheep-myubuntu:/home/blacsheep# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
ubuntu              latest              0458a4468cbc        2 days ago          112MB
ubuntu              16.10               7d3f705d307c        6 months ago        107MB
training/webapp     latest              6fae60ef3446        2 years ago         349MB
root@blacsheep-myubuntu:/home/blacsheep#

查找镜像

可以从docker hub的网站来搜索镜像,网址为https://hub.docker.com/ 如果想用命令行,可以用docker search xxx,比如我们想找一个httpd的镜像作为web服务,可以

root@blacsheep-myubuntu:/home/blacsheep# docker search httpd
NAME                                DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED
httpd                               The Apache HTTP Server Project                  1470                [OK]                
hypriot/rpi-busybox-httpd           Raspberry Pi compatible Docker Image with a …   40                                      
centos/httpd                                                                        15                                      [OK]
centos/httpd-24-centos7             Platform for running Apache httpd 2.4 or bui…   8                                       
armhf/httpd                         The Apache HTTP Server Project                  8                                       
macadmins/netboot-httpd             use in combination with bruienne/bsdpy          4                                       [OK]
lolhens/httpd                       Apache httpd 2 Server                           2                                       [OK]
salim1983hoop/httpd24               Dockerfile running apache config                2                                       [OK]
fboaventura/dckr-httpd              Small footprint http server to use with othe…   1                                       [OK]
rgielen/httpd-image-simple          Docker image for simple Apache httpd based o…   1                                       [OK]
lead4good/httpd-fpm                 httpd server which connects via fcgi proxy h…   1                                       [OK]
epflidevelop/os-wp-httpd            WP httpd                                        1                                       [OK]
rgielen/httpd-image-php5            Docker image for Apache httpd with PHP 5 bas…   1                                       [OK]
publici/httpd                       httpd:latest                                    0                                       [OK]
tplatform/aws-linux-httpd24-php70   aws-linux-httpd24-php70                         0                                       [OK]
dockerpinata/httpd                                                                  0                                       
trollin/httpd                                                                       0                                       
manasip/httpd                                                                       0                                       
manageiq/httpd                      Container with httpd, built on CentOS for Ma…   0                                       [OK]
jbpt/httpd                                                                          0                                       [OK]
fintaffy/fintaffy-httpd                                                             0                                       
efrecon/httpd                       A micro-sized httpd. Start serving files in …   0                                       [OK]
ppc64le/httpd                       The Apache HTTP Server Project                  0                                       
sbutler/pie-httpd                   PIE httpd server                                0                                       
camptocamp/os-wp-httpd              Wordpress httpd                                 0                                       [OK]
root@blacsheep-myubuntu:/home/blacsheep#

name:表示镜像仓库源的名称 description:镜像描述 official:是否是docker官方发布的

托取镜像

root@blacsheep-myubuntu:/home/blacsheep# docker pull httpd

Using default tag: latest
latest: Pulling from library/httpd
f49cf87b52c1: Pull complete 
02ca099fb6cd: Pull complete 
de7acb18da57: Pull complete 
770c8edb393d: Pull complete 
0e252730aeae: Pull complete 
6288e83d58fa: Pull complete 
a91ad03b2178: Pull complete 
Digest: sha256:6261d80fe154a7d7f1cbb0ca90eb344fafb4511afd06ebfc2d41915367ce25ad
Status: Downloaded newer image for httpd:latest
root@blacsheep-myubuntu:/home/blacsheep#

之后docker run httpd就可以了

创建镜像(重点)

如果我们从docker镜像仓库里面下载的镜像不能满足我们的需求的话,有两种方式可以对镜像进行更改 - 1.从已经创建的容器中更新镜像,并且提交这个镜像 - 2.使用docker file来创建一个新的镜像

更新镜像

更新之前先用镜像创建一个容器

1	root@blacsheep-myubuntu:/home/blacsheep# docker run -t -i ubuntu:16.10 /bin/bashroot@000b42c94ddd:/#

容器内使用apt-get update更新一下完成之后exit退出这个容器是按我们的需求修改的容器,可以使用docker commit来提交容器副本

1
2
3

root@blacsheep-myubuntu:/home/blacsheep# docker commit -m="update ubuntu" -a="blacsheep" 000b42c94ddd blacsheep/ubuntu:v1
sha256:3846343d3b39a77b3dbadb32cdef5a3669560bbb96d52d639f24cc06f8d2655e
root@blacsheep-myubuntu:/home/blacsheep#

-m:提交的描述 -a:镜像作者 000b42c94ddd:容器id blacsheep/ubuntu:v1:镜像名:标签然后docker images查看

root@blacsheep-myubuntu:/home/blacsheep# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED              SIZE
blacsheep/ubuntu    v1                  3846343d3b39        About a minute ago   107MB
httpd               latest              2e202f453940        2 days ago           179MB
ubuntu              latest              0458a4468cbc        2 days ago           112MB
ubuntu              16.10               7d3f705d307c        6 months ago         107MB
training/webapp     latest              6fae60ef3446        2 years ago          349MB
root@blacsheep-myubuntu:/home/blacsheep#

这样就可以使用新的镜像来创建容器了

1 2	root@blacsheep-myubuntu:/home/blacsheep# docker run -t -i blacsheep/ubuntu:v1 /bin/bash root@02b45e36003d:/#

dockerfile创建镜像

使用docker build可以从零开始创建一个镜像。但是我们必须创建一个Dockerfile来告诉docker怎么来创建我们的镜像 dockerfile自己写写完了大概就是

root@blacsheep-myubuntu:/home/blacsheep# cat Dockerfile
From ubuntu:16.04
RUN /bin/echo 'root:123456' chpasswd
RUN useradd blacsheep
RUN /bin/echo 'blacsheep:123456' chpasswd
RUN /bin/echo -e "LANG=\"en_US.UTF-8\"" >/etc/default/local
EXPOSE 22
EXPOSE 80
CMD /usr/sbin/sshd -D

From:表示使用哪个镜像源 RUN:表示告诉docker在镜像里面执行什么命令然后使用docker build -t xxx .来创建注意,不要忘记指令最后的一个点,点表示dockerfile在当前目录

root@blacsheep-myubuntu:/home/blacsheep# docker build -t blacsheep/ubuntu:dockerfile .
ERRO[0036] Can't add file /home/blacsheep/.gnupg/S.gpg-agent to tar: archive/tar: sockets not supported 
Sending build context to Docker daemon   2.19GB
Step 1/8 : From ubuntu:16.04
16.04: Pulling from library/ubuntu
1be7f2b886e8: Already exists 
6fbc4a21b806: Already exists 
c71a6f8e1378: Already exists 
4be3072e5a37: Already exists 
06c6d2f59700: Already exists 
Digest: sha256:2b80e7fbfd1b0a3784dd0e55fb6f2750ebc33e596c2ccee5201ecf018ac5ae05
Status: Downloaded newer image for ubuntu:16.04
 ---> 0458a4468cbc
Step 2/8 : RUN /bin/echo 'root:123456' chpasswd
 ---> Running in b3d12aa12f6c
Removing intermediate container b3d12aa12f6c
 ---> 99c6e9ccdd81
Step 3/8 : RUN useradd blacsheep
 ---> Running in fe025de84d56
Removing intermediate container fe025de84d56
 ---> e5180f2047b3
Step 4/8 : RUN /bin/echo 'blacsheep:123456' chpasswd
 ---> Running in aa3c30d8f07b
Removing intermediate container aa3c30d8f07b
 ---> 9bda89fa8c14
Step 5/8 : RUN /bin/echo -e "LANG=\"en_US.UTF-8\"" >/etc/default/local
 ---> Running in d63a51e6d430
Removing intermediate container d63a51e6d430
 ---> a3b879d7090e
Step 6/8 : EXPOSE 22
 ---> Running in d2f15040553b
Removing intermediate container d2f15040553b
 ---> 65916c8dda3e
Step 7/8 : EXPOSE 80
 ---> Running in 62dde9991ee4
Removing intermediate container 62dde9991ee4
 ---> 5bf05e8d377f
Step 8/8 : CMD /usr/sbin/sshd -D
 ---> Running in 62528b637ebc
Removing intermediate container 62528b637ebc
 ---> 7ba34ce933fb
Successfully built 7ba34ce933fb
Successfully tagged blacsheep/ubuntu:dockerfile
root@blacsheep-myubuntu:/home/blacsheep# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED              SIZE
blacsheep/ubuntu    dockerfile          7ba34ce933fb        About a minute ago   112MB
blacsheep/ubuntu    v1                  3846343d3b39        22 minutes ago       107MB
httpd               latest              2e202f453940        2 days ago           179MB
ubuntu              16.04               0458a4468cbc        2 days ago           112MB
ubuntu              latest              0458a4468cbc        2 days ago           112MB
ubuntu              16.10               7d3f705d307c        6 months ago         107MB
training/webapp     latest              6fae60ef3446        2 years ago          349MB
root@blacsheep-myubuntu:/home/blacsheep#

最后的docker images也可以看出镜像安装成功了然后至于用户

root@blacsheep-myubuntu:/home/blacsheep# docker run -i -t blacsheep/ubuntu:dockerfile /bin/bash
root@1b52c348bf31:/# id blacsheep
uid=1000(blacsheep) gid=1000(blacsheep) groups=1000(blacsheep)
root@1b52c348bf31:/#

设置镜像标签

使用docker tag命令比如

root@blacsheep-myubuntu:/home/blacsheep# docker tag 7ba34ce933fb blacsheep/ubuntu:practice
root@blacsheep-myubuntu:/home/blacsheep# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
blacsheep/ubuntu    dockerfile          7ba34ce933fb        19 minutes ago      112MB
blacsheep/ubuntu    practice            7ba34ce933fb        19 minutes ago      112MB
blacsheep/ubuntu    v1                  3846343d3b39        40 minutes ago      107MB
httpd               latest              2e202f453940        2 days ago          179MB
ubuntu              16.10               7d3f705d307c        6 months ago        107MB
training/webapp     latest              6fae60ef3446        2 years ago         349MB
root@blacsheep-myubuntu:/home/blacsheep#

可以看到blacsheep/ubuntu多了一个practice标签.