Configure EC2 CentOS 7 instance for running JAVA Applications, Also Connect Tomcat and Apace with mod_jk

Prerequisites

Knowledge of creating EC2 instance.

Configure CentOS 7


STEP 1 :
Launch terminal  of CentOS EC2 instance by using private key file.

Note : Private key file publicly not visible. set it

         chmod 400 <privatekeyfile>

      connect terminal by using

      ssh -i <path to privatekeyfile/privatekeyfile.pem> centos@<elasticIP>

                          or
      ssh -i <path to privatekeyfile/privatekeyfile.pem> centos@<public dns>


Note 2 : You can get this information By Clicking on connect button of ec2 instance web console

Note 3 : 

Information about connection

STEP 1 : $ sudo yum -y update

Step 2 : Download latest version or required version of jdk 

$ wget --no-check-certificate -c --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/9.0.1+11/jdk-9.0.1_linux-x64_bin.tar.gz

Step 3 : extract tar file in your software installation directory , I preferred /opt

$ tar -xvzf jdk-9.0.1_linux-x64_bin.tar.gz --strip-component=1 -C /opt/

if we don't want to extract jdk tar file /opt directory then we can extact it other place and create a soft link by using following command

$ ln -s <place where jdk is extracted> /opt/java-latest

it create a directory inside /opt name java-latest

Step 4 :  Configure PATH and CLASSPATH Variable

if we required system wide change then we use /etc/profile file otherwise we ~/.bash_profile

########JAVA Enviornment Variable ########

export JAVA_HOME=/opt/java-latest

export PATH=$PATH:$JAVA_HOME/bin

export CLASSPATH=.:$JAVA_HOME/jre/bin:$JAVA_HOME/lib:$JAVA_HOME/lib/tools.jar

Step 5 : test JAVA

$ java 

$ javac

Step 6 : If more than one java version is install then we can alternatives command to set current version.

Step 7 : install apache

•  $ yum -y update
• $yum -y install httpd

Step 8 Install tomcat

• Create Tomcat User and group - which will be used to run tomcat services
• First we create new tomcat group
• $ sudo groupadd tomcat
• now we create tomcat user with home directory where we installed tomcat and with shell /bin/false(so nobody can login this account)
• $ sudo useradd -g tomcat <-G secondary group if required> -d  <where tomcat is extracted i.e. tomcat home directory> -s /bin/false tomcat 
• we can check result of above command in for user /etc/passwd and for group /etc/group
• Now we download tomcat latest version using wget
• extract tomcat 
• $ tar -xvzf  <path to file> --strip-component =1 -C /opt/tomcat-latest
• now setup permissions
• sudo chgrp -R tomcat conf
• sudo chmod g+rwx conf
• sudo chmod g+r conf/*
• now made tomcat user owner of work , temp ,logs, and webapps directories
• sudo chown -R tomcat  /work /temp /logs /webapps
• configure tomcat-user.xml for login
• create user name and password in it
• create auto run service in centos 7 in /etc/systemd/system/tomcat.service

• # Systemd unit file for tomcat
  [Unit]
  Description=Apache Tomcat Web Application Container
  After=syslog.target network.target
  
  [Service]
  Type=forking
  
  Environment=JAVA_HOME=/opt/java-latest/
  Environment=CATALINA_PID=/var/lib/tomcat8/temp/tomcat.pid
  Environment=CATALINA_HOME=/var/lib/tomcat8
  Environment=CATALINA_BASE=/var/lib/tomcat8
  Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC'
  Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'
  
  ExecStart=/var/lib/tomcat8/bin/startup.sh
  ExecStop=/bin/kill -15 $MAINPID
  
  User=tomcat
  Group=tomcat
  
  [Install]
  WantedBy=multi-user.target

• reload systemd to load tomcat unit file
• $ sudo systemctl daemon-reload
• now we can start tomcat services with systemctl command
• $ systemctl start tomcat
• $systemctl stop tomcat
• $systemctl restart tomcat
• auto run tomcat
• $systemctl enable tomcat
• Deploy war file by using web console of tomcat or copy war to webapps directory
• Crontab
  To restart tomcat8 when it's not running, I set a cron job running /var/lib/tomcat8/cron/launch.sh as root:

  #!/bin/bash
  
  ps -ef | grep catalina.startup.Bootstrap | grep -v grep > /dev/null
  if [ $? != 0 ]
  then
     echo "tomcat is not running..."
     systemctl start tomcat > /dev/null
  else
     echo "tomcat is running..."
  fi
  

  Cron runs every minute:

  [root@sf ~]# crontab -e
  * * * * * /var/lib/tomcat8/cron/launch.sh
  

Now Connect Apache and tomcat with mod_jk