kubernetes與docker的關係（Kubernetes全棧架構師Docker基礎）

2023-04-12 14:28:45

kubernetes與docker的關係?Docker：它是一個開源的軟體項目，在Linux作業系統上，docker提供了一個額外的軟體抽象層及作業系統層虛擬化的自動管理機制，接下來我們就來聊聊關於kubernetes與docker的關係?以下內容大家不妨參考一二希望能幫到您!

kubernetes與docker的關係

Docker：它是一個開源的軟體項目，在Linux作業系統上，docker提供了一個額外的軟體抽象層及作業系統層虛擬化的自動管理機制。

物理機：

虛擬機：

容器化：

容器：把自己的應用程式，根據某個依賴的基礎鏡像，生成一個應用程式鏡像應用程式鏡像，可以運行在任何部署了Docker環境的機器上。

[root@k8s-master01 ~]# docker versionClient: Docker Engine - Community Version: 20.10.7 API version: 1.40 Go version: go1.13.15 Git commit: f0df350 Built: Wed Jun 2 11:58:10 2021 OS/Arch: linux/amd64 Context: default Experimental: trueServer: Docker Engine - Community Engine: Version: 19.03.15 API version: 1.40 (minimum version 1.12) Go version: go1.13.15 Git commit: 99e3ed8919 Built: Sat Jan 30 03:16:33 2021 OS/Arch: linux/amd64 Experimental: false containerd: Version: 1.4.6 GitCommit: d71fcd7d8303cbf684402823e425e9dd2e99285d runc: Version: 1.0.0-rc95 GitCommit: b9ee9c6314599f1b4a7f497e1f1f856fe433d3b7 docker-init: Version: 0.18.0 GitCommit: fec3683

[root@k8s-master01 ~]# docker infoClient: Context: default Debug Mode: false # 可以按需修改 Plugins: app: Docker App (Docker Inc., v0.9.1-beta3) buildx: Build with BuildKit (Docker Inc., v0.5.1-docker) scan: Docker Scan (Docker Inc., v0.8.0)Server: Containers: 6 Running: 4 Paused: 0 Stopped: 2 Images: 9 Server Version: 19.03.15 Storage Driver: overlay2 # 官方推薦的存儲驅動，要求文件系統是xfs，必須支持d_type（目錄條目類型，內核上的一個數據，安裝系統的時候必須把ftype設置為1，不然的話很影響docker的性能），目前流行的Storage Driver有aufs（ubuntu支持）、overlay、brtfs Backing Filesystem: xfs Supports d_type: true Native Overlay Diff: true Logging Driver: json-file # docker日誌的存儲類型，json-file會存儲在本地，目錄在Docker Root Dir Cgroup Driver: systemd Plugins: Volume: local Network: bridge host ipvlan macvlan null overlay Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog Swarm: inactive # 容器編排工具，inactive未啟動 Runtimes: runc Default Runtime: runc # docker運行的核心 Init Binary: docker-init containerd version: d71fcd7d8303cbf684402823e425e9dd2e99285d runc version: b9ee9c6314599f1b4a7f497e1f1f856fe433d3b7 init version: fec3683 Security Options: seccomp Profile: default Kernel Version: 4.19.12-1.el7.elrepo.x86_64 # 內核版本低於3.18不能使用overlay2存儲驅動，linux3.18才加入的 Operating System: CentOS Linux 7 (Core) OSType: linux Architecture: x86_64 CPUs: 2 Total Memory: 1.923GiB Name: k8s-master01 ID: PYSL:2OAV:4C7N:WAI3:7G3J:IBR5:6BXI:7OEG:YNCL:6RAR:3CTF:CTDD Docker Root Dir: /var/lib/docker # 這個目錄可以修改，生產環境推薦使用ssd硬碟存儲，掛載在該目錄，可以提高docker的性能，條件不足的情況下，最好使用一個單獨的磁碟進行掛載，不要和宿主機用同一個磁碟 Debug Mode: false Registry: https://index.docker.io/v1/ # 官方鏡像倉庫，訪問較慢，可以修改為自己的鏡像倉庫 Labels: Experimental: false Insecure Registries: # 如果使用的非官方鏡像倉庫地址不是https，需要把連結加入到此非安全列表 127.0.0.0/8 Live Restore Enabled: false # 生產環境中需要打開，重啟docker進程不會重啟正在運行的容器，如果容器沒有設置自動重啟就會被關閉，不會重啟

查看d_type信息（ftype=1說明系統支持d_type）

[root@k8s-master01 ~]# xfs_info /meta-data=/dev/mapper/centos-root isize=512 agcount=4, agsize=1113856 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0 spinodes=0data = bsize=4096 blocks=4455424, imaxpct=25 = sunit=0 swidth=0 blksnaming =version 2 bsize=4096 ascii-ci=0 ftype=1log =internal bsize=4096 blocks=2560, version=2 = sectsz=512 sunit=0 blks, lazy-count=1realtime =none extsz=4096 blocks=0, rtextents=0

進入Docker Root Dir，進入任何一個容器目錄既可查看對應容器的日誌，每次docker重啟的時候日誌就會被清除

[root@k8s-master01 ~]# cd /var/lib/docker/containers/[root@k8s-master01 containers]# lltotal 0drwx-----x 4 root root 165 Jul 12 10:54 10b58a593a5f417d466fbb2eba54c6ac0e8322a3712cbc6eb46f9cae5b48e4d8[root@k8s-master01 10b58a593a5f417d466fbb2eba54c6ac0e8322a3712cbc6eb46f9cae5b48e4d8]# lltotal 16-rw-r----- 1 root root 4042 Jul 12 10:53 10b58a593a5f417d466fbb2eba54c6ac0e8322a3712cbc6eb46f9cae5b48e4d8-json.log

Insecure Registries目錄

[root@k8s-master01 ~]# vim /etc/docker/daemon.json{ "registry-mirrors": [ "https://registry.docker-cn.com", "http://hub-mirror.c.163.com", "https://docker.mirrors.ustc.edu.cn" ], "exec-opts": ["native.cgroupdriver=systemd"], "max-concurrent-downloads": 10, # 並發下載的線程數 "max-concurrent-uploads": 5, # 並發上傳的線程數 "log-opts": { "max-size": "300m", # 限制日誌文件最大容量，超過則分割 "max-file": "2" # 日誌保存最大數量 }, "live-restore": true # 更改docker配置之後需要重啟docker才能生效，這個參數可以使得重啟docker不影響正在運行的容器進程}

[root@k8s-master01 ~]# docker search centosNAME DESCRIPTION STARS OFFICIAL AUTOMATEDcentos The official build of CentOS. 6631 [OK] ansible/centos7-ansible Ansible on Centos7 134 [OK]consol/centos-xfce-vnc Centos container with "headless" VNC session… 129 [OK]jdeathe/centos-ssh OpenSSH / Supervisor / EPEL/IUS/SCL Repos - … 118 [OK]centos/systemd systemd enabled base container. 100 [OK]centos/mysql-57-centos7 MySQL 5.7 SQL database server 88 imagine10255/centos6-lnmp-php56 centos6-lnmp-php56 58 [OK]tutum/centos Simple CentOS docker image with SSH access 48 centos/postgresql-96-centos7 PostgreSQL is an advanced Object-Relational … 45 jdeathe/centos-ssh-apache-php Apache PHP - CentOS. 31 [OK]kinogmt/centos-ssh CentOS with SSH 29 [OK]guyton/centos6 From official centos6 container with full up… 10 [OK]nathonfowlie/centos-jre Latest CentOS image with the JRE pre-install… 8 [OK]centos/tools Docker image that has systems administration… 7 [OK]drecom/centos-ruby centos ruby 6 [OK]mamohr/centos-java Oracle Java 8 Docker image based on Centos 7 3 [OK]darksheer/centos Base Centos Image -- Updated hourly 3 [OK]miko2u/centos6 CentOS6 日本語環境 2 [OK]amd64/centos The official build of CentOS. 2 dokken/centos-7 CentOS 7 image for kitchen-dokken 2 indigo/centos-maven Vanilla CentOS 7 with Oracle Java Developmen… 2 [OK]mcnaughton/centos-base centos base image 1 [OK]blacklabelops/centos CentOS Base Image! Built and Updates Daily! 1 [OK]starlabio/centos-native-build Our CentOS image for native builds 0 [OK]smartentry/centos centos with smartentry 0 [OK]

OFFICIAL的值是ok代表官方容器，一般都是使用官方的

alpine可以作為基礎鏡像，拉取鏡像的時候如果本地已經存在，則不會重複拉取

可以通過官網搜索鏡像：https://hub.docker.com/

拉取鏡像，如果本地已有該鏡像，則不會重複拉取

[root@k8s-master01 ~]# docker pull alpine:latestlatest: Pulling from library/alpine5843afab3874: Pull complete Digest: sha256:234cb88d3020898631af0ccbbcca9a66ae7306ecd30c9720690858c1b007d2a0Status: Downloaded newer image for alpine:latestdocker.io/library/alpine:latest

默認拉取官方鏡像，如果需要拉取指定鏡像，需要添加地址，版本號

查看鏡像

[root@k8s-master01 ~]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEnginx latest 4cdc5dd7eaad 7 days ago 133MBkubernetesui/dashboard v2.3.1 e1482a24335a 3 weeks ago 220MBalpine latest d4ff818577bc 4 weeks ago 5.6MBregistry.cn-beijing.aliyuncs.com/dotbalo/node v3.15.3 d45bf977dfbf 10 months ago 262MBregistry.cn-beijing.aliyuncs.com/dotbalo/pod2daemon-flexvol v3.15.3 963564fb95ed 10 months ago 22.8MBregistry.cn-beijing.aliyuncs.com/dotbalo/cni v3.15.3 ca5564c06ea0 10 months ago 110MBkubernetesui/dashboard v2.0.3 503bc4b7440b 12 months ago 225MBregistry.cn-beijing.aliyuncs.com/dotbalo/coredns 1.7.0 bfe3a36ebd25 13 months ago 45.2MBregistry.cn-beijing.aliyuncs.com/dotbalo/metrics-scraper v1.0.4 86262685d9ab 15 months ago 36.9MBregistry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64 3.2 80d28bedfe5d 17 months ago 683kB

鏡像打標籤到自己的鏡像倉庫

[root@k8s-master01 ~]# docker tag registry.cn-beijing.aliyuncs.com/dotbalo/pod2daemon-flexvol:v3.15.3 mingsonzheng/pod2daemon-flexvol:v3.15.3

登錄遠程鏡像倉庫

[root@k8s-master01 ~]# docker loginLogin with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.Username: mingsonzhengPassword: WARNING! Your password will be stored unencrypted in /root/.docker/config.json.Configure a credential helper to remove this warning. Seehttps://docs.docker.com/engine/reference/commandline/login/#credentials-storeLogin Succeeded

登錄到指定倉庫

docker login xxx.com

推送鏡像

[root@k8s-master01 ~]# docker push mingsonzheng/pod2daemon-flexvol:v3.15.3The push refers to repository [docker.io/mingsonzheng/pod2daemon-flexvol]f0e55d2e215d: Pushed 7b2f85666007: Pushed 752045c6df15: Pushed ca07dc9dd06e: Pushed 1d0352c1c217: Pushed 540c65dd0455: Pushed 48855504bcc3: Pushed v3.15.3: digest: sha256:6bd1246d0ea1e573a6a050902995b1666ec0852339e5bda3051f583540361b55 size: 1788

前臺啟動，如果本地沒有鏡像會先拉取

[root@k8s-master01 ~]# docker run -ti centos:8 bashUnable to find image 'centos:8' locally8: Pulling from library/centos7a0437f04f83: Pull complete Digest: sha256:5528e8b1b1719d34604c87e11dcd1c0a20bedf46e83b5632cdeac91b8c04efc1Status: Downloaded newer image for centos:8[root@a4cb8f5d6bd5 /]#

後臺啟動

[root@k8s-master01 ~]# docker run -d centos:8 bash617a1213ae5ce5c4bed0716fd5b3212b25ed7bcc2099ba329db54cccd3c0b8d5[root@k8s-master01 ~]#

查看正在運行的容器

[root@k8s-master01 ~]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES617a1213ae5c centos:8 "bash" About a minute ago Exited (0) About a minute ago vigilant_boyd04b21dff00f5 centos:8 "bash" 2 minutes ago Exited (0) 2 minutes ago objective_satoshia4cb8f5d6bd5 centos:8 "bash" 5 minutes ago Exited (127) 2 minutes ago reverent_elgamal

查看所有狀態的容器

[root@k8s-master01 ~]# docker ps -aCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES1d906297395d centos:8 "bash" 2 minutes ago Exited (0) 2 minutes ago wonderful_hermann617a1213ae5c centos:8 "bash" 22 minutes ago Exited (0) 22 minutes ago vigilant_boyd04b21dff00f5 centos:8 "bash" 22 minutes ago Exited (0) 22 minutes ago objective_satoshia4cb8f5d6bd5 centos:8 "bash" 26 minutes ago Exited (127) 22 minutes ago reverent_elgamala3db403fd0be kubernetesui/dashboard "/dashboard --insecu…" 46 hours ago Up 46 hours k8s_kubernetes-dashboard_kubernetes-dashboard-67484c44f6-brz2z_kubernetes-dashboard_bb016e8e-a4b1-48e6-912c-022addfb72bf_08cd76e9123b3 registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.2 "/pause" 46 hours ago Up 46 hours k8s_POD_kubernetes-dashboard-67484c44f6-brz2z_kubernetes-dashboard_bb016e8e-a4b1-48e6-912c-022addfb72bf_0dbec965d88da registry.cn-beijing.aliyuncs.com/dotbalo/node "start_runit" 2 days ago Up 2 days k8s_calico-node_calico-node-gn8ws_kube-system_16eeb29c-3383-4e62-b84c-40bf3dae7d07_0e9869813fc1b registry.cn-beijing.aliyuncs.com/dotbalo/pod2daemon-flexvol "/usr/local/bin/flex…" 2 days ago Exited (0) 2 days ago k8s_flexvol-driver_calico-node-gn8ws_kube-system_16eeb29c-3383-4e62-b84c-40bf3dae7d07_010b58a593a5f registry.cn-beijing.aliyuncs.com/dotbalo/cni "/install-cni.sh" 2 days ago Exited (0) 2 days ago k8s_install-cni_calico-node-gn8ws_kube-system_16eeb29c-3383-4e62-b84c-40bf3dae7d07_0610909969be1 registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.2 "/pause" 2 days ago Up 2 days k8s_POD_calico-node-gn8ws_kube-system_16eeb29c-3383-4e62-b84c-40bf3dae7d07_0

查看正在運行的容器的id

[root@k8s-master01 ~]# docker ps -qa3db403fd0be8cd76e9123b3dbec965d88da610909969be1

查看所有的容器的id

[root@k8s-master01 ~]# docker ps -aq1d906297395d617a1213ae5c04b21dff00f5a4cb8f5d6bd5a3db403fd0be8cd76e9123b3dbec965d88dae9869813fc1b10b58a593a5f610909969be1

[root@k8s-master01 ~]# docker logs -f a3db403fd0be

對應日誌路徑

/var/lib/docker/containers/a3db403fd0be5eacb8aa1769cc8d215da93eb74da84262aa1aac11551c37a84d

啟動容器

[root@k8s-master01 ~]# docker run -ti nginx:1.14.2 sh#

Xshell 7新建一個連結到伺服器

查看運行中的容器

[root@k8s-master01 ~]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES2ef850f11136 nginx:1.14.2 "sh" 29 seconds ago Up 28 seconds 80/tcp funny_leavitta3db403fd0be kubernetesui/dashboard "/dashboard --insecu…" 2 days ago Up 2 days k8s_kubernetes-dashboard_kubernetes-dashboard-67484c44f6-brz2z_kubernetes-dashboard_bb016e8e-a4b1-48e6-912c-022addfb72bf_08cd76e9123b3 registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.2 "/pause" 2 days ago Up 2 days k8s_POD_kubernetes-dashboard-67484c44f6-brz2z_kubernetes-dashboard_bb016e8e-a4b1-48e6-912c-022addfb72bf_0dbec965d88da registry.cn-beijing.aliyuncs.com/dotbalo/node "start_runit" 3 days ago Up 3 days k8s_calico-node_calico-node-gn8ws_kube-system_16eeb29c-3383-4e62-b84c-40bf3dae7d07_0610909969be1 registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.2 "/pause" 3 days ago Up 3 days k8s_POD_calico-node-gn8ws_kube-system_16eeb29c-3383-4e62-b84c-40bf3dae7d07_0

進入容器

[root@k8s-master01 ~]# docker exec -ti 2ef850f11136 sh# lsbin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var# exit[root@k8s-master01 ~]#

後臺啟動nginx

[root@k8s-master01 ~]# docker run -tid -p 12345:80 nginx:latestb75ad319e61326e05905d41d67616112be51af4d1234f51bef5d21807e9bc42d[root@k8s-master01 ~]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMESb75ad319e613 nginx:latest "/docker-entrypoint.…" 8 seconds ago Up 6 seconds 0.0.0.0:12345->80/tcp upbeat_brahmagupta

訪問地址：http://192.168.232.128:12345/

進入容器

[root@k8s-master01 ~]# docker exec -ti b75ad319e613 bashroot@b75ad319e613:/# cd /usr/share/nginx/html/root@b75ad319e613:/usr/share/nginx/html# ls50x.html index.htmlroot@b75ad319e613:/usr/share/nginx/html# exitexit

複製文件到容器中

[root@k8s-master01 ~]# echo "test cp" > index.html[root@k8s-master01 ~]# docker cp index.html b75ad319e613:/usr/share/nginx/html/

訪問地址：http://192.168.232.128:12345/

複製容器中的文件到本地

[root@k8s-master01 ~]# docker cp b75ad319e613:/usr/share/nginx/html/index.html .

[root@k8s-master01 ~]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEnginx latest 4cdc5dd7eaad 8 days ago 133MB[root@k8s-master01 ~]# docker rmi 4cdc5dd7eaadError response from daemon: conflict: unable to delete 4cdc5dd7eaad (cannot be forced) - image is being used by running container b75ad319e613# 刪除容器[root@k8s-master01 ~]# docker rm b75ad319e613Error response from daemon: You cannot remove a running container b75ad319e61326e05905d41d67616112be51af4d1234f51bef5d21807e9bc42d. Stop the container before attempting removal or force remove# 停止容器運行[root@k8s-master01 ~]# docker stop b75ad319e613b75ad319e613[root@k8s-master01 ~]# docker rm b75ad319e613b75ad319e613[root@k8s-master01 ~]# docker rmi 4cdc5dd7eaadError response from daemon: conflict: unable to delete 4cdc5dd7eaad (must be forced) - image is being used by stopped container cd2a20f47459[root@k8s-master01 ~]# docker rm cd2a20f47459cd2a20f47459[root@k8s-master01 ~]# docker rmi 4cdc5dd7eaadUntagged: nginx:latestUntagged: nginx@sha256:353c20f74d9b6aee359f30e8e4f69c3d7eaea2f610681c4a95849a2fd7c497f9Deleted: sha256:4cdc5dd7eaadff5080649e8d0014f2f8d36d4ddf2eff2fdf577dd13da85c5d2fDeleted: sha256:63d268dd303e176ba45c810247966ff8d1cb9a5bce4a404584087ec01c63de15Deleted: sha256:b27eb5bbca70862681631b492735bac31d3c1c558c774aca9c0e36f1b50ba915Deleted: sha256:435c6dad68b58885ad437e5f35f53e071213134eb9e4932b445eac7b39170700Deleted: sha256:bdf28aff423adfe7c6cb938eced2f19a32efa9fa3922a3c5ddce584b139dc864Deleted: sha256:2c78bcd3187437a7a5d9d8dbf555b3574ba7d143c1852860f9df0a46d5df056aDeleted: sha256:764055ebc9a7a290b64d17cf9ea550f1099c202d83795aa967428ebdf335c9f7

[root@k8s-master01 ~]# docker imagesregistry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64 3.2 80d28bedfe5d 17 months ago 683kB[root@k8s-master01 ~]# docker history registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.2IMAGE CREATED CREATED BY SIZE COMMENT80d28bedfe5d 17 months ago ENTRYPOINT ["/pause"] 0B buildkit.dockerfile.v0 17 months ago ADD bin/pause-amd64 /pause # buildkit 683kB buildkit.dockerfile.v0 17 months ago ARG ARCH 0B buildkit.dockerfile.v0

假設我們複製了文件到容器中，想要保存容器狀態需要使用 docker commit

# 拉取鏡像[root@k8s-master01 ~]# docker pull nginx:latestlatest: Pulling from library/nginxb4d181a07f80: Pull complete 66b1c490df3f: Pull complete d0f91ae9b44c: Pull complete baf987068537: Pull complete 6bbc76cbebeb: Pull complete 32b766478bc2: Pull complete Digest: sha256:353c20f74d9b6aee359f30e8e4f69c3d7eaea2f610681c4a95849a2fd7c497f9Status: Downloaded newer image for nginx:latestdocker.io/library/nginx:latest# 後臺啟動容器[root@k8s-master01 ~]# docker run -tid -p 12345:80 nginx:latest8ddcc9d728450c9398579155e793aca873713632d72a8402e5684ebb6f613437# 獲取容器ID[root@k8s-master01 ~]# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES8ddcc9d72845 nginx:latest "/docker-entrypoint.…" 28 seconds ago Up 27 seconds 0.0.0.0:12345->80/tcp confident_leavitt# 複製文件到容器中[root@k8s-master01 ~]# docker cp index.html 8ddcc9d72845:/usr/share/nginx/html/# 提交修改記錄[root@k8s-master01 ~]# docker commit -a "mingsonzheng" -m "update index.html" 8ddcc9d72845 nginx:commitsha256:f62c69e4853e45951b1b83eec2432e48e436d65a14a62b087e5fe6c7c9398771# 查看鏡像[root@k8s-master01 ~]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEnginx commit f62c69e4853e 40 seconds ago 133MB# 啟動容器，加上--rm，則關閉之後會刪除，不會產生大量狀態為Exited的容器[root@k8s-master01 ~]# docker run -ti --rm nginx:commit bashroot@c657e57078c1:/# cd /usr/share/nginx/html/root@c657e57078c1:/usr/share/nginx/html# ls50x.html index.htmlroot@c657e57078c1:/usr/share/nginx/html# exitexit# 查看容器，該容器不會出現在列表中[root@k8s-master01 ~]# docker ps

nginx官方Dockerfile：https://github.com/nginxinc/docker-nginx/blob/master/Dockerfile-alpine.template

繼承alpine基礎鏡像

FROM alpine:%%ALPINE_VERSION%%

MAINTAINER：鏡像製作作者信息，新版本推薦使用LABEL

LABEL

執行shell命令

RUN set -x

apk是alpine安裝包的工具

apk add --no-cache --virtual .cert-deps

暴露埠號

EXPOSE 80

啟動容器默認執行的命令

CMD ["nginx", "-g", "daemon off;"]

CMD命令可以被覆蓋，比如bash

[root@k8s-master01 ~]# docker run -ti --rm nginx:commit bash

CMD 和 ENTRYPOINT 必須有一個，如果兩者都有的話，ENTRYPOINT 就是啟動命令，而 CMD 就是它的參數

ENTRYPOINT 對應 k8s 的 COMMAND

CMD 對應 k8s 的 arg

VOLUME 是一個匿名的掛載點，Docker 不建議保留容器產生的文件，但是有一些文件是必須保留的，比如資料庫，我們可以為其創建一個掛載點，將宿主機的目錄掛載到容器裡面，這樣就可以保留它的數據

配置環境變量

ENV NGINX_VERSION %%NGINX_VERSION%%ENV NJS_VERSION %%NJS_VERSION%%ENV PKG_RELEASE %%PKG_RELEASE%%

但是不建議寫在 Dockerfile 中，建議通過命令行 -e 傳入參數，獨立到鏡像之外，可以動態修改

[root@k8s-master01 ~]# docker run -ti -e a=b -e c=d

ADD：複製文件到容器，如果複製壓縮文件會自動解壓

COPY：複製文件到容器，不會解壓，直接複製

WORKDIR：設置容器的工作目錄，如果有設置則進入容器時會進入到該目錄下

USER：容器使用的用戶，系統默認用戶是root，但是在業務容器容器化的時候不建議使用root，因為不安全，可能會造成對宿主機有危險的操作

[root@k8s-master01 ~]# whoamiroot

新增Dockerfile

[root@k8s-master01 ~]# mkdir dockerfiles[root@k8s-master01 ~]# cd dockerfiles/[root@k8s-master01 dockerfiles]# vim Dockerfile# 添加以下內容FROM centos:8LABELLABEL test=dockerfileRUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng

在當前目錄下構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:user .Sending build context to Docker daemon 2.048kBStep 1/5 : FROM centos:8 ---> 300e315adb2fStep 2/5 : LABEL ---> Running in cccd20f9b0f5Removing intermediate container cccd20f9b0f5 ---> f6dc016add09Step 3/5 : LABEL test=dockerfile ---> Running in e4d1962c630bRemoving intermediate container e4d1962c630b ---> 3977dc88a2f2Step 4/5 : RUN useradd mingsonzheng ---> Running in d3905f2c7dc4Removing intermediate container d3905f2c7dc4 ---> 30968f5c2285Step 5/5 : RUN mkdir /opt/mingsonzheng ---> Running in 811c4ceb3e70Removing intermediate container 811c4ceb3e70 ---> 0cd811c2fadfSuccessfully built 0cd811c2fadfSuccessfully tagged centos:user

啟動鏡像

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:user bash[root@828f29ae30bf /]#

調試的時候一定要加上 --rm，不然會有很多Exited記錄

查看用戶

[root@828f29ae30bf /]# cat /etc/passwdmingsonzheng:x:1000:1000::/home/mingsonzheng:/bin/bash

製作完鏡像之後，如果調試沒有問題，記得推送到鏡像倉庫

如果測試通過之後，需要優化一下RUN語句，沒有必要分開寫，因為docker有緩存機制，假設有20個RUN語句，執行第18個的時候失敗了，前面17個執行成功的沒有必要再執行一次，修改之後直接從第18個RUN語句繼續執行

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfile#RUN useradd mingsonzheng#RUN mkdir /opt/mingsonzhengRUN useradd mingsonzheng && /opt/mingsonzheng

這樣docker的層級會少一層，存儲大小會小一點

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileRUN useradd mingsonzhengRUN mkdir /opt/mingsonzhengCMD [ "sh", "-c", "echo 1"]#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:cmd .

如果文件不在當前目錄，可以使用-f

[root@k8s-master01 dockerfiles]# mkdir t[root@k8s-master01 dockerfiles]# cp Dockerfile t[root@k8s-master01 dockerfiles]# docker build -t centos:cmd -f t/Dockerfile

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEcentos cmd a008df4670f8 2 minutes ago 210MB

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:cmd1

可以看到列印了一個1就退出了

使用bash覆蓋CMD命令

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:cmd bash[root@924006c7dc0e /]# exitexit

可以看到它就不列印了，覆蓋了CMD命令

在k8s中不建議將CMD命令打到鏡像中，因為我們遵循的構建策略是一次構建到處運行，啟動的命令可能不是統一的，可以指定配置文件讓啟動命令根據配置文件變成不同環境的命令，這樣可以使用k8s的arg或者cmd去覆蓋掉它的啟動參數，所以CMD可以不打到鏡像中，當然也可以使用變量的注入方式

使用ENTRYPIOINT，CMD可以被覆蓋，如果有ENTRYPIOINT的話，CMD就是ENTRYPIOINT的參數

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileRUN useradd mingsonzhengRUN mkdir /opt/mingsonzhengENTRYPOINT ["echo"]CMD [ "3"]#RUN useradd mingsonzheng && /opt/mingsonzheng

打包鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:ep .

運行容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:ep 1010[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:ep mingsonzhengmingsonzheng

可以看到CMD就是ENTRYPIOINT的參數，CMD可以被覆蓋，我們可以把命令相同的部分打入到ENTRYPIOINT，不同的部分通過CMD覆蓋

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng#ENTRYPOINT ["echo"]CMD echo "test_env1 test_env2"#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:env .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:envtest_env1 test_env2

環境變量也可以這麼寫

ENV env1=test1 env2=test2

正式應用的ENV變量不要寫在Dockerfile裡面，應該使用k8s資源文件，或者docker的-e參數注入進去，這樣也能減少構建鏡像的層數

# 新增文件[root@k8s-master01 dockerfiles]# echo 123 > index.html# 壓縮文件[root@k8s-master01 dockerfiles]# tar zcf index.tar.gz index.html t/# 編輯Dockerfile[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng#ENTRYPOINT ["echo"]ENV env1=test1 env2=test2ADD ./index.tar.gz /opt/CMD echo "test_env1 test_env2"#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:add .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:add bash[root@b2dacca0f34f /]# cd /opt/[root@b2dacca0f34f opt]# lsindex.html mingsonzheng t

可以看到文件被複製到容器的指定目錄下，並且自動解壓了

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng#ENTRYPOINT ["echo"]ENV env1=test1 env2=test2ADD ./index.tar.gz /opt/COPY ./t /opt/mingsonzheng/CMD echo "test_env1 test_env2"#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:add .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:add bash[root@3ca8cddbf8b3 /]# cd /opt/mingsonzheng/[root@3ca8cddbf8b3 mingsonzheng]# lsDockerfile

可以看到docker把t目錄下的文件複製進來了，並不會複製目錄，如果想要複製目錄的話，只能多加一層目錄

COPY複製壓縮文件的話不會解壓

docker build的時候會把當前目錄下所有東西發送到內存中，所以文件必須要放在執行docker build命令的文件目錄下

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng#ENTRYPOINT ["echo"]ENV env1=test1 env2=test2ADD ./index.tar.gz /opt/COPY ./t /opt/mingsonzheng/CMD echo "test_env1 test_env2"WORKDIR /opt/mingsonzhengCMD pwd ; ls#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:workdir .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:workdir/opt/mingsonzhengDockerfile

# 啟動容器[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:workdir bash# 查看當前用戶[root@87983e2581da mingsonzheng]# whoamiroot# 查看系統其他用戶[root@87983e2581da mingsonzheng]# cat /etc/passwdmingsonzheng:x:1000:1000::/home/mingsonzheng:/bin/bash

切換用戶

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng#ENTRYPOINT ["echo"]ENV env1=test1 env2=test2ADD ./index.tar.gz /opt/COPY ./t /opt/mingsonzheng/CMD echo "test_env1 test_env2"WORKDIR /opt/mingsonzhengUSER 1000CMD pwd ; ls#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:workdir .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:workdir bash[mingsonzheng@f6110f7e8e3a mingsonzheng]$ whoamimingsonzheng

使用鏡像倉庫地址（xxx.com）構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t xxx.com/centos:workdir .

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZExxx.com/centos workdir cf9572a3833e 3 minutes ago 210MB

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容FROM centos:8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN useradd mingsonzhengRUN mkdir /opt/mingsonzheng#ENTRYPOINT ["echo"]ENV env1=test1 env2=test2ADD ./index.tar.gz /opt/COPY ./t /opt/mingsonzheng/CMD echo "test_env1 test_env2"WORKDIR /opt/mingsonzheng#USER 1000VOLUME /dataCMD pwd ; ls#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:workdir .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm centos:workdir bash[root@6aecced2b780 mingsonzheng]# cd / [root@6aecced2b780 /]# lsbin data dev etc home lib lib64 lost found media mnt opt proc root run sbin srv sys tmp usr var

可以看到data目錄，它會與本地 /var/lib/docker/volumes/ 的目錄下生成一個volume的目錄，然後掛載到容器中的data下，退出容器則會清除本地目錄下的data

通過-v將mysql_data目錄掛載到容器中，使用-v則系統不會自動創建掛載目錄

[root@k8s-master01 ~]# mkdir mysql_data[root@k8s-master01 ~]# docker run -ti -v /root/mysql_data/:/data xxx.com/centos:workdir bash

一定不要使用centos基礎鏡像，可以使用alpine，busybox，scratch，debian

修改基礎鏡像

[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容#FROM centos:8FROM alpine:3.8LABELLABEL test=dockerfileENV test_env1 env1ENV test_env2 env2RUN adduser -D mingsonzhengRUN mkdir -p /opt/mingsonzheng#ENTRYPOINT ["echo"]ENV env1=test1 env2=test2ADD ./index.tar.gz /opt/COPY ./t /opt/mingsonzheng/WORKDIR /opt/mingsonzheng#USER 1000VOLUME /dataCMD pwd ; ls#RUN useradd mingsonzheng && /opt/mingsonzheng

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t centos:workdir .

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEalpine workdir 7fc05207414a 22 seconds ago 4.42MBcentos workdir b165153a0132 36 minutes ago 210MB

alpine與centos相比，SIZE非常小，適合做為基礎鏡像，基礎鏡像可以在官方倉庫查找，不需要自己製作

如果需要用到glibc，可以使用node:slim，python:slim，net作為基礎鏡像

分開兩個步驟：編譯操作和生成最終鏡像的操作

新建一個go文件

[root@k8s-master01 dockerfiles]# vim main.go# 修改為以下內容package mainimport "fmt"func main { fmt.Println("Hello World")}

新建一個Dockerfile文件

[root@k8s-master01 dockerfiles]# mv Dockerfile t/123[root@k8s-master01 dockerfiles]# vim Dockerfile# 修改為以下內容FROM golang:1.14.4-alpineWORKDIR /optCOPY main.go /optRUN go build /opt/main.goCMD "./main"

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t hello:single_build .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm hello:single_buildHello World

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEhello single_build ca11178a0c13 44 seconds ago 372MB

查看包大小

[root@k8s-master01 dockerfiles]# docker run -ti --rm hello:single_build sh/opt # ls -lhtotal 2M -rwxr-xr-x 1 root root 2.0M Jul 16 08:30 main-rw-r--r-- 1 root root 77 Jul 16 08:24 main.go/opt #

2M的包生成的鏡像有372M，我們應該使用分階段構建

[root@k8s-master01 dockerfiles]# vim Dockerfile# 修改為以下內容# build stepFROM golang:1.14.4-alpineWORKDIR /optCOPY main.go /optRUN go build /opt/main.goCMD "./main"# create real app imageFROM alpine:3.8COPY --from=0 /opt/main /CMD "./opt/main"

--from=0就是第一步的操作（# create real app image上面的操作）

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t hello:alpine .

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm hello:alpine sh/ # lsbin dev etc home lib main media mnt proc root run sbin srv sys tmp usr var/ # ./mainHello World

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEhello alpine 66fa14e35f3c About a minute ago 6.48MBhello single_build ca11178a0c13 11 minutes ago 372MB

可以看到單階段和多階段鏡像大小的區別，所以一定要進行分階段構建

使用builder命令複製包到根目錄

[root@k8s-master01 dockerfiles]# vim Dockerfile# 修改為以下內容# build stepFROM golang:1.14.4-alpine as builderWORKDIR /optCOPY main.go /optRUN go build /opt/main.goCMD "./main"# create real app imageFROM alpine:3.8COPY --from=builder /opt/main /CMD "./opt/main"

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t hello:alpine .

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEhello alpine 66fa14e35f3c 9 minutes ago 6.48MB

鏡像大小和前面的差別不大，我們只是將第一個步驟打包成鏡像，然後把它裡面的文件複製到現在的鏡像裡面

php Dockerfile

[root@k8s-master01 dockerfiles]# mv Dockerfile goDockerfile[root@k8s-master01 dockerfiles]# vim Dockerfile# 修改為以下內容FROM php:7.1.22-fpm-alpineRUN apk add --no-cache binutils freetype libpng libjpeg-turbo freetype-dev libpng-dev libjpeg-turbo-dev libc6-compat libxml2 libxml2-dev libmcrypt libmcrypt-dev libc-dev icu-dev gettext-dev openssl-dev bzip2-devRUN docker-php-ext-install pdo pdo_mysql mcrypt zip gd pcntl opcache bcmath#RUN docker-php-ext-install gettextRUN docker-php-ext-install mysqli#RUN apk add --no-cache php7-sysvsem php7-pdo_dblib php7-sockets php-soap php7-xmlrpc##RUN apk add --no-cache php7-sysvsem php7-pdo_dblib php7-sockets php-soap php7-xmlrpc##RUN apk add --no-cache freetds-dev##RUN docker-php-ext-install pdo_dblib#RUN docker-php-ext-install soap#RUN docker-php-ext-install sockets#RUN docker-php-ext-install sysvsem#RUN docker-php-ext-install xmlrpc#RUN apk add --no-cache freetds-dev#RUN docker-php-ext-install pdo_dblib#RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/#RUN docker-php-ext-install -j$(nproc) gd#FROM php:7.1.22-fpm-alpine#COPY --from=0 /usr/local/lib/php/extensions/no-debug-non-zts-20160303 /usr/local/lib/php/extensions/no-debug-non-zts-20160303#RUN apk add --no-cache freetds-dev php7-sysvsem php7-pdo_dblib php7-sockets php-soap php7-xmlrpc binutils freetype libpng libjpeg-turbo freetype-dev libpng-dev libjpeg-turbo-dev libc6-compat libxml2 libxml2-dev libmcrypt libmcrypt-dev libc-dev icu-dev gettext-dev openssl-dev bzip2-dev && cd /usr/local/lib/php/extensions/no-debug-non-zts-20160303 && docker-php-ext-enable *.so && rm -rf /var/cache/apk/*

多階段的就是編譯在一個鏡像裡面完成，第二個鏡像使用第一個鏡像編譯的產物，省去了編譯產生的緩存

Scratch空鏡像不可拉取，但是可以直接使用

使用scratch

[root@k8s-master01 dockerfiles]# cp Dockerfile t/phpDockerfile[root@k8s-master01 dockerfiles]# cp goDockerfile Dockerfilecp: overwrite 『Dockerfile』? y[root@k8s-master01 dockerfiles]# vim Dockerfile # 修改為以下內容# build stepFROM golang:1.14.4-alpine as builderWORKDIR /optCOPY main.go /optRUN go build /opt/main.goCMD "./main"# create real app imageFROM scratchCOPY --from=builder /opt/main /CMD "./main"

構建鏡像

[root@k8s-master01 dockerfiles]# docker build -t hello:scratch .

查看鏡像

[root@k8s-master01 dockerfiles]# docker imagesREPOSITORY TAG IMAGE ID CREATED SIZEhello scratch 4d747be3b21b About a minute ago 2.07MB

啟動容器

[root@k8s-master01 dockerfiles]# docker run -ti --rm hello:scratch /mainHello World

基於最基礎的鏡像，製作依賴環境的鏡像可以使用，但是建議使用官方製作好的鏡像

如果Dockerfile中引用的鏡像發生了更新，需要使用pull參數

http://www.kubeasy.com/