centos 安装 Docker

// 1. 删除以前安装的
yum remove -y docker \
		  docker-client \
		  docker-client-latest \
		  docker-common \
		  docker-latest \
		  docker-latest-logrotate \
		  docker-logrotate \
		  docker-engine			  
// 2. 				  
yum install -y yum-utils \
			  device-mapper-persistent-data \
			  lvm2
// 3.  
yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
// 4. 
yum -y install docker-ce docker-ce-cli containerd.io
// 5. 启动docker
systemctl start docker
// 6. 查看docker版本
docker version
// 7. 运行官网样例
docker run hello-world

虚拟机和容器对比

什么是 Image

  • 文件和 meta data的集合（root filesystem)
  • 分层的，并且每一层都可以添加改变删除文件，成为一个新的image
  • 不同的image可以共享相同的 layer
  • Image本身是read-ony的

 

DIY一个Base Image

运行官方的  hello-world

docker pull hello-world
docker run hello-world

 安装依赖

yum install -y gcc glibc-static

[yuanyu@localhost root]$ cd ~
[yuanyu@localhost ~]$ mkdir hello-world
[yuanyu@localhost ~]$ cd hello-world/
[yuanyu@localhost hello-world]$ vi hello.c
[yuanyu@localhost hello-world]$ cat hello.c 
#include<stdio.h>
int main(){
	printf("hello docker\n");
	return 0;
}
[yuanyu@localhost hello-world]$ gcc -static hello.c -o hello
[yuanyu@localhost hello-world]$ ll
total 848
-rwxrwxr-x. 1 yuanyu yuanyu 860831 Aug 29 03:41 hello
-rw-rw-r--. 1 yuanyu yuanyu     70 Aug 29 03:41 hello.c
[yuanyu@localhost hello-world]$ ./hello 
hello docker

[yuanyu@localhost hello-world]$ pwd
/home/yuanyu/hello-world
[yuanyu@localhost hello-world]$ vim Dockerfile
[yuanyu@localhost hello-world]$ vim Dockerfile
[yuanyu@localhost hello-world]$ docker build -t yuanyu1997/hello-wrold .
Sending build context to Docker daemon  864.8kB
Step 1/3 : FROM scratch
 ---> 
Step 2/3 : ADD hello /
 ---> 37094e3b9c83
Step 3/3 : CMD ["/hello"]
 ---> Running in f676ab846a22
Removing intermediate container f676ab846a22
 ---> 2e3b8931eff5
Successfully built 2e3b8931eff5
Successfully tagged yuanyu1997/hello-wrold:latest
[yuanyu@localhost hello-world]$ docker image ls
REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
yuanyu1997/hello-wrold   latest              2e3b8931eff5        25 seconds ago      861kB
wordpress                latest              fc03dc56d371        7 days ago          502MB
hello-world              latest              fce289e99eb9        8 months ago        1.84kB
[yuanyu@localhost hello-world]$ ls -lh
total 852K
-rw-rw-r--. 1 yuanyu yuanyu   40 Aug 29 03:48 Dockerfile
-rwxrwxr-x. 1 yuanyu yuanyu 841K Aug 29 03:41 hello
-rw-rw-r--. 1 yuanyu yuanyu   70 Aug 29 03:41 hello.c
[yuanyu@localhost hello-world]$ docker history 2e3b8931eff5
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
2e3b8931eff5        7 minutes ago       /bin/sh -c #(nop)  CMD ["/hello"]               0B                  
37094e3b9c83        7 minutes ago       /bin/sh -c #(nop) ADD file:eb323f2aea3aa1fc1…   861kB 

[yuanyu@localhost hello-world]$ docker run yuanyu1997/hello-wrold
hello docker

  Dockerfile

FROM scratch
ADD hello /
CMD ["/hello"]

 hello.c

#include<stdio.h>
int main(){
   printf("hello docker\n");
   return 0;
}

 

什么是 Container 

  • 通过Image创建（copy）
  • 在 Image layer之上建立一个container layer（可读写）
  • 类比面向对象：类和实例
  • Image负责app的存储和分发，Container负责运行app

 

 常用命令

查看运行中的 container

  • docker container ls
  • docker ps

查看所有的 container 

  • docker container ls -a
  • docker ps -a

删除指定的 container 

  • docker container rm id
  • docker rm id

查看 image

  • docker image ls
  • docker images

删除 image  

  • docker image rm id 
  • docker rmi id

显示所有的 container 的id

  • docker container ls -aq
  • docker container ls -a | awk {'print$1'}

 清理所有 container

  •  清理所有：docker rm $(docker container ls -aq)
  • 清理所有退出的：docker rm $(docker container ls -f "status=exited" -q)
[yuanyu@localhost hello-world]$ docker pull centos
//交互式运行
[yuanyu@localhost hello-world]$ docker run -it centos
//进入了centos 系统里面
[root@6eee110ca26f /]# ls
anaconda-post.log  bin  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var

构建自己的Docker镜像

  •  docker container commit
  • docker commit
  • docker image build 
  • docker build

 方式一：基于已经存在的container构建成image

这种方式不太安全，也不知道image是如何产生的

[root@localhost ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos              latest              67fa590cfc1c        8 days ago          202MB
[root@localhost ~]# docker run -it centos
//安装一些软件
[root@7ead4429f041 /]# yum install -y vim
[root@d26d6adc06a4 ~]# exit 
//构建docker image
[root@localhost ~]# docker commit crazy_beaver yuanyu1997/centos-vim:latest
sha256:79811bb06ce7be0011bfa18a058f04d527d1154c4503178594fbbed6fc367119
[root@localhost ~]# docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
yuanyu1997/centos-vim   latest              79811bb06ce7        21 seconds ago      369MB
centos                  latest              67fa590cfc1c        8 days ago          202MB
//原始的centos
[root@localhost ~]# docker history 6
IMAGE               CREATED             CREATED BY                                      SIZE                COMMENT
67fa590cfc1c        8 days ago          /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B                  
<missing>           8 days ago          /bin/sh -c #(nop)  LABEL org.label-schema.sc…   0B                  
<missing>           8 days ago          /bin/sh -c #(nop) ADD file:4e7247c06de9ad117…   202MB               
//构建的centos（可以看到是在原始的基础上构建的）
[root@localhost ~]# docker history 7
IMAGE               CREATED              CREATED BY                                      SIZE                COMMENT
79811bb06ce7        About a minute ago   /bin/bash                                       167MB               
67fa590cfc1c        8 days ago           /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B                  
<missing>           8 days ago           /bin/sh -c #(nop)  LABEL org.label-schema.sc…   0B                  
<missing>           8 days ago           /bin/sh -c #(nop) ADD file:4e7247c06de9ad117…   202MB

方式二：通过 Dockerfile 构建

[root@localhost ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos              latest              67fa590cfc1c        8 days ago          202MB
[root@localhost ~]# mkdir docker-centos-vim
[root@localhost ~]# cd docker-centos-vim/
[root@localhost docker-centos-vim]# vim Dockerfile
[root@localhost docker-centos-vim]# cat Dockerfile 
FROM centos
RUN yum install -y vim
[root@localhost docker-centos-vim]# docker build -t yuanyu1997/centos-vim-new .

[root@localhost docker-centos-vim]# docker images
REPOSITORY                  TAG                 IMAGE ID            CREATED             SIZE
yuanyu1997/centos-vim-new   latest              544ee7564cfd        3 minutes ago       369MB
centos                      latest              67fa590cfc1c        8 days ago          202MB

Dockerfile 

FROM centos
RUN yum install -y vim

Dockerfile语法梳理及最佳实践

FROM

尽量使用官方的image作为 base image！

scratch 的意思是重头制作一个base image

LABEL

Metadata不可少！

作者、版本、描述

RUN

  1. 为了美观，复杂的RUN请用反斜线换行！
  2. 避免无用分层，合并多条命令成一行！

WORKDIR

  1. 用 WORKDIR，不要用 RUN cd！
  2. 尽量使用绝对目录！

ADD and COPY

  1. 大部分情况，COPY优于ADD！
  2. ADD除了COPY还有额外功能（解压）！
  3. 添加 远程文件/目录 请使用crul成者wget！

ENV

  • 尽量使用ENV增加可维护性！

VOLUME and EXPOSE

CMD and ENTRYPOINT

  • RUN：执行命令并创建新的 Image Layer
  • CMD：设置容器启动后默认执行的命令和参数 
  • ENTRYPOINT：设置容器启动时运行的命令

 Shell和Exec格式

[root@localhost ~]# mkdir cmd_vs_entrypoint
[root@localhost ~]# cd cmd_vs_entrypoint/
[root@localhost cmd_vs_entrypoint]# ll
total 0
[root@localhost cmd_vs_entrypoint]# vim Dockerfile
[root@localhost cmd_vs_entrypoint]# cat Dockerfile 
FROM centos
ENV name Docker
ENTRYPOINT echo "hello $name"
[root@localhost cmd_vs_entrypoint]# docker build -t yuamyu1997/centos-entrypoint-shell .

[root@localhost cmd_vs_entrypoint]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
yuamyu1997/centos-entrypoint-shell   latest              2cf971bce716        3 seconds ago       202MB
yuanyu1997/centos-vim                latest              79811bb06ce7        2 hours ago         369MB
centos                               latest              67fa590cfc1c        8 days ago          202MB
[root@localhost cmd_vs_entrypoint]# docker run yuamyu1997/centos-entrypoint-shell
hello Docker

//-----------------------
[root@localhost cmd_vs_entrypoint]# vim Dockerfile 
[root@localhost cmd_vs_entrypoint]# cat Dockerfile 
FROM centos
ENV name Docker
ENTRYPOINT ["/bin/bash", "-c", "echo hello $name"]

[root@localhost cmd_vs_entrypoint]# docker build -t yuamyu1997/centos-entrypoint-exec .
[root@localhost cmd_vs_entrypoint]# docker run yuamyu1997/centos-entrypoint-exec
hello $name

CMD 

  • 容器启动时默认执行的命令
  • 如果 docker run指定了其它命令，CMD命令被忽略
  • 如果定义了多个CMD，只有最后一个会执行

ENTRYPOINT

  • 让容器以应用程序或者服务的形式运行
  • 不会被忽略，一定会执行
  • 最佳实践：写一个she脚本作为 entrypoint 

 

CMD 和 ENTRYPOINT 演示

[root@localhost cmd_vs_entrypoint]# cat Dockerfile 
FROM centos
ENV name Docker
CMD echo "hello $name"
[root@localhost cmd_vs_entrypoint]# docker build -t yuamyu1997/centos-cmd-shell .
[root@localhost cmd_vs_entrypoint]# docker run yuamyu1997/centos-cmd-shell
hello Docker
[root@localhost cmd_vs_entrypoint]# docker run -it  yuamyu1997/centos-cmd-shell /bin/bash

//----------------------
//centos-entrypoint-shell 前面演示有创建过
[root@localhost cmd_vs_entrypoint]# docker run yuamyu1997/centos-entrypoint-shell
hello Docker
[root@localhost cmd_vs_entrypoint]# docker run -it yuamyu1997/centos-entrypoint-shell /bin/bash
hello Docker

 手动构建上传到DockerHub

[root@localhost ~]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
yuanyu1997/hello-wrold               latest              9c72be46c8ac        10 hours ago        861kB                           latest              67fa590cfc1c        9 days ago          202MB
//登录
[root@localhost ~]# docker login
Login Succeeded
//push 到 docker hub
[root@localhost ~]# docker push yuanyu1997/hello-wrold:latest

//删除本地image，后测试
[root@localhost ~]# docker pull yuanyu1997/hello-wrold
[root@localhost ~]# docker run yuanyu1997/hello-wrold:latest
hello docker

 DockerHub基于Github自动化构建

 搭建私有仓库

 游览器查看：http://192.168.1.5:5000/v2/_catalog

//ip: 192.168.1.5
// 私有docker服务器下载 registry
[root@localhost ~]# docker run -d -p 5000:5000 --restart always --name registry registry:2
[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                    NAMES
09a666dd5a14        registry:2          "/entrypoint.sh /etc…"   9 seconds ago       Up 6 seconds        0.0.0.0:5000->5000/tcp   registry

//测试是否 私有docker服务器 5000 端口是否可用
[root@localhost ~]# telnet 192.168.1.5 5000
Trying 192.168.1.5...
Connected to 192.168.1.5.
Escape character is '^]'.
//
[root@localhost hello-world]# docker build -t 192.168.1.5:5000/hello-world .
[root@localhost hello-world]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
192.168.1.5:5000/hello-world         latest              1fc300c17ce3        14 seconds ago      861kB

//
[root@localhost docker]# ls /etc/docker/
daemo.json  key.json
[root@localhost docker]# vim /etc/docker/daemo.json
[root@localhost docker]# cat /etc/docker/daemo.json 
{
  "insecure-registries" : ["192.168.1.5:5000"]
}

[root@localhost docker]# vim /lib/systemd/system/docker.service 
[root@localhost docker]# cat /lib/systemd/system/docker.service 
[Service]
Type=notify
# the default is not to use systemd for cgroups because the delegate issues still
# exists and systemd currently does not support the cgroup feature set required
# for containers run by docker
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

# 添加这一句
EnvironmentFile=-/etc/docker/daemo.json

[root@localhost docker]# service docker restart
Redirecting to /bin/systemctl restart  docker.service
Warning: docker.service changed on disk. Run 'systemctl daemon-reload' to reload units.
[root@localhost docker]# systemctl daemon-reload
[root@localhost docker]# 
[root@localhost docker]# docker push 192.168.1.5:5000/hello-world
The push refers to repository [192.168.1.5:5000/hello-world]
Get https://192.168.1.5:5000/v2/: http: server gave HTTP response to HTTPS client
[root@localhost docker]#

dockerfile实战

app.py

from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello():
    return "hello docker"
if __name__ == '__main__':
    app.run(host="127.0.0.1", port=5000)

Dockerfile

FROM python:2.7
LABEL maintainer="Yuan Yu<1750762853@qq.com>"
RUN pip install flask
COPY app.py /app/
WORKDIR /app
EXPOSE 5000
CMD ["python", "app.py"]
[root@localhost flask-hello-world]# pwd
/root/flask-hello-world
[root@localhost flask-hello-world]# ll
total 8
-rw-r--r--. 1 root root 167 Aug 30 02:20 app.py
-rw-r--r--. 1 root root 152 Aug 30 02:25 Dockerfile
[root@localhost flask-hello-world]# docker build -t yuanyu1997/flask-hello-world .
//后台运行
[root@localhost flask-hello-world]# docker run -d yuanyu1997/flask-hello-world

//进入临时 image检查错误
docker run -it id /bin/bash

docker run -d -p 5000:5000 yuanyu1997/flask-hello-world

普通用户执行docker命令 

//使我的的用户可以执行sudo命令
	//切换到root用户下
	//添加sudo文件的写权限
	chmod u+w /etc/sudoers
	//编辑sudoers文件
	vi /etc/sudoers
	找到这行 root ALL=(ALL) ALL,在他下面添加xxx ALL=(ALL) ALL (这里的xxx是你的用户名)
		ps:这里说下你可以sudoers添加下面四行中任意一条
		youuser            ALL=(ALL)                ALL
		%youuser           ALL=(ALL)                ALL
		youuser            ALL=(ALL)                NOPASSWD: ALL
		%youuser           ALL=(ALL)                NOPASSWD: ALL
		第一行:允许用户youuser执行sudo命令(需要输入密码).
		第二行:允许用户组youuser里面的用户执行sudo命令(需要输入密码).
		第三行:允许用户youuser执行sudo命令,并且在执行的时候不输入密码.
		第四行:允许用户组youuser里面的用户执行sudo命令,并且在执行的时候不输入密码.
	//撤销sudoers文件写权限
	chmod u-w /etc/sudoers
	这样普通用户就可以使用sudo了

//添加分组
sudo groupadd docker
//普通用户添加到分组
sudo gpasswd -a yuanyu  docker
docker version
//重启docker，并且重启shell
sudo service docker restart
//测试
docker image ls

 

Logo
华为开发者空间

华为开发者空间，是为全球开发者打造的专属开发空间，汇聚了华为优质开发资源及工具，致力于让每一位开发者拥有一台云主机，基于华为根生态开发、创新。

更多推荐

cover

华为开发者空间云开发环境（容器）操作指导

avatar 华为开发者空间
cover

【openGauss】Oracle与openGauss/GaussDB数据一致性高效核对方案

avatar 华为开发者空间

【GaussDB】在逻辑复制中剔除指定用户的事务

基于逻辑复制标签实现过滤，技术上可行，但打标签这个附加操作需要在执行sql前执行（除非使用触发器，但触发器属于高风险操作，不建议使用），如果漏执行，将会存在错误覆盖目标库的风险。历史表归档方案通过在源库建立历史表存储归档数据，配置复制规则排除历史表的删除操作，虽然会增加IO开销，但实现简单、安全性高，避免了事务过滤可能带来的风险。虽然插入历史表会产生额外IO，可能使数据归档操作时间翻倍，但相比剔除

avatar 华为开发者空间