一：Docker简介

（1）概念

Docker 是一个开源的应用容器引擎，让开发者可以打包他们的应用以及依赖包到一个可移植的镜像中，然后发布到任何流行的。

Linux或Windows 机器上，也可以实现虚拟化。容器是完全使用沙箱机制，相互之间不会有任何接口。非常方便。

（2）架构

一个完整的Docker有以下几个部分组成：

DockerClient客户端
Docker Daemon守护进程
Docker Image镜像
DockerContainer容器

微信图片_20220509162256.png

Docker daemon 一般在宿主主机后台运行，等待接收来自客户端的消息。 Docker

客户端则为用户提供一系列可执行命令，用户用这些命令实现跟 Docker daemon 交互

（3）特性

Automating the packaging and deployment of applications（使应用的打包与部署自动化）
Creation of lightweight, private PAAS environments（创建轻量、私密的PAAS环境）
Automated testing and continuous integration/deployment（实现自动化测试和持续的集成/部署）
Deploying and scaling web apps, databases and backend services（部署与扩展webapp、数据库和后台服务）

由于其基于LXC的轻量级虚拟化的特点，docker相比KVM之类最明显的特点就是启动快，资源占用小。因此对于构建隔离的标准化的运行环境，轻量级的PaaS(如dokku),

构建自动化测试和持续集成环境，以及一切可以横向扩展的应用(尤其是需要快速启停来应对峰谷的web应用)。

（4）局限

Docker是基于Linux 64bit的，无法在32bit的linux/Windows/unix环境下使用

LXC是基于cgroup等linux kernel功能的，因此container的guest系统只能是linux base的

隔离性相比KVM之类的虚拟化方案还是有些欠缺，所有container公用一部分的运行库网络管理相对简单，主要是基于namespace隔离

cgroup的cpu和cpuset提供的cpu功能相比KVM的等虚拟化方案相比难以度量(所以dotcloud主要是按内存收费)

Docker对disk的管理比较有限 container随着用户进程的停止而销毁，container中的log等用户数据不便收集

（5）Docker和Vm区别

1.实现原理不同

VM通过Hypervisor提供基础环境实现虚拟机 Docker通过docker

engine与物理机共享操作系统而不是在向虚拟机一样，完全仿真一个虚拟操作系统，Docker达到了类似虚拟机的效果，但是又没有虚拟机的开销，它虚拟的层次更加高。

Docker不虚拟机器，仅仅虚拟应用的运行环境

微信图片_20220509162548.png

2.使用上的区别

Docker在宿主机器的操作系统上创建Docker引擎，直接在宿主主机的操作系统上调用硬件资源，而不是虚拟化操作系统和硬件资源，所以操作速度快。

这个其实安装一个ubuntu的虚拟机和拉取一个Docker的ubuntu镜像文件，运行一下就知道了，区别很明显，虚拟机开一下大概得2分多钟，而Docker只需要2秒钟。

二：docker三个特征

镜像

容器

仓库

docker实际可以理解为简易版的linux系统

容器就是镜像的一个实例

仓库（Repository）是存放镜像的厂所

仓库注册服务器（Registry）放着多个仓库，每个仓库又放着多个镜像，每个镜像又有不同的标签（类似版本号）

仓库分为公开仓库和私有仓库两种形式最大的公开库是Docker Hub。（太慢，国外网站）国内公开仓库包括阿里云，网易云

三、docker的安装及测试

部署环境：

[root@a ~]# ping qq.com
PING qq.com (125.39.52.26) 56(84) bytes of data.
64 bytes from no-data (125.39.52.26): icmp_seq=1 ttl=50 time=59.6 ms
64 bytes from no-data (125.39.52.26): icmp_seq=2 ttl=50 time=152 ms
64 bytes from no-data (125.39.52.26): icmp_seq=3 ttl=50 time=210 ms
64 bytes from no-data (125.39.52.26): icmp_seq=4 ttl=50 time=88.2 ms
^C
--- qq.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3015ms
rtt min/avg/max/mdev = 59.646/127.784/210.411/58.431 ms
[root@a ~]# cat /etc/redhat-release
CentOS Linux release 7.7.1908 (Core)
[root@a ~]# uname -r
3.10.0-1062.el7.x86_64

1、设置yum源

[root@a ~]# yum install -y yum-utils
[root@a ~]# yum-config-manager \
    --add-repo \
   https://download.docker.com/linux/centos/docker-ce.repo
[root@a ~]# yum makecache fast
Docker安装报错：containerd.io-1.2.13-3.1.el7.x86_64 (docker-ce-stable) 需要：container-selinux >= 2:2.74
解决方案：
[root@a ~]# yum install -y wget
[root@a ~]# wget -O http://mirrors.aliyun.com/repo/Centos-7.repo
[root@a ~]# mv Centos-7.repo /etc/yum.repos.d/
[root@a ~]# yum install epel-release
[root@a ~]# yum install container-selinux

2、安装最新版本的 Docker Engine-Community 和 containerd

[root@a ~]# yum install docker-ce docker-ce-cli containerd.io
...
Installed:
  containerd.io.x86_64 0:1.2.13-3.2.el7              docker-ce.x86_64 3:19.03.8-3.el7
  docker-ce-cli.x86_64 1:19.03.8-3.el7
Complete!

3、启动服务

[root@a ~]# systemctl start docker
[root@a ~]# docker --version
Docker version 19.03.8, build afacb8b

4、配置镜像加速器

登录阿里云搜素镜像加速器
[root@a ~]# mkdir -p /etc/docker
[root@a ~]# tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://..............."]
}
EOF
[root@a ~]# systemctl daemon-reload
[root@a ~]# systemctl restart docker
[root@a ~]# ps -ef |grep docker
root      12225      1  0 08:10 ?        00:00:00 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
root      12362   1737  0 08:12 pts/0    00:00:00 grep --color=auto docker

5、测试

[root@a ~]# docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
0e03bdcc26d7: Pull complete
Digest: sha256:6a65f928fb91fcfbc963f7aa6d57c8eeb426ad9a20c7ee045538ef34847f44f1
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.
To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash
Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/
For more examples and ideas, visit:
 https://docs.docker.com/get-started/

6、run有什么用？

开始>>>docker在本机中寻找镜像>>>本机是否有该镜像{1.有，以镜像为模板生产容器实例运行 2.没有，去dockerHub上找}>>>dockerHub上能否找到{1.能，下载镜像到本地，以镜像为模板生产容器实例运行 2.不能，返回错误值结束}

7、基础命令

一、帮助命令

1、docker version（查看docker基本信息）
[root@a ~]# docker version
Client: Docker Engine - Community
 Version:           19.03.8
 API version:       1.40
 Go version:        go1.12.17
 Git commit:        afacb8b
 Built:             Wed Mar 11 01:27:04 2020
 OS/Arch:           linux/amd64
 Experimental:      false
Server: Docker Engine - Community
 Engine:
  Version:          19.03.8
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.17
  Git commit:       afacb8b
  Built:            Wed Mar 11 01:25:42 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.2.13
  GitCommit:        7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc:
  Version:          1.0.0-rc10
  GitCommit:        dc9208a3303feef5b3839f4323d9beb36df0a9dd
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683

二、docker info(查看容器信息)

[root@a ~]# docker info
Client:
 Debug Mode: false
Server:
 Containers: 1
  Running: 0
  Paused: 0
  Stopped: 1
 Images: 1
 Server Version: 19.03.8
 Storage Driver: overlay2
  Backing Filesystem: <unknown>
  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: 7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc version: dc9208a3303feef5b3839f4323d9beb36df0a9dd
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 3.10.0-1062.el7.x86_64
 Operating System: CentOS Linux 7 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 972.4MiB
 Name: a
 ID: VIBZ:LAXM:EH6G:R2JL:MQYU:7D25:HCZT:V234:BEP5:ZV67:RPG7:LZFY
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://wuz1gh9p.mirror.aliyuncs.com/
 Live Restore Enabled: false

三、docker --help

[root@a ~]# docker --help
Usage:  docker [OPTIONS] COMMAND
A self-sufficient runtime for containers
Options:
      --config string      Location of client config files (default "/root/.docker")
  -c, --context string     Name of the context to use to connect to the daemon (overrides DOCKER_HOST env var
                           and default context set with "docker context use")
  -D, --debug              Enable debug mode
  -H, --host list          Daemon socket(s) to connect to
  -l, --log-level string   Set the logging level ("debug"|"info"|"warn"|"error"|"fatal") (default "info")
      --tls                Use TLS; implied by --tlsverify
      --tlscacert string   Trust certs signed only by this CA (default "/root/.docker/ca.pem")
      --tlscert string     Path to TLS certificate file (default "/root/.docker/cert.pem")
      --tlskey string      Path to TLS key file (default "/root/.docker/key.pem")
      --tlsverify          Use TLS and verify the remote
  -v, --version            Print version information and quit
Management Commands:
  builder     Manage builds
  config      Manage Docker configs
  container   Manage containers
  context     Manage contexts
  engine      Manage the docker engine
  image       Manage images
  network     Manage networks
  node        Manage Swarm nodes
  plugin      Manage plugins
  secret      Manage Docker secrets
  service     Manage services
  stack       Manage Docker stacks
  swarm       Manage Swarm
  system      Manage Docker
  trust       Manage trust on Docker images
  volume      Manage volumes
Commands:
  attach      Attach local standard input, output, and error streams to a running container
  build       Build an image from a Dockerfile
  commit      Create a new image from a container's changes
  cp          Copy files/folders between a container and the local filesystem
  create      Create a new container
  diff        Inspect changes to files or directories on a container's filesystem
  events      Get real time events from the server
  exec        Run a command in a running container
  export      Export a container's filesystem as a tar archive
  history     Show the history of an image
  images      List images
  import      Import the contents from a tarball to create a filesystem image
  info        Display system-wide information
  inspect     Return low-level information on Docker objects
  kill        Kill one or more running containers
  load        Load an image from a tar archive or STDIN
  login       Log in to a Docker registry
  logout      Log out from a Docker registry
  logs        Fetch the logs of a container
  pause       Pause all processes within one or more containers
  port        List port mappings or a specific mapping for the container
  ps          List containers
  pull        Pull an image or a repository from a registry
  push        Push an image or a repository to a registry
  rename      Rename a container
  restart     Restart one or more containers
  rm          Remove one or more containers
  rmi         Remove one or more images
  run         Run a command in a new container
  save        Save one or more images to a tar archive (streamed to STDOUT by default)
  search      Search the Docker Hub for images
  start       Start one or more stopped containers
  stats       Display a live stream of container(s) resource usage statistics
  stop        Stop one or more running containers
  tag         Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
  top         Display the running processes of a container
  unpause     Unpause all processes within one or more containers
  update      Update configuration of one or more containers
  version     Show the Docker version information
  wait        Block until one or more containers stop, then print their exit

Docker系列（1）--Docker原理及安装

一：Docker简介

（1）概念

（2）架构

（3）特性

（4）局限

（5）Docker和Vm区别

二：docker三个特征

三、docker的安装及测试

部署环境：

1、设置yum源

2、安装最新版本的 Docker Engine-Community 和 containerd

3、启动服务

4、配置镜像加速器

5、测试

6、run有什么用？

7、基础命令

一、帮助命令

二、docker info(查看容器信息)

三、docker --help

热门文章

最新文章

相关课程

相关电子书

相关实验场景

推荐镜像

热门

活动广场

任务中心

开发者评测

高校计划

乘风者计划

训练营

阿里云MVP

话题

直播

下载

镜像站

技术资料

插件

Docker系列（1）--Docker原理及安装

一：Docker简介

（1）概念

（2）架构

（3）特性

（4）局限

（5）Docker和Vm区别

二：docker三个特征

三、docker的安装及测试

部署环境：

1、设置yum源

2、安装最新版本的 Docker Engine-Community 和 containerd

3、启动服务

4、配置镜像加速器

5、测试

6、run有什么用？

7、基础命令

一、帮助命令

二、docker info(查看容器信息)

三、docker --help

热门文章

最新文章

相关课程

相关电子书

相关实验场景

推荐镜像