Enabling Core on Ubuntu

Check  
 ulimit -c   It should not be zero.
set ulimit -c unlimited

1. Vim /etc/sysctl.conf
2. Add the lines:
   kernel.core_uses_pid = 1
   kernel.core_pattern = core-%e-%s-%u-%g-%p-%t    
   fs.suid_dumpable = 2
3. If  we need to redirect core in some path mention that in kernel.core_pattern = /tmp/core-%e-%s-%u-%g-%p-%t
4. sysctl -p