tomcat的单机多实例启动

部署目的

单机多实例便于升级管理，充分利用系统资源

单机多实例部署的本质

1、对于启动脚本

启动Tomcat时，版本包中提供的启动脚本$CATALINA_HOME/bin/startup.sh就是调用了$CATALINA_HOME/bin/catalina.sh，并且catalina.sh是通过环境变量中的$CATALINA_HOME和$CATALINA_BASE来启动tomcat的

2、对于库文件

Tomcat启动依赖的库文件是相同的，包括$CATALINA_HOME/bin目录下实例化catalina的bootstrap.jar和lib目录下的jar文件等，多个实例版本更新的时候直接替换lib就可以了。

综上，通过修改$CATALINA_BASE就可以启动多实例了。

3、CATALINA_BASE与CATALINA_HOME的区别

#   CATALINA_HOME   May point at your Catalina "build" directory.
#
#   CATALINA_BASE   (Optional) Base directory for resolving dynamic portions
#                   of a Catalina installation.  If not present, resolves to
#                   the same directory that CATALINA_HOME points to.

CATALINA_BASE是工作目录（存放工程项目的），CATALINA_HOME是家目录（存放可执行文件的），是不同的

当CATALINA_BASE不存在的时候会使用 CATALINA_HOME 配置的路径

安装过程

部署单实例可以参考： https://www.cnblogs.com/zh-dream/p/13511041.html

配置第二个实例

$ mkdir instance2
$ cp -r apache-tomcat-8.5.6 instance2/inst_sec
$ cd instance2/inst_sec

$ rm -rf bin/* lib/

启动脚本

$ vim bin/start.sh
#!/bin/bash
export CATALINA_BASE=`cd $(dirname $0)/../; pwd`

tomcat_Pid=`ps aux |grep "java"|grep "Dcatalina.base=$CATALINA_BASE "|grep -v "grep"|awk '{ print $2}'`

export JAVA_OPTS="-Djava.security.egd=file:/dev/./urandom";

if [ -n "$tomcat_Pid" ] ; then
echo "tomcat($tomcat_Pid) still running now , please shutdown it first";
    exit 2;
fi

star_Prg=`$CATALINA_HOME/bin/startup.sh`

if [ "$?" = "0" ]; then
        echo "shell script: $0"
    echo "CATALINA_BASE: $CATALINA_BASE"
    echo "tomcat thread: $tomcat_Pid"
    echo "start succeed!!!"
else
    echo "$0 $CATALINA_BASE start failed"
    echo $star_Prg
fi

停止脚本

[test@tomcat inst_sec]$ vim bin/stop.sh
#!/bin/bash
export CATALINA_BASE=`cd $(dirname $0)/../; pwd`

tomcat_Pid=`ps aux |grep "java"|grep "[D]catalina.base=$CATALINA_BASE "|awk '{ print $2}'`


if [ -n "$tomcat_Pid" ] ; then
stop_Prg=`$CATALINA_HOME/bin/shutdown.sh`
else
    echo "Tomcat instance not found : $CATALINA_BASE"
    exit
fi

if [ "$?" = "0" ]; then
    echo "shell script: $0"
    echo "CATALINA_BASE: $CATALINA_BASE"
    echo "stop succeed!!!"
else
    echo "$0 $CATALINA_BASE stop failed"
    echo $stop_Prg
fi

重启脚本

[test@tomcat inst_sec]$ cat bin/restart.sh
#!/bin/bash

source ~/.bash_profile
export CATALINA_BASE=$(cd $(dirname $0); cd .. ; pwd)
GREEN_COLOR='E[1;32m' #绿
RES='E[0m'

TOMCAT_ID=`ps aux |grep "java"|grep "Dcatalina.base=$CATALINA_BASE "|grep -v "grep"|awk '{ print $2}'`

SLEEP_TIME=1

echo "----------------------------------"
echo "Using CATALINA_BASE:$CATALINA_BASE"
echo "Using CATALINA_HOME:$CATALINA_HOME"
echo "----------------------------------"

if [ -n "$TOMCAT_ID" ] ; then
    echo -e "${GREEN_COLOR}found tomcat instance in pid $TOMCAT_ID , shutdown now!${RES}";
    echo -e "${GREEN_COLOR}---------------start shutdown-------------------${RES}"
    source $(dirname $0)/stop.sh;
    echo -e "${GREEN_COLOR}--------------- end shutdown -------------------${RES}"
fi

while [ -n "$TOMCAT_ID" ]
do  
  sleep $SLEEP_TIME
  echo wait "$SLEEP_TIME" s
  TOMCAT_ID=`ps aux |grep "java"|grep "Dcatalina.base=$CATALINA_BASE "|grep -v "grep"|awk '{ print $2}'`
done 

echo -e "${GREEN_COLOR}---------------start startup-------------------${RES}"
source $(dirname $0)/start.sh
echo -e "${GREEN_COLOR}---------------end startup-------------------${RES}"

接下来，修改server.xml中不同协议对应的端口后启动服务即可