Manually build a new image in docker

View local existing mirrors:

[root@docker ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               latest              c59f17fe53b0        4 days ago          108MB
ubuntu              latest              747cb2d60bbe        3 weeks ago         122MB
centos              latest              196e0ce0c9fb        6 weeks ago         197MB

Now use the basic image centos to manually build a web service on this basis, using nginx here

Start a container and enter the container:

[root@docker ~]# docker run -it --name=web centos /bin/bash
[root@bab3b6991467 /]#

Then install the nginx service in the container:

[root@bab3b6991467 /]# cd /usr/local/src/
[root@bab3b6991467 src]# yum install wget vim

Here, nginx is installed by compiling, so download the nginx source package and install the compilation environment:

[root@bab3b6991467 src]# wget http://nginx.org/download/nginx-1.12.2.tar.gz

Compiler Environment:

[root@bab3b6991467 src]# yum install gcc gcc-c++ glibc make autoconf openssl openssl-devel

Install some dependencies of nginx:

[root@bab3b6991467 src]# yum install libxslt-devel -y gd gd-devel GeoIP GeoIP-devel pcre pcre-devel

Then spend to perform the installation:

[root@bab3b6991467 src]# ll
total 960
-rw-r--r--. 1 root root 981687 Oct 17 13:20 nginx-1.12.2.tar.gz
[root@bab3b6991467 src]# tar xf nginx-1.12.2.tar.gz 
[root@bab3b6991467 src]# cd nginx-1.12.2
[root@bab3b6991467 nginx-1.12.2]# ./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --with-file-aio  --with-http_ssl_module  --with-http_realip_module    --with-http_addition_module    --with-http_xslt_module   --with-http_image_filter_module    --with-http_geoip_module  --with-http_sub_module  --with-http_dav_module --with-http_flv_module    --with-http_mp4_module --with-http_gunzip_module  --with-http_gzip_static_module  --with-http_auth_request_module  --with-http_random_index_module   --with-http_secure_link_module   --with-http_degradation_module   --with-http_stub_status_module

Create the required user:

useradd -M -s /sbin/nologin nginx

Continue to compile:

make && make install

chown -R nginx:nginx /usr/local/nginx/

这里需要介绍nginx命令的一个参数：

[root@bab3b6991467 ~]# /usr/local/nginx/sbin/nginx -h 
　　-g directives : set global directives out of configuration file

-g:为nginx的配置文件设置指令

现在退出container，回到host本机

[root@bab3b6991467 ~]# exit
exit

查看此时容器的状态：

[root@docker ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                      PORTS               NAMES
bab3b6991467        centos              "/bin/bash"         37 minutes ago      Exited (0) 21 seconds ago                       web

利用docker diff查看该容器进行了哪些修改，由于输出太多，这里不给予显示了

利用docker commit将web容器进行加层成一个新镜像：

[root@docker ~]# docker commit --help
    Usage:  docker commit [OPTIONS] CONTAINER [REPOSITORY[:TAG]]
    Create a new image from a container's changes

    -m, --message string   Commit message
    -a, --author string    Author (e.g., "John Hannibal Smith <[email protected]>")
    

现在开始commit：

[root@docker ~]# docker commit -m "compile nginx on centos" web wadeson/centos_nginx:v1
sha256:210a202d37b8d2c31155c29adf0c7c0b49cfab7ff38234109919de7f4e76d1de

查看本地镜像：

[root@docker ~]# docker images
REPOSITORY             TAG                 IMAGE ID            CREATED             SIZE
wadeson/centos_nginx   v1                  210a202d37b8        33 seconds ago      464MB
nginx                  latest              c59f17fe53b0        4 days ago          108MB
ubuntu                 latest              747cb2d60bbe        3 weeks ago         122MB
centos                 latest              196e0ce0c9fb        6 weeks ago         197MB

可以看见刚刚docker commit的新镜像了，现在由此镜像进行启动一个container提供nginx服务：

[root@docker ~]# docker run -d -p80:80 wadeson/centos_nginx:v1 /usr/local/nginx/sbin/nginx -g "daemon off;"
c12669357e2b09a05a396ac480a04dd1956303b784f894b615d4edb889a737ab

然后查看container：

[root@docker ~]# docker ps -l
CONTAINER ID        IMAGE                     COMMAND                  CREATED             STATUS              PORTS                NAMES
c12669357e2b        wadeson/centos_nginx:v1   "/usr/local/nginx/..."   41 seconds ago      Up 40 seconds       0.0.0.0:80->80/tcp   thirsty_murdock

可以看见nginx服务已经开启了，于是进行访问：

 

 于是整个手动构建就成功了

 

针对上面的一些命令做下解释：

　　docker run -d -p80:80 wadeson/centos_nginx:v1 /usr/local/nginx/sbin/nginx -g "daemon off;"

后面运行的命令都是旨在container的命令，由于没有进行环境变量设置，所以全路径，而nginx -g这个参数是指可以在外面添加指令到nginx的配置文件中，daemon off是指nginx服务不运行在后端而是在前台运行（container中的服务必须运行在前台）

利用docker top可以查看container的运行进程：

[root@docker ~]# docker top c12669357e2b
UID                 PID                 PPID                C                   STIME               TTY                 TIME                CMD
root                35468               35451               0                   02:55               ?                   00:00:00            nginx: master process /usr/local/nginx/sbin/nginx -g daemon off;
1000                35489               35468               0                   02:55               ?                   00:00:00            nginx: worker process

利用docker exec进入到容器内：

[root@docker ~]# docker exec -it c12669357e2b /bin/bash
[root@c12669357e2b /]# ps -ef
UID         PID   PPID  C STIME TTY          TIME CMD
root          1      0  0 06:55 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx -g daemon off;
nginx         5      1  0 06:55 ?        00:00:00 nginx: worker process
root          6      0  1 07:01 pts/0    00:00:00 /bin/bash
root          20       6   0  07 : 01 pts/ 0     00 : 00 : 00  ps -ef

And use ctrl+p+q to put the container in the background instead of exited immediately