Docker快速入门基础教程

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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

Docker 快速入门基础教程

3、docker 组件
镜像、容器、仓库

4、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

5、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

6、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

7、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