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Docker第二回(Docker的使用)

运维开发网 https://www.qedev.com 2020-07-15 15:10 出处:网络 作者:运维开发网整理
一、使用Docker的限制 1、要想使用linux容器,内核版本要高于3.8以上,并且至少在linux内核级要支持两种技术,namespaces和CGroups。接着借助于在用户空间组织一些工具,利用内核级所提供的这些技术, 从而实现容器运行的目的,Docker在容器运行使用简化的道路上又近了一步,Docker提供了镜像,而且是分层构建联合挂载的方式,使得容器技术的使用更加被简化。后来在Docke

一、使用Docker的限制

1、要想使用Linux容器,内核版本要高于3.8以上,并且至少在Linux内核级要支持两种技术,namespaces和CGroups。接着借助于在用户空间组织一些工具,利用内核级所提供的这些技术, 从而实现容器运行的目的,Docker在容器运行使用简化的道路上又近了一步,Docker提供了镜像,而且是分层构建联合挂载的方式,使得容器技术的使用更加被简化。后来在Docker的主导下,又有了OCI和OCF标准。

OCI(Open Container Initiative):由Linux基金会主导于2015年6月创立,OCI定义了容器运行时的标准,

OCI有两部分组成:

                        the Runtime Specification:运行时标准

                        the image Specification:镜像格式标准

 

OCF(Open Container Format):runC是Docker按照开放容器格式标准(OCF)制定的一种具体实现,runC是从Docker的libcontainer中迁移而来的,实现了容器启停,资源隔离等功能,Docker默认提供了docker-runc实现。

 

二、Docker的镜像

默认Docker的镜像是集中放置在Docker Hub上的,docker在创建容器时,Docker会先检查本地是否有镜像,如果没有会到docker hub上去下载指定的镜像到本地,并且下载下来的镜像在容器使用结束后不会删除,镜像是不可修改的,只能重构。下面是docker的整体架构

Docker第二回(Docker的使用)

 

 

三、Docker的安装及使用

3.1、依赖及基础环境:

                        1、64 bits CPU

                        2、Linux Kernel 3.10+

                        3、 Linux Kernel  cgroups and namespaces

3.2、centos 7安装方式

1、extras repository;默认centos7的yum仓库extras就有docker,版本比较老,下载新版本的docker的yum仓库

[[email protected] ~]# cd /etc/yum.repos.d/ [[email protected] yum.repos.d]# wget https://mirrors.tuna.tsinghua.edu.cn/docker-ce/Linux/centos/docker-ce.repo [[email protected] yum.repos.d]# sed -i ‘s#https://download.docker.com#https://mirrors.tuna.tsinghua.edu.cn/docker-ce#g‘ docker-ce.repo [[email protected] yum.repos.d]# yum update [[email protected] yum.repos.d]# yum install docker-ce
 

 

2、docker-ce的配置文件;需要手动创建

[[email protected] yum.repos.d]# mkdir /etc/docker/ [[email protected] docker]# echo -e ‘{\n\t"registry-mirrors": ["https://registry.docker-cn.com"]\n}‘ >/etc/docker/daemon.json [[email protected] docker]# systemctl start docker.service [[email protected] docker]# docker info Containers: 0 Running: 0 Paused: 0 Stopped: 0 Images: 0 Server Version: 18.06.1-ce Storage Driver: overlay2 # docker要实现分层构建,联合挂载。必须使用这种文件系统来支持。在centos7.4以前用的是device mapper,这种是lvm的实现,在docker上性能极差,还不稳定,已经废弃。 ...... ...... ......
 

在能看到上面的一系列信息,说明docker已经安装成功并可以使用了

 

3、docker 仓库格式

[[email protected] docker]# docker search nginx NAME DESCRIPTION STARS OFFICIAL AUTOMATED nginx Official build of Nginx. 10034 [OK] jwilder/nginx-proxy Automated Nginx reverse proxy for docker con?? 1440 [OK] richarvey/nginx-php-fpm Container running Nginx + PHP-FPM capable of?? 633 [OK] jrcs/letsencrypt-nginx-proxy-companion LetsEncrypt container to use with nginx as p?? 428 [OK] kong Open-source Microservice & API Management la?? 237 [OK] webdevops/php-nginx Nginx with PHP-FPM 117 [OK] kitematic/hello-world-nginx A light-weight nginx container that demonstr?? 112 zabbix/zabbix-web-nginx-mysql Zabbix frontend based on Nginx web-server wi?? 74 [OK] bitnami/nginx Bitnami nginx Docker Image 58 [OK] 1and1internet/ubuntu-16-nginx-php-phpmyadmin-mysql-5 ubuntu-16-nginx-php-phpmyadmin-mysql-5 48 [OK] Linuxserver/nginx An Nginx container, brought to you by LinuxS?? 42 tobi312/rpi-nginx NGINX on Raspberry Pi / armhf 23 [OK] blacklabelops/nginx Dockerized Nginx Reverse Proxy Server. 12 [OK] wodby/drupal-nginx Nginx for Drupal container image 11 [OK] centos/nginx-18-centos7 Platform for running nginx 1.8 or building n?? 8 webdevops/nginx Nginx container 8 [OK] nginxdemos/hello NGINX webserver that serves a simple page co?? 8 [OK] centos/nginx-112-centos7 Platform for running nginx 1.12 or building ?? 5 1science/nginx Nginx Docker images that include Consul Temp?? 4 [OK] travix/nginx NGinx reverse proxy 2 [OK] mailu/nginx Mailu nginx frontend 2 [OK] pebbletech/nginx-proxy nginx-proxy sets up a container running ngin?? 2 [OK] toccoag/openshift-nginx Nginx reverse proxy for Nice running on same?? 1 [OK] ansibleplaybookbundle/nginx-apb An APB to deploy NGINX 0 [OK] wodby/nginx Generic nginx 0 [OK]
 

 

上面列表中,没有/分隔开的仓库是顶级仓库,一般是docker hub官方的。带/分隔开的是个人用户创建的镜像

 

4、启动一个docker镜像

docker run命令启动容器时会先在本地仓库查找镜像,如果没有在去docker hub仓库中下载镜像并启动

[[email protected] docker]# docker container run --name nginx1 -d nginx:stable Unable to find image ‘nginx:stable‘ locally # 说明本地仓库中没有nginx:stable镜像 stable: Pulling from library/nginx f17d81b4b692: Pull complete 3df1ab0a1750: Pull complete 576b56a453df: Pull complete Digest: sha256:8b600a4d029481cc5b459f1380b30ff6cb98e27544fc02370de836e397e34030 Status: Downloaded newer image for nginx:stable # 从docker hub仓库中下载nginx:stable镜像成功 d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1 [[email protected] docker]# docker container ls # 查看正在运行的容器,发现nginx:stable已经正常运行 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d5eb28ecbc5c nginx:stable "nginx -g ‘daemon of?? 4 minutes ago Up 4 minutes 80/tcp nginx1
 

 

查看正在运行的容器详细信息

[[email protected] docker]# docker container inspect nginx1 [ { "Id": "d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1", "Created": "2018-10-31T13:45:39.761183953Z", "Path": "nginx", "Args": [ "-g", "daemon off;" ], "State": { "Status": "running", "Running": true, "Paused": false, "Restarting": false, "OOMKilled": false, "Dead": false, "Pid": 30605, "ExitCode": 0, "Error": "", "StartedAt": "2018-10-31T13:45:40.064902138Z", "FinishedAt": "0001-01-01T00:00:00Z" }, "Image": "sha256:ecc98fc2f376d6560311b66d6958e4350a5a485ee07aa2d1235842d0bce440da", "ResolvConfPath": "/var/lib/docker/containers/d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1/resolv.conf", "HostnamePath": "/var/lib/docker/containers/d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1/hostname", "HostsPath": "/var/lib/docker/containers/d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1/hosts", "LogPath": "/var/lib/docker/containers/d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1/d5eb28ecbc5cbe86fb430c4098361b7199c9147e79c06096868746dc638ebec1-json.log", "Name": "/nginx1", "RestartCount": 0, "Driver": "overlay2", "Platform": "Linux", "MountLabel": "", "ProcessLabel": "", "AppArmorProfile": "", "ExecIDs": null, "HostConfig": { "Binds": null, "ContainerIDFile": "", "LogConfig": { "Type": "json-file", "Config": {} }, "NetworkMode": "default", "PortBindings": {}, "RestartPolicy": { "Name": "no", "MaximumRetryCount": 0 }, "AutoRemove": false, "VolumeDriver": "", "VolumesFrom": null, "CapAdd": null, "CapDrop": null, "Dns": [], "DnsOptions": [], "DnsSearch": [], "ExtraHosts": null, "GroupAdd": null, "IpcMode": "shareable", "Cgroup": "", "Links": null, "OomScoreAdj": 0, "PidMode": "", "Privileged": false, "PublishAllPorts": false, "ReadonlyRootfs": false, "SecurityOpt": null, "UTSMode": "", "UsernsMode": "", "ShmSize": 67108864, "Runtime": "runc", "ConsoleSize": [ 0, 0 ], "Isolation": "", "CpuShares": 0, "Memory": 0, "NanoCpus": 0, "CgroupParent": "", "BlkioWeight": 0, "BlkioWeightDevice": [], "BlkioDeviceReadBps": null, "BlkioDeviceWriteBps": null, "BlkioDeviceReadIOps": null, "BlkioDeviceWriteIOps": null, "CpuPeriod": 0, "CpuQuota": 0, "CpuRealtimePeriod": 0, "CpuRealtimeRuntime": 0, "CpusetCpus": "", "CpusetMems": "", "Devices": [], "DeviceCgroupRules": null, "DiskQuota": 0, "KernelMemory": 0, "MemoryReservation": 0, "MemorySwap": 0, "MemorySwappiness": null, "OomKillDisable": false, "PidsLimit": 0, "Ulimits": null, "CpuCount": 0, "CpuPercent": 0, "IOMaximumIOps": 0, "IOMaximumBandwidth": 0, "MaskedPaths": [ "/proc/acpi", "/proc/kcore", "/proc/keys", "/proc/latency_stats", "/proc/timer_list", "/proc/timer_stats", "/proc/sched_debug", "/proc/scsi", "/sys/firmware" ], "ReadonlyPaths": [ "/proc/asound", "/proc/bus", "/proc/fs", "/proc/irq", "/proc/sys", "/proc/sysrq-trigger" ] }, "GraphDriver": { "Data": { "LowerDir": "/var/lib/docker/overlay2/99e98bcb3268cca54fb9964a69452a424e9de607df50ef6ce1631da4be9f203b-init/diff:/var/lib/docker/overlay2/30039edd43cad0ec36a0fb2e546da0b33bb38336d2fa548e2cfca11a382b1ecb/diff:/var/lib/docker/overlay2/3e588e0ac8a29338bf759041cee08eff0bc955e47f7f32b0fe65c6536cb83a2b/diff:/var/lib/docker/overlay2/c80f5826b0afb09f3cd5ff12fa5a16e67aa2aaed0ae7ea0b36aeffc218559abd/diff", "MergedDir": "/var/lib/docker/overlay2/99e98bcb3268cca54fb9964a69452a424e9de607df50ef6ce1631da4be9f203b/merged", "UpperDir": "/var/lib/docker/overlay2/99e98bcb3268cca54fb9964a69452a424e9de607df50ef6ce1631da4be9f203b/diff", "WorkDir": "/var/lib/docker/overlay2/99e98bcb3268cca54fb9964a69452a424e9de607df50ef6ce1631da4be9f203b/work" }, "Name": "overlay2" }, "Mounts": [], "Config": { "Hostname": "d5eb28ecbc5c", "Domainname": "", "User": "", "AttachStdin": false, "AttachStdout": false, "AttachStderr": false, "ExposedPorts": { "80/tcp": {} }, "Tty": false, "OpenStdin": false, "StdinOnce": false, "Env": [ "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "NGINX_VERSION=1.14.0-1~stretch", "NJS_VERSION=1.14.0.0.2.0-1~stretch" ], "Cmd": [ "nginx", "-g", "daemon off;" ], "ArgsEscaped": true, "Image": "nginx:stable", "Volumes": null, "WorkingDir": "", "Entrypoint": null, "OnBuild": null, "Labels": { "maintainer": "NGINX Docker Maintainers <[email protected]>" }, "StopSignal": "SIGTERM" }, "NetworkSettings": { "Bridge": "", "SandboxID": "045cba9e5a6f39424dfb35c57d0ca43c9e335004d76c3dda36552aac740e014f", "HairpinMode": false, "LinkLocalIPv6Address": "", "LinkLocalIPv6PrefixLen": 0, "Ports": { "80/tcp": null }, "SandboxKey": "/var/run/docker/netns/045cba9e5a6f", "SecondaryIPAddresses": null, "SecondaryIPv6Addresses": null, "EndpointID": "3c28fb379c1c2018d05ae03ff163aae9a0c5c12621282e0d98f803daadaf97a6", "Gateway": "172.17.0.1", "GlobalIPv6Address": "", "GlobalIPv6PrefixLen": 0, "IPAddress": "172.17.0.2", "IPPrefixLen": 16, "IPv6Gateway": "", "MacAddress": "02:42:ac:11:00:02", "Networks": { "bridge": { "IPAMConfig": null, "Links": null, "Aliases": null, "NetworkID": "0a0cc62c3f1fba5667917f833b002ad0f5c1342acb61ff67317e17544e7a7ea1", "EndpointID": "3c28fb379c1c2018d05ae03ff163aae9a0c5c12621282e0d98f803daadaf97a6", "Gateway": "172.17.0.1", "IPAddress": "172.17.0.2", "IPPrefixLen": 16, "IPv6Gateway": "", "GlobalIPv6Address": "", "GlobalIPv6PrefixLen": 0, "MacAddress": "02:42:ac:11:00:02", "DriverOpts": null } } } } ]
 

IPAddress是当前容器监听的网络地址,下面尝试访问nginx

[[email protected] docker]# curl 172.17.0.2 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html>
 

 

5、停止一个容器

[[email protected] docker]# docker container stop nginx1 # 停止一个运行中的容器,kill相当于 kill -9 ,stop相当于kill -15 nginx1 [[email protected] docker]# docker container ls # ls 只能看到正在运行中的容器 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES [[email protected] docker]# docker container ls -a # ls -a 可以看到停止状态的容器 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d5eb28ecbc5c nginx:stable "nginx -g ‘daemon of?? 11 minutes ago Exited (0) 10 seconds ago nginx1
 

 

6、启动一个停止的容器

[[email protected] docker]# docker container start nginx1 nginx1 [[email protected] docker]# docker container ls CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d5eb28ecbc5c nginx:stable "nginx -g ‘daemon of?? 14 minutes ago Up 3 seconds 80/tcp nginx1
 

 

7、暂停/取消暂停一个运行中的容器

[[email protected] docker]# docker container pause nginx1 # 暂停一个nginx容器 nginx1 [[email protected] docker]# docker container ls # 可以看到nginx的容器现在处于Paused状态 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d5eb28ecbc5c nginx:stable "nginx -g ‘daemon of?? 15 minutes ago Up About a minute (Paused) 80/tcp nginx1 [[email protected] docker]# [[email protected] docker]# docker container unpause nginx1 # 取消一个容器的暂停状态 nginx1 [[email protected] docker]# docker container ls # nginx容器的状态又恢复运行 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES d5eb28ecbc5c nginx:stable "nginx -g ‘daemon of?? 16 minutes ago Up About a minute 80/tcp nginx1
 

 

8、在容器中执行交互命令

[[email protected] docker]# docker container exec -it redis1 /bin/sh

/data # ps

PID   USER     TIME  COMMAND

    1 redis     0:00 redis-server

   25 root      0:00 /bin/sh

   29 root      0:00 ps

 

9、在终端查看容器中进程的日志

[[email protected] docker]# docker container logs nginx1 172.17.0.1 - - [31/Oct/2018:13:54:40 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.29.0" "-" 172.17.0.1 - - [31/Oct/2018:14:02:19 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.29.0" "-" 172.17.0.1 - - [31/Oct/2018:14:14:17 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.29.0" "-"
 

 

四、Docker容器的状态转换和各常用命令

Docker第二回(Docker的使用)

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