rancher构建镜像镜像构建工具

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mob64ca140a8e67 2024-03-19 13:19:50

文章标签 rancher构建镜像 docker openshift linux java 文章分类 云原生云计算

s2i是红帽开源的一款镜像构建工具，属于openshift的一部分，可以提供一套模板化的构建方案，让开发人员为各种不同类型的源代码提前准备好运行环境（builder-image），并进行快速构建和运行。在学习了一段时间之后，我对s2i总结的优势可以分为以下几点：

模板化及扩展能力（builder-image）：可以提前准备好不同的源代码执行环境，这部分工作和docker build并没有本质上的区别，builder image本身也是一个基于docker file构建出来的镜像，不同点在于s2i的builder image 在构建过程里可以封装进一组脚本，这些脚本在镜像构建及运行的各个阶段发挥着关键作用，使镜像的构建者能够更全面的掌控构建过程。
层次化及快速构建（增量构建）：s2i允许在构建时指定一个增量构建对象（s2i build --incremental），这里不称之为基础镜像主要是为了和builder image区分。使用增量构建时，save-artifacts脚本将发挥作用，将当前镜像内部的数据进行转移，新镜像构建时assemble脚本执行，将数据进行拷贝，典型的数据传输对象可以是maven .m2文件夹等等。这个过程带来的好处除了加速构建之外，还有层次化：builder image 提供了横向扩展（例如 html、java、python等运行环境），而被增量构建的镜像则体现了相同运行环境中的纵向扩展（例如一般maven项目、 spring boot项目等）。
开发过程及概念上的转变：s2i使开发人员不用再去关注docker file的编写过程，专注于源代码的更新迭代，容器的运行环境均由s2i的builder image和增量构建镜像准备。

一个标准的s2i构建过程，可以分为以下几个步骤：

准备builder image的上下文环境，其本质是一个docker image 所以包括docker file，s2i脚本，及相关依赖。
使用docker build命令构建builder image。
使用s2i build命令构建目标镜像 s2i build <source location> <builder image> [<tag>] [flags]builder image参数是第二步构建出来的镜像。
使用上一步中构建的镜像进行增量构建。

以下为一个war包运行环境的builder image构建方式：

rancher构建镜像镜像构建工具_openshift

rancher构建镜像镜像构建工具_rancher构建镜像_02

#Dockerfile

FROM openshift/base-centos7
EXPOSE 8080

ENV TOMCAT_VERSION=8.5.53 \
    MAVEN_VERSION=3.6.3

LABEL io.k8s.description="Platform for building and running JEE applications on Tomcat" \
      io.k8s.display-name="Tomcat Builder" \
      io.openshift.expose-services="8080:http" \
      io.openshift.tags="builder,tomcat" \
      io.openshift.s2i.destination="/opt/s2i/destination"
      #这个label比较重要，在s2i build时，s2i会将基础镜像的上下文环境包括源码、脚本拷贝进指定目录

COPY apache-maven-$MAVEN_VERSION-bin.tar.gz /
COPY apache-tomcat-$TOMCAT_VERSION.tar.gz /

# Install Maven, Tomcat 
RUN INSTALL_PKGS="tar java-1.8.0-openjdk java-1.8.0-openjdk-devel" && \
    yum install -y --enablerepo=centosplus $INSTALL_PKGS && \
    rpm -V $INSTALL_PKGS && \
    yum clean all -y && \
    tar -zxvf /apache-maven-$MAVEN_VERSION-bin.tar.gz -C /usr/local && \
    ln -sf /usr/local/apache-maven-$MAVEN_VERSION/bin/mvn /usr/local/bin/mvn && \
    mkdir -p $HOME/.m2 && \
    mkdir -p /tomcat && \
    tar -zxvf /apache-tomcat-$TOMCAT_VERSION.tar.gz --strip-components=1 -C /tomcat && \ 
    rm -rf /tomcat/webapps/* && \
    mkdir -p /opt/s2i/destination && \
    mkdir /tmp/src


# Add s2i customizations
ADD ./settings.xml $HOME/.m2/

# Copy the S2I scripts from the specific language image to $STI_SCRIPTS_PATH
COPY ./s2i/bin/ $STI_SCRIPTS_PATH

RUN chmod -R a+rw /tomcat && \
    chmod a+rwx /tomcat/* && \
    chmod +x /tomcat/bin/*.sh && \
    chmod -R a+rw $HOME && \
    chmod -R +x $STI_SCRIPTS_PATH && \
    chmod -R g+rw /opt/s2i/destination

USER 1001

CMD $STI_SCRIPTS_PATH/usage

#assemble

if [[ "$1" == "-h" ]]; then
	exec /usr/libexec/s2i/usage
fi

# Restore artifacts from the previous build (if they exist).
#
# restore build artifacts


if [ -d /opt/s2i/destination/artifacts/.m2 ]; then
    echo "restore build artifacts"
    rm -rf $HOME/.m2
    mv /opt/s2i/destination/artifacts/.m2 $HOME/
fi

echo "---> Installing application source..."
#cp -Rf /tmp/src/. ./
a=`ls /tmp/`
echo $a
echo "**********"
b=`ls /opt/s2i/destination/`
echo $b
echo "------***"
c=`ls /opt/s2i/destination/src`
echo $c

cp -R /opt/s2i/destination/src/.  ./
cp /opt/s2i/destination/src/config/catalina.sh /tomcat/bin/catalina.sh


echo "---> Building application from source..."
# TODO: Add build steps for your application, eg npm install, bundle install, pip install, etc.

mvn -Dmaven.test.skip=true clean package
#mv ./target/*.war /tomcat/webapps/ROOT.war
find ./ -name *.war -exec mv {}   /tomcat/webapps/ROOT.war \;

#run

bash -c "/tomcat/bin/catalina.sh run"

#save-artifacts

#!/bin/bash
pushd ${HOME} >/dev/null
if [ -d .m2 ]; then
    # all .m2 contents to tar stream
    tar cf - .m2
fi
popd >/dev/null

builder image 中封装了centos7，jdk，maven和一个tomcat。
save-artifacts和assemble脚本在镜像构建期间执行，完成增量构建的数据传输，源代码拷贝及编译工作。
run脚本在镜像运行阶段执行。

JAR运行环境

rancher构建镜像镜像构建工具_linux_03

# DockerFile

FROM openshift/base-centos7
EXPOSE 8080

ENV MAVEN_VERSION=3.6.3

LABEL io.k8s.description="Platform for building and running JEE applications on Tomcat" \
      io.k8s.display-name="Tomcat Builder" \
      io.openshift.expose-services="8080:http" \
      io.openshift.tags="builder,tomcat" \
      io.openshift.s2i.destination="/opt/s2i/destination"

COPY apache-maven-$MAVEN_VERSION-bin.tar.gz /

# Install Maven
RUN INSTALL_PKGS="tar java-1.8.0-openjdk java-1.8.0-openjdk-devel" && \
    yum install -y --enablerepo=centosplus $INSTALL_PKGS && \
    rpm -V $INSTALL_PKGS && \
    yum clean all -y && \
    tar -zxvf /apache-maven-$MAVEN_VERSION-bin.tar.gz -C /usr/local && \
    ln -sf /usr/local/apache-maven-$MAVEN_VERSION/bin/mvn /usr/local/bin/mvn && \
    mkdir -p $HOME/.m2 && \
    mkdir -p /opt/s2i/destination && \
    mkdir -p /webapps && \
    mkdir /tmp/src


# Add s2i customizations
ADD ./settings.xml $HOME/.m2/

# Copy the S2I scripts from the specific language image to $STI_SCRIPTS_PATH
COPY ./s2i/bin/ $STI_SCRIPTS_PATH

RUN chmod -R a+rw /webapps && \
     chmod -R a+rw $HOME && \
    chmod -R +x $STI_SCRIPTS_PATH && \
    chmod -R g+rw /opt/s2i/destination

USER 1001

CMD $STI_SCRIPTS_PATH/usage

#assemble

if [[ "$1" == "-h" ]]; then
	exec /usr/libexec/s2i/usage
fi

# Restore artifacts from the previous build (if they exist).
#
# restore build artifacts


if [ -d /opt/s2i/destination/artifacts/.m2 ]; then
    echo "restore build artifacts"
    rm -rf $HOME/.m2
    mv /opt/s2i/destination/artifacts/.m2 $HOME/
fi

echo "---> Installing application source..."
#cp -Rf /tmp/src/. ./
a=`ls /tmp/`
echo $a
echo "**********"
b=`ls /opt/s2i/destination/`
echo $b
echo "------***"
c=`ls /opt/s2i/destination/src`
echo $c

cp -R /opt/s2i/destination/src/.  ./


echo "---> Building application from source..."
# TODO: Add build steps for your application, eg npm install, bundle install, pip install, etc.

mvn -Dmaven.test.skip=true clean package
find ./ -name *.jar -exec mv {}   /tomcat/webapps/ROOT.jar \;

#save-artifacts

pushd ${HOME} >/dev/null
if [ -d .m2 ]; then
    # all .m2 contents to tar stream
    tar cf - .m2
fi
popd >/dev/null

#run

bash -c "java -jar -Dserver.port=8080 /webapps/ROOT.jar"

NGINX运行环境

rancher构建镜像镜像构建工具_rancher构建镜像_04

FROM openshift/base-centos7

EXPOSE 8080
EXPOSE 8443

ENV NAME=nginx \
    NGINX_VERSION=1.16 \
    NGINX_SHORT_VER=116 \
    VERSION=0

ENV SUMMARY="Platform for running nginx $NGINX_VERSION or building nginx-based application" \
    DESCRIPTION="Nginx is a web server and a reverse proxy server for HTTP, SMTP, POP3 and IMAP \
protocols, with a strong focus on high concurrency, performance and low memory usage. The container \
image provides a containerized packaging of the nginx $NGINX_VERSION daemon. The image can be used \
as a base image for other applications based on nginx $NGINX_VERSION web server. \
Nginx server image can be extended using source-to-image tool."

LABEL summary="${SUMMARY}" \
      description="${DESCRIPTION}" \
      io.k8s.description="${DESCRIPTION}" \
      io.k8s.display-name="Nginx ${NGINX_VERSION}" \
      io.openshift.expose-services="8080:http" \
      io.openshift.expose-services="8443:https" \
      io.openshift.tags="builder,${NAME},rh-${NAME}${NGINX_SHORT_VER}" \
      com.redhat.component="rh-${NAME}${NGINX_SHORT_VER}-container" \
      name="centos/${NAME}-${NGINX_SHORT_VER}-centos7" \
      version="${NGINX_VERSION}" \
      maintainer="SoftwareCollections.org <sclorg@redhat.com>" \
      help="For more information visit https://github.com/sclorg/${NAME}-container" \
      usage="s2i build <SOURCE-REPOSITORY> centos/${NAME}-${NGINX_SHORT_VER}-centos7:latest <APP-NAME>"

ENV NGINX_CONFIGURATION_PATH=${APP_ROOT}/etc/nginx.d \
    NGINX_CONF_PATH=/etc/opt/rh/rh-nginx${NGINX_SHORT_VER}/nginx/nginx.conf \
    NGINX_DEFAULT_CONF_PATH=${APP_ROOT}/etc/nginx.default.d \
    NGINX_CONTAINER_SCRIPTS_PATH=/usr/share/container-scripts/nginx \
    NGINX_APP_ROOT=${APP_ROOT} \
    NGINX_LOG_PATH=/var/opt/rh/rh-nginx${NGINX_SHORT_VER}/log/nginx

RUN yum install -y yum-utils gettext hostname && \
    yum install -y centos-release-scl-rh && \
    INSTALL_PKGS="nss_wrapper bind-utils rh-nginx${NGINX_SHORT_VER} rh-nginx${NGINX_SHORT_VER}-nginx \
                  rh-nginx${NGINX_SHORT_VER}-nginx-mod-stream" && \
    yum install -y centos-release-scl-rh && \
    yum install -y --setopt=tsflags=nodocs $INSTALL_PKGS && \
    rpm -V $INSTALL_PKGS && \
    yum -y clean all --enablerepo='*'

# Copy the S2I scripts from the specific language image to $STI_SCRIPTS_PATH
COPY ./s2i/bin/ $STI_SCRIPTS_PATH

# Copy extra files to the image.
COPY ./root/ /

# In order to drop the root user, we have to make some directories world
# writeable as OpenShift default security model is to run the container under
# random UID.
RUN sed -i -f ${NGINX_APP_ROOT}/nginxconf.sed ${NGINX_CONF_PATH} && \
    chmod a+rwx ${NGINX_CONF_PATH} && \
    mkdir -p ${NGINX_APP_ROOT}/etc/nginx.d/ && \
    mkdir -p ${NGINX_APP_ROOT}/etc/nginx.default.d/ && \
    mkdir -p ${NGINX_APP_ROOT}/src/nginx-start/ && \
    mkdir -p ${NGINX_CONTAINER_SCRIPTS_PATH}/nginx-start && \
    mkdir -p ${NGINX_LOG_PATH} && \
    ln -s ${NGINX_LOG_PATH} /var/log/nginx && \
    ln -s /etc/opt/rh/rh-nginx${NGINX_SHORT_VER}/nginx /etc/nginx && \
    ln -s /opt/rh/rh-nginx${NGINX_SHORT_VER}/root/usr/share/nginx /usr/share/nginx && \
    chmod -R a+rwx ${NGINX_APP_ROOT}/etc && \
    chmod -R a+rwx /var/opt/rh/rh-nginx${NGINX_SHORT_VER} && \
    chmod -R a+rwx ${NGINX_CONTAINER_SCRIPTS_PATH}/nginx-start && \
    chown -R 1001:0 ${NGINX_APP_ROOT} && \
    chown -R 1001:0 /var/opt/rh/rh-nginx${NGINX_SHORT_VER} && \
    chown -R 1001:0 ${NGINX_CONTAINER_SCRIPTS_PATH}/nginx-start && \
    chmod -R a+rwx /var/run && \
    chown -R 1001:0 /var/run && \
    rpm-file-permissions

USER 1001

# Not using VOLUME statement since it's not working in OpenShift Online:
# https://github.com/sclorg/httpd-container/issues/30
# VOLUME ["/opt/rh/rh-nginx116/root/usr/share/nginx/html"]
# VOLUME ["/var/opt/rh/rh-nginx116/log/nginx/"]

ENV BASH_ENV=${NGINX_APP_ROOT}/etc/scl_enable \
    ENV=${NGINX_APP_ROOT}/etc/scl_enable \
    PROMPT_COMMAND=". ${NGINX_APP_ROOT}/etc/scl_enable"

CMD $STI_SCRIPTS_PATH/usage

#assemble

set -e

echo "---> Installing application source"
ls -a
cp -Rf /tmp/src/. ./

# Fix source directory permissions
fix-permissions ./

if [ -f ./nginx.conf ]; then
  echo "---> Copying nginx.conf configuration file..."
  cp -v ./nginx.conf "${NGINX_CONF_PATH}"
  rm -f ./nginx.conf
fi

if [ -d ./nginx-cfg ]; then
  echo "---> Copying nginx configuration files..."
  if [ "$(ls -A ./nginx-cfg/*.conf)" ]; then
    cp -av ./nginx-cfg/*.conf "${NGINX_CONFIGURATION_PATH}"
    rm -rf ./nginx-cfg
  fi
  chmod -Rf g+rw ${NGINX_CONFIGURATION_PATH}
fi

if [ -d ./nginx-default-cfg ]; then
  echo "---> Copying nginx default server configuration files..."
  if [ "$(ls -A ./nginx-default-cfg/*.conf)" ]; then
    cp -av ./nginx-default-cfg/*.conf "${NGINX_DEFAULT_CONF_PATH}"
    rm -rf ./nginx-default-cfg
  fi
  chmod -Rf g+rw ${NGINX_DEFAULT_CONF_PATH}
fi

if [ -d ./nginx-start ]; then
  echo "---> Copying nginx start-hook scripts..."
  if [ "$(ls -A ./nginx-start/* 2>/dev/null)" ]; then
    cp -av ./nginx-start/* "${NGINX_CONTAINER_SCRIPTS_PATH}/nginx-start/"
    rm -rf ./nginx-start
  fi
fi

#run

source /opt/app-root/etc/generate_container_user

set -e

source ${NGINX_CONTAINER_SCRIPTS_PATH}/common.sh

process_extending_files ${NGINX_APP_ROOT}/src/nginx-start ${NGINX_CONTAINER_SCRIPTS_PATH}/nginx-start

if [ ! -v NGINX_LOG_TO_VOLUME -a -v NGINX_LOG_PATH ]; then
    /bin/ln -s /dev/stdout ${NGINX_LOG_PATH}/access.log
    /bin/ln -s /dev/stderr ${NGINX_LOG_PATH}/error.log
fi

exec nginx -g "daemon off;"

除上述内容之外，源代码也需要一个上下文环境，这并不是必要的，但这样做的好处是可以提供一些类似nginx及tomcat的配置文件来实现不同项目的定制化。这也是s2i脚本的核心能力体现。

由于网上的资料不够充分，所以使用过程里难免碰到很多坑，也并不能对s2i充分理解物尽其用。比如在增量构建阶段，目前发现必须是同名镜像才能够被识别出来，所以有时候不得不先将一个需要增量构建的镜像tag成目标镜像名称再进行增量构建。

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