# docker學習
###### tags: `RD5`
* docker概述
* docker安裝
* docker命令
* 容器命令
* 鏡像命令
* 操作命令
* docker鏡像
* 容器數據券
# docker 概述
傳統：開發jar，運維來做
現在：開發打包部署上線，一套流程做完！
java --- jar(環境) ---打包項目帶上環境(鏡像) ---(docker倉庫：商店) ---下載我們發佈的鏡像 ---直接運行即可！
docker給以上的問題提出了解決方案
docker思想就來自於集裝箱
jre --多個應用(端口衝突) --原來都是交叉的
隔離：docker核心思想 打包裝箱 每個箱子都是互相隔離的
docker 通過隔離機制 可以將服務器利用到極致
在容器技術出現之前 都是使用虛擬機技術
虛擬機也是屬於虛擬化技術 docker容器技術也是一種虛擬化技術
虛擬機技術缺點
1. 資源佔用多
2. 設定步驟多
3. 啟動慢
容器化技術
docker vs 虛擬機
* 傳統虛擬機 虛擬出一條硬件 運行一個完整的操作系統 然後在這個系統上安裝和運行軟件
* 容器內的應用直接運行在 宿主機的內容 容器是沒有自己的內核 也沒有虛擬硬件 所以輕便
* 每個容器間相互隔離 每個容器都有一個屬於自己的文件系統 互不影響
## devops
**應用更快速的交付和部署**
傳統：一堆幫助文檔，安裝程序
docker：打包鏡像發布測試，一鍵運行
**更便捷的升級和擴縮容**
使用了docker之後，我們部署應用就和搭積木一樣
項目打包為一個鏡像 擴展 服務器A 服務器Ｂ
**更簡單的系統運維**
在容器化之後 我們的開發 測試環境都高度一致
**更高效的計算資源利用**
docker是內核級別的虛擬化 可以在一個電腦上運行很多的容器實例 服務器性能最大化
## docker 基本組成
**鏡像(image):**
docker鏡像就好比是一個模板，可以通過這個模板來創建容器服務 tomcat鏡像===>run==>tomcat01容器(提供服務器)，通過這個鏡像可以創建多個容器(最終服務運行或者項目運行就是在容器中)
**容器(container):**
docker利用容器技術 獨立運行一個或者一個組應用 通過鏡像來創建的
啟動 停止 刪除 基本命令
目前就可以把這個容器理解為就是一個簡易的linux系統
**倉庫(repository):**
存放鏡像的地方
倉庫分為公有倉庫和私有倉庫
docker hub
容器=啟動後的鏡像
鏡像就是安裝包 容器就是已安裝的app
遊戲光碟=鏡像 裝好後就是容器
可以簡單理解為安裝包和軟件的關西
## docker run流程圖
## 底層原理
**docker工作原理**
docker 是一個client - server 結構系統 docker的守護進程運行在主機上 通過socket從客戶端訪問
dockerserver接收到docker-client的指令 就會執行這個命令
**docker為什麼比vm快**
## docker 常用命令
### 幫助命令
```shell
docker version # 顯示docker的版本信息
docker info # 顯示docker的系統信息，包括鏡像和容器的數量
docker 命令 --help # 幫助命令
```
### 鏡像命令
**docker images** 查看所有本地主機上的鏡像
```shell
tangrendeiPro:~ mrtang3838$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest bf756fb1ae65 8 months ago 13.3kB
# 解釋
REPOSITORY 鏡像倉庫源
TAG 鏡像標籤
IMAGE ID 鏡像id
CREATED 鏡像創建時間
SIZE 鏡像大小
# 可選項
-a, --all # 列出所有鏡像
-q, --quiet # 只顯示鏡像id
```
**docker search 搜索鏡像**
```shell
tangrendeiPro:~ mrtang3838$ docker search mysql
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
mysql MySQL is a widely used, open-source relation… 9958 [OK]
mariadb MariaDB is a community-developed fork of MyS… 3642 [OK]
# 可選項,通過搜索來過濾
--filter=stars=3000 # 搜索出來的鏡像就是stars大於3000的
tangrendeiPro:~ mrtang3838$ docker search mysql --filter=stars=3000
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
mysql MySQL is a widely used, open-source relation… 9958 [OK]
mariadb MariaDB is a community-developed fork of MyS… 3642 [OK]
```
**docker pull 下載鏡像**
```shell
# 下載鏡像 docker pull 鏡像名[:tag]
tangrendeiPro:~ mrtang3838$ docker pull mysql
Using default tag: latest # 如果不寫 tag,默認就是 latest
latest: Pulling from library/mysql
d121f8d1c412: Pull complete # 分層下載, docker image的核心 聯合文件系統
f3cebc0b4691: Pull complete
1862755a0b37: Pull complete
489b44f3dbb4: Pull complete
690874f836db: Pull complete
baa8be383ffb: Pull complete
55356608b4ac: Pull complete
dd35ceccb6eb: Pull complete
429b35712b19: Pull complete
162d8291095c: Pull complete
5e500ef7181b: Pull complete
af7528e958b6: Pull complete
Digest: sha256:e1bfe11693ed2052cb3b4e5fa356c65381129e87e38551c6cd6ec532ebe0e808 # 簽名
Status: Downloaded newer image for mysql:latest
docker.io/library/mysql:latest # 真實地址
# 等價於他
docker pull mysql
docker pull docker.io/library/mysql:latest
# 指定版本下載
tangrendeiPro:~ mrtang3838$ docker pull mysql:5.7
5.7: Pulling from library/mysql
d121f8d1c412: Already exists # 可共存 可想成是git的歷史版本 不衝突
f3cebc0b4691: Already exists
1862755a0b37: Already exists
489b44f3dbb4: Already exists
690874f836db: Already exists
baa8be383ffb: Already exists
55356608b4ac: Already exists
277d8f888368: Pull complete
21f2da6feb67: Pull complete
2c98f818bcb9: Pull complete
031b0a770162: Pull complete
Digest: sha256:14fd47ec8724954b63d1a236d2299b8da25c9bbb8eacc739bb88038d82da4919
Status: Downloaded newer image for mysql:5.7
docker.io/library/mysql:5.7
```
**docker rmi 刪除鏡像**
```shell
tangrendeiPro:~ mrtang3838$ docker rmi -f 容器id # 刪除指定的容器
tangrendeiPro:~ mrtang3838$ docker rmi -f 容器id 容器id 容器id # 刪除多個容器
tangrendeiPro:~ mrtang3838$ docker rmi -f $(docker images -aq) # 刪除全部的容器
```
### 容器命令
**說明：我們有了鏡像才可以創建容器**
ex:下載centos
```shell
docker pull centos
```
**新建容器並啟動**
```shell
docker run [可選參數] image
# 參數說明
--name="Name" 容器名字 tomcat01 tomcat02, 用來區分容器
-d 後台方式運行
-it 使用交互方式運行,進入容器查看內容
-p 指定容器的端口 -p 8080:8080
-p ip:主機端口：容器端口
-p 主機端口:容器端口 (常用)
-p 容器端口
容器端口
-p 隨機指定端口
# 測試,啟動並進入容器
AlaniMac-Pro:~ mrtang3838$ docker run -it centos /bin/bash
[root@0d7b2ebb856a /]# ls #查看容器內的centos,基礎版本 root後面的0d7b是centos的id
bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
# 從容器內退回主機
[root@0d7b2ebb856a /]# exit
exit
AlaniMac-Pro:~ mrtang3838$
```
**列出所有運行中的容器**
```shell
# docker ps 命令
# 列出當前正在運行的容器
-a # 列出當前正在運行的容器+帶出歷史運行過的容器
-n=? # 顯示最近創建的容器
-q #只顯示容器編號
AlaniMac-Pro:~ mrtang3838$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
AlaniMac-Pro:~ mrtang3838$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
0d7b2ebb856a centos "/bin/bash" 4 minutes ago Exited (0) About a minute ago hopeful_leakey
d179e798eec9 centos "/bin/bash" 7 minutes ago Exited (0) 4 minutes ago agitated_yalow
369e3f7e24f0 centos "/Users/mrtang3838" 7 minutes ago Created magical_wu
b59d6f8a02c1 bf756fb1ae65 "/hello" 4 hours ago Exited (0) 4 hours ago quizzical_proskuriakova
AlaniMac-Pro:~ mrtang3838$ docker ps -a -n=1
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
0d7b2ebb856a centos "/bin/bash" 6 minutes ago Exited (0) 3 minutes ago hopeful_leakey
```
**退出容器**
```shell
exit # 直接從容器停止並退出
Ctrl + P + Q # 容器不停止退出
```
**刪除容器**
```shell
docker rm 容器id # 刪除指定的容器
docker rm -f $(docker ps -aq) #(刪除所有的容器)查出所有容器id並遞歸刪除
docker ps -a -q|xargs docker rm #刪除所有的容器
```
**啟動和停止容器的操作**
```shell
docker start 容器id # 啟動容器
docer restart 容器id # 重啟容器
docker stop 容器id # 停止當前正在運行的容器
docker kill 容器id # 強制停止當前容器
```
### 常用其他命令
**後台啟動容器**
```shell
# 命令 docker run -d 鏡像名
AlaniMac-Pro:~ mrtang3838$ docker run -d centos
# 問題docker ps, 發現 centos 停止了
# 常見的坑：docker 容器使用後台運行,就必須要有一個前台進程,docker發現沒有應用,就會自動停止
# nginx, 容器啟動後,發現自己沒有提供服務,就會立刻停止,就是沒有程序了
```
**查看日誌**
```shell
docker logs -f -t --tail 要查看的日誌數 容器id
# 顯示日誌
-tf # 顯示日誌
--tail number # 要顯示日誌條數
AlaniMac-Pro:~ mrtang3838$ docker logs -tf --tail 10 dce7b86171bf
```
**查看容器中進程信息**
```shell
# 命令 docker top 容器id
AlaniMac-Pro:~ mrtang3838$ docker top 59c856f8d486
PID USER TIME COMMAND
2542 root 0:00 /bin/bash
```
**查看鏡像的元數據**
```shell
# 命令
docker inspect 容器id
# 測試
AlaniMac-Pro:~ mrtang3838$ docker inspect 59c856f8d486
[
{
"Id": "59c856f8d4864f7eeef779d9ef29b4adab4da702f1fb9ee1d5d3a1afa3e58277",
"Created": "2020-09-13T14:01:28.785236983Z",
"Path": "/bin/bash",
"Args": [],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Restarting": false,
"OOMKilled": false,
"Dead": false,
"Pid": 2542,
"ExitCode": 0,
"Error": "",
"StartedAt": "2020-09-13T14:01:29.047764443Z",
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "sha256:0d120b6ccaa8c5e149176798b3501d4dd1885f961922497cd0abef155c869566",
"ResolvConfPath": "/var/lib/docker/containers/59c856f8d4864f7eeef779d9ef29b4adab4da702f1fb9ee1d5d3a1afa3e58277/resolv.conf",
"HostnamePath": "/var/lib/docker/containers/59c856f8d4864f7eeef779d9ef29b4adab4da702f1fb9ee1d5d3a1afa3e58277/hostname",
"HostsPath": "/var/lib/docker/containers/59c856f8d4864f7eeef779d9ef29b4adab4da702f1fb9ee1d5d3a1afa3e58277/hosts",
"LogPath": "/var/lib/docker/containers/59c856f8d4864f7eeef779d9ef29b4adab4da702f1fb9ee1d5d3a1afa3e58277/59c856f8d4864f7eeef779d9ef29b4adab4da702f1fb9ee1d5d3a1afa3e58277-json.log",
"Name": "/loving_bohr",
"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/overlay2/251b0e3576f3c67baff07a13e6ad3e7e348e50297d36acc531f5bb78585f1347-init/diff:/var/lib/docker/overlay2/407114731b002a8d080ac00a1b070d3982a04101de9bfc99836212671dd1df95/diff",
"MergedDir": "/var/lib/docker/overlay2/251b0e3576f3c67baff07a13e6ad3e7e348e50297d36acc531f5bb78585f1347/merged",
"UpperDir": "/var/lib/docker/overlay2/251b0e3576f3c67baff07a13e6ad3e7e348e50297d36acc531f5bb78585f1347/diff",
"WorkDir": "/var/lib/docker/overlay2/251b0e3576f3c67baff07a13e6ad3e7e348e50297d36acc531f5bb78585f1347/work"
},
"Name": "overlay2"
},
"Mounts": [],
"Config": {
"Hostname": "59c856f8d486",
"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": "20200809",
"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": "50e7e4004f3677104177b67379a4533a76a1e9877075ced84e79e016264c5834",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {},
"SandboxKey": "/var/run/docker/netns/50e7e4004f36",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "362d897ad1aa4be95b155df389f69a823b4c19f024c98b749a51daf945d4c586",
"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": "4528f6449b63918c0c2211fb26ed48659db66caf9c9ebe0b9b83c3d3a694abcb",
"EndpointID": "362d897ad1aa4be95b155df389f69a823b4c19f024c98b749a51daf945d4c586",
"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
}
}
}
}
]
```
**進入當前正在運行的容器**
```shell
# 我們通常容器都是使用後台方式運行的,需要進入容器,修改一些配置
# 命令
$ docker exec -it 容器id bashShell
```
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