.::: How To Change UUID Bios Machine Linux Using KVM Redhat Enterprise Linux (RHEL) ::.

A universally unique identifier (UUID) is an identifier standard used in software construction. A UUID is simply a 128-bit value. The meaning of each bit is defined by any of several variants.

For human-readable display, many systems use a canonical format using hexadecimal text with inserted hyphen characters. For example:

lshal | grep system.hardware.uuid | tr '[A-Z]' '[a-z]'
   
[root@TEGUHapp ~]# lshal | grep system.hardware.uuid | tr '[A-Z]' '[a-z]'
  system.hardware.uuid = 'ecf8da19-bcae-4e95-8725-c4e2d7aaba50'  (string)
[root@TEGUHapp ~]#



The intent of UUIDs is to enable distributed systems to uniquely identify information without significant central coordination. In this context the word unique should be taken to mean "practically unique" rather than "guaranteed unique". Since the identifiers have a finite size, it is possible for two differing items to share the same identifier. This is a form of hash collision. The identifier size and generation process need to be selected so as to make this sufficiently improbable in practice. Anyone can create a UUID and use it to identify something with reasonable confidence that the same identifier will never be unintentionally created by anyone to identify something else. Information labeled with UUIDs can therefore be later combined into a single database without needing to resolve identifier (ID) conflicts.

Adoption of UUIDs is widespread with many computing platforms providing support for generating UUIDs and for parsing/generating their textual representation
UUID old : ecf8da19-bcae-4e95-8725-c4e2d7aaba50
  ->> type on uuid.bios = "ec f8 da 19 bc ae 4e 95-87 25 c4 e2 d7 aa ba 50"
UUID Newest: 36353332-3030-5347-4834-353258334455
  ->> type on uuid.bios = "36 35 33 32 30 30 53 47-48 34 35 32 58 33 44 55"
 
1. Check UUID machine before modify
UUID old :
[root@TEGUHapp ~]# lshal | grep system.hardware.uuid | tr '[A-Z]' '[a-z]'
  system.hardware.uuid = 'ecf8da19-bcae-4e95-8725-c4e2d7aaba50'  (string)
[root@TEGUHapp ~]#

2. Backup ifcfg-eth0
   # cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0backup
[root@TEGUHapp ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1-backup
DEVICE="eth0"
BOOTPROTO="static"
HWADDR="00:0C:29:AA:BA:50"
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
IPADDR=192.168.1.200
NETMASK=255.255.255.0
DNS1=8.8.8.8
UUID="ecf8da19-bcae-4e95-8725-c4e2d7aaba50"
[root@TEGUHapp ~]#

3. Stop service your application and shutdown your machine
  # init 5
  or
  # poweroff
 
4. Open Datastore Browser & download bios image example bios.vmx to laptop/PC

5. Backup bios.vmx & Open bios.vmx using Notepad++ or ultraedit & replace uuid.bios old with uuid.bios newest then save

Replace UUID old
uuid.bios = "ec f8 da 19 bc ae 4e 95-87 25 c4 e2 d7 aa ba 50"

Using New UUID
uuid.bios = "36 35 33 32 30 30 53 47-48 34 35 32 58 33 44 55"

6. Open Datastore Browser & upload bios image example bios.vmx to laptop/PC

7. Power on Machine

8. For connection network, modify ifcfg-eth0 base on new UUID
[root@TEGUHapp ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"
BOOTPROTO="static"
HWADDR="00:0C:29:33:44:55"
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
IPADDR=192.168.1.200
NETMASK=255.255.255.0
DNS1=8.8.8.8
UUID="36353332-3030-5347-4834-353258334455"
[root@TEGUHapp ~]#

9. Save and close the file. Finally, you need to restart the network service, run:
# /etc/init.d/network restart
or
# service network restart

10. Check UUID machine after modify

UUID Newest:
[root@TEGUHapp ~]# lshal | grep system.hardware.uuid | tr '[A-Z]' '[a-z]'
  system.hardware.uuid = '36353332-3030-5347-4834-353258334455'  (string)
[root@TEGUHapp ~]#

11. Delete ifcfg-eth0backup if need
   # rm /etc/sysconfig/network-scripts/ifcfg-eth0backup

.::: How To Change eth1 to eth0 Permanent :::.