环境
- virtual box 6.1
- centos 7.8
- docker 19.03
多阶段构建
定义 Dockerfile
FROM maven:3.6.3-openjdk-8-slim as builder
LABEL author=jiangbo version=1.0.3
COPY . /
#RUN mvn clean package
FROM openjdk:8-jdk-alpine
ARG JAR_FILE=*.jar
COPY --from=builder /${JAR_FILE} app.jar
EXPOSE 8080
ENTRYPOINT ["java","-jar","/app.jar"]
准备 spring boot 应用
可以在官网生成一个。
构建
[root@master multi]# docker build -t demo:1.0.3 .
Sending build context to Docker daemon 17.01MB
Step 1/8 : FROM maven:3.6.3-openjdk-8-slim as builder
---> 05187405e310
Step 2/8 : LABEL author=jiangbo version=1.0.3
---> Using cache
---> e93004b2e682
Step 3/8 : COPY . /
---> 48b9b04102d8
Step 4/8 : FROM openjdk:8-jdk-alpine
---> a3562aa0b991
Step 5/8 : ARG JAR_FILE=*.jar
---> Running in a88ae571ffe5
Removing intermediate container a88ae571ffe5
---> ae5612bd07e8
Step 6/8 : COPY --from=builder /${JAR_FILE} app.jar
---> 99022253d767
Step 7/8 : EXPOSE 8080
---> Running in aec2d6a48621
Removing intermediate container aec2d6a48621
---> cbf4c735bb9b
Step 8/8 : ENTRYPOINT ["java","-jar","/app.jar"]
---> Running in a06af9a28f44
Removing intermediate container a06af9a28f44
---> 9747915cf8a3
Successfully built 9747915cf8a3
Successfully tagged demo:1.0.3
查看镜像大小
[root@master multi]# docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
demo 1.0.3 9747915cf8a3 8 minutes ago 122MB
maven 3.6.3-openjdk-8-slim 05187405e310 17 hours ago 306MB
openjdk 8-jdk-alpine a3562aa0b991 19 months ago 105MB
[root@master multi]#
可以看到第一次引入的镜像构建完成后，就没有使用了。
总结
介绍了 Docker 的多阶段构建。