Docker讲解与实战，精炼易懂！

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IT张sir 2018-08-17 10:09:15 博主文章分类：linux ©著作权

文章标签 Docker 搭建实战 文章分类 运维

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1、docker简介

docker通过内核虚拟化技术（namespace及cgroups等）来提供容器的资源隔离与安全保障等，由于docker通过操作系统层的虚拟化实现隔离，所以docker容器在运行时，不需要类似虚拟机额外的操作系统开销，提供资源利用率

2、docker vs kvm

3、docker vs vms

4、docker三大组件

镜像（image）、容器（container）、仓库（repository）

一、docker安装

[root@docker ~]#tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/7/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF
[root@docker ~]# yum install docker-engine -y

二、比较常用命令参数

查看Docker的版本信息
 docker version

在Docker Hub上搜索一个指定镜像
docker search

在Docker Hub上搜索一个指定镜像并至少有10颗星
docker search -s 10 ubuntu

从一个Docker的注册服务器上拉取一个镜像或一个私有仓库
 docker pull ubuntu

查看镜像列表
docker images

在一个新的容器中运行一个命令
docker run

移除一个或多个镜像
docker rmi

移除一个或多个容器
docker rm

附着一个运行的容器
docker attach

运行一个命令在一个运行的容器中
docker exec

从一个Dockerfile文件中构建一个镜像
docker build

查看镜像构建历史
docker history

查看容器更为详细的配置信息
docker inspect

保存一个镜像对归档tar中
docker save

从一个归档tar中加载一个镜像
docker load

启动、停止、重启一个运行的容器
docker start| stop| restart

杀掉一个正在运行的容器
docker kill

进入容器命令：
docker attach:登陆到运行的容器中
docker exec：在宿主机上运行命令到容器内部，类似在打开一个容器的终端
docker nsenter：连接到容器，需要容器PID

三、docker基础操作

[root@docker ~]# systemctl enable docker.service
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@docker ~]# systemctl start docker.service
[root@docker ~]# 
[root@docker ~]# docker pull centos  #拉取镜像
[root@docker ~]# docker pull daocloud.io/library/nginx

有时候拉取速度很慢，采用国内源加速

root@docker ~]# vim /usr/lib/systemd/system/docker.service  增加下面这行
EnvironmentFile=/etc/sysconfig/docker


新建配置文件[root@docker ~]# vim /etc/sysconfig/docker
在https://dashboard.daocloud.io/  注册，然后点击加速器生成加速链接

OPTIONS=--registry-mirror=curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s 


[root@docker ~]# docker search nginx  #搜索镜像
[root@docker ~]# docker images 
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
centos              latest              0584b3d2cf6d        2 weeks ago         196.5 MB

导出镜像
[root@docker ~]# docker save -o nginx.tar daocloud.io/library/nginx  

[root@docker ~]# docker save -o cnetos.tar centos
导入镜像
[root@docker ~]# docker load --input cnetos.tar  或者  [root@docker ~]# docker load < cnetos.tar
删除镜像
[root@docker ~]# docker rmi 0584b3d2cf6d （镜像ID） 


[root@docker ~]# docker run centos /bin/echo "Hello world"
Hello world
[root@docker ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                     PORTS               NAMES
5e381e68a385        centos              "/bin/echo 'Hello wor"   6 seconds ago       Exited (0) 5 seconds ago                       clever_lamarr

[root@docker ~]# docker run --name mydocker -t -i centos /bin/bash
[root@1a67f4c92b6e /]# 

[root@1a67f4c92b6e /]# ps -ef
UID         PID   PPID  C STIME TTY          TIME CMD
root          1      0  0 18:56 ?        00:00:00 /bin/bash
root         14      1  0 18:56 ?        00:00:00 ps -ef

[root@1a67f4c92b6e /]# exit
exit
[root@docker ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                      PORTS               NAMES
1a67f4c92b6e        centos              "/bin/bash"              12 minutes ago      Exited (0) 6 seconds ago                        mydocker
5e381e68a385        centos              "/bin/echo 'Hello wor"   16 minutes ago      Exited (0) 16 minutes ago                       clever_lamarr

[root@docker ~]# docker run --name docker-demo -d centos /bin/bash    -d代表放入后台执行
6c5a777467b9552714f9cd3322e677750e2b8b5b0bd2d81e79094ad560828a5e
[root@docker ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                      PORTS               NAMES
6c5a777467b9        centos              "/bin/bash"              11 seconds ago      Exited (0) 11 seconds ago                       docker-demo
1a67f4c92b6e        centos              "/bin/bash"              17 minutes ago      Exited (0) 4 minutes ago                        mydocker
5e381e68a385        centos              "/bin/echo 'Hello wor"   21 minutes ago      Exited (0) 21 minutes ago                       clever_lamarr

[root@docker ~]# docker stop mydocker    停止容器
[root@docker ~]# docker start 1a67f4c92b6e   启动容器

[root@docker ~]# docker run -d --name mynginx daocloud.io/library/nginx
225a9b0459630c62dcf2199d6244b16a74ad9412471abf0be03755768df3ae63
[root@docker ~]# 
[root@docker ~]# docker ps
CONTAINER ID        IMAGE                       COMMAND                  CREATED             STATUS              PORTS               NAMES
225a9b045963        daocloud.io/library/nginx   "nginx -g 'daemon off"   6 seconds ago   
    Up 5 seconds        80/tcp, 443/tcp     mynginx



进入容器脚步
[root@docker ~]# cat docker_in.sh 
#!/bin/bash

docker_in(){

  NAME_ID=$1
  PID=$(docker inspect --format "{{ .State.Pid }}" $NAME_ID)
  nsenter -t $PID -m -u -i -n -p

}


docker_in $1

四、docker网络

root@docker ~]# docker run -d -P --name nginx-test1 daocloud.io/library/nginx
9b1d36d40127fe2c84bbe7750802e435a817a15b4159b24fc49bfb1107a2cb74

[root@docker ~]# docker ps -l
CONTAINER ID        IMAGE                       COMMAND                  CREATED             STATUS              PORTS                                           NAMES
9b1d36d40127        daocloud.io/library/nginx   "nginx -g 'daemon off"   2 minutes ago       Up 2 minutes        0.0.0.0:32769->80/tcp, 0.0.0.0:32768->443/tcp   nginx-test1

[root@docker ~]# netstat -lntup|grep 32768
tcp6       0      0 :::32768                :::*                    LISTEN      11213/docker-proxy  

[root@docker ~]# curl -I http://172.16.80.132:32769
HTTP/1.1 200 OK
Server: nginx/1.11.5
Date: Thu, 24 Nov 2016 05:58:47 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 11 Oct 2016 15:03:01 GMT
Connection: keep-alive
ETag: "57fcff25-264"
Accept-Ranges: bytes


转换前
[root@docker ~]# iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            state NEW tcp dpt:22
REJECT     all  --  0.0.0.0/0            0.0.0.0/0            reject-with icmp-host-prohibited

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
DOCKER-ISOLATION  all  --  0.0.0.0/0            0.0.0.0/0           
DOCKER     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
REJECT     all  --  0.0.0.0/0            0.0.0.0/0            reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain DOCKER (1 references)
target     prot opt source               destination         

Chain DOCKER-ISOLATION (1 references)
target     prot opt source               destination         
RETURN     all  --  0.0.0.0/0            0.0.0.0/0           


转换后
[root@docker ~]# docker run -d -P --name nginx-test1 daocloud.io/library/nginx
42783cf5053639383004f82b9e72fe0223c7c028d2754b2d0f74429824715f05
[root@docker ~]# docker ps -l
CONTAINER ID        IMAGE                       COMMAND                  CREATED             STATUS              PORTS                                           NAMES
42783cf50536        daocloud.io/library/nginx   "nginx -g 'daemon off"   9 seconds ago       Up 7 seconds        0.0.0.0:32769->80/tcp, 0.0.0.0:32768->443/tcp   nginx-test1
[root@docker ~]# iptables -L -n
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            state RELATED,ESTABLISHED
ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            state NEW tcp dpt:22
REJECT     all  --  0.0.0.0/0            0.0.0.0/0            reject-with icmp-host-prohibited

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
DOCKER-ISOLATION  all  --  0.0.0.0/0            0.0.0.0/0           
DOCKER     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0            ctstate RELATED,ESTABLISHED
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
REJECT     all  --  0.0.0.0/0            0.0.0.0/0            reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain DOCKER (1 references)
target     prot opt source               destination         
ACCEPT     tcp  --  0.0.0.0/0            172.17.0.2           tcp dpt:443
ACCEPT     tcp  --  0.0.0.0/0            172.17.0.2           tcp dpt:80

Chain DOCKER-ISOLATION (1 references)
target     prot opt source               destination         
RETURN     all  --  0.0.0.0/0            0.0.0.0/0           

[root@docker ~]# sh docker_in.sh nginx-test1
root@42783cf50536:/# 
root@42783cf50536:/# 
root@42783cf50536:/# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
4: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:2/64 scope link 
       valid_lft forever preferred_lft forever

五、docker数据存储

[root@docker ~]# docker run -d --name nginx-volume-test1 -v /data daocloud.io/library/nginx
88b24d79a4f3b021325592ceac20e86291166d675b213d60db017548c4d9d960

[root@docker ~]# sh docker_in.sh nginx-volume-test1
root@88b24d79a4f3:/# cd /data/
root@88b24d79a4f3:/data# ls
root@88b24d79a4f3:/data# touch hehe
root@88b24d79a4f3:/data# ls -l      
total 0
-rw-r--r-- 1 root root 0 Nov 24 06:30 hehe

[root@docker ~]# cd /var/lib/docker/
[root@docker docker]# ll
total 32
drwx------ 6 root root 4096 Nov 24 14:28 containers
drwx------ 5 root root 4096 Nov 24 02:05 devicemapper
drwx------ 3 root root 4096 Nov 24 01:20 image
drwxr-x--- 3 root root 4096 Nov 24 01:20 network
drwx------ 2 root root 4096 Nov 24 01:20 swarm
drwx------ 2 root root 4096 Nov 24 10:09 tmp
drwx------ 2 root root 4096 Nov 24 01:20 trust
drwx------ 3 root root 4096 Nov 24 14:28 volumes
[root@docker docker]# cd volumes/
[root@docker volumes]# ls
4c60775f938a840e5484aee9088bc612977c25a01f5bd164690d94c962e66e60  metadata.db
[root@docker volumes]# cd 4c60775f938a840e5484aee9088bc612977c25a01f5bd164690d94c962e66e60/
[root@docker 4c60775f938a840e5484aee9088bc612977c25a01f5bd164690d94c962e66e60]# ls
_data
[root@docker 4c60775f938a840e5484aee9088bc612977c25a01f5bd164690d94c962e66e60]# cd _data/    容器内的文件实际在物理机上面的的保存目录
[root@docker _data]# ls
hehe

[root@docker ~]# docker run -d --name nginx-volume-test2 -v /data/mysql:/mysql daocloud.io/library/nginx   
f7278ce9bd88c26a0c5aaefcb2b39f1f9df0066bc94edb7a530213815e166f5e

#-v /data/mysql:/mysql  表示把物理机的/data/mysql目录挂载到容器内的/mysql目录下面


[root@docker ~]# docker run -d --name nginx-volumes -v /data/mysql:/mysql daocloud.io/library/nginx
28c616e44352fc4eafeb2f87dbbb7b6eb9df447235afe027034efa96df1c5071

[root@docker ~]# 
[root@docker ~]# docker run -d --name web-node1 --volumes-from nginx-volumes daocloud.io/library/nginx
0f022ce56e8b800cb1a4ac76bb8a326d42e198093146e8661ad3ac8925ad317d
[root@docker ~]# 
[root@docker ~]# docker run -d --name web-node2 --volumes-from nginx-volumes daocloud.io/library/nginx
03d5e88c15f6604eeee2b8af500b8f356ba69adc34710f3c19b813530f19dc3d

六、基于Dockerfile来创建mysql镜像

1）创建Dockerfile文件

[root@localhost ~]# mkdir mysql_ubuntu
[root@localhost ~]# cd mysql_ubuntu/
[root@localhost mysql_ubuntu]# cat Dockerfile 
FROM ubuntu:14.04

RUN apt-get update

RUN apt-get -y install mysql-client mysql-server
RUN sed -i -e"s/^bind-address\s*=\s*127.0.0.1/bind-address = 0.0.0.0/" /etc/mysql/my.cnf

ADD ./startup.sh /opt/startup.sh

EXPOSE 3306

CMD ["/bin/bash", "/opt/startup.sh"]

2）创建mysql服务启动脚本文件

[root@localhost mysql_ubuntu]# cat startup.sh 
#!/bin/bash

if [ ! -f /var/lib/mysql/ibdata1 ]; then

    mysql_install_db

    /usr/bin/mysqld_safe &
    sleep 10s

    echo "GRANT ALL ON *.* TO admin@'%' IDENTIFIED BY 'changeme' WITH GRANT OPTION; FLUSH PRIVILEGES" | mysql

    killall mysqld
    sleep 10s
fi

/usr/bin/mysqld_safe

3）构建mysql镜像

docker build -t centos/mysql .

4）查看镜像

[root@localhost ~]# docker images
REPOSITORY           TAG                 IMAGE ID            CREATED              VIRTUAL SIZE
centos/mysql        latest              f58add96ecb7        About a minute ago   338.9 MB

5）基于新镜像创建mysql容器

[root@localhost ~]# mkdir /data/mysql -p
[root@localhost ~]# docker run -d -p 3306:3306 -v /data/mysql:/var/lib/mysql centos/mysql
0112ba90e4a30a13e4f3af26f4a5bcd73e91ae3afa881a36fadd34cd953d0ada
[root@localhost ~]# docker ps -l
CONTAINER ID        IMAGE                  COMMAND                CREATED             STATUS              PORTS                    NAMES
0112ba90e4a3        centos/mysql:latest   "/bin/bash /opt/star   4 seconds ago       Up 3 seconds        0.0.0.0:3306->3306/tcp   reverent_hawking    
[root@localhost ~]# ll /data/mysql/
total 28680
-rw-rw----. 1 103  106 18874368 Apr 25 17:46 ibdata1
-rw-rw----. 1 103  106  5242880 Apr 25 19:09 ib_logfile0
-rw-rw----. 1 103  106  5242880 Apr 25 17:45 ib_logfile1
drwx------. 2 103 root     4096 Apr 25 17:45 mysql
drwx------. 2 103  106     4096 Apr 25 17:45 performance_schema

6）测试mysql容器

[root@localhost ~]# mysql -uadmin -p123456 -h192.168.0.104 -P 3306 -e 'show databases'
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
+--------------------+

或者提供一个登陆mysql客户端脚本

run-client.sh

#!/bin/sh

TAG="mysql"

CONTAINER_ID=$(docker ps | grep $TAG | awk '{print $1}')

IP=$(docker inspect $CONTAINER_ID | python -c 'import json,sys;obj=json.load(sys.stdin);print obj[0]["NetworkSettings"]["IPAddress"]')

mysql -u admin -p -h $IP

用dockerfile文件构建docker镜像灵活简便，推荐多多运用。

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