Docker容器技术介绍（一）Docker安装和简单使用

容器技术被认为是未来部署软件的主流趋势之一&＃xff0c;高性能&＃xff0c;轻量级及跨平台是容器技术的主要特征&＃xff0c;传统的应用部署过程大概是&＃xff1a;下载软件->编译安装->启动软件&＃xff0c;比如现在要安装 LNMP 软件&＃xff0c;就得先下载Nginx&＃43;Mysql&＃43;PHP&＃xff0c;然后一个个安装&＃xff0c;这对于一两台服务器时还能接受&＃xff0c;要是面对成千上万的服务器集群&＃xff0c;还不得累死吗&＃xff0c;有没有办法把这几个软件打包成一个软件一次性安装呢&＃xff0c;容器的出现使得很好的解决了这类问题。

什么是容器&＃xff1f;

以上是摘自Docker官网的一段话&＃xff0c;应该说是比较权威的解释&＃xff1a;容器以一种特定的格式来打包软件&＃xff0c;这种格式可以各自独立的运行在同一个操作系统之上&＃xff0c;不像虚拟机&＃xff0c;容器不会捆绑一个完整的操作系统&＃xff0c;而仅仅打包软件运行所需要的依赖库和设置。这样可以实现一个高效、轻量级、自给自足的系统&＃xff0c;并且可以保证软件总是以相同的方式运行&＃xff0c;而不管它被部署在哪里。

从上可知&＃xff0c;容器是一种打包应用的方式&＃xff0c;可以帮你打包应用中的所有软件和软件所依赖的环境&＃xff0c;并且可以实现跨平台部署。相比虚拟机&＃xff0c;容器更高效和轻量化&＃xff0c;一台服务器运行1000个虚拟机基本是难以想象的&＃xff0c;但IBM的服务器据称已经在一台服务器上运行万级的容器。

为什么使用容器&＃xff1f;

Docker是什么&＃xff1f; docker是容器领导者。

Docker是世界领先的软件容器平台&＃xff0c;在进行多人协作开发时&＃xff0c;开发者可以使用Docker来消除所谓“我这里运行是好的”&＃xff08;works on my machine&＃xff09;问题&＃xff0c;运维人员使用Docker来并行的运行和管理应用来获得更优计算密度&＃xff0c;基于各自独立的容器。企业使用Docker来建立敏捷的交付方式&＃xff0c;实现更快的、更安全的和更自信的交付新功能而不管是Linux或Windos服务器。

Docker安装&＃xff1a;

Centos 6.x

[root&＃64;localhost ~]# yum install epel-release
[root&＃64;localhost ~]# yum install docker-io
[root&＃64;localhost ~]# service docker start


输入docker version 验证安装是否成功

[root&＃64;localhost ~]# docker version
Client version: 1.7.1
Client API version: 1.19
Go version (client): go1.4.2
Git commit (client): 786b29d/1.7.1
OS/Arch (client): linux/amd64
Server version: 1.7.1
Server API version: 1.19
Go version (server): go1.4.2
Git commit (server): 786b29d/1.7.1
OS/Arch (server): linux/amd64


Centos 7.x

最新版的Docker需要64位CentOS 7系统&＃xff0c;并且分社区版&＃xff08;CE&＃xff09;和企业版&＃xff08;EE&＃xff09;&＃xff0c;一般选择免费的社区版即可

1.卸载旧版本&＃xff08;如果安装了的话&＃xff09;

[root&＃64;localhost ~]# yum remove docker docker-common docker-selinux docker-engine
Loaded plugins: fastestmirror
No Match for argument: docker
No Match for argument: docker-common
No Match for argument: docker-selinux
No Match for argument: docker-engine
No Packages marked for removal


2.安装

最简单的安装方式是直接 yum install&＃xff1a;

[root&＃64;localhost ~]# yum install docker

如果想要安装最新的稳定版&＃xff0c;可以使用下面的安装方式&＃xff1a;

[root&＃64;localhost software]# wget https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-17.06.2.ce-1.el7.centos.x86_64.rpm
[root&＃64;localhost software]# ls
docker-ce-17.06.2.ce-1.el7.centos.x86_64.rpm
[root&＃64;localhost software]# yum install docker-ce-17.06.2.ce-1.el7.centos.x86_64.rpm 


3.启动Docker服务

[root&＃64;localhost software]# systemctl start docker
[root&＃64;localhost software]# ps -aux | grep docker
root 23624 2.0 2.5 434500 25768 ? Ssl 06:43 0:00 /usr/bin/dockerd
root 23627 0.1 0.7 263940 7544 ? Ssl 06:43 0:00 docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval&＃61;0 --start-timeout 2m --state-dir /var/run/docker/libcontainerd/containerd --shim docker-containerd-shim --runtime docker-runc
root 23744 0.0 0.0 112660 972 pts/0 S&＃43; 06:43 0:00 grep --color&＃61;auto docker


可以看到Docker在后台启动了两个守护进程&＃xff1a;dockerd 和 docker-containerd

Docker的三个基本概念&＃xff1a;镜像、容器、仓库

镜像相当于创建容器的一个模具&＃xff0c;一个说明书&＃xff0c;而容器就是一个实实在在运行的镜像实例&＃xff0c;可以用可执行文件和进程来比喻镜像和容器的关系&＃xff0c;而仓库就是用来存放镜像的&＃xff0c;相当于git仓库&＃xff0c;用来存放不同版本的镜像。

Docker安装和简单使用

安装运行Nginx

[root&＃64;localhost ~]# docker search nginx
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
nginx Official build of Nginx. 6903 [OK]
jwilder/nginx-proxy Automated Nginx reverse proxy for docker c... 1130 [OK]
richarvey/nginx-php-fpm Container running Nginx &＃43; PHP-FPM capable ... 446 [OK]
jrcs/letsencrypt-nginx-proxy-companion LetsEncrypt container to use with nginx as... 227 [OK]
kong Open-source Microservice & API Management ... 115 [OK]
webdevops/php-nginx Nginx with PHP-FPM 90 [OK]
kitematic/hello-world-nginx A light-weight nginx container that demons... 86
bitnami/nginx Bitnami nginx Docker Image 36 [OK]
linuxserver/nginx An Nginx container, brought to you by Linu... 24
1and1internet/ubuntu-16-nginx-php-phpmyadmin-mysql-5 ubuntu-16-nginx-php-phpmyadmin-mysql-5 16 [OK]
tobi312/rpi-nginx NGINX on Raspberry Pi / armhf 11 [OK]
wodby/drupal-nginx Nginx for Drupal 8 [OK]
webdevops/nginx Nginx container 8 [OK]
.....


/* pull 镜像 */

[root&＃64;localhost software]# docker pull nginx
latest: Pulling from nginx
1cb018da208f: Pull complete
c1a0d2b79b3f: Pull complete
0aec54b378f5: Pull complete
b599d18a520b: Pull complete
a1cfc1b806a4: Pull complete
c2504687d157: Pull complete
a00416541f84: Pull complete
6adf11c406b6: Pull complete
9daddd1b8b0f: Pull complete
036477bc0d5a: Pull complete
Digest: sha256:248f3c1a01b35a098c85b31c356787068b1c1adbbd2f902fb2d6f49b95fd380f
Status: Downloaded newer image for nginx:latest


/* 列出本地镜像 */

[root&＃64;localhost software]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               latest              da5939581ac8        2 days ago          108MB


/* 启动一个容器&＃xff0c;并把容器中的80端口映射到宿主机的8080端口 -d表示让容器在后台运行 */

[root&＃64;localhost software]# docker run -d -p 8080:80 nginx
9af52c8b4dab91643860a7355acb1f04013ed5fd8d0b313568322f26affa2c40


/* 列出当前正在运行的容器 */

[root&＃64;localhost software]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS                  NAMES
9af52c8b4dab        nginx               "nginx -g &＃39;daemon ..."   About a minute ago   Up About a minute   0.0.0.0:8080->80/tcp   xenodochial_volhard


/* 可以看到上面docker ps的信息没有显示全&＃xff0c;有的被截断了 可以在命令加上 --no-trunc 参数强制完全显示 */

[root&＃64;localhost ~]# docker ps --no-trunc
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
724db6813f511ade01cb907ec82008a8930e4db0275cbaf36f6c8503a0cec7c9 nginx "nginx -g &＃39;daemon off;&＃39;" 16 seconds ago Up 15 seconds 0.0.0.0:8080->80/tcp goofy_morse


/* 测试nginx是否正常启动 */

[root&＃64;localhost software]# curl &＃39;127.0.0.1:8080&＃39;





...


/* 停止容器运行 */

[root&＃64;localhost software]# docker stop 9af52c8b4dab
9af52c8b4dab
[root&＃64;localhost software]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES


/* -a 参数会列出所有的容器&＃xff0c;包括已停止的 */

[root&＃64;localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
724db6813f51 nginx "nginx -g &＃39;daemon of 5 minutes ago Exited (0) 6 seconds ago goofy_morse


/* docker rm 删除容器 */

[root&＃64;localhost ~]# docker rm 724db6813f51
724db6813f51
[root&＃64;localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES


/* docker rmi 删除镜像 */

[root&＃64;localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
ubuntu 14.04 b44ce450cb60 12 days ago 188 MB
nginx latest 036477bc0d5a 13 days ago 108.3 MB
[root&＃64;localhost ~]# docker rmi 036477bc0d5a
Untagged: nginx:latest
Deleted: 036477bc0d5a32c5618eb350669ebadcf082c41f1be3b0141d22284742bc796f
Deleted: 9daddd1b8b0faf3af09a3b25704ac2cb742a9a31114c0773c69f745364ac9569
Deleted: 6adf11c406b68fe96f4e5cbb5f8baf7123f8df13f77cda9d2439e8e3c994fc5b
Deleted: a00416541f8403247a87f49310e7ae687397bacd613b055a644aafedd4c0cbe1
Deleted: c2504687d1573cf99eb64283cfa4c160d4e2d15befbd617f5551e5a02242513e
Deleted: a1cfc1b806a41781e27bef106fb38e49f8d158253d318e032927d507c0285a37
Deleted: b599d18a520b37f6e0a587485e54dcc141c3a181f25b651fd45d071670b61b72
Deleted: 0aec54b378f58193513ddf12e1f855d44fb11ccf5810bd93687f6e13d107e8a0
Deleted: c1a0d2b79b3f6e909c6c621d4e33a3bda0ac46560d18602ca7ff3367360251e7
Deleted: 1cb018da208f97b77e79f5d42a29a05246afae8f7072683d93e06576af32b470
[root&＃64;localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
ubuntu 14.04 b44ce450cb60 12 days ago 188 MB

只输入docker可以查看docker支持的所有命令&＃xff0c;输入docker COMMAND --help可以查看特定命令的帮助

[root&＃64;localhost software]# dockerUsage: docker COMMANDA self-sufficient runtime for containersOptions:--config string Location of client config files (default "/root/.docker")-D, --debug Enable debug mode--help Print usage-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 quitManagement Commands:config Manage Docker configscontainer Manage containersimage Manage imagesnetwork Manage networksnode Manage Swarm nodesplugin Manage pluginssecret Manage Docker secretsservice Manage servicesstack Manage Docker stacksswarm Manage Swarmsystem Manage Dockervolume Manage volumesCommands:attach Attach local standard input, output, and error streams to a running containerbuild Build an image from a Dockerfilecommit Create a new image from a container&＃39;s changescp Copy files/folders between a container and the local filesystemcreate Create a new containerdiff Inspect changes to files or directories on a container&＃39;s filesystemevents Get real time events from the serverexec Run a command in a running containerexport Export a container&＃39;s filesystem as a tar archivehistory Show the history of an imageimages List imagesimport Import the contents from a tarball to create a filesystem imageinfo Display system-wide informationinspect Return low-level information on Docker objectskill Kill one or more running containersload Load an image from a tar archive or STDINlogin Log in to a Docker registrylogout Log out from a Docker registrylogs Fetch the logs of a containerpause Pause all processes within one or more containersport List port mappings or a specific mapping for the container
.....

[root&＃64;localhost software]# docker run --helpUsage: docker run [OPTIONS] IMAGE [COMMAND] [ARG...]Run a command in a new containerOptions:--add-host list Add a custom host-to-IP mapping (host:ip)-a, --attach list Attach to STDIN, STDOUT or STDERR--blkio-weight uint16 Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0)--blkio-weight-device list Block IO weight (relative device weight) (default [])--cap-add list Add Linux capabilities--cap-drop list Drop Linux capabilities--cgroup-parent string Optional parent cgroup for the container--cidfile string Write the container ID to the file--cpu-period int Limit CPU CFS (Completely Fair Scheduler) period--cpu-quota int Limit CPU CFS (Completely Fair Scheduler) quota--cpu-rt-period int Limit CPU real-time period in microseconds--cpu-rt-runtime int Limit CPU real-time runtime in microseconds-c, --cpu-shares int CPU shares (relative weight)--cpus decimal Number of CPUs--cpuset-cpus string CPUs in which to allow execution (0-3, 0,1)
......

Docker的简单使用就介绍到这里&＃xff0c;想更深入了解Docker技术欢迎关注后续文章&＃xff01;

That‘s it ^^