Step upgrade problem from CentOS 4 server

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Step upgrade problem from CentOS 4 server

Post by icjs » 2017/11/24 07:38:25

Hello all,

I have inherited a CentOS 4 server which is still in production. Using the vault repo's I have updated it to 4.9

The CentOS server has been added to over the years and has many services running and 1700+ packages installed.

The server owner wants to upgrade it to a supported CentOS version such a CentOS 6.

I am simulating a step upgrade it to CentOS 5 first by setting up a new CentOS 4 server and installing the package list from the real production system.

I have been following the guide here:

I have pointed the Centos-Base.repo file to use the 5.11 vault.

It has gone "by the book" so far except that I keep hitting "road blocks" in resolving all the dependency problems in the "yum upgrade" step.

The current road block is this error:

Error: Missing Dependency: is needed by package python-pyblock
Error: Missing Dependency: is needed by package python-pyblock

I have managed these by removing the problem module, in this case "python-pyblock" whoever I can find no trace of it on the system and "yum remove" or "rpm -e" fails to work.

I currently have a bootable system which has the CentOS 5.x kernel and thinks it is CentOS 5.3 but all the packages are still from 4.9.

Any ideas? Thanks

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Re: Step upgrade problem from CentOS 4 server

Post by TrevorH » 2017/11/24 07:51:26

Sorry, there is no upgrade path from one major version to the next. There was no upgrade path from 4 to 5 nor from 5 to 6 and from 6 to 7 just will not work at all.

Given that CentOS 6 is already in production phase 3 upstream - which means it only receives updates for critical security problems not for anything less - it's not really worth considering that as a stopping point. If you want to get to a supported version, go straight to CentOS 7. To get there, you'll almost certainly find it easier to set up a new system entirely and migrate your services over one by one. Each of your proposed migration steps will be a massive chunk of work for which you'll need to set aside months. Add those together 3 times over and the time spent to do it properly will be far less.

Also, because there is no official way to do this, you will never know if it was successful or if you have potential problems lurking in the background.
CentOS 6 died in November 2020 - migrate to a new version!
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Re: Step upgrade problem from CentOS 4 server

Post by icjs » 2017/11/24 09:48:42

Hello Trevor, thanks for quick reply.

According to comments in the upgrade page in my original post, many others have had success with 4-to-5 step upgrade. It also seems I am close but just out of reach. However I must then face it again in 5-to-6.

At least one other person has recommended I re-install with CentOS 7 and migrate each service/config manually. I might have to accept that a step upgrade is just going to cause background problems. I'll get a few more opinions before deciding for sure.

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