Docker-dockerfile镜像优化

---

无优化构建镜像

mkdir /nginx
 
vim Dockerfile
FROM centos:7
RUN yum install -y gcc pcre pcre-devel devel zlib-devel make
ADD nginx-1.15.9.tar.gz /opt 
WORKDIR /opt/nginx-1.15.9
RUN sed -i 's/CFLAGS="$CFLAGS -g"/#CFLAGS="$CFLAGS -g"/g' auto/cc/gcc 
RUN ./configure --prefix=/usr/local/nginx 
RUN make
RUN make install
EXPOSE 80
VOLUME ["/usr/local/nginx/html"]
CMD ["/usr/local/nginx/sbin/nginx","-g","daemon off;"]

未优化前

不需要输出的指令丢入/dev/null

FROM centos:7
RUN yum install -y gcc pcre pcre-devel devel zlib-devel make &> /dev/null && yum clean all
ADD nginx-1.15.9.tar.gz /opt
WORKDIR /opt/nginx-1.15.9
RUN sed -i 's/CFLAGS="$CFLAGS -g"/#CFLAGS="$CFLAGS -g"/g' auto/cc/gcc
RUN ./configure --prefix=/usr/local/nginx &> /dev/null
RUN make &> /dev/null
RUN make install &> /dev/null
RUN rm -rf /opt/nginx-1.15.9.tar.gz
EXPOSE 80
VOLUME ["/usr/local/nginx/html"]
CMD ["/usr/local/nginx/sbin/nginx""-g","daemon off;"]

优化二：减少RUN构建

FROM centos:7
ADD nginx-1.15.9.tar.gz /opt
WORKDIR /opt/nginx-1.15.9
RUN yum install -y gcc pcre pcre-devel devel zlib-devel make &> /dev/null && \
 yum clean all && \
 sed -i 's/CFLAGS="$CFLAGS -g"/#CFLAGS="$CFLAGS -g"/g' auto/cc/gcc && \
 ./configure --prefix=/usr/local/nginx &> /dev/null && \
 make &> /dev/null && make install &> /dev/null &&\
 rm -rf /opt/nginx-1.15.9
EXPOSE 80
VOLUME ["/usr/local/nginx/html"]
CMD ["/usr/local/nginx/sbin/nginx","-g","daemon off;"]

优化三：多阶段构建

FROM centos:7 as build 
ADD nginx-1.15.9.tar.gz /opt/nginx 
WORKDIR /opt/nginx-1.15.9
RUN yum install -y gcc pcre pcre-devel devel zlib-devel make &> /dev/null && \
yum clean all &&\
sed -i 's/CFLAGS="$CFLAGS -g"/#CFLAGS="$CFLAGS -g"/g' auto/cc/gcc && \
./configure --prefix=/usr/local/nginx &> /dev/null && \
make &>/dev/null && \
make install &>/dev/null && \
rm -rf /opt/nginx-1.15.9

FROM centos:7
EXPOSE 80
VOLUME ["/usr/local/nginx/html"]
COPY --from=build /usr/local/nginx /usr/local/nginx
CMD ["/usr/local/nginx/sbin/nginx","-g","daemon off;"]

优化四：选择更轻量级的模板

wget http://download.openvz.org/template/precreated/debian-7.0-x86-minimal.tar.gz
#下载debian压缩包

docker import debian-7.0-x86-minimal.tar.gz -- debian:v1