I have a RHEL system and I'm thinking of changing to CentOW. How can this be done most easily. It is important that the e-mail setup not be disturbed, since it was crafted to work with an IP that requires authentication.
Thanks,
On Tue, Jun 7, 2011 at 6:55 AM, John J. Boyer john.boyer@abilitiessoft.com wrote:
I have a RHEL system and I'm thinking of changing to CentOW. How can this be done most easily. It is important that the e-mail setup not be disturbed, since it was crafted to work with an IP that requires authentication.
Not sure if this will help, but I went the other way from CentOS to RedHat by grabbing a list of packages with "rpm -qa", cleaning up the package names a bit, installing a base RedHat based on the same update level, then "yum update" or "yum install"ing from the list of packages. Next I diffed the configuration directories and manually moved the changed files. Finally just backed up/restored the database and application LVMs (dd/gzip the entire partition).
On Tuesday, June 07, 2011 07:40:26 AM Kwan Lowe wrote:
Not sure if this will help, but I went the other way from CentOS to RedHat by grabbing a list of packages with "rpm -qa", cleaning up the package names a bit, installing a base RedHat based on the same update level, then "yum update" or "yum install"ing from the list of packages. Next I diffed the configuration directories and manually moved the changed files. Finally just backed up/restored the database and application LVMs (dd/gzip the entire partition).
Whee, that's a lot of work. With EL6 you have 'yum distro-sync' at your beckon call; a patch to add a 'distro-sync full' exists that goes as far as checking checksums, which probably has a greater chance of working correctly.
On an EL6 it should be as simple as changing the repositories and issuing yum distro-sync (with some rhn-specific steps depending on the direction of the cross-grade, though). But I say 'should' for a reason, as I've not tried. Yet. I likely will try this once C6 is out, since I have a 32-bit system to cross-grade (want to use the subscription entitlement on a different machine).
I have a RHEL system and I'm thinking of changing to CentOW. How can this be done most easily. It is important that the e-mail setup not be disturbed, since it was crafted to work with an IP that requires authentication.
I switch a RHEL machine in EL6 to scientific linux a while ago, and I suppose it's the exact same thing for Centos.
Note this applies to my x64 machine, if you're in i686, you'll just have to change the distrio/package name.
Here's what I did :
1. Harvest the sl-release-6.0-6.0.1.x86_64.rpm and redhat-logos-60.0.14-1.sl6.1.noarch.rpm from the repository.
2. Remove unneeded packages :
rpm -e rhnlib rhn-client-tools rhn-setup yum-rhn-plugin rhn-check rhnsd redhat-indexhtml redhat-lsb
Remove old packages and replice it with the one you downloaded :
rpm -e --nodeps redhat-release-server-6Server rpm -hiv sl-release-6.0-6.0.1.x86_64.rpm
rpm -e --nodeps redhat-logos rpm -hiv redhat-logos-60.0.14-1.sl6.1.noarch.rpm
On Tuesday, June 07, 2011 09:43:24 AM Nicolas Ross wrote:
I switch a RHEL machine in EL6 to scientific linux a while ago, and I suppose it's the exact same thing for Centos.
[snip process]
You do realize that you didn't replace the RHEL binaries, right? To completely switch you need to replace all the binaries with the equivalent ones from either SL6 or C6 (when it's released). Not just the logos; there are other changes (kernel signing, for instance). That's what 'yum distro-sync full' would do (once you've patched it in).
On Jun 7, 2011, at 9:49 AM, Lamar Owen wrote:
On Tuesday, June 07, 2011 09:43:24 AM Nicolas Ross wrote:
I switch a RHEL machine in EL6 to scientific linux a while ago, and I suppose it's the exact same thing for Centos.
[snip process]
You do realize that you didn't replace the RHEL binaries, right? To completely switch you need to replace all the binaries with the equivalent ones from either SL6 or C6 (when it's released). Not just the logos; there are other changes (kernel signing, for instance). That's what 'yum distro-sync full' would do (once you've patched it in). _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
On Tuesday, June 07, 2011 10:30:18 AM Dvorkin, Asya wrote:
On Jun 7, 2011, at 9:49 AM, Lamar Owen wrote:
On Tuesday, June 07, 2011 09:43:24 AM Nicolas Ross wrote:
I switch a RHEL machine in EL6 to scientific linux a while ago, and I suppose it's the exact same thing for Centos.
[snip process]
You do realize that you didn't replace the RHEL binaries, right?
While Phil's guide is a very good one for C5; however, the OP is asking about EL6, not 5. EL5 doesn't have 'yum distro-sync' available; this is a seriously handy tool for this kind of migration. EL6 does have 'yum distro-sync' available.
There's a thread in the Scientific Linux Users mailing list on a similar topic; grep the archives for the subject "How to migrate yum installed on RHEL 6 to update from SL6 repository?" to get more information, especially on the need to replace all the upstream binary packages, not just the logos and the repository configs.
On Tuesday, June 07, 2011 10:30:18 AM Dvorkin, Asya wrote:
On Jun 7, 2011, at 9:49 AM, Lamar Owen wrote:
On Tuesday, June 07, 2011 09:43:24 AM Nicolas Ross wrote:
I switch a RHEL machine in EL6 to scientific linux a while ago, and I suppose it's the exact same thing for Centos.
[snip process]
You do realize that you didn't replace the RHEL binaries, right?
While Phil's guide is a very good one for C5; however, the OP is asking about EL6, not 5. EL5 doesn't have 'yum distro-sync' available; this is a seriously handy tool for this kind of migration. EL6 does have 'yum distro-sync' available.
There's a thread in the Scientific Linux Users mailing list on a similar topic; grep the archives for the subject "How to migrate yum installed on RHEL 6 to update from SL6 repository?" to get more information, especially on the need to replace all the upstream binary packages, not just the logos and the repository configs.
By looking at the man page, distro-sync wouldn't re-install a package with the same version. For exemple, on my rhel boxes, I have tzdata-2011g-1.el6.noarch installed, and on my sl6's one, I have tzdata-2011g-1.el6.noarch. It's the same exact version number. So the installed package wouldn't be re-installed.
You would need to do yum reinstall * to properly re-install the package from the new repo (sl6 or c6 for instance).
On Tuesday, June 07, 2011 02:07:41 PM Nicolas Ross wrote:
By looking at the man page, distro-sync wouldn't re-install a package with the same version.
Right; if the NEVR is the same, it won't be reinstalled unless you apply the 'distro-sync full' patch that is in yum 3.4. Karanbir pointed to the patch a few days ago, and it might apply cleanly to yum 3.2.29 (EL6's version). With that patch to yum, 'distro-sync full' will check the checksums and do a reinstall if the installed package's checksum doesn't match the repo.
In theory, changing the repo sources, removing the rhn-specific plugins and modules, reinstalling yum, patching yum for 'distro-sync full', then issuing 'yum distro-sync full' should do a full in-place reinstall of all packages.
When C6 is out, I plan to do just that with my personal tesbed RHEL6 i386 system (it's part of the reason I installed on that box to begin with; I always planned to run RHEL6 on another box later (I bought a subscription....)). But it will have to wait until C6 is out. Or if I wanted to go to SL6.....
On Tue, 7 Jun 2011, Nicolas Ross wrote:
By looking at the man page, distro-sync wouldn't re-install a package with the same version. For exemple, on my rhel boxes, I have tzdata-2011g-1.el6.noarch installed, and on my sl6's one, I have tzdata-2011g-1.el6.noarch. It's the same exact version number. So the installed package wouldn't be re-installed.
You would need to do yum reinstall * to properly re-install the package from the new repo (sl6 or c6 for instance).
Are there many packages with identical names that you'd *care* about reinstalling? tzdata for example I assuming is functionally identical (if not pretty much bit-for-bit). Given it's got the same NEVRA, it's not going to get updated any differently either.
jh
By looking at the man page, distro-sync wouldn't re-install a package with the same version. For exemple, on my rhel boxes, I have tzdata-2011g-1.el6.noarch installed, and on my sl6's one, I have tzdata-2011g-1.el6.noarch. It's the same exact version number. So the installed package wouldn't be re-installed.
You would need to do yum reinstall * to properly re-install the package from the new repo (sl6 or c6 for instance).
Are there many packages with identical names that you'd *care* about reinstalling? tzdata for example I assuming is functionally identical (if not pretty much bit-for-bit). Given it's got the same NEVRA, it's not going to get updated any differently either.
tzdata was just an exemple, it was the first one I tought that was updated frequently...
For my part, no I didn't care and left those packages that were already installed alone.
Nicolas Ross wrote:
By looking at the man page, distro-sync wouldn't re-install a package with the same version. For exemple, on my rhel boxes, I have tzdata-2011g-1.el6.noarch installed, and on my sl6's one, I have tzdata-2011g-1.el6.noarch. It's the same exact version number. So the installed package wouldn't be re-installed.
You would need to do yum reinstall * to properly re-install the package from the new repo (sl6 or c6 for instance).
Are there many packages with identical names that you'd *care* about reinstalling? tzdata for example I assuming is functionally identical (if not pretty much bit-for-bit). Given it's got the same NEVRA, it's not going to get updated any differently either.
tzdata was just an exemple, it was the first one I tought that was updated frequently...
For my part, no I didn't care and left those packages that were already installed alone.
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Only changed packages (not binary compatible) are in CentOS marked with .centos. so those should be replaced without question. For others, running "yum reinstall *" is advised but not necessary. You are allowed to run RHEL but are not allowed updates, so using base of RHEL and updates from CentOS should generally be OK.
Ljubomir
On Wednesday, June 08, 2011 11:03:14 AM Ljubomir Ljubojevic wrote:
Only changed packages (not binary compatible) are in CentOS marked with .centos. so those should be replaced without question. For others, running "yum reinstall *" is advised but not necessary. You are allowed to run RHEL but are not allowed updates, so using base of RHEL and updates from CentOS should generally be OK.
I'm not sure about that. At least not if you have valid entitlements and you want to continue to use them (go look at the agreement and see if I'm misreading a few clauses that imply that in order to legally use *any* subscription entitlements you must properly subscribe *all* systems running upstream binaries; but I'm not a lawyer). To be safe I plan to do the full binary replacement dance, but that's just me.
And while CentOS does its best to be 100% binary compatible, I wonder how supportable a combined system (partial upstream binaries, partial CentOS or SL binaries) really will be over the complete release cycle, and what sort of oddball bugs you might run up against six years from now.
On Wed, 8 Jun 2011, Lamar Owen wrote:
And while CentOS does its best to be 100% binary compatible, I wonder how supportable a combined system (partial upstream binaries, partial CentOS or SL binaries) really will be over the complete release cycle, and what sort of oddball bugs you might run up against six years from now.
I'd bet on no problems myself, mixing RHEL and CentOS.
jh
On Wed, Jun 08, 2011 at 04:59:01PM +0100, John Hodrien wrote:
On Wed, 8 Jun 2011, Lamar Owen wrote:
And while CentOS does its best to be 100% binary compatible, I wonder how supportable a combined system (partial upstream binaries, partial CentOS or SL binaries) really will be over the complete release cycle, and what sort of oddball bugs you might run up against six years from now.
I'd bet on no problems myself, mixing RHEL and CentOS.
FWIW, back in the day when I ran Tao Linux at home, the Tao developer needed to get out from under (new job, family commitments, etc.), so he (and Johnny Hughes, as I recall) pushed out a (set of??) yum update(s??) that once run converted Tao Linux into Centos. No problems occurred at all, at least not for me, and all subsequent yum invocations went to the centos repos rather than the Tao repos. That was during the era of Centos-3, and my system ran this way for some time (no, I don't recall how much time, but it was at least a large fraction of a year, if not longer) until Centos 4 came along, at which time I did a fresh install.
Too bad I don't know (and probably never knew) exactly what it was that those updates did.
In my ignorance I'd sorta assume the same (sort of) thing could be done to convert rhel to centos. but what do I know? :)
Lamar Owen wrote:
On Wednesday, June 08, 2011 11:03:14 AM Ljubomir Ljubojevic wrote:
Only changed packages (not binary compatible) are in CentOS marked with .centos. so those should be replaced without question. For others, running "yum reinstall *" is advised but not necessary. You are allowed to run RHEL but are not allowed updates, so using base of RHEL and updates from CentOS should generally be OK.
I'm not sure about that. At least not if you have valid entitlements and you want to continue to use them (go look at the agreement and see if I'm misreading a few clauses that imply that in order to legally use *any* subscription entitlements you must properly subscribe *all* systems running upstream binaries; but I'm not a lawyer). To be safe I plan to do the full binary replacement dance, but that's just me.
And while CentOS does its best to be 100% binary compatible, I wonder how supportable a combined system (partial upstream binaries, partial CentOS or SL binaries) really will be over the complete release cycle, and what sort of oddball bugs you might run up against six years from now.
Well, only packages will remain with Red Hat signatures. All logos and trademarks will be replaced with CentOS made packages. System will be reported as CentOS.
I am not legal expert, nor do I have precise knowledge about those legal issues.
I wrote that reinstall is advised, but my view is that conversion can be done now, but full reinstall can wait a while when unit is not on full load.
Ljubomir
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Dvorkin, Asya -
fred smith -
John Hodrien -
John J. Boyer -
Kwan Lowe -
Lamar Owen -
Ljubomir Ljubojevic -
Nicolas Ross