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From Dor Laor <...@scylladb.com>
Subject Re: Bootstraping a Node With a Newer Version
Date Wed, 17 May 2017 07:59:51 GMT
We've done such in-place upgrade in the past but not for a real production.

However you're MISSING the point. The root filesystem along with the entire
OS should be completely separated from your data directories. It should
reside
in a different logical volume and thus you can easily change the OS while
not
changing the data volume. Not to mention that there are fancier options like
snapshoting the data volume and thus having zero risk.

Happy LVMing.
Dor

On Wed, May 17, 2017 at 12:51 AM, Shalom Sagges <shaloms@liveperson.com>
wrote:

> Our DevOPS team told me that their policy is not to perform major kernel
> upgrades but simply install a clean new version.
> I also checked online and found a lot of recommendations *not *to do so
> as there might be a lot of dependencies issues that may affect processes
> such as yum.
> e.g.
> https://www.centos.org/forums/viewtopic.php?t=53678
> "The upgrade from CentOS 6 to 7 is a process that is fraught with danger
> and very very untested. Almost no-one succeeds without extreme effort. The
> CentOS wiki page about it has a big fat warning saying "Do not do this". If
> at all possible you should do a parallel install, migrate your data, apps
> and settings to the new box and decommission the old one.
>
> The problem comes about because there are a large number of packages in
> el6 that already have a higher version number than those in el7. This means
> that the el6 packages take precedence in the update and there are quite a
> few orphans left behind and these break lilttle things like yum. For
> example, one that I know about is openldap which is
> openldap-2.4.40-5.el6.x86_64 and openldap-2.4.39-6.el7.x86_64 so the el6
> package is seen as newer than the el7 one. Anything that's linked against
> openldap (a *lot*) now will not function until that package is replaced
> with its el7 equivalent, The easiest way to do this would be to yum
> downgrade openldap but, ooops, one of the things that needs openldap is
> yum so it doesn't work."
>
>
> I've also checked the Centos Wiki page and found the same recommendation:
> https://wiki.centos.org/FAQ/General?highlight=%28upgrade%
> 29%7C%28to%29%7C%28centos7%29#head-3ac1bdb51f0fecde1f98142cef90e8
> 87b1b12a00 :
>
> *"Upgrades in place are not supported nor recommended by CentOS or TUV. A
> backup followed by a fresh install is the only recommended upgrade path.
> See the Migration Guide for more information."*
>
>
> Since I have around twenty 2TB nodes in each DC (2 DCs in 6 different
> farms) and I don't want it to take forever, perhaps the best way would be
> to either leave it with Centos 6 and install Python 2.7 (I understand
> that's not so user friendly) or perform the backup recommendations shown on
> the Centos page (which sounds extremely agonizing as well).
>
> What do you think?
>
> Thanks!
>
>
> Shalom Sagges
> DBA
> T: +972-74-700-4035 <074-700-4035>
> <http://www.linkedin.com/company/164748> <http://twitter.com/liveperson>
> <http://www.facebook.com/LivePersonInc> We Create Meaningful Connections
>
>
>
> On Tue, May 16, 2017 at 6:48 PM, daemeon reiydelle <daemeonr@gmail.com>
> wrote:
>
>> What makes you think you cannot upgrade the kernel?
>>
>> “All men dream, but not equally. Those who dream by night in the dusty
>> recesses of their minds wake up in the day to find it was vanity, but the
>> dreamers of the day are dangerous men, for they may act their dreams with
>> open eyes, to make it possible.” — T.E. Lawrence
>>
>> sent from my mobile
>> Daemeon Reiydelle
>> skype daemeon.c.m.reiydelle
>> USA 415.501.0198 <(415)%20501-0198>
>>
>> On May 16, 2017 5:27 AM, "Shalom Sagges" <shaloms@liveperson.com> wrote:
>>
>>> Hi All,
>>>
>>> Hypothetically speaking, let's say I want to upgrade my Cassandra
>>> cluster, but I also want to perform a major upgrade to the kernel of all
>>> nodes.
>>> In order to upgrade the kernel, I need to reinstall the server, hence
>>> lose all data on the node.
>>>
>>> My question is this, after reinstalling the server with the new kernel,
>>> can I first install the upgraded Cassandra version and then bootstrap it to
>>> the cluster?
>>>
>>> Since there's already no data on the node, I wish to skip the agonizing
>>> sstable upgrade process.
>>>
>>> Does anyone know if this is doable?
>>>
>>> Thanks!
>>>
>>>
>>>
>>> Shalom Sagges
>>> DBA
>>> T: +972-74-700-4035 <+972%2074-700-4035>
>>> <http://www.linkedin.com/company/164748> <http://twitter.com/liveperson>
>>> <http://www.facebook.com/LivePersonInc> We Create Meaningful Connections
>>>
>>>
>>>
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>>
>
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