什么是docker
docker中的容器：
- lxc –> libcontainer –> runC
OCI&OCF
OCI
Open Container-initiative
- 由Linux基金会主导于2015年6月创立
- 旨在围绕容器格式和运行时制定一个开放的工业化标准
-
contains two specifications
- the Runtime Specification（runtime-spec）
- the Image Specification（image-spec）
OCF
开放容器格式
- runC 是一个 CLI 工具，用于根据 OCI 规范生成和运行容器
- 容器作为 runC 的子进程启动，可以嵌入到各种其他系统中，而无需运行守护程序
-
runC 建立在 libcontainer 之上，libcontainer 是支持数百万个 Docker 引擎安装的相同容器技术
docker提供了一个专门容纳容器镜像的站点：
https://hub.docker.com
docker架构
docker镜像与镜像仓库
为什么镜像仓库名字是Registry而不是repository？在docker中仓库的名字是以应用的名称取名的。
镜像是静态的，而容器是动态的，容器有其生命周期，镜像与容器的关系类似于程序与进程的关系。镜像类似于文件系统中的程序文件，而容器则类似于将一个程序运行起来的状态，也即进程。所以容器是可以删除的，容器被删除后其镜像是不会被删除的。
docker对象
When you use docker, you are creating and using images, containers, networks, volumes, pluginns, and other objects.
镜像
- 映像是一个只读模板，其中包含有关创建 docker 容器的说明。
- 通常，一个映像基于另一个映像，并具有一些额外的自定义。
- 您可以创建自己的映像，也可以只使用其他人创建并在注册表中发布的映像。
容器
- 连接器是图像的可运行实例。
- 您可以使用 Docker API 或 CLI 创建、运行、停止、移动或删除容器。
-
可以将容器连接到一个或多个网络，将存储附加到该网络，甚至可以根据其当前状态创建新映像。
安装及使用docker
docker安装
//添加docker的yum库
[root@localhost yum.repos.d]# curl -o docker-ce.repo https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/centos/docker-ce.repo
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --: 0 0 0 0 0 0 0 0 --:--:-- --:100 1919 100 1919 0 0 1845 0 0:00:01 0:00:01 --:--:-- 1845
[root@localhost yum.repos.d]# sed -i 's@https://download.docker.com@https://mirrors.tuna.tsinghua.edu.cn/docker-ce@g' docker-ce.repo
[root@localhost yum.repos.d]# ls
CentOS-Base.repo docker-ce.repo redhat.repo
[root@localhost yum.repos.d]#
//安装docker
[root@localhost ~]# yum -y install docker-ce
docker加速
docker-ce的配置文件是/etc/docker/daemon.json，此文件默认不存在，需要我们手动创建并进行配置，而docker的加速就是通过配置此文件来实现的。
docker的加速有多种方式：
- docker cn
- 中国科技大学加速器
- 阿里云加速器（需要通过阿里云开发者平台注册帐号，免费使用个人私有的加速器）
[root@localhost ~]# systemctl start docker //需要先启动docker，才会生成/etc/docker
[root@localhost ~]# cd /etc/docker/
[root@localhost docker]# ls
key.json
[root@localhost docker]# vim daemon.json
{
"registry-mirrors": ["https://uemehekj.mirror.aliyuncs.com"]
}
[root@localhost docker]# systemctl daemon-reload
[root@localhost docker]# systemctl restart docker
docker常用操作
| 命令 | 功能 |
|---|---|
| docker search | Search the Docker Hub for images |
| docker pull | Pull an image or a repository from a registry |
| docker images | List images |
| docker create | Create a new conntainer |
| docker start | Start one or more stopped containers |
| docker run | Run a command in a new container |
| docker attach | Attach to a runninng container |
| docker ps | List containers |
| docker logs | Fetch the logs of a container |
| docker restart | Restart a container |
| docker stop | Stop one or more running containers |
| docker kill | Kill one or more running containers |
| docker rm | Remove onne or more containers |
| docker exec | Run a command in a running container |
| docker info | Display system-wide information |
| docker inspect | Return low-level information on Docker objects |
docker event state
docker search
在 docker hub 仓库中搜索 指定 镜像
[root@localhost docker]# docker search hello-world
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
hello-world Hello World! (an example of minimal Dockeriz… 1589 [OK]
kitematic/hello-world-nginx A light-weight nginx container that demonstr… 150
tutum/hello-world Image to test docker deployments. Has Apache… 87 [OK]
dockercloud/hello-world Hello World! 19 [OK]
crccheck/hello-world Hello World web server in under 2.5 MB 15 [OK]
vad1mo/hello-world-rest A simple REST Service that echoes back all t… 5 [OK]
arm32v7/hello-world Hello World! (an example of minimal Dockeriz… 3
ppc64le/hello-world Hello World! (an example of minimal Dockeriz… 2
souravpatnaik/hello-world-go hello-world in Golang 1
infrastructureascode/hello-world A tiny "Hello World" web server with a healt… 1 [OK]
thomaspoignant/hello-world-rest-json This project is a REST hello-world API to bu… 1
datawire/hello-world Hello World! Simple Hello World implementati… 1 [OK]
ansibleplaybookbundle/hello-world-db-apb An APB which deploys a sample Hello World! a… 1 [OK]
markmnei/hello-world-java-docker Hello-World-Java-docker 1 [OK]
ansibleplaybookbundle/hello-world-apb An APB which deploys a sample Hello World! a… 1 [OK]
garystafford/hello-world Simple hello-world Spring Boot service for t… 0 [OK]
strimzi/hello-world-streams 0
burdz/hello-world-k8s To provide a simple webserver that can have … 0 [OK]
koudaiii/hello-world 0
businessgeeks00/hello-world-nodejs 0
nirmata/hello-world 0 [OK]
strimzi/hello-world-consumer 0
freddiedevops/hello-world-spring-boot 0
strimzi/hello-world-producer 0
dandando/hello-world-dotnet 0
docker pull
从指定位置拉取镜像
[root@localhost docker]# docker pull hello-world
Using default tag: latest
latest: Pulling from library/hello-world
2db29710123e: Pull complete
Digest: sha256:cc15c5b292d8525effc0f89cb299f1804f3a725c8d05e158653a563f15e4f685
Status: Downloaded newer image for hello-world:latest
docker.io/library/hello-world:latest
docker images
查看镜像列表
[root@localhost docker]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest feb5d9fea6a5 2 months ago 13.3kB
docker create
创建指定的容器（不运行）
[root@localhost ~]# docker create nginx
Unable to find image 'nginx:latest' locally
latest: Pulling from library/nginx
eff15d958d66: Pull complete
1e5351450a59: Pull complete
2df63e6ce2be: Pull complete
9171c7ae368c: Pull complete
020f975acd28: Pull complete
266f639b35ad: Pull complete
Digest: sha256:097c3a0913d7e3a5b01b6c685a60c03632fc7a2b50bc8e35bcaa3691d788226e
Status: Downloaded newer image for nginx:latest
23e547fb5cd48a94cc193364b8807644acf6fec05726bc4f4d13b86cd953b8e3
docker start
将指定的容器启动
[root@localhost ~]# docker start 23e547fb5cd48a94cc193364b8807644acf6fec05726bc4f4d13b86cd953b8e3
23e547fb5cd48a94cc193364b8807644acf6fec05726bc4f4d13b86cd953b8e3
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
23e547fb5cd4 nginx "/docker-entrypoint.…" 2 minutes ago Up 8 seconds 80/tcp hopeful_kalam
[root@localhost ~]#
docker run
将指定的容器创建并允许（若使用该命令时，镜像列表中没有镜像时，它会自动pull并将其创建、运行）
[root@localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest ea335eea17ab 13 days ago 141MB
hello-world latest feb5d9fea6a5 2 months ago 13.3kB
[root@localhost ~]# docker run httpd
Unable to find image 'httpd:latest' locally //拉取新镜像
latest: Pulling from library/httpd
eff15d958d66: Already exists
ba1caf8ba86c: Pull complete
ab86dc02235d: Pull complete
0d58b11d2867: Pull complete
e88da7cb925c: Pull complete
Digest: sha256:1d71eef54c08435c0be99877c408637f03112dc9f929fba3cccdd15896099b02
Status: Downloaded newer image for httpd:latest
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.3. Set the 'ServerName' directive globally to suppress this message
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.3. Set the 'ServerName' directive globally to suppress this message
[Wed Dec 01 10:05:20.782123 2021] [mpm_event:notice] [pid 1:tid 140162964778304] AH00489: Apache/2.4.51 (Unix) configured -- resuming normal operations
[Wed Dec 01 10:05:20.782256 2021] [core:notice] [pid 1:tid 140162964778304] AH00094: Command line: 'httpd -D FOREGROUND'
[root@localhost ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
httpd latest ad17c88403e2 12 days ago 143MB
nginx latest ea335eea17ab 13 days ago 141MB
hello-world latest feb5d9fea6a5 2 months ago 13.3kB
docker stop
停止指定容器
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca661b022404 httpd "httpd-foreground" 2 minutes ago Exited (0) About a minute ago epic_jemison
23e547fb5cd4 nginx "/docker-entrypoint.…" 6 minutes ago Up 3 minutes 80/tcp hopeful_kalam
[root@localhost ~]# docker stop 23e547fb5cd4
23e547fb5cd4
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca661b022404 httpd "httpd-foreground" 3 minutes ago Exited (0) 2 minutes ago epic_jemison
23e547fb5cd4 nginx "/docker-entrypoint.…" 7 minutes ago Exited (0) 2 seconds ago hopeful_kalam
docker logs
查看指定容器的日志
[root@localhost ~]# docker logs 23e547fb5cd4
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2021/12/01 10:03:24 [notice] 1#1: using the "epoll" event method
2021/12/01 10:03:24 [notice] 1#1: nginx/1.21.4
2021/12/01 10:03:24 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6)
2021/12/01 10:03:24 [notice] 1#1: OS: Linux 4.18.0-193.el8.x86_64
2021/12/01 10:03:24 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2021/12/01 10:03:24 [notice] 1#1: start worker processes
2021/12/01 10:03:24 [notice] 1#1: start worker process 32
2021/12/01 10:03:24 [notice] 1#1: start worker process 33
2021/12/01 10:03:24 [notice] 1#1: start worker process 34
2021/12/01 10:03:24 [notice] 1#1: start worker process 35
2021/12/01 10:08:21 [notice] 1#1: signal 3 (SIGQUIT) received, shutting down
2021/12/01 10:08:21 [notice] 32#32: gracefully shutting down
2021/12/01 10:08:21 [notice] 33#33: gracefully shutting down
2021/12/01 10:08:21 [notice] 33#33: exiting
2021/12/01 10:08:21 [notice] 32#32: exiting
2021/12/01 10:08:21 [notice] 32#32: exit
2021/12/01 10:08:21 [notice] 33#33: exit
2021/12/01 10:08:21 [notice] 34#34: gracefully shutting down
2021/12/01 10:08:21 [notice] 34#34: exiting
2021/12/01 10:08:21 [notice] 35#35: gracefully shutting down
2021/12/01 10:08:21 [notice] 34#34: exit
2021/12/01 10:08:21 [notice] 35#35: exiting
2021/12/01 10:08:21 [notice] 35#35: exit
2021/12/01 10:08:21 [notice] 1#1: signal 17 (SIGCHLD) received from 35
2021/12/01 10:08:21 [notice] 1#1: worker process 33 exited with code 0
2021/12/01 10:08:21 [notice] 1#1: worker process 35 exited with code 0
2021/12/01 10:08:21 [notice] 1#1: signal 29 (SIGIO) received
2021/12/01 10:08:21 [notice] 1#1: signal 17 (SIGCHLD) received from 32
2021/12/01 10:08:21 [notice] 1#1: worker process 32 exited with code 0
2021/12/01 10:08:21 [notice] 1#1: worker process 34 exited with code 0
2021/12/01 10:08:21 [notice] 1#1: exit
docker rm
删除指定容器（正在运行的容器不可删除）
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca661b022404 httpd "httpd-foreground" 10 minutes ago Exited (0) 9 minutes ago epic_jemison
377f8fc3fca8 nginx "/docker-entrypoint.…" 10 minutes ago Exited (0) 10 minutes ago stoic_rosalind
23e547fb5cd4 nginx "/docker-entrypoint.…" 14 minutes ago Exited (0) 7 minutes ago hopeful_kalam
[root@localhost ~]# docker stop 23e547fb5cd4
23e547fb5cd4
[root@localhost ~]# docker rm 23e547fb5cd4
23e547fb5cd4
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca661b022404 httpd "httpd-foreground" 11 minutes ago Exited (0) 10 minutes ago epic_jemison
377f8fc3fca8 nginx "/docker-entrypoint.…" 11 minutes ago Exited (0) 11 minutes ago stoic_rosalind
docker attach
进入正在运行的容器中（不能进行交互，会进入http容器进程的前台）
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca661b022404 httpd "httpd-foreground" 11 minutes ago Exited (0) 10 minutes ago epic_jemison
377f8fc3fca8 nginx "/docker-entrypoint.…" 12 minutes ago Exited (0) 11 minutes ago stoic_rosalind
[root@localhost ~]# docker attach ca661b022404
You cannot attach to a stopped container, start it first
[root@localhost ~]# docker start 377f8fc3fca8
377f8fc3fca8
[root@localhost ~]# docker attach 377f8fc3fca8
docker exec
进入指定容器中，并能够进行交互
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca661b022404 httpd "httpd-foreground" 13 minutes ago Exited (0) 12 minutes ago epic_jemison
377f8fc3fca8 nginx "/docker-entrypoint.…" 13 minutes ago Exited (0) 3 seconds ago stoic_rosalind
[root@localhost ~]# docker start 377f8fc3fca8
377f8fc3fca8
[root@localhost ~]# docker exec -it 377f8fc3fca8 /bin/bash
root@377f8fc3fca8:/# ls
bin boot dev docker-entrypoint.d docker-entrypoint.sh etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var
root@377f8fc3fca8:/# cd /etc/
root@377f8fc3fca8:/etc# ls
adduser.conf cron.daily fonts host.conf ld.so.cache mke2fs.conf pam.conf rc2.d security subuid
alternatives debconf.conf fstab hostname ld.so.conf motd pam.d rc3.d selinux systemd
apt debian_version gai.conf hosts ld.so.conf.d mtab passwd rc4.d shadow terminfo
bash.bashrc default group init.d libaudit.conf netconfig passwd- rc5.d shadow- timezone
bindresvport.blacklist deluser.conf group- inputrc localtime nginx profile rc6.d shells ucf.conf
ca-certificates dpkg gshadow issue login.defs nsswitch.conf profile.d rcS.d skel update-motd.d
ca-certificates.conf e2scrub.conf gshadow- issue.net logrotate.d opt rc0.d resolv.conf ssl xattr.conf
cron.d environment gss kernel machine-id os-release rc1.d rmt subgid
root@377f8fc3fca8:/etc#
docker info
查看docker详细信息
[root@localhost ~]# docker info
Client:
Context: default
Debug Mode: false
Plugins:
app: Docker App (Docker Inc., v0.9.1-beta3)
buildx: Build with BuildKit (Docker Inc., v0.6.3-docker)
scan: Docker Scan (Docker Inc., v0.9.0)
Server:
Containers: 2
Running: 1
Paused: 0
Stopped: 1
Images: 4
Server Version: 20.10.11
Storage Driver: overlay2
Backing Filesystem: xfs
Supports d_type: true
Native Overlay Diff: true
userxattr: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
Cgroup Version: 1
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: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 7b11cfaabd73bb80907dd23182b9347b4245eb5d
runc version: v1.0.2-0-g52b36a2
init version: de40ad0
Security Options:
seccomp
Profile: default
Kernel Version: 4.18.0-193.el8.x86_64
Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 3.664GiB
Name: 192.168.75.142
ID: PVYK:ATCY:YAQC:MGB4:UDPM:NNPW:KCNO:WXRA:LHEL:XMD6:P3GY:FK66
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://uemehekj.mirror.aliyuncs.com/
Live Restore Enabled: false
[root@localhost ~]#
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