REDHAT 6 to 7 OS Migration Document
Step 1: Please verify RHEL6 Server patched for latest version.
Step 2: Please verify space availability in RHEL6 for / and /var
a) / must be atleast 6GB free
b) /var must be atleast 2GB free
Note: If space is not available, please contact VM team for additional disc and
increase the file system.
Step 3: Install the PreUPG tool packages by executing below command.
Command:
# yum -y install preupgrade-assistant preupgrade-assistant-el6toel7 redhatupgrade-tool
Step 4: Please execute the Preupg command.
Step 5: Once successfully executed preupg command, please go to the path
/root/preupgrade. You will be finding result.html file
a) Please open the result.html file in web and verify the below categories and if
any action needed go and troubleshoot accordingly.
b) Once we verified the result.html file successfully, please copy the RHEL7 ISO
image from source server to migration server where we have more than
5GB space in file system (Try to copy mostly in /root)
Step 6: Please execute the below command from the path of RHEL7 ISO image
present.
Command:
# redhat-upgrade-tool --iso rhel-server-7.6-x86_64-dvd.iso --cleanup-post
Step 7: Once successfully completed the above command, please reboot the
server.
a) Reboot the server
Command:
# /sbin/shutdown -r now
b) Verify by below two commands for successful migration.
Command:
#cat /etc/redhat-release
#uname –r
Note: OS release must be changed to 6.x to 7.x
Step 8: Please shutdown the machine and handover to VM team for below two
action:
a) Please remove the Existing NIC card and assign New NIC card with same
vlan.
b) Please modify the Guest OS to RHEL7 and PowerOn on VM
Step 9: Once VM team completed above action, please go to the console, login to
the server and verify the Ethernet name changed as below
Command:
# ip a s (to verify)
Note: Name must be ens192
Step 10: Once VM team completed above action, please go to the console, login
to the server and verify the Ethernet name changed as below.
Command:
#cd /etc/sysconfig/network-scripts
Step 11: Rename the Ethernet name as below.
Command:
#mv ifcfg-eth0 if-cfg-ens192
a) Edit the file ifcfg-ens192 and change the name to eth0 to ens192 wherever
you find inside the file like below and comment the mac address.
Command:
#vi ifcfg-ens192
b) Restart the network service or reboot the server for clean reboot.
Command:
#systemctl restart network.service
Step 12: Remove the RHEL6 existing package from the server
Command:
# rpm -qa | grep -i el6.*
#rpm -e packagename –nodeps
(Or)
Use below bash script for this action to make work easier.
# rpm -qa | grep -i el6.* > /tmp/rpmold
# for i in `cat /tmp/rpmold`
>do
>rpm -e $i –nodeps
>done
Step 13: Patch the server to current version
Command:
# yum update
Note: For rhel7 repo file you can copy from source server GTWTPLJSMWPV01
under path /opt/tmp
Step 14: For additional package installation:
(LOGRHYTHM, VMware tools and crowdstrike packages, Rejoin with AD)
Please copy the packages from source server GTWTPLJSMWPV01 under path
/opt/tmp to our migration server by creating same path on destination
(/opt/tmp) to avoid conflict.