Recover Webmin's root pasword

There are cases where you don't have root password and can't login to webmin. Like the one i came across AWS RedHat 7 instance recently, AWS doesn't provide you root password for security reason. And you need admin login for webmin.

Also, in Ubuntu by default, root password is disabled, and you won't be able to log in to the Webmin webpage, as the Webmin root login will be disabled too. To fix this, you need to manually change the Webmin root password.

You can do this in one of two ways:

Procedure 1

After you perform # apt-get install webmin or yum install webmin ,you have to do the following:

Find your webmin binary install directory and webmin configuration directory.

If you don't know where it is, you can find it by running:

$ locate changepass.pl or $ sudo find / -name changepass.pl
$ #and
$ locate miniserv.conf

Then follow these instructions to change the password. Change your working path to the webmin binary install directory and then run changepass.pl:

$ cd <webmin-install-dir>
$ sudo ./changepass.pl <webmin-config-dir> root <newpassword>

Note this ONLY changes the webmin root login password and does not change the your 'real' root password.

Procedure 2

Get your encrypted password from /etc/shadow.

For example, the following command will output the password to the screen:
$sudo grep your_username /etc/shadow |cut -f2 -d:

Next we edit this file:

$sudo vi /etc/webmin/miniserv.users

Note: you will need superuser rights to save it

Replace the asterisk in the first line with the password you aquired from /etc/shadow, so that the line looks something like this: 

root:$1$e/9mjoasd$asdasljjwynSD42

Save the file and exit the editor after that.

Restart webmin with this command:

$sudo /etc/init.d/webmin restart
After that, you can go to https://localhost:10000/ in your web browser and login using root as the username and the password of your non-root user.

Ref: https://help.ubuntu.com/community/WebminWithoutARootAccount

Apache Tomcat 8 Installation and Configuration in CentOS 6.8

I had to work recently on a project where i got to install Java 1.8 and Apache Tomcat 8 in CentOS 6.8 x64 bit. Below are step by step instructions for full configuration of Apache Tomcat and adding it as init.d service. Hope you enjoy this tutorial.

1.Install Java 1.8

#cd /opt/

#wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u111-b14/jdk-8u111-linux-x64.tar.gz"

#tar xzf jdk-8u111-linux-x64.tar.gz

# cd /opt/jdk1.8.0_111/

# alternatives --install /usr/bin/java java /opt/jdk1.8.0_111/bin/java 2

# alternatives --config java
This will display programs which provide 'java'. Below is example:

  Selection    Command
-----------------------------------------------
*  1           /opt/jdk1.7.0_71/bin/java
 + 2           /opt/jdk1.8.0_45/bin/java
    3           /opt/jdk1.8.0_91/bin/java
    4           /opt/jdk1.8.0_111/bin/java

Enter to keep the current selection[+], or type selection number: 4

# alternatives --install /usr/bin/jar jar /opt/jdk1.8.0_111/bin/jar 2

# alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_111/bin/javac 2

# alternatives --set jar /opt/jdk1.8.0_111/bin/jar

# alternatives --set javac /opt/jdk1.8.0_111/bin/javac

Verify java version
[root@centos]# java -version

java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)


Configuring Environment Variables

Most of Java based application’s uses environment variables to work. Set the Java environment variables using following commands

•Setup JAVA_HOME Variable
# export JAVA_HOME=/opt/jdk1.8.0_111

•Setup JRE_HOME Variable
# export JRE_HOME=/opt/jdk1.8.0_111/jre

•Setup PATH Variable
# export PATH=$PATH:/opt/jdk1.8.0_111/bin:/opt/jdk1.8.0_111/jre/bin

#vi /etc/environment
JAVA_HOME=/opt/jdk1.8.0_111|
JRE_HOME=/opt/jdk1.8.0_111/jre
PATH=$PATH:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin:/opt/jdk1.8.0_111/bin:/opt/jdk1.8.0_111/jre/bin

2. Tomcat 8 Intallation:

#cd /tmp
#wget http://mirror.ventraip.net.au/apache/tomcat/tomcat-8/v8.0.39/bin/apache-tomcat-8.0.39.tar.gz
#tar zxvf apache-tomcat-8.0.39.tar.gz
#ls –l
#mv apache-tomcat-8.0.39 /opt/
#cd /opt/apache-tomcat-8.0.39/bin
#./startup.sh  (to start tomcat 8)
#./shutdown.sh  (to stop tomcat 8)

#netstat -antp | grep 8080
tcp        0      0 :::8080                     :::*                        LISTEN      4180/java

Go to browser and type:
http://localhost:8080

You need to setup user login to access “Server status”, “Manager App” and “Host Manager”.

#vi /opt/apache-tomcat-8.0.39/conf/tomcat-users.xml
<user username="tomcat" password="P@ssw0rd" roles="manager-gui,manager-status,manager-script,admin-gui"/>

#cd /opt/apache-tomcat-8.0.39/bin
#./shutdown.sh
#./startup.sh

Now you can login with the user above to access.
(Note: you cannot specify “admin” user as it’ll be locked out due to security settings)

Adding tomcat as init.d service (In this case, there is no dedicated ‘tomcat’ user but it’s built under ‘root’)

Here, user ‘tomcatuser’ is allowed to start/stop/restart (in addition to root)

#vi /etc/init.d/tomcat

#!/bin/bash
# description: Tomcat Start Stop Restart
# processname: tomcat
# chkconfig: 234 20 80

TOMCAT_HOME=/opt/apache-tomcat-8.0.39
TOMCAT_USER=tomcatuser
case $1 in
start)
/usr/bin/sudo $TOMCAT_HOME/bin/startup.sh
;;
stop)
/usr/bin/sudo $TOMCAT_HOME/bin/shutdown.sh
;;
restart)
/usr/bin/sudo $TOMCAT_HOME/bin/shutdown.sh
/usr/bin/sudo $TOMCAT_HOME/bin/startup.sh
;;
esac
exit 0

#chmod 755 tomcat
# chkconfig --add tomcat
# chkconfig --level 345 tomcat on
# chkconfig --list tomcat

To start tomcat during boot: add below
#vi /etc/rc.local
/etc/init.d/tomcat start

#service tomcat start/stop/restart

#vi /etc/sudoers
tomcatuser ALL = /sbin/service httpd24-httpd restart, /etc/init.d/httpd24-httpd restart, /bin/cat /var/log/httpd24/access_log, /bin/cat /var/log/httpd24/error_log, /etc/init.d/tomcat start, /etc/init.d/tomcat stop, /etc/init.d/tomcat restart, /bin/sh /opt/apache-tomcat-8.0.39/bin/shutdown.sh, /bin/sh /opt/apache-tomcat-8.0.39/bin/startup.sh

#Start as user ‘tomcatuser’
$sudo /etc/init.d/tomcat start/stop/restart

#Lastly reboot the server and check it’s loading at startup
#netstat –antp | grep 8080

#Also check PATH is loading correctly after restart
#echo $PATH

Ref: http://tecadmin.net/install-java-8-on-centos-rhel-and-fedora/#

Ref: http://tutorialforlinux.com/2014/03/07/how-to-install-apache-tomcat-8-on-centos-6-x-32-64bit-linux-easy-guide/

Ref: https://www.digitalocean.com/community/tutorials/how-to-install-apache-tomcat-8-on-centos-7

Ref: http://tomcat.apache.org/download-80.cgi