在正式学习docker build命令前，我们先准备一个简单的Dockerfile文件，如下：
# 继承基础镜像centos:latest FROM centos # 设置作者信息 MAINTAINER myName<myName@163.com> # 定义环境变量 ENV mypath /tmp WORKDIR $mypath # 安装 vim 和 ifconfig RUN yum -y install vim RUN yum -y install net-tools # 暴露80端口 EXPOSE 80 CMD echo $mypath CMD echo "success-------------------------ok" CMD /bin/bash
docker build 命令根据 Dockerfile 构建一个镜像。可以使用“docker build --help”查看命令的帮助信息，如下：
[root@localhost ~]# docker build --help Usage: docker build [OPTIONS] PATH | URL | - Build an image from a Dockerfile Options: --add-host list Add a custom host-to-IP mapping (host:ip) --build-arg list Set build-time variables --cache-from strings Images to consider as cache sources --cgroup-parent string Optional parent cgroup for the container --compress Compress the build context using gzip --cpu-period int Limit the CPU CFS (Completely Fair Scheduler) period --cpu-quota int Limit the CPU CFS (Completely Fair Scheduler) quota -c, --cpu-shares int CPU shares (relative weight) --cpuset-cpus string CPUs in which to allow execution (0-3, 0,1) --cpuset-mems string MEMs in which to allow execution (0-3, 0,1) --disable-content-trust Skip image verification (default true) -f, --file string Name of the Dockerfile (Default is 'PATH/Dockerfile') --force-rm Always remove intermediate containers --iidfile string Write the image ID to the file --isolation string Container isolation technology --label list Set metadata for an image -m, --memory bytes Memory limit --memory-swap bytes Swap limit equal to memory plus swap: '-1' to enable unlimited swap --network string Set the networking mode for the RUN instructions during build (default "default") --no-cache Do not use cache when building the image --pull Always attempt to pull a newer version of the image -q, --quiet Suppress the build output and print image ID on success --rm Remove intermediate containers after a successful build (default true) --security-opt strings Security options --shm-size bytes Size of /dev/shm -t, --tag list Name and optionally a tag in the 'name:tag' format --target string Set the target build stage to build. --ulimit ulimit Ulimit options (default [])
实例1：下面使用“docker build -t myimage:v1.0 .”命令构建一个镜像，如下：
[root@localhost ~]# docker build -t myimage:v1.0 . Sending build context to Docker daemon 204.8MB Step 1/10 : FROM centos latest: Pulling from library/centos 8ba884070f61: Already exists Digest: sha256:a799dd8a2ded4a83484bbae769d97655392b3f86533ceb7dd96bbac929809f3c Status: Downloaded newer image for centos:latest ---> 9f38484d220f ...... Step 9/10 : CMD echo "success-------------------------ok" ---> Running in 68159fa364b9 Removing intermediate container 68159fa364b9 ---> c9fc0eb65daa Step 10/10 : CMD /bin/bash ---> Running in 7aceb6325f5b Removing intermediate container 7aceb6325f5b ---> 12298d1c5307 Successfully built 12298d1c5307 Successfully tagged myimage:v1.0
其中：
上面命令最后有个点，代表使用当前路径的 Dockerfile 进行构建
-t myimage:v1.0 给新构建的镜像取名为 myimage，并设定版本为 v1.0
实例2：使用“-f”参数指定Dockerfile的绝对路径地址，如下：
[root@localhost ~]# docker build -f /root/Dockerfile -t myimage:v1.0 . Sending build context to Docker daemon 204.8MB Step 1/10 : FROM centos ---> 9f38484d220f Step 2/10 : MAINTAINER myName<myName@163.com> ---> Running in 070c207cef23 ... more ... Step 9/10 : CMD echo "success-------------------------ok" ---> Running in 646ff518ed0c Removing intermediate container 646ff518ed0c ---> 61ff096c4209 Step 10/10 : CMD /bin/bash ---> Running in e947787cc98e Removing intermediate container e947787cc98e ---> 0821278552a7 Successfully built 0821278552a7 Successfully tagged myimage:v1.0 [root@localhost ~]#
实例3：下面将docker build命令的最后一个选项由“.”改为一个目录绝对地址（指向Dockerfile存在的目录）。此时，不使用 -f 选项指定Dockerfile的位置，构建Docker镜像。如下：
[root@localhost ~]# docker build -t myimage:v1.0 /root/ Sending build context to Docker daemon 204.8MB Step 1/10 : FROM centos ---> 9f38484d220f Step 2/10 : MAINTAINER myName<myName@163.com> ---> Running in 52bc79f06ac5 Removing intermediate container 52bc79f06ac5 ...more... Step 9/10 : CMD echo "success-------------------------ok" ---> Running in cabefa916c4e Removing intermediate container cabefa916c4e ---> 05a9ff2b63ce Step 10/10 : CMD /bin/bash ---> Running in fef263c32a80 Removing intermediate container fef263c32a80 ---> 280a2c1a770d Successfully built 280a2c1a770d Successfully tagged myimage:v1.0
实例4：使用“-q”选项开启静默构建镜像，即在构建镜像时不输出过程信息。在镜像构建完成后，输出镜像的ID。如下：
[root@localhost ~]# docker build -q -f ./Dockerfile -t myimage:v1.0 . sha256:729e175d50dbf51c08b4b23c34679520f13d0e2feea440a6991626547ad8046b [root@localhost ~]# docker images myimage REPOSITORY TAG IMAGE ID CREATED SIZE myimage v1.0 729e175d50db 12 seconds ago 468MB
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