Month: April 2013

To reset Tomcat manager password, follow simple steps.

1) Got to the apache-tomcat directory and open file following in your favorite editor

cd /usr/local/apache-tomcat-6.0.20/conf/

vi tomcat-users.xml

Part of file contents before update.

<tomcat-users>
<!--
<role rolename="tomcat"/>
<role rolename="role1"/>
<user username="tomcat" password="tomcat" roles="tomcat"/>
<user username="both" password="tomcat" roles="tomcat,role1"/>
<user username="role1" password="tomcat" roles="role1"/>
-->

</tomcat-users>

Now , update the file as follows

<tomcat-users>
<!--
<role rolename="tomcat"/>
<role rolename="role1"/>
<user username="tomcat" password="tomcat" roles="tomcat"/>
<user username="both" password="tomcat" roles="tomcat,role1"/>
<user username="role1" password="tomcat" roles="role1"/>
-->

<role rolename="manager"/>
  <role rolename="admin"/>
  <user username="admin" password="YOURPASSWORD" roles="admin,manager"/>
</tomcat-users>

For changes to take effect, restart the Tomcat service and check by logging with the user admin and password that you have set.

Fedora is one of the widely used Linux distro for desktop. It offers good experience to the users and provides lots of new features.

Once can watch video, listen to audio and use audio/video software's too. In case if your Fedora is unable to play audio/video then it might be an issue with the audio/video codecs.

To install the video and audio plugins/codecs on Fedora 18:

1) Install and enable the RPM Fusion repositories

wget http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-18.noarch.rpm
rpm -ivh rpmfusion-free-release-18.noarch.rpm
wget http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-18.noarch.rpm
rpm -ivh rpmfusion-nonfree-release-18.noarch.rpm

2) Install the plugins/codecs

su -c 'yum -y install gstreamer-plugins-bad gstreamer-plugins-ugly gstreamer-ffmpeg vlc'

3) Restart the machine (not required but worked in my case)

Note: The plugins are also available  HERE for download.

That's it!  😉

After cloning a CentOS machine from Oracle Virtualbox or from VMware template and generating new MAC address, I received following error message wile starting networking service.

Device eth0 does not seem to be present, delaying initialisation

Initially, I thought the issue might be with the network adapter but was not sure exactly which network adapter settings should be kept or changed.On further investigation and searching the error on world wide web, I came with following solution.

Basically, the problem occurs due to old NIC record which does not get erased even though new NIC record is assigned. In short when you import a cloned virtual machine, you have to generate a new MAC address. This is important to avoid network issues when the original and cloned virtual machine are on line at a same time.

Steps to resolve the error

1) Open following file which holds record of NIC templates

vi /etc/udev/rules.d/70-persistent-net.rules

The above file should contain similar records as below

# PCI device 0x15ad:0x07b0 (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:27:3e:ae:00:1a", 
ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

# PCI device 0x15ad:0x07b0 (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:27:3e:ae:00:1b", 
ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"

2) Remove previous eth entries, change the last entry name from eth1 to eth0 and save the file.

# PCI device 0x15ad:0x07b0 (e1000)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:27:3e:ae:00:1b", 
ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

3) Open following file, modify the MAC address and save the file.

vi /etc/sysconfig/network-scripts/ifcfg-eth0

4) Reload udev configuration for the changes that we made to reflect.

start_udev

5) Update /etc/resolv.conf file with correct name-servers.

6) Restart network service.

service network restart

or

/etc/init.d/network restart

That's it !

While installing application from binary, following error occurred

checking whether the C++ compiler works... no
configure: error: in `/usr/local/src/iptux':
configure: error: C++ compiler cannot create executables

While checking the log, it was found to be issue with missing c/c++ compiler.

If you find that GNU C  / C++ compiler is missing , it can be installed using yum or apt-get utility.

CentOS/RedHat/Fedora:

yum install gcc gcc-c++ autoconf automake

Ubuntu:

sudo aptitude install build-essential

This will install the compiler which should resolve the issues while installing new applications.