Clean install RHEL 7

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Hi

So a little background, I have a old system running RHEL 6 i would like to upgrade the OS to RHEL 7.

I tried the rhel 6-7 upgrade tool which failed, i was recommend to do a clean install of rhel 7.

  • What i have done so far created a virtual machine with RHEL 7
  • Ran the following command on the old Rhel 6 system:
    rpm -qa --queryformat "%{NAME}\n" |sort|uniq|tee sorted_uniq_rpmlist | xargs echo > sorted_rpmlist

My problem is this :
- This is the first time i am doing a move over from old rhel 6 server to a fresh install , and was wondering if there is a guide or best practice i can follow to do the move.

I have looked, but strangely found nothing, your assistance will be greatly appriciated.

Thank you

Responses

Hi Sarfaraz,

Have you checked this Red Hat KB https://access.redhat.com/solutions/637583 ?. This provides all the details for an in-place upgrade from 6 to 7. I'd strongly suggest that you read thoroughly the document and understand what is supported and what is not.

Mainly, upgrade from 6.10 to latest release of 7 which is 7.7 is recommended. So, if you are running on older release of 6 then need to move it to the latest first and then proceed with upgrade. I guess the KB has not been updated recently and that is the reason it says "Red Hat Enterprise Linux 6.10 to Red Hat Enterprise Linux 7.6" under "Environment" at the top.

Next point is about the "Product Variant" and "Architecture" being supported for upgrade. Only "Server Edition" on "x86_64 architecture" is supported.

So, please read the KB article completely and understand the pros-cons and then proceed. I'd say only proceed if the "Preupg" goes green. Again, clean/fresh installation is the final verdict in case in-place upgrade fails. I hope this helps. All the best!

Hi

Mainly, upgrade from 6.10 to latest release of 7 which is 7.7 is recommended. So, if you are running on older release of 6 then need to move it to the latest first and then proceed with upgrade. I guess the KB has not been updated recently and that is the reason it says "Red Hat Enterprise Linux 6.10 to Red Hat Enterprise Linux 7.6" under "Environment" at the top.

I am currently running on the prod server : Red Hat Enterprise Linux Server release 6.10 (Santiago)

Tried the in place upgrade with : 7.7 first then 7.6 as well , both did not complete successfully

Next point is about the "Product Variant" and "Architecture" being supported for upgrade. Only "Server Edition" on "x86_64 architecture" is supported. - Did the check as well and was the correct versions.

This is the link when i tried last year with the preupg : https://access.redhat.com/discussions/4669211#comment-1692841

the preupg failed, and was recommended clean/fresh install , but because i inherited the system need to make sure all the configs and everything is there when the move is completed

Sarfaraz, you need to understand why it failed? If the preup is suggesting you to do a clean installation then it it is impossible to do a upgrade with your current environment. Go as suggested. I had initially thought you had not followed proper steps for the upgrade.

So, you would need to backup everything and do a kill & build your systems. I'd recommend that you backup your configuration files along with data, and other required files for later reference. Once you build a new RHEL7 system, make sure to get it updated first and then install applications one by one, test, test, verify that is working, move application data from backup, verify by bring the required app up, test again.. I know and understand that it is not as easy as saying, there are many challenges that might come across in the process.

It is better to keep a disaster recovery image ready. For such purpose, I'd prefer to make a disaster ready image using ReaR utility. This helps you to bring up a ready system with exact/copy of your current setup with minimal downtime or efforts. Please refer this article for more details What is Relax and Recover(ReaR) and how can I use it for disaster recovery?

Hi Sarfaraz, for IPU RHEL 6 -> 7 you should follow only this articlet (https://access.redhat.com/solutions/637583) that we keep up-to-date. For IPU RHEL 6 -> 7 there is no more planned latest-to-latest upgrade path. You need to upgrade to RHEL 7.6 and then od usuall update from RHEL 7.6 to the newer one you wish to use (if you find

I am not sure what I issue you discovered during IPU as there is not anything specific. You can try to open customer case. Guys from the support team already met various issues, so they could help you. Please ensure, you never you --force option for redhat-upgrade-tool as well - usually that signalize that upgrade will fail in wrong way..

In case you would like to proceed with clean installation instead of doind an in-place upgrade, I suggest you to just use the Preupgrade-Assistant (the preupg command). It will generate report for you, that could help you at least with some particular tasks when you install the new machine. E.g. in the /root/preupgrade directory you could find several files containing lists of rpms that are expected to have installed on RHEL 7. as well, in the cleanconf directory, you can find some configurations, that you can safely use on the clean system. Some of them are migrated to be compatible with RHEL 7 and if possible to preserve original functionality as on RHEL 6. Some configuration files in dirtyconf are migrated already as well, but these I do not suggest to copy just like that on the fresh system - rather look at them and those that are modified could point you to some changes you should maybe do in the RHEL 7 system manually.

If you are using satellite and ansible, maybe there is a tool/project that could help you with migration of RHEL6 to RHEL 7 on a new machine (different HW). But I dunno anything closer, just maybe you find something.

I hope that you find at least something useful in my comment.