Docker基础二（基本安装）

一、操作系统版本要求

    CentOS 7 要求系统为 64 位、系统内核版本为 3.10 以上。（最好用7）
    CentOS-6.5 或更高的版本的 CentOS 上，要求系统为 64 位、系统内核版本为 2.6.32-431 或者更高版本。

1、查看系统内核版本

[root@master ~]# uname  -r
3.10.0-1127.el7.x86_64
[root@master ~]# cat /etc/redhat-release
CentOS Linux release 7.8.2003 (Core)
[root@master ~]#

2、关闭系统防火墙与 Selinux

[root@master ~]# systemctl stop firewalld
[root@master ~]# systemctl status firewalld
[root@master ~]# getenforce
Enforcing
[root@master ~]# setenforce 0
[root@master ~]# sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
[root@master ~]# reboot

3、装 Docker 的准备

1、删除机器自动docker软件包
[root@master ~]# yum remove docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-engine
2、安装依赖包
[root@master ~]# yum install -y yum-utils device-mapper-persistent-data lvm2 

4、下载 Docker CE Yum 源 (社区版)和开机启动

[root@master ~]# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
[root@master ~]# yum install wget net-tools vim -y
[root@docker ~]# yum search docker-ce
[root@docker ~]# yum install docker-ce-19.03.6 docker-ce-cli-19.03.6 containerd.io 
[root@master ~]# systemctl start docker
[root@master ~]# systemctl enable docke

5、Docker 信息查询

Docker 是传统的 CS 架构分为 Docker Client 和 Docker Server

[root@master ~]# docker version
Client: Docker Engine - Community
 Version:           19.03.6
 API version:       1.40
 Go version:        go1.12.16
 Git commit:        369ce74a3c
 Built:             Thu Feb 13 01:29:29 2020
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.6
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.16
  Git commit:       369ce74a3c
  Built:            Thu Feb 13 01:28:07 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.2.10
  GitCommit:        b34a5c8af56e510852c35414db4c1f4fa6172339
 runc:
  Version:          1.0.0-rc8+dev
  GitCommit:        3e425f80a8c931f88e6d94a8c831b9d5aa481657
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

6、查看 ip 地址

[root@master ~]# ip a
3: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether 02:42:c2:45:a0:88 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:c2ff:fe45:a088/64 scope link
       valid_lft forever preferred_lft forever

7、Docker 状态信息查看

[root@master ~]# docker info
 Docker Root Dir: /var/lib/docker   #默认数据存储目录
 Registry Mirrors:
  https://registry.docker-cn.com/   #默认镜像加速器

8、修改 Docker 存储数据存储目录

# 修改ExecStart
[root@master ~]# vim /usr/lib/systemd/system/docker.service
# ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
ExecStart=/usr/bin/dockerd  --graph=/data/docker  -H fd:// --containerd=/run/containerd/containerd.sock
[root@master docker]# systemctl restart  docker
Warning: docker.service changed on disk. Run 'systemctl daemon-reload' to reload units.
[root@master docker]# systemctl daemon-reload
[root@master docker]# systemctl restart  docker
[root@master docker]# ls /data/
docker
[root@master docker]# docker info
Docker Root Dir: /data/docke

9、添加阿里云镜像加速器

[root@master docker]# mkdir -p /etc/docker
[root@master ~]# cat /etc/docker/daemon.json
{
"registry-mirrors": ["https://plqjafsr.mirror.aliyuncs.com"]
}
[root@master ~]# systemctl daemon-reload
[root@master ~]# systemctl restart docker
[root@master ~]# docker info
 Registry Mirrors:
  https://plqjafsr.mirror.aliyuncs.com/

10、运行第一个 Docker 应用

[root@master ~]# docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
0e03bdcc26d7: Pull complete
Digest: sha256:7f0a9f93b4aa3022c3a4c147a449bf11e0941a1fd0bf4a8e6c9408b2600777c5
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

11、C/S 模式

    Docker 客户端和服务端是使用 Socket 方式连接，主要有以下几种方式:

　　1、本地的 socket 文件 unix:///var/run/docker/sock (默认)

　　2、tcp://host:prot (演示)

　　3、fd://socketfd

    1、未启动的状态, 说明 Docker 在默认情况下使用本地的 var/run/docker.sock 连接

[root@master ~]# systemctl stop  docker
[root@master ~]# docker info
Client:
 Debug Mode: false

Server:
ERROR: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
errors pretty printing info

    2、设置 Docker 远程使用 TCP 的连接方式，打开 sock 与 tcp 连接方式，并查看状态和地址端口监听

[root@master ~]# vim /usr/lib/systemd/system/docker.service
# ExecStart=/usr/bin/dockerd  --graph=/data/docker  -H fd:// --containerd=/run/containerd/containerd.sock
ExecStart=/usr/bin/dockerd --graph=/data/docker -H tcp://0.0.0.0:2375 -H unix://var/run/docker.sock -H fd:// --containerd=/run/containerd/containerd.sock
[root@master ~]# systemctl  restart docker
Warning: docker.service changed on disk. Run 'systemctl daemon-reload' to reload units.
[root@master ~]# systemctl daemon-reload
[root@master ~]# systemctl  restart docker
[root@master ~]# docker info
WARNING: API is accessible on http://0.0.0.0:2375 without encryption.      #警告：API是可访问的http://0.0.0.0：2375未加密。
         Access to the remote API is equivalent to root access on the host. Refer
         to the 'Docker daemon attack surface' section in the documentation for
         more information: https://docs.docker.com/engine/security/security/#docker-daemon-attack-surfac
[root@master ~]# systemctl  status docker　　
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since 日 2020-08-23 10:59:17 EDT; 5min ago
     Docs: https://docs.docker.com
 Main PID: 16304 (dockerd)
    Tasks: 10
   Memory: 43.7M
   CGroup: /system.slice/docker.service
           └─16304 /usr/bin/dockerd --graph=/data/docker -H tcp://0.0.0.0:2375 -H unix://var/run/docker.sock -H fd:// --containerd=/run/containerd/containerd.soc
# 查看监听端口
[root@master ~]# netstat -tnlup |grep 2375
tcp6       0      0 :::2375                 :::*                    LISTEN      16304/docker

12、远程连接 Docker TCP 查看 Docker 信息

    1、在另外一台安装 Docker 的宿主机连接(从 172.16.73.158 客户端远程到 172.16.73.157 服务端)172.16.73.158 需要安装 Docker 客户端

[root@node-1 ~]# docker -H 172.16.73.157:2375 info
Client:
 Debug Mode: false

Server:
 Containers: 1
  Running: 0
  Paused: 0
  Stopped: 1
 Images: 1
 Server Version: 19.03.6
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: b34a5c8af56e510852c35414db4c1f4fa6172339
 runc version: 3e425f80a8c931f88e6d94a8c831b9d5aa481657
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 3.10.0-1127.el7.x86_64
 Operating System: CentOS Linux 7 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 3.682GiB
 Name: master
 ID: JMG5:PS5E:YD7Z:6DI6:LJ3Q:NKMQ:JEM6:TCDC:4R5X:THJR:K437:R222
 Docker Root Dir: /data/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://plqjafsr.mirror.aliyuncs.com/
 Live Restore Enabled: false

    2、远程连接查看 Docker Images

[root@node-1 ~]# docker -H 172.16.73.157:2375 images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              bf756fb1ae65        7 months ago        13.3kB
# 查看远程Docker容器
[root@node-1 ~]# docker -H 172.16.73.157:2375 ps --all     
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                      PORTS               NAMES
6b9ab6487ac0        hello-world         "/hello"            58 minutes ago      Exited (0) 58 minutes ago                       gallant_ride
# 远程启动容器
[root@node-1 ~]# docker -H 172.16.73.157:2375 start 6b9ab6487ac0
6b9ab6487ac0

13、Docker 应用程序运行条件

     1、计算机硬件: CPU、内存、磁盘、显卡、网卡(物理机/虚拟机)。
     2、支持运行 Docker 的操作系统 (NS、Cgroups、OverlayFS)。
     3、安装 Docker 服务，并且能够正常运行。
     4、需要可以运行在 Docker 里面的镜像, 镜像来自本地、docker hub、远程私有仓库。

    5、在镜像加载需要运行的程序(最终目的)。

14、程序在容器中运行条件逻辑图