docker中Dockerfile的ONBUILD命令怎么用

这篇文章将为大家详细讲解有关docker中Dockerfile的ONBUILD命令怎么用，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。

ONBUILD：当构建一个被继承的Dockerfile时运行的命令，父镜像在被子镜像继承后父镜像的onbuild被触发。可以把ONBUID理解为一个触发器。

[root@t-docker CMD]# cat Dockerfile2 from centosRUN yum -y install curlENTRYPOINT ["curl","-s","http://ip.cn"]ONBUILD RUN echo "father images  onbuild -----886" #表示哪个镜像继承了我，我就打出这句话

[root@t-docker CMD]# docker build -f Dockerfile2 -t myip_father .Sending build context to Docker daemon  3.072kBStep 1/4 : from centos ---> 5182e96772bfStep 2/4 : RUN yum -y install curl ---> Using cache ---> a35f6ad9700fStep 3/4 : ENTRYPOINT ["curl","-s","http://ip.cn"] ---> Using cache ---> b772af142e86Step 4/4 : ONBUILD RUN echo "father images  onbuild -----886" #表示哪个镜像继承了我，我就打出这句话。 ---> Running in 8366a71cb8baRemoving intermediate container 8366a71cb8ba ---> 8615f1d828edSuccessfully built 8615f1d828edSuccessfully tagged myip_father:latest

[root@t-docker CMD]# docker imagesREPOSITORY          TAG                 IMAGE ID            CREATED             SIZEmyip_father         latest              8615f1d828ed        28 seconds ago      293MB

[root@t-docker CMD]# cat Dockerfile3from myip_fatherRUN yum -y install curlCMD ["curl","-s","http://ip.cn"]

[root@t-docker CMD]# docker build -f Dockerfile3 -t myip_son .Sending build context to Docker daemon  4.096kBStep 1/3 : from myip_father# Executing 1 build trigger ---> Running in c0ec856045b2father images  onbuild -----886Removing intermediate container c0ec856045b2 ---> 533afe432759Step 2/3 : RUN yum -y install curl ---> Running in 943e0afa4268Loaded plugins: fastestmirror, ovlLoading mirror speeds from cached hostfile * base: mirrors.huaweicloud.com * extras: mirrors.huaweicloud.com * updates: mirrors.neusoft.edu.cnPackage curl-7.29.0-46.el7.x86_64 already installed and latest versionNothing to doRemoving intermediate container 943e0afa4268 ---> 54ddf5f440ecStep 3/3 : CMD ["curl","-s","http://ip.cn"] ---> Running in beff0a4f1b82Removing intermediate container beff0a4f1b82 ---> 68d373aea823Successfully built 68d373aea823Successfully tagged myip_son:latest

上面看到在构建Dockerfile3时输出了# Executing 1 build trigger这句话。说明子镜像继承父镜像时，父镜像触发了相应的动作。

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