My quick note on setting up my personnel Ubuntu Server nodes. I update this as I ran up with issues setting up any components.

Nice tip to download Oracle JDK 

wget --no-cookies --no-check-certificate --header "Cookie: gpwe24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jdk-7u79-linux-x64.tar.gz"

Configure environment

/opt/jdk1.7.079/>

alternatives --install /usr/bin/java java /opt/jdk1.7.079/bin/java 2
alternatives --config java
Reference -


Network troubleshooting

List all interfaces, even those are inactive using option all ( -a )

  ifconfig -a  
  ip addr   
Path for network configuration file - https://gist.github.com/fernandoaleman/2172388

  /etc/sysconfig/network-scripts/ifcfg-xxx  
Make sure following options are present.
 BOOTPROTO=dhcp
  ONBOOT=yes  
To restart network use ifconfig <inf> up | down or below command. 

 /etc/init.d/network restart  

 service network restart  
To manually get DHCP 

 dhclient -v <inf>  
Managing Disks 

To detect devices and mounting shared partitions use dmesg 
Mount virtual box partition
 mount -t vboxsf drive /drive   
Managing Repositories <a href="http://www.rackspace.com/knowledgecenter/article/install-epel-and-additional-repositories-on-centos-and-red-hat">...

yum

Adding a repo is simply copying file to yum.repos.d/


Install from disabled repo

yum --enablerepo=rpmforge install aria2

Enabling a repo

yum repolist
vim /etc/yum.repos.d/rhelxx # enabled = 1
Alt.  sudo yum-config-manager --disable rpmforge

Enable Firewall ...

firewall-cmd is utility that writes into iptables

firewall-cmd —reload
firewall-cmd --zone=public --add-port=80/tcp —permanent
To stop firewalld, run the following command as root:

systemctl stop|disable|start firewalld

Iptables


References :-

Redhat official guide
How LVM Works
Use disk to create new partition 
Extending partitions on Linux VMware virtual machines
http://wiki.centos.org/HowTos/Network/SecuringSSH