自定义 jenkins jnlp-slave 镜像

环境：centos7.6 、Docker version 19.03.5、Jenkins 2.263.1、jenkins url 172.28.31.214:8080
完整 github 项目 https://github.com/pretendhigh/jenkins-jnlp-slave
1、从 https://repo.jenkins-ci.org/public/org/jenkins-ci/main/remoting 下载对应版本的 remoting.jar，重命名为 slave.jar, 此处使用 https://repo.jenkins-ci.org/public/org/jenkins-ci/main/remoting/3.16/remoting-3.16.jar
2、Dockerfile 文件内容如下：

[root@mapleaves dockerMaker]# cat Dockerfile 
FROM centos:7.6.1810

COPY CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo
RUN mkdir -p /usr/share/jenkins \
    && yum install -y java-1.8.0-openjdk
COPY jenkins-slave /usr/local/bin/jenkins-slave
COPY slave.jar /usr/share/jenkins

USER root

WORKDIR /home/jenkins

ENTRYPOINT ["jenkins-slave"]

3、CentOS-Base.repo 内容如下：

[root@mapleaves dockerMaker]# cat CentOS-Base.repo 
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the 
# remarked out baseurl= line instead.
#
#
 
[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
 
#released updates 
[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
 
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
 
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

还是建议使用国内的 yum 源不然还是有点慢
4、jenkins-slave 内容如下：

[root@mapleaves dockerMaker]# cat jenkins-slave 
#!/usr/bin/env sh

#change docker options and start docker daemon

if [ $# -eq 1 ]; then

	# if `docker run` only has one arguments, we assume user is running alternate command like `bash` to inspect the image
	exec "$@"

else

	# if -tunnel is not provided try env vars
	case "$@" in
		*"-tunnel "*) ;;
		*)
		if [ ! -z "$JENKINS_TUNNEL" ]; then
			TUNNEL="-tunnel $JENKINS_TUNNEL"
		fi ;;
	esac

	# if -workDir is not provided try env vars
	if [ ! -z "$JENKINS_AGENT_WORKDIR" ]; then
		case "$@" in
			*"-workDir"*) echo "Warning: Work directory is defined twice in command-line arguments and the environment variable" ;;
			*)
			WORKDIR="-workDir $JENKINS_AGENT_WORKDIR" ;;
		esac
	fi

	if [ -n "$JENKINS_URL" ]; then
		URL="-url $JENKINS_URL"
	fi

	if [ -n "$JENKINS_NAME" ]; then
		JENKINS_AGENT_NAME="$JENKINS_NAME"
	fi  

	if [ -z "$JNLP_PROTOCOL_OPTS" ]; then
		echo "Warning: JnlpProtocol3 is disabled by default, use JNLP_PROTOCOL_OPTS to alter the behavior"
		JNLP_PROTOCOL_OPTS="-Dorg.jenkinsci.remoting.engine.JnlpProtocol3.disabled=true"
	fi

	# If both required options are defined, do not pass the parameters
	OPT_JENKINS_SECRET=""
	if [ -n "$JENKINS_SECRET" ]; then
		case "$@" in
			*"${JENKINS_SECRET}"*) echo "Warning: SECRET is defined twice in command-line arguments and the environment variable" ;;
			*)
			OPT_JENKINS_SECRET="${JENKINS_SECRET}" ;;
		esac
	fi
	
	OPT_JENKINS_AGENT_NAME=""
	if [ -n "$JENKINS_AGENT_NAME" ]; then
		case "$@" in
			*"${JENKINS_AGENT_NAME}"*) echo "Warning: AGENT_NAME is defined twice in command-line arguments and the environment variable" ;;
			*)
			OPT_JENKINS_AGENT_NAME="${JENKINS_AGENT_NAME}" ;;
		esac
	fi

	#TODO: Handle the case when the command-line and Environment variable contain different values.
	#It is fine it blows up for now since it should lead to an error anyway.

	exec java $JAVA_OPTS $JNLP_PROTOCOL_OPTS -cp /usr/share/jenkins/slave.jar hudson.remoting.jnlp.Main -headless $TUNNEL $URL $WORKDIR $OPT_JENKINS_SECRET $OPT_JENKINS_AGENT_NAME "$@"
fi

5、构建 docker image

docker build -t mapleaves/jenkins-jnlp:v2 .
docker push  mapleaves/jenkins-jnlp:v2

6、jenkins 添加 docker 静态节点，步骤参考https://blog.youkuaiyun.com/Man_In_The_Night/article/details/111573798，其中将
cnych/jenkins:jnlp 换成 mapleaves/jenkins-jnlp:v2。此处不再详细介绍

参考文章：
enkins k8s 动态增减 jenkins-salve (2) 实现 slave 节点动态构建
https://github.com/cnych/kubernetes-learning/tree/master/jenkins
https://www.bladewan.com/2018/10/23/jenkins_slave/