Build a Java runtime environment on Sakura VPS

First VPS and first Java environment construction. Install Tomcat to make Java 8 executable.

Environment so far

--Sakura VPS

• SentOS7
• Apache/2.4.6

While reading "Understanding even with cats! Sakura's VPS course", we will use the environment that was built in a traceable manner. https://knowledge.sakura.ad.jp/8218/

Installation of Java Runtime Environment (JRE)

Use 8 of OpenJDK (Open Java Development Kit). It is named java-1.8.0-openjdk in the standard CentOS yum repository.

# yum install java-1.8.0-openjdk

Execute the following command and switch to 8 if there are multiple versions.

# alternatives --config java 

Install tomcat

Download the tar.gz format file [apache-tomcat-8.5.34.tar.gz] from the distribution page of Tomcat.

• https://archive.apache.org/dist/tomcat/tomcat-8/v8.5.34/bin/

Transfer the downloaded file by FTP (appropriately / var / www / html / test or the directory where FTP access was set when building the Web server), and expand it on CentOS with the following command.

# tar xvfz apache-tomcat-8.5.34.tar.gz 

Move the extracted folder to the / usr / local directory

# mv apache-tomcat-8.5.34 /usr/local 

Set a symbolic link so that you can access it with the name [tomcat]

# cd /usr/local 
# ln -s apache-tomcat-8.5.34 tomcat

Deploy MySQL Connector / J

It absorbs the differences between databases. Move the mysql-connector-java-x.x.x-bin.jar included in the download to / usr / local / tomcat / lib https://dev.mysql.com/downloads/connector/j/5.1.html

# mv mysql-connector-java-x.x.x-bin.jar /usr/local/tomcat/lib 

Tomcat web application manager settings

The following are the settings required if you want to use the Tomcat GUI. You can place it by moving the war file to / usr / local / tomcat / webapps without GUI.

– Add the following settings to /usr/local/tomcat/conf/tomcat-users.xml

tomcat-users.xml

<role rolename="admin-gui"/>
<role rolename="manager-gui"/>
<user username="【username】" password="【password】" roles="admin-gui,manager-gui"/> 

Allow access to the Tomcat management screen from the host machine side Add the following settings to the following 2 files

-　/usr/local/tomcat/webapps/manager/METAINF/context.xml -　/usr/local/tomcat/webapps/host-manager/METAINF/context.xml

By default, the GUI is restricted so that it can only be accessed locally, so if you want to access it from the outside, do the following or comment it out. * Security precautions

context.xml

<Valve className="org.apache.catalina.valves.RemoteAddrValve"
allow="127¥.¥d+¥.¥d+¥.¥d+|::1|0:0:0:0:0:0:0:1|¥d+¥.¥d+¥.¥d+¥.¥d+"/>

Opening 8080 port for tomcat

Immediate reflection
# firewall-cmd --zone=public --add-port=8080/tcp
Reflection of permanent settings
# firewall-cmd --zone=public --add-port=8080/tcp --permanent
Reload
# firewall-cmd --reload
Check settings
# firewall-cmd --list-all

Quit and start tomcat

If you change something, it will not be reflected unless you restart

# /usr/local/tomcat/bin/startup.sh 
# /usr/local/tomcat/bin/shutdown.sh 

Success if you can access the GUI with the URL below.

http://[IP address of VPS]:8080/

Register tomcat as a service

Set Tomcat to start when the server starts. Create a user

# useradd -s /sbin/nologin tomcat

Change the owner of the tomcat directory to tomcat

# chown -R tomcat /usr/local/apache-tomcat-8.x.x 

Creating a startup script file

# vi /etc/init.d/tomcat

/etc/init.d/tomcat

#!/bin/bash
#
# Startup script for the Tomcat Servlet Container
#
# chkconfig: 2345 80 10
# description: Tomcat is the servlet container that is used in the official \
#              Reference Implementation for the Java Servlet and JavaServer \
#              Pages technologies

TOMCAT_USER=tomcat
CATALINA_HOME=/usr/local/tomcat

. /etc/rc.d/init.d/functions
prog=tomcat

start() {
    echo -n $"Starting $prog: "
    daemon --user $TOMCAT_USER $CATALINA_HOME/bin/startup.sh > /dev/null
    RETVAL=$?
    if [ $RETVAL -eq 0 ]; then
        echo_success
    else
        echo_failure
    fi
    echo
    [ $RETVAL = 0 ] && touch /var/lock/subsys/$prog
    return $RETVAL
}
stop() {
    echo -n $"Stopping $prog: "
    daemon --user $TOMCAT_USER $CATALINA_HOME/bin/shutdown.sh > /dev/null
    RETVAL=$?
    if [ $RETVAL -eq 0 ]; then
        echo_success
    else
        echo_failure
    fi
    echo
    [ $RETVAL = 0 ] && rm -f /var/lock/subsys/$prog
    return $RETVAL
}

# See how we were called.
case "$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  restart)
    stop
    start
    ;;
  status)
    INSTANCES=`ps --columns 512 -aef|grep java|grep tomcat|grep org.apache.catalina.startup.Bootstrap|wc -l`
    if [ $INSTANCES -eq 0 ]; then
        echo $prog is stopped
        RETVAL=3
    else
        if [ $INSTANCES -eq 1 ]; then
            echo $prog is running 1 instance...
        else
            echo $prog is running $INSTANCES instances...
        fi
        RETVAL=0
    fi
    ;;
  *)
    echo $"Usage: $prog {start|stop|restart|status|help}"
    exit 1
esac

exit $RETVAL

Grant execute permission to the startup script file

# chmod a+x /etc/init.d/tomcat 

Enable automatic service start with the chkconfig command

# chkconfig tomcat on