Docker的学习第二天

Posted 2020-12-18 lxhaaron

Docker架构图

 

镜像：image，类似于模板的意思，通过这个模板创建容器服务，如tomcat 镜像，---》run--->tomcat1容器，提供给服务器

　　通过这个镜像可以创建多个容器，最终服务运行或者项目就是在容器中

容器：container：

Docker利用容器技术，独立运行一个或者一个应用，通过镜像来创建的

启动、删除、停止 、基本命令

目前可以把容器理解为一个简易的linux系统，项目就放在这个微型的linux系统

仓库：respository：用来存放镜像的地方，仓库分为公有仓库和私有仓库，docker hub,阿里云、华为云等，默认配置国外的，需配置镜像加速

 基础环境配置以下：

[root@fengfang ~]# uname -r
3.10.0-957.el7.x86_64
[root@fengfang ~]# cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

 

第一步，卸载旧的版本Docker各版本，命令如下：

$ sudo yum remove docker                   docker-client                   docker-client-latest                   docker-common                   docker-latest                   docker-latest-logrotate                   docker-logrotate                   docker-engine
第二步：安装所需环境的命令
sudo yum install -y yum-utils

第三步：设置镜像的仓库，默认使用国外的，会比较慢

yum-config-manager     --add-repo     https://download.docker.com/linux/centos/docker-ce.repo

yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo  #推荐使用阿里云

第四步，更新yum
yum makeccache fast

第五步：安装Docker相关的配置 docker-ce 社区版本  ee 企业版本，一般使用社区版本
yum install docker-ce docker-ce-cli containerd.io

安装过程中可能要提示是否确认，输入Y就行
第六步：启动docker
systemctl start docker
第七步：查看docker版本
docker version

 

 第八步：测试hello world

docker run hello-world

 

 第九步：查看一下下载的的hello-world 镜像

docker images

 

 

 了解：卸载docker

第一步：yum remove docker-ce docker-ce-cli containerd.io

第二步：删除资源：rm -rf /var/lib/docker

#/var/lib/docker默认工作空间

 

阿里云镜像加速方法

1、登陆阿里云，找到镜像加速器

sudo mkdir -p /etc/docker

sudo tee /etc/docker/daemon.json <<-‘EOF‘

{

"registry-mirrors": ["https://hcqmmgyf.mirror.aliyuncs.com"]

}

EOF

sudo systemctl daemon-reload

sudo systemctl restart docker

 

 按上图，四个步骤执行

完成后就完成了阿里云镜像加速

 run的运行流程图：

 

 docker的工作原理

docker是一个client-server结构的系统，docker的守护进程运行在主机上，通过socket从客户端访问

dockerServer接收到dockerClient的指令就会执行这个命令

 

 

 docker为什么比VM快

1、docker有着比VM更少的抽象层

2、docker利用的是宿主机的内核，VM需要的的guestOs

 

                         Vm                                                                docker

所以说，新建一个容器的时候，docker不需要像虚拟机一样重新加载一个操作系统内核，避免引导操作，虚拟机是加载guest OS，分钟级别

而docker是利用宿主的操作系统，省略了了这个复杂的过程

 

学完完所有的命令，再回头来看这段理论，就会更清晰

 

docker的常用命令

 1、帮助命令

docker version  #显示docker的版本信息

docker info   #显示docker的系统信息，包括镜像和容器的数量

docker 命令 --help    

帮助文档地址：https://docs.docker.com/reference/

 

镜像命令

1、docker images  #查看所有的镜像

 

 perpository:镜像的仓库源

tag:镜像的标签

image id：镜像的ID

created：镜像的创建时间

size:镜像的大小

-a,--all    #列出所有镜像

-q,-quiet  #只显示镜像的ID

 如使用命令：docker images -aq

2、docker search mysql 命令，搜索镜像

 

 -f  过滤条件，搜索stars大于3000的

docker search mysql -f=stars=3000

docker search mysql --limit 5   #取前五条数据

3、docker pull 下载镜像

下载mysql镜像

[root@fengfang ~]# docker pull mysql
Using default tag: latest    #如果不写tag，默认是latest
latest: Pulling from library/mysql    
8559a31e96f4: Pull complete    #分层下载，docker image的核心，联合文件系统
d51ce1c2e575: Pull complete
c2344adc4858: Pull complete
fcf3ceff18fc: Pull complete
16da0c38dc5b: Pull complete
b905d1797e97: Pull complete
4b50d1c6b05c: Pull complete
571e8a282156: Pull complete
e7cc823c6090: Pull complete
89f6364a8689: Pull complete
55e5b10f33a4: Pull complete
68129e7a0316: Pull complete
Digest: sha256:c455bbcaa8b9c5c636c45f6184f970caeb3d8b545a0390e1b72a253e07aef8fd  #签名
Status: Downloaded newer image for mysql:latest    
docker.io/library/mysql:latest     #真实地址

 

docker pull mysql   等价于：docker pull docker.io/library/mysql:latest  

指定版本下载mysql 5.7版本

[root@fengfang ~]# docker pull mysql:5.7
5.7: Pulling from library/mysql
8559a31e96f4: Already exists    #已经存在的，就不会再下载
d51ce1c2e575: Already exists
c2344adc4858: Already exists
fcf3ceff18fc: Already exists
16da0c38dc5b: Already exists
b905d1797e97: Already exists
4b50d1c6b05c: Already exists
0a52a5c57cd9: Pull complete
3b816a39d367: Pull complete
13ee22d6b3bb: Pull complete
e517c3d2ba35: Pull complete
Digest: sha256:ea560da3b6f2f3ad79fd76652cb9031407c5112246a6fb5724ea895e95d74032
Status: Downloaded newer image for mysql:5.7
docker.io/library/mysql:5.7

 

4、删除镜像docker rmi 

docker rmi -f 容器Id    #指定容器ID删除

docker rmi -f 容器Id 容器Id 容器Id     #删除多个容器

docker rmi -f $(docker images -aq)   #删除所有容器

[root@fengfang ~]# docker rmi --help

Usage: docker rmi [OPTIONS] IMAGE [IMAGE...]

Remove one or more images

Options:
-f, --force Force removal of the image
--no-prune Do not delete untagged parents

[root@fengfang ~]# docker rmi -f 5ac22cccc3ae   #指定ID删除镜像
Untagged: mysql:latest
Untagged: mysql@sha256:c455bbcaa8b9c5c636c45f6184f970caeb3d8b545a0390e1b72a253e07aef8fd
Deleted: sha256:5ac22cccc3ae67ca42ed92b55c8fa7c68967ec6b875d15d761467d40097368b6
Deleted: sha256:86c56823286628a66aa344188924e576c85b94b4734c418a6a0e123068170c4f
Deleted: sha256:28f36292125ccc90319e3153c5eb83d374d2875c9e46a7538568fc32458ec034
Deleted: sha256:291205778291931aee087875f7d1c30382db776809095e30260079f998025426
Deleted: sha256:620e22d166022716e2d8984417abecdd637b30e3815e9f3b543e93cdde1d09e9
Deleted: sha256:f67b13ad42222e45e0eaf18adbc9f408e2dc32cdb814be4f3243a6ab0b5bcd0a
[root@fengfang ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
mysql 5.7 d05c76dbbfcf 7 days ago 448MB
hello-world latest bf756fb1ae65 6 months ago 13.3kB
[root@fengfang ~]# docker rmi -f $(docker images -aq)   #删除所有镜像
Untagged: mysql:5.7
Untagged: mysql@sha256:ea560da3b6f2f3ad79fd76652cb9031407c5112246a6fb5724ea895e95d74032
Deleted: sha256:d05c76dbbfcf3e1d969eecc04d0aa461e0f95204f6833f62edb73cca7b62fcd4
Deleted: sha256:840de3dd46e7b6203f85075d3bbc784b151e0de21f77dfa37744fc8edeaf766b
Deleted: sha256:7438475d185887f36358065f793c5699b459bc13271aee0b606b9d68230452ef
Deleted: sha256:323859cca1e70d6db23f15dd1d6c0c66e08f116147477663f3be2d94c89ba3a8
Deleted: sha256:14a1c67348bc38b8f7316be7993dea0c03c5375e7728dcffb2da90ceed74c1f0
Deleted: sha256:09687cd9cdf4c704fde969fdba370c2d848bc614689712bef1a31d0d581f2007
Deleted: sha256:b704a4a65bf536f82e5d8b86e633d19185e26313de8380162e778feb2852011a
Deleted: sha256:c37206160543786228aa0cce738e85343173851faa44bb4dc07dc9b7dc4ff1c1
Deleted: sha256:12912c9ec523f648130e663d9d4f0a47c1841a0064d4152bcf7b2a97f96326eb
Deleted: sha256:57d29ad88aa49f0f439592755722e70710501b366e2be6125c95accc43464844
Deleted: sha256:b17c024283d0302615c6f0c825137da9db607d49a83d2215a79733afbbaeb7c3
Deleted: sha256:13cb14c2acd34e45446a50af25cb05095a17624678dbafbcc9e26086547c1d74
Untagged: hello-world:latest
Untagged: hello-world@sha256:49a1c8800c94df04e9658809b006fd8a686cab8028d33cfba2cc049724254202
Deleted: sha256:bf756fb1ae65adf866bd8c456593cd24beb6a0a061dedf42b26a993176745f6b

 

容器命令

说明：有了镜像才可以创建容器，linux下载一个centos镜像来测试学习

docker pull centos    #下载linux容器

1、新建容器并启动

docker run [可选参数]   image

参数说明：

--name ="name"    #给容器命名 如tomcat1 /tomcat2

-d                           #后台方式运行

-i/-t                         #使用交互方式运行，进入容器查看内容

-p 　　　　　　　#指定容器端口

 #测试/启动并进入容器

[root@fengfang ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
centos latest 831691599b88 4 weeks ago 215MB
[root@fengfang ~]# docker run -it centos /bin/bash
[root@3c8a42e17e53 /]# ls    #进入容器
bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
[root@3c8a42e17e53 /]# exit   #退出容器
exit

2、列出所有在运行的容器：docker ps

　　 #列出当前正在运行的容器

-a     #列出当前正在运行的容器+带出历史运行过的容器

-n=?    #列出最近创建的容器，？表示容器个数

-q       #只显示容器的编号

3、退出容器

exit     #直接窗口停止并退出

ctrl+p+Q   #容器不停止退出

4、删除容器

docker rm   容器id       #删除指定的容器，不能删除正在运行的容器，如果要强制删除使用：rm -f

docker rm -f $(docker ps -aq)    #删除所有容器

docker rm -a -q|xargs docker rm    #删除所有容器

 5、启动或停止容器的操作

docker start 容器Id           #启动容器

docker restart 容器Id　　#重启容器

docker stop 容器Id       　#停止容器

docker Kill 容器Id            #强制停止当前容器

6、后台启动命令

#    命令    docker run -d 容器

docker run -d centos      #后台启动centos容器      

#问题：docker ps 发现centos 停止了

常见的坑：docker容器使用后台运行，就必须要有一个前台进程，docker发现没有应用，就会自动停止

#nginx    容器启动后，发现自己没有提供服务，就会立刻停止，就是没有程序了

7、查看日志

docker logs -tf  --tail   容器Id

 #自己编写一段shell脚本，并在后台执行

命令：docker run -d centos /bin/sh -c "while true;do echo ok;sleep 1;done;"

#显示指定行数日志的命令

docker logs -tf --tail 10 5207c831e6fc

 

8、查看容器中的进程信息：docker top 容器Id

[root@fengfang ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5207c831e6fc centos "/bin/sh -c ‘while t…" 4 minutes ago Up 4 minutes beautiful_satoshi
[root@fengfang ~]# docker top 5207c831e6fc
UID PID PPID C STIME TTY TIME CMD
root 27638 27620 0 10:59 ? 00:00:00 /bin/sh -c while true;do echo ok;sleep 1;done;
root 28077 27638 0 11:03 ? 00:00:00 /usr/bin/coreutils --coreutils-prog-shebang=sleep /usr/bin/sleep 1
[root@fengfang ~]#

9、查看镜像的元数据:docker inspect 容器Id

docker inspect 90f6e62833a2
[
{
"Id": "90f6e62833a20d21d1bb6ae6fcf008d1dfaa6847ce0c3e9d8974480f5401054d",
"Created": "2020-07-22T01:51:22.216515504Z",
"Path": "/bin/bash",
"Args": [],
"State": {
"Status": "exited",
"Running": false,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 0,
"ExitCode": 0,
"Error": "",
"StartedAt": "2020-07-22T01:51:22.648729597Z",
"FinishedAt": "2020-07-22T02:54:29.039817622Z"
},
"Image": "sha256:831691599b88ad6cc2a4abbd0e89661a121aff14cfa289ad840fd3946f274f1f",
"ResolvConfPath": "/var/lib/docker/containers/90f6e62833a20d21d1bb6ae6fcf008d1dfaa6847ce0c3e9d8974480f5401054d/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/90f6e62833a20d21d1bb6ae6fcf008d1dfaa6847ce0c3e9d8974480f5401054d/hostname",
"HostsPath": "/var/lib/docker/containers/90f6e62833a20d21d1bb6ae6fcf008d1dfaa6847ce0c3e9d8974480f5401054d/hosts",
"LogPath": "/var/lib/docker/containers/90f6e62833a20d21d1bb6ae6fcf008d1dfaa6847ce0c3e9d8974480f5401054d/90f6e62833a20d21d1bb6ae6fcf008d1dfaa6847ce0c3e9d8974480f5401054d-json.log",
"Name": "/great_aryabhata",
"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,
"Capabilities": null,
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "private",
"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,
"DeviceRequests": null,
"KernelMemory": 0,
"KernelMemoryTCP": 0,
"MemoryReservation": 0,
"MemorySwap": 0,
"MemorySwappiness": null,
"OomKillDisable": false,
"PidsLimit": null,
"Ulimits": null,
"CpuCount": 0,
"CpuPercent": 0,
"IOMaximumIOps": 0,
"IOMaximumBandwidth": 0,
"MaskedPaths": [
"/proc/asound",
"/proc/acpi",
"/proc/kcore",
"/proc/keys",
"/proc/latency_stats",
"/proc/timer_list",
"/proc/timer_stats",
"/proc/sched_debug",
"/proc/scsi",
"/sys/firmware"
],
"ReadonlyPaths": [
"/proc/bus",
"/proc/fs",
"/proc/irq",
"/proc/sys",
"/proc/sysrq-trigger"
]
},
"GraphDriver": {
"Data": {
"LowerDir": "/var/lib/docker/overlay2/acf06b0e9661512964a44a9967550a22dc18541ace3285a9a37e360cad69f080-init/diff:/var/lib/docker/overlay2/bf12b9b766266fb81c51f7af319f6e39c0315c70ad4967d4dd609e732e153803/diff",
"MergedDir": "/var/lib/docker/overlay2/acf06b0e9661512964a44a9967550a22dc18541ace3285a9a37e360cad69f080/merged",
"UpperDir": "/var/lib/docker/overlay2/acf06b0e9661512964a44a9967550a22dc18541ace3285a9a37e360cad69f080/diff",
"WorkDir": "/var/lib/docker/overlay2/acf06b0e9661512964a44a9967550a22dc18541ace3285a9a37e360cad69f080/work"
},
"Name": "overlay2"
},
"Mounts": [],
"Config": {
"Hostname": "90f6e62833a2",
"Domainname": "",
"User": "",
"AttachStdin": true,
"AttachStdout": true,
"AttachStderr": true,
"Tty": true,
"OpenStdin": true,
"StdinOnce": true,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],
"Cmd": [
"/bin/bash"
],
"Image": "centos",
"Volumes": null,
"WorkingDir": "",
"Entrypoint": null,
"OnBuild": null,
"Labels": {
"org.label-schema.build-date": "20200611",
"org.label-schema.license": "GPLv2",
"org.label-schema.name": "CentOS Base Image",
"org.label-schema.schema-version": "1.0",
"org.label-schema.vendor": "CentOS"
}
},
"NetworkSettings": {
"Bridge": "",
"SandboxID": "4bb6f0a87d2e52f97ea9afdec457ace346421b318e511ae04dd52d39f681d8d2",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {},
"SandboxKey": "/var/run/docker/netns/4bb6f0a87d2e",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "",
"Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "",
"IPPrefixLen": 0,
"IPv6Gateway": "",
"MacAddress": "",
"Networks": {
"bridge": {
"IPAMConfig": null,
"Links": null,
"Aliases": null,
"NetworkID": "f3f639d8384219f8537fd152bb9e368be7194e28733694f67340f259bb33804b",
"EndpointID": "",
"Gateway": "",
"IPAddress": "",
"IPPrefixLen": 0,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "",
"DriverOpts": null
}
}
}
}
]

11、进入当前正在运行的容器

#我们通常容器都是使用后台方式运行的，需要进入容器，修改一些配置

#命令

方式1：docker exec -it 容器Id bashShell

 

 

 方式2：docker attach 容器Id

备注：

#docker exec #进入容器后开启一个新的终端，可以在里面操作（常用 ）

# docker attach   #进入容器正在执行的终端，不会启动新的

 

12、从容器内拷贝文件到主机上

docker cp 容器Id:容器内路径   目的主机路径

[root@fengfang ~]# docker run -it centos /bin/bash
[root@72cab24d142f /]# [root@fengfang ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
72cab24d142f centos "/bin/bash" 14 seconds ago Up 13 seconds nifty_merkle
[root@fengfang ~]# cd /home
[root@fengfang home]# ls
[root@fengfang home]# mkdir lxh
[root@fengfang home]# ls
lxh
[root@fengfang home]# docker attach 72cab24d142f    #进入容器，并创建一个test.java文件
[root@72cab24d142f /]# ls
bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
[root@72cab24d142f /]# cd /home
[root@72cab24d142f home]# ls
[root@72cab24d142f home]# touch test.java    #创建一个文件
[root@72cab24d142f home]# ls
test.java
[root@72cab24d142f home]# exit
exit
[root@fengfang home]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
72cab24d142f centos "/bin/bash" 8 minutes ago Exited (0) 7 seconds ago nifty_merkle
[root@fengfang home]# ls
lxh
[root@fengfang home]# cd /

[root@fengfang /]# docker start 72cab24d142f

72cab24d142f
[root@fengfang /]# ls
bin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var
[root@fengfang /]# cd /home
[root@fengfang home]# ls
lxh

[root@fengfang home]# docker cp 72cab24d142f:/home/test.java /home/lxh   #从容器中拷贝文件到主机上

[root@fengfang home]# cd lxh
[root@fengfang lxh]# ls    #查看文件
test.java

备注：拷贝是一个手动过程，未来我们使用  -V 卷的技术，可以实现容器的/home和主机的/home目录联动