SpringBoot 2.3 打包分层 Docker 镜像

Spring Boot 2.3 开始支持把 fat jar 按层拆开,配合 Docker 多阶段构建,可以让每次发布只重新构建有变化的层,大幅加速镜像构建。

pom.xml:

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <layers>
            <enabled>true</enabled>
        </layers>
    </configuration>
</plugin>

Dockerfile:

FROM openjdk:8-jdk-alpine as builder
WORKDIR application
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} application.jar
RUN java -Djarmode=layertools -jar application.jar extract
FROM openjdk:8-jdk-alpine

RUN echo "http://mirrors.aliyun.com/alpine/v3.11/main" > /etc/apk/repositories
RUN echo "http://mirrors.aliyun.com/alpine/v3.11/community" >> /etc/apk/repositories
RUN apk --update add --no-cache

# 修改时区为东八区
# 添加CA根证书
RUN apk --no-cache add tzdata && \
ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && \
echo "Asia/Shanghai" > /etc/timezone && \
apk --no-cache add ca-certificates && \
rm -rf /var/cache/apk/* /tmp/*

WORKDIR application
COPY --from=builder application/dependencies/ ./
COPY --from=builder application/spring-boot-loader/ ./
COPY --from=builder application/snapshot-dependencies/ ./
COPY --from=builder application/application/ ./
ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]