會用Docker的人都別裝了，這多簡單吶

{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"學術又官方的說法"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Docker 是一個開源的應用容器引擎，讓開發者可以打包他們的應用以及依賴包到一個可移植的容器中,然後發佈到任何流行的Linux機器或Windows 機器上,也可以實現虛擬化,容器是完全使用沙箱機制,相互之間不會有任何接口。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"沒用過的人能看懂這段話？ "}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"用過的人爲什麼要看這段話？ "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"還是要自己動手。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"試用完感受"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"試用了一下，就是下載運行官方製作的MySQL鏡像，沒自建鏡像倉庫，沒製作鏡像，用完覺得功能像是yum外加微型vmware。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"docker就是安裝自帶ENV軟件包的yum"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/d9/d9f9d43cbd0a2b93590f9fa11e93642b.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"左邊的MySQL啓動後，和服務器環境互相作用，像把一個新生兒放在了混合病房。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"右邊的MySQL啓動後，自帶一套環境變量，和服務器環境互不影響，像把一個新生兒放進了保溫箱，保溫箱有自己的溫度溼度氧氣，保溫箱再放進病房裏。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"像yum"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我們想安裝某個軟件，直接yum install 軟件，如果yum源服務器有安裝包，自動就安裝上了，然後啓動軟件開始工作。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"docker方式類似的，我們想使用某個軟件並且要求它以docker方式運行，那麼先要docker search命令看docker倉庫（官方倉庫有大量軟件鏡像可以直接使用）是否有該軟件的鏡像， "}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/16/1650af06bc02d81a3f66433a9d51c836.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"有的話先將鏡像pull到本地，然後run鏡像，軟件就開始工作了。這些鏡像具有Build once,Run anyWhere的優勢，和java機制很像。run起來的鏡像被稱作容器container，查看鏡像用docker images命令，查看容器用docker ps命令。 "}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"像vmware"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"微型vmware是指，docker啓動某個軟件的鏡像後，就相當於啓動的這個軟件，不同的是這個軟件彷彿運行在一個和操作系統隔離的環境中，這個環境有自己的環境變量，並且它的環境變量不影響操作系統，只對本鏡像內的軟件有效，就好像每個軟件都運行在各自的vmware虛擬機中，虛擬機之間互不影響。例如同一操作系統中有docker MySQL（docker啓動的MySQL鏡像）和docker nginx兩個進程在工作，兩個進程完全互不干涉，MySQL運行在給它配置好的環境裏，nginx運行在給它配置好的環境裏，一個的死活和變化和另一個無關，也和操作系統無關。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"說容易，我做一遍試試"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"安裝Docker"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"下載libcgroup "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"搜索“libcgroup rpm” 。 RedHat系統就選擇centos的安裝包，下載 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"libcgroup-0.41-21.el7.x86_64.rpm。ftp上傳到Redhat服務器。 "}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/0c/0c31545252acd62b005d6db9baadfc3c.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":" "}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"安裝libcgroup "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@bogon dockerab]# rpm -ivh libcgroup-0.41-21.el7.x86_64.rpm \nPreparing... ################################# [100%]\nUpdating / installing...\n1:libcgroup-0.41-21.el7 ################################# [100%]"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"下載docker包 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# wget https://get.docker.com/rpm/1.7.1/centos-6/RPMS/x86_64/docker-engine-1.7.1-1.el6.x86_64.rpm\n--2020-06-17 08:34:52-- https://get.docker.com/rpm/1.7.1/centos-6/RPMS/x86_64/docker-engine-1.7.1-1.el6.x86_64.rpm\nResolving get.docker.com... 99.86.193.96, 99.86.193.12, 99.86.193.128, ...\nConnecting to get.docker.com|99.86.193.96|:443... connected.\nHTTP request sent, awaiting response... 200 OK\nLength: 4762280 (4.5M) [binary/octet-stream]\nSaving to: docker-engine-1.7.1-1.el6.x86_64.rpm\n\n16% [============> ] 801,777 35.5K/s eta 1m 49s "}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"安裝docker "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# rpm -ivh docker-engine-1.7.1-1.el6.x86_64.rpm\nPreparing... ########################################### [100%]\n 1:docker-engine ########################################### [100%]"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"啓動docker服務"}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# service docker start\nStarting cgconfig service: [ OK ]\nStarting docker: [ OK ]"}]},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"起個MySQL"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Docker啓動了，相當於有了yum命令而已。yum當然要用來安裝各種軟件啦。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"查看倉庫是否有MySQL "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"類似yum search命令，"}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# docker search mysql\nNAME DESCRIPTION STARS OFFICIAL AUTOMATED\nmysql MySQL is a widely used, open-source relati... 9634 [OK] \nmariadb MariaDB is a community-developed fork of M... 3500 [OK]"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"下載MySQL鏡像到本地 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# docker pull mysql\nlatest: Pulling from mysql\n8011c293a399: Downloading [> ] 277.6 kB/27.1 MB\n2455a1403f59: Download complete \n2f535805fb57: Download complete \nebf295599c35: Downloading [=========> ] 768.5 kB/4.178 MB"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"如果網絡不好，需要等待時間較長，並且報錯退出的話要反覆執行docker pull mysql，直至下載成功。成功後會打印下面語句。 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"Digest: sha256:0648b8559643d01be3bfb0210ead5fdcb9a99ff7a6a1d5cb881bbd1f7f7b11bc\nStatus: Downloaded newer image for mysql:latest"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"查看鏡像 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# docker images\nREPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE\nmysql latest 9cd0a11a66df 7 days ago 540.6 MB"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"看到MySQL鏡像下載成功。 "}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"啓動MySQL鏡像"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"啓動命令各個參數含義略。 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@bogon ~]# docker run -p 3306:3306 -e MYSQL_ROOT_PASSWORD=123456 -d mysql\n54fc423d7b42db8151e8fe916e33e6e0b0f5fd62fc4a455950f26d6a956a97e3"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"查看容器 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"理解成ps -ef | grep mysqld吧"}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@bogon ~]# docker ps\nCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES\n54fc423d7b42 mysql \"docker-entrypoint.s 8 seconds ago Up 6 seconds 33060/tcp, 0.0.0.0:3306->3306/tcp backstabbing_ptolemy "}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"執行sql"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"redhat沒安裝連MySQL的工具，沒法測試。如果有，不用進入容器，在redhat環境就可以訪問數據庫。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"現在只能容器內試試了。docker exec進入容器，需要用到上面的CONTAINER ID，進入後可以查看容器的文件系統和環境變量。 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@bogon ~]# docker exec -it 54fc423d7b42 bash"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"成功進入MySQL 容器，連接數據庫試試 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"root@54fc423d7b42:/# mysql -uroot -p123456\nmysql: [Warning] Using a password on the command line interface can be insecure.\nWelcome to the MySQL monitor. Commands end with ; or \\g.\nYour MySQL connection id is 8\nServer version: 8.0.20 MySQL Community Server - GPL\n\nCopyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.\n\nOracle is a registered trademark of Oracle Corporation and/or its\naffiliates. Other names may be trademarks of their respective\nowners.\n\nType 'help;' or '\\h' for help. Type '\\c' to clear the current input statement.\n\nmysql> show databases;\n+--------------------+\n| Database |\n+--------------------+\n| information_schema |\n| mysql |\n| performance_schema |\n| sys |\n+--------------------+\n4 rows in set (0.00 sec)\n\nmysql>"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"到此就能使用MySQL了。如果直接安裝MySQL遇到的問題可能很多，最順利的情況也就和剛纔一樣吧！並且每臺服務器都要解決不一樣的問題，現在就能初步感受到docker的方便之處了。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"容器內外環境對比"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/de/dec19cadec528f47b4d858206489967e.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"看看容器內環境變量，變量很少 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"root@54fc423d7b42:/# env \nMYSQL_MAJOR=8.0\nHOSTNAME=54fc423d7b42\nPWD=/\nMYSQL_ROOT_PASSWORD=123456\nHOME=/root\nMYSQL_VERSION=8.0.20-1debian10\nGOSU_VERSION=1.12\nSHLVL=1\nPATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\n_=/usr/bin/env"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"看文件系統就ls cd就可以了"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"退出容器，回到操作系統，查看環境變量 "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"root@54fc423d7b42:/# exit\nexit\n[root@bogon ~]# env #操作系統的環境變量\nXDG_SESSION_ID=1\nHOSTNAME=bogon\nSELINUX_ROLE_REQUESTED=\nTERM=vt100\nSHELL=/bin/bash\nHISTSIZE=1000\nSSH_CLIENT=192.168.56.1 49661 22\nSELINUX_USE_CURRENT_RANGE=\nSSH_TTY=/dev/pts/0\nUSER=root\nLS_COLORS=rs=0:di=01;34:....\nSSH_AUTH_SOCK=/tmp/ssh-gSRfCMVd4x/agent.3732\nMAIL=/var/spool/mail/root\nPATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin\nPWD=/root\nLANG=en_US.UTF-8\nSELINUX_LEVEL_REQUESTED=\nHISTCONTROL=ignoredups\nSHLVL=1\nHOME=/root\nLOGNAME=root\nSSH_CONNECTION=192.168.56.1 49661 192.168.56.106 22\nLESSOPEN=||/usr/bin/lesspipe.sh %s\nXDG_RUNTIME_DIR=/run/user/0\n_=/usr/bin/env"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"完全是兩個世界，主環境沒有一點安裝過MySQL的痕跡，而這個服務器卻實實在在的有MySQL的功能。 "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"一些坑"}]},{"type":"numberedlist","attrs":{"start":"1","normalizeStart":1},"content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":1,"align":null,"origin":null},"content":[{"type":"text","text":" 遇到報錯"}]}]}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"Cannot connect to the Docker daemon. Is 'docker -d' running on this host?"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"，重啓docker "}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# service docker stop 直接restart也可\n[root@basicserver dockertest]# service docker start"}]},{"type":"numberedlist","attrs":{"start":"2","normalizeStart":"2"},"content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","text":" radhat7需要先安裝libcgroup，然後安裝docker的rpm包才能成功。"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"numberedlist","attrs":{"start":"3","normalizeStart":"3"},"content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":3,"align":null,"origin":null},"content":[{"type":"text","text":" redhat6無法運行本文版本的docker，當docker run時報錯。所以如果安裝本文版本的docker，Redhat版本要7以及更高。 "}]}]}]},{"type":"codeblock","attrs":{"lang":""},"content":[{"type":"text","text":"[root@basicserver dockertest]# docker run mysql #Redhat6 run不起來\nFATAL: kernel too old"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"總結"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"誰再說不會用docker，非要一步一步配環境，裝軟件，就問他，“你會用yum嗎？” "}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"話說回來，剛開始用總感覺不踏實，和系統隔了一層，不如直接安裝的東西手感好。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}