文章目录
Docker和虚拟机
之前面试有被问到docker和虚拟机都是容器，他们有什么区别呢，当时也是摸棱两可，年代过于久远也不记得当时怎么回答的了。
先上一张虚拟机和docker的架构图：
| 对比项 | 虚拟机 | docker |
|---|---|---|
| 启动速度 | 秒级别 | 分钟级别 |
| 隔离级别 | 彻底隔离整个运行环境 | 通常用于隔离不同的应用 |
| 使用内核 | Guest OS 是虚拟机安装的操作系统，是一个完整的系统内核 | 直接使用宿主机的系统内核 |
| 硬件资源 | 需要Hypervisor实现硬件资源的虚拟化 | 直接使用的都是实际物理机的硬件资源 |
安装docker
查看yum中的docker版本
yum list docker-ce --showduplicates | sort -r
[root@localhost /]# yum list docker --showduplicates | sort -r
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
已加载插件：fastestmirror, product-id, search-disabled-repos, subscription-manager
已安装的软件包
可安装的软件包
* updates: mirrors.aliyun.com
This system is not registered with an entitlement server. You can use subscription-manager to register.
Loading mirror speeds from cached hostfile
* extras: mirrors.aliyun.com
* epel: mirrors.ustc.edu.cn
docker.x86_64 2:1.13.1-203.git0be3e21.el7.centos extras
docker.x86_64 2:1.13.1-162.git64e9980.el7.centos extras
docker.x86_64 2:1.13.1-161.git64e9980.el7_8 extras
docker.x86_64 2:1.13.1-161.git64e9980.el7_8 @extras
docker.x86_64 2:1.13.1-109.gitcccb291.el7.centos extras
docker.x86_64 2:1.13.1-108.git4ef4b30.el7.centos extras
docker.x86_64 2:1.13.1-103.git7f2769b.el7.centos extras
docker.x86_64 2:1.13.1-102.git7f2769b.el7.centos extras
* base: mirrors.aliyun.com
安装
yum install docker
验证安装
[root@localhost /]# docker version
Client:
Version: 1.13.1
API version: 1.26
Package version: docker-1.13.1-161.git64e9980.el7_8.x86_64
Go version: go1.10.3
Git commit: 64e9980/1.13.1
Built: Tue Apr 28 14:43:01 2020
OS/Arch: linux/amd64
Server:
Version: 1.13.1
API version: 1.26 (minimum version 1.12)
Package version: docker-1.13.1-161.git64e9980.el7_8.x86_64
Go version: go1.10.3
Git commit: 64e9980/1.13.1
Built: Tue Apr 28 14:43:01 2020
OS/Arch: linux/amd64
Experimental: false
开机启动
systemctl enable docker
镜像分层结构
一个docker镜像由多个可读的镜像层组成，然后运行的容器会在这个docker的镜像上面多加一层可写的容器层，任何的对文件的更改都只存在此容器层。因此任何对容器的操作均不会影响到镜像。原理图如下:
实现原理:
如果需要获取某个文件，容器会从上到下的一层一层的寻找文件，如果当前层不存在，则去下一层寻找，直到找到为止，如果找不到则去远端仓库去寻找。
镜像和容器的关系
我们在平时安装windows系统的时候，都会使用到系统镜像，通过进入引导页我们可以根据提示一步一步的安装我们的系统，同理，这里我们这里可以把docker的镜像想象成我们安装window或Linux系统的那个镜像，docker中的容器呢就是我们买的实体的笔记本或者台式机。
要运行容器，必须现有镜像，他提供了我们需要的程序，文件。
配置阿里云镜像源
因为官方地址在国外，访问起来比较慢，需要配置下国内地址，这个和Java中的Maven，php中的Composer类似。
参考csdn博客地址：
扫描二维码关注公众号，回复：
13582587 查看本文章
https://blog.csdn.net/abc8125/article/details/106858862
镜像命令
搜素镜像
docker search 镜像名称:版本号
[root@localhost /]# docker search mysql
INDEX NAME DESCRIPTION STARS OFFICIAL AUTOMATED
docker.io docker.io/mysql MySQL is a widely used, open-source relati... 10600 [OK]
docker.io docker.io/mariadb MariaDB Server is a high performing open s... 3973 [OK]
docker.io docker.io/mysql/mysql-server Optimized MySQL Server Docker images. Crea... 778 [OK]
docker.io docker.io/percona Percona Server is a fork of the MySQL rela... 528 [OK]
docker.io docker.io/centos/mysql-57-centos7 MySQL 5.7 SQL database server 87
docker.io docker.io/mysql/mysql-cluster Experimental MySQL Cluster Docker images. ... 79
docker.io docker.io/centurylink/mysql Image containing mysql. Optimized to be li... 59 [OK]
docker.io docker.io/bitnami/mysql Bitnami MySQL Docker Image 49 [OK]
docker.io docker.io/deitch/mysql-backup REPLACED! Please use http://hub.docker.com... 41 [OK]
docker.io docker.io/databack/mysql-backup Back up mysql databases to... anywhere! 40
docker.io docker.io/prom/mysqld-exporter 37 [OK]
docker.io docker.io/tutum/mysql Base docker image to run a MySQL database ... 35
docker.io docker.io/schickling/mysql-backup-s3 Backup MySQL to S3 (supports periodic back... 29 [OK]
docker.io docker.io/linuxserver/mysql A Mysql container, brought to you by Linux... 27
docker.io docker.io/centos/mysql-56-centos7 MySQL 5.6 SQL database server 20
docker.io docker.io/circleci/mysql MySQL is a widely used, open-source relati... 20
docker.io docker.io/mysql/mysql-router MySQL Router provides transparent routing ... 18
docker.io docker.io/arey/mysql-client Run a MySQL client from a docker container 17 [OK]
docker.io docker.io/fradelg/mysql-cron-backup MySQL/MariaDB database backup using cron t... 12 [OK]
docker.io docker.io/yloeffler/mysql-backup This image runs mysqldump to backup data u... 7 [OK]
docker.io docker.io/openshift/mysql-55-centos7 DEPRECATED: A Centos7 based MySQL v5.5 ima... 6
docker.io docker.io/devilbox/mysql Retagged MySQL, MariaDB and PerconaDB offi... 3
docker.io docker.io/ansibleplaybookbundle/mysql-apb An APB which deploys RHSCL MySQL 2 [OK]
docker.io docker.io/jelastic/mysql An image of the MySQL database server main... 1
docker.io docker.io/widdpim/mysql-client Dockerized MySQL Client (5.7) including Cu... 1 [OK]
#当然也可以加上版本号
docker search mysql:5.7
查看所有镜像
docker images #查看所有镜像
说明：
REPOSITORY：来源于哪个仓库
TAG:版本信息
IMAGE ID：镜像ID
下拉镜像
docker pull 镜像名称
这里能看到镜像的加密校验，这个地址就是镜像的源下载地址
docker inspect # 查看镜像的详细信息
[
{
"Id": "sha256:c8562eaf9d81c779cbfc318d6e01b8e6f86907f1d41233268a2ed83b2f34e748",
"RepoTags": [
"docker.io/mysql:latest"
],
"RepoDigests": [
"docker.io/mysql@sha256:feada149cb8ff54eade1336da7c1d080c4a1c7ed82b5e320efb5beebed85ae8c"
],
"Parent": "",
"Comment": "",
"Created": "2021-01-18T23:25:55.311110441Z",
"Container": "1b772a9e2045f2e123c3ff1d11cc67c9a5fe78b33af9f6a9213aa8cf91f58a6b",
"ContainerConfig": {
"Hostname": "1b772a9e2045",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"3306/tcp": {
},
"33060/tcp": {
}
},
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"GOSU_VERSION=1.12",
"MYSQL_MAJOR=8.0",
"MYSQL_VERSION=8.0.23-1debian10"
],
"Cmd": [
"/bin/sh",
"-c",
"#(nop) ",
"CMD [\"mysqld\"]"
],
"Image": "sha256:ec58f145c941b51747ba729ab510ff01ca99fa797ec6f4bb8830f6e878e5c66e",
"Volumes": {
"/var/lib/mysql": {
}
},
"WorkingDir": "",
"Entrypoint": [
"docker-entrypoint.sh"
],
"OnBuild": null,
"Labels": {
}
},
"DockerVersion": "19.03.12",
"Author": "",
"Config": {
"Hostname": "",
"Domainname": "",
"User": "",
"AttachStdin": false,
"AttachStdout": false,
"AttachStderr": false,
"ExposedPorts": {
"3306/tcp": {
},
"33060/tcp": {
}
},
"Tty": false,
"OpenStdin": false,
"StdinOnce": false,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"GOSU_VERSION=1.12",
"MYSQL_MAJOR=8.0",
"MYSQL_VERSION=8.0.23-1debian10"
],
"Cmd": [
"mysqld"
],
"Image": "sha256:ec58f145c941b51747ba729ab510ff01ca99fa797ec6f4bb8830f6e878e5c66e",
"Volumes": {
"/var/lib/mysql": {
}
},
"WorkingDir": "",
"Entrypoint": [
"docker-entrypoint.sh"
],
"OnBuild": null,
"Labels": null
},
"Architecture": "amd64",
"Os": "linux",
"Size": 546118644,
"VirtualSize": 546118644,
"GraphDriver": {
"Name": "overlay2",
"Data": {
"LowerDir": "/var/lib/docker/overlay2/21e75f2653178360dbded589fd4c4b25767bf6e961a57cb139d4c8c5b013a4c4/diff:/var/lib/docker/overlay2/1b9437e9132a2f383ca74fa6d5909c9db83a8c2bb101c0acd5ae48e0e6c6019d/diff:/var/lib/docker/overlay2/b5b4e337a6a1c935eb50a04d1237c3e7c1fe812751e97aab35d3a30a6647adf9/diff:/var/lib/docker/overlay2/6ebf68814fe7f82cef2109a5f13086a2400be95e1a10252f11cf87d7eef49a85/diff:/var/lib/docker/overlay2/9930e0f82b9cff4ded81dd568a09f49910c2a76bf2b72773f2b56571e21ac32d/diff:/var/lib/docker/overlay2/4e7efadbbbeedae89db83a23eaafbb92a28edca708af20af37574b0a04c7e74a/diff:/var/lib/docker/overlay2/9f0f64f15b78fc6de71e01789fa09dc7a638c130bab0e92eb7df18aa1a47cc50/diff:/var/lib/docker/overlay2/3440fb790f6a92cdfef95a745e2d88377234a7b81d800f17759837a7227f6e33/diff:/var/lib/docker/overlay2/eb80053be47b77817e134af2d5e5cd4cdff52dc96556d7d21658fe4441945f7c/diff:/var/lib/docker/overlay2/672458b17f1cbbee646ac3a935eeffb266768b836f0ac7d383e3a2181a89d23d/diff:/var/lib/docker/overlay2/365d2d5c5be78a9bd464e25b74ae0a447db78596e4efcd42bec16adc26d95352/diff",
"MergedDir": "/var/lib/docker/overlay2/5bb510e93d6165f3d858b3458e78189d3527654d1a2a3fab418bab8098ea52a0/merged",
"UpperDir": "/var/lib/docker/overlay2/5bb510e93d6165f3d858b3458e78189d3527654d1a2a3fab418bab8098ea52a0/diff",
"WorkDir": "/var/lib/docker/overlay2/5bb510e93d6165f3d858b3458e78189d3527654d1a2a3fab418bab8098ea52a0/work"
}
},
"RootFS": {
"Type": "layers",
"Layers": [
"sha256:cb42413394c4059335228c137fe884ff3ab8946a014014309676c25e3ac86864",
"sha256:ef4a33cee7a02ffa3c1dd5d2618dcb95e37b899fb7e90d0bb2df32a37396e174",
"sha256:74c86dffd46f095d4961730b731a33b19c1abd19f0a7ec1b81ddf09e6d3dfe85",
"sha256:6d23902c2a54f36f80946d7225044b2681bac18570af3a58970e325b40ac0d60",
"sha256:c484a3b6d84133f3618780f11216facc49f743cefc86e04409f28784a3a0a733",
"sha256:0394a41efa739604258181808606eb47798a83383ff52241547583939ffb297c",
"sha256:98d98806c8acefda16226c37045e3733a751c3cb165fde1182cbc324cde06f78",
"sha256:d35a1217c926c4d5fc2e8a9f914e565d46a1da65f461e5cb9f09f7b34953bb97",
"sha256:9577a2d5d759695f1b0e92efd95e7e46b1ac4c4c75350bac0045c94bd308732a",
"sha256:d60ed0726e3751a08f8d1d1696f51bb3ac47276b2c4f271272f167f532b4285a",
"sha256:ab82e085fd825c64ed10839fcae191d2169657b9585438676d1f54fb626162be",
"sha256:c080af299e3f1cab9e0bbe183259aa64014e6c560fea1c0534ffe95b0180b2a3"
]
}
}
]
# 说明
Id:我们在镜像列表中看到的镜像id的完整版。
删除镜像
docker rmi imageId #删除镜像 rmove image 简称rmi
镜像历史
docker history imageID
##执行结果
[root@localhost ~]# docker history c8562eaf9d81
IMAGE CREATED CREATED BY SIZE COMMENT
c8562eaf9d81 7 weeks ago /bin/sh -c #(nop) CMD ["mysqld"] 0 B
<missing> 7 weeks ago /bin/sh -c #(nop) EXPOSE 3306 33060 0 B
<missing> 7 weeks ago /bin/sh -c #(nop) ENTRYPOINT ["docker-ent... 0 B
<missing> 7 weeks ago /bin/sh -c ln -s usr/local/bin/docker-entr... 34 B
<missing> 7 weeks ago /bin/sh -c #(nop) COPY file:a209112a748b68... 13.1 kB
<missing> 7 weeks ago /bin/sh -c #(nop) COPY dir:2e040acc386ebd2... 1.12 kB
<missing> 7 weeks ago /bin/sh -c #(nop) VOLUME [/var/lib/mysql] 0 B
<missing> 7 weeks ago /bin/sh -c {
echo mysql-community-server... 411 MB
<missing> 7 weeks ago /bin/sh -c echo 'deb http://repo.mysql.com... 55 B
<missing> 7 weeks ago /bin/sh -c #(nop) ENV MYSQL_VERSION=8.0.2... 0 B
<missing> 8 weeks ago /bin/sh -c #(nop) ENV MYSQL_MAJOR=8.0 0 B
<missing> 8 weeks ago /bin/sh -c set -ex; key='A4A9406876FCBD3C... 2.61 kB
<missing> 8 weeks ago /bin/sh -c apt-get update && apt-get insta... 52.2 MB
<missing> 8 weeks ago /bin/sh -c mkdir /docker-entrypoint-initdb.d 0 B
<missing> 8 weeks ago /bin/sh -c set -eux; savedAptMark="$(apt-... 4.17 MB
<missing> 8 weeks ago /bin/sh -c #(nop) ENV GOSU_VERSION=1.12 0 B
<missing> 8 weeks ago /bin/sh -c apt-get update && apt-get insta... 9.34 MB
<missing> 8 weeks ago /bin/sh -c groupadd -r mysql && useradd -r... 329 kB
<missing> 8 weeks ago /bin/sh -c #(nop) CMD ["bash"] 0 B
<missing> 8 weeks ago /bin/sh -c #(nop) ADD file:422aca8901ae3d8... 69.2 MB
容器命令
容器列表
docker ps -a # 如果不加-a，能看到的当前正在运行的容器，-a查看所有的容器
docker ps -q # 只显示容器ID
运行容器
格式:
docker run [可选参数] image
常用参数:
--name="" #容器名称
-p #指定容器的端口,三种用法:
# -p ip:主机端口:容器端口
# -p 主机端口:容器端口
# -p 容器端口
-P #随机指定端口
-d #后台模式运行，这里有一个问题就是直接这样子运行，在使用docker ps 查看容器的时候时查不到刚刚运行的，因为docker发现你这个容器没有对外提供服务，所以会自动停止运行。
-it #以交互模式运行
#运行容器并且执行一段shell脚本
docker run -d 容器名称 /bin/sh -c "shell脚本"
进入运行的容器
#两种方式
1.docker exec it 容器ID /bin/bash
[root@localhost ~]# docker exec -it b2dd3493abaf /bin/bash
Error response from daemon: Container b2dd3493abaf29033299695ca3777c68846c1c6d0cf59833d73f6d9bb074a106 is not running
2.docker attach 容器ID
两者的区别:exec时进入容器新打开新的终端，attach时进入当前正在运行的终端界面。
退出容器
exit #直接退出
ctrl +P +Q #退出，后台运行
删除容器
docker rm 容器ID #如果容器正在运行，rm -f强制删除
常用命令
查看日志，进程
#日志
-tf #显示日志
--tailf number #显示日志条数
docker logs [参数] 容器ID
#执行
# docker logs -tf --tail 2 b2dd3493abaf
2021-03-10T10:25:40.490119000Z 2021-03-10T10:25:40.486Z [INFO] agent: Endpoints down
2021-03-10T10:25:40.490752000Z 2021-03-10T10:25:40.486Z [INFO] agent: Exit code: code=1
#进程
docker top 容器ID
[root@localhost ~]# docker top b2dd3493abaf
#容器没运行会报如下错误
Error response from daemon: Container b2dd3493abaf29033299695ca3777c68846c1c6d0cf59833d73f6d9bb074a106 is not running
容器和宿主机通信
拷贝文件
docker cp 容器id:容器路径 宿主机目录
#先运行一个，创建一个文件，发现root@后面的发生了变化，变成了容器ID。
[root@localhost ~]# docker run -it centos /bin/bash
#以下命令都是在容器中操作
[root@5f911c5ddb49 /]#
[root@5f911c5ddb49 /]# pwd
/
[root@5f911c5ddb49 /]# mkdir test.php
[root@5f911c5ddb49 /]# ls
bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys test.php tmp usr var
#拷贝文件
宿主机新开一个窗口，执行：
[root@localhost /]# cd /
[root@localhost /]# ll |grep test
drwxr-xr-x 2 root root 6 3月 11 17:55 test.php
挂载目录
#使用 -v命令来挂载
docker run -it -v 主机目录:容器目录 容器名称