參考 https://www.cnblogs.com/CloudMan6/p/6830067.html   Dockerfile構建映象過程分析   [email protected]:~/111# ls    #    檢視當前目錄下存在Dockerfile檔案 Dockerfile [email protected]:~/111# cat Dockerfile    #    檢視Dockerfile問價內容，執行centos容器，然後安裝wget命令 FROM centos RUN yum install -y wget [email protected]:~/111# docker build -t centos-wget .    #    執行docker build 命令使用Dockerfile檔案構建映象 Sending build context to Docker daemon  2.048kB    #    傳送build context（當前目錄） 下所有檔案和子目錄到dokcer daemon。建議當前目錄不要存放與構建映象無關的檔案，耗時且容易失敗 Step 1/2 : FROM centos    #    開始執行centos容器 latest: Pulling from library/centos    #    從Docker Hub下載centos映象 a02a4930cb5d: Pull complete     Digest: sha256:184e5f35598e333bfa7de10d8fb1cebb5ee4df5bc0f970bf2b1e7c7345136426 Status: Downloaded newer image for centos:latest ---> 1e1148e4cc2c    #    centos容器啟動成功，id：1e1148e4cc2c Step 2/2 : RUN yum install -y wget    #    開始安裝wget命令 ---> Running in a127bab51f51    #    執行臨時容器 a127bab51f51 Loaded plugins: fastestmirror, ovl Determining fastest mirrors * base: mirrors.huaweicloud.com * extras: mirrors.neusoft.edu.cn * updates: mirrors.neusoft.edu.cn Resolving Dependencies --> Running transaction check ---> Package wget.x86_64 0:1.14-18.el7 will be installed --> Finished Dependency Resolution   Dependencies Resolved   ================================================================================ Package         Arch              Version                Repository       Size ================================================================================ Installing: wget            x86_64            1.14-18.el7            base            547 k   Transaction Summary ================================================================================ Install  1 Package   Total download size: 547 k Installed size: 2.0 M Downloading packages: warning: /var/cache/yum/x86_64/7/base/packages/wget-1.14-18.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID f4a80eb5: NOKEY Public key for wget-1.14-18.el7.x86_64.rpm is not installed Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 Importing GPG key 0xF4A80EB5: Userid     : "CentOS-7 Key (CentOS 7 Official Signing Key) <[email protected]>" Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5 Package    : centos-release-7-6.1810.2.el7.centos.x86_64 (@CentOS) From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 Running transaction check Running transaction test Transaction test succeeded Running transaction   Installing : wget-1.14-18.el7.x86_64                                      1/1 install-info: No such file or directory for /usr/share/info/wget.info.gz   Verifying  : wget-1.14-18.el7.x86_64                                      1/1   Installed:   wget.x86_64 0:1.14-18.el7                                                        Complete! Removing intermediate container a127bab51f51    #    刪除臨時容器 a127bab51f51  ---> 8486cf558bf9 Successfully built 8486cf558bf9    #    成功構建映象 8486cf558bf9 Successfully tagged centos-wget:latest       [email protected]:~/111# docker images    #    檢視映象列表，確認centos-wget 映象建立成功 REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE centos-wget         latest              8486cf558bf9        59 seconds ago      272MB centos              latest              1e1148e4cc2c        3 weeks ago         202MB [email protected]:~/111# docker history centos-wget    #    檢視映象centos-wget 構建記錄，即docker的分層結構 IMAGE               CREATED              CREATED BY                                      SIZE                COMMENT 8486cf558bf9        About a minute ago   /bin/sh -c yum install -y wget                  70.7MB               1e1148e4cc2c        3 weeks ago          /bin/sh -c #(nop)  CMD ["/bin/bash"]            0B                   <missing>           3 weeks ago          /bin/sh -c #(nop)  LABEL org.label-schema.sc…   0B                   <missing>           3 weeks ago          /bin/sh -c #(nop) ADD file:6f877549795f4798a…   202MB