Upgrading CentOS 6 to 7

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DonSea
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Upgrading CentOS 6 to 7

Post by DonSea » 2019/01/09 17:15:33

Hello Guys,

I'm new using CentOS. In my new job, my boss asked me to upgrade CentOS from 6 to 7. I've read a lot of forums here and outside and there is different information related with this upgrade. Some people say that there is tool to make this upgrade but looks like is old and not working with latest versions.
Also I've found the following page with some steps: https://linuxacademy.com/blog/linux/cen ... -in-place/ but I'm not sure to follow this stems. Iv'e searched in several topics here, but I cannot found a clear answer or answer are too old.

Please, can you assist me with my question?

It is possible to upgrade CentOS from 6 to 7 without a fresh installation?

If yes, do you have a step by step site or any how to?

This is a critical server for my Company, so I don't want to brake it.

Thank you for your support an assistance.

Best,
SV.

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TrevorH
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Re: Upgrading CentOS 6 to 7

Post by TrevorH » 2019/01/09 17:38:57

There is no upgrade from CentOS 6 to 7 at all. For a brief period around 7.0 time there was a vaguely working utility but it never worked very well and was prone to errors. Once 7.1 came along even that stopped working and has never worked since and never will.

The recommended approach is to reinstall in parallel and migrate your apps and services from old to new machines.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

dunch
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Re: Upgrading CentOS 6 to 7

Post by dunch » 2019/01/30 14:30:42

There is (or at least was) a RedHat utility for upgrading 6 to 7 that ran on the server edition only. It had some limitations, if couldn't handle EFI boot and couldn't upgrade the GUI but otherwise ran quite nicely. You will need a RedHat support contract to get hold of a copy.

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TrevorH
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Re: Upgrading CentOS 6 to 7

Post by TrevorH » 2019/01/30 16:57:40

The RHEL version will not work with CentOS.

The withdrawn CentOS tool was based on the orginal RHEL version of that utility and had so many changes that the person who made it work then walked away saying "never again". And since then there have been no newer versions though several people have looked at it and then all has gone very quiet...
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

dunch
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Re: Upgrading CentOS 6 to 7

Post by dunch » 2019/01/31 09:00:35

I can confirm that the RedHat utility most definitely will work on CentOS, in my previous job I used it to update a couple of hundred machines. You do have to do some malarkey with the yum console to swap the centos-release rpm and redhat-release-server rpms first though.

amrgfahmed
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Joined: 2020/06/19 21:22:09

Re: Upgrading CentOS 6 to 7

Post by amrgfahmed » 2020/06/19 21:26:43

dunch wrote:
2019/01/31 09:00:35
I can confirm that the RedHat utility most definitely will work on CentOS, in my previous job I used it to update a couple of hundred machines. You do have to do some malarkey with the yum console to swap the centos-release rpm and redhat-release-server rpms first though.
Hi dunch,
Can you please help out more what needs to be done. I tried to install the upgrade tool but am unable to get it. There is a link referring to http://dev.centos.org as the location of the repo. That's not working though.
Thanks.

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TrevorH
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Re: Upgrading CentOS 6 to 7

Post by TrevorH » 2020/06/20 12:36:28

I'll say it again, just to be sure.

There is no upgrade from one CentOS major version to the next. Never has been. If you attempt it, there are lots of things that could go wrong and probably will and when that happens you get to keep all of the pieces.

The CentOS project recommends that you install a new system in parallel and migrate your services from the old to the new system in a controlled manner, testing as you go to make sure that it all works.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

dunch
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Location: Yorkshire

Re: Upgrading CentOS 6 to 7

Post by dunch » 2020/06/27 07:47:51

amrgfahmed wrote:
2020/06/19 21:26:43
I tried to install the upgrade tool but am unable to get it.
The only way to get the tool is through your RedHat account manager. You will need a RHEL subscription first.

kluch
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Re: Upgrading CentOS 6 to 7

Post by kluch » 2020/10/02 12:49:33

Assistant:
https://buildlogs.centos.org/centos/6/u ... /Packages/
Latest build that can do upgrade
http://vault.centos.org/centos/7.2.1511/os/x86_64/
And remember to full upgrade to latest 7.x version at the end or you will stay on CentOS 7.2 !!

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TrevorH
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Re: Upgrading CentOS 6 to 7

Post by TrevorH » 2020/10/03 15:23:24

Please do not use those packages. They WILL break systems and render them unbootable.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

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