Setting up CTDB on OCFS2 and VMs ...

[Rowland Penny]

On 13/12/14 11:48, Stefan Kania wrote:
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> Hi Michael, hi Rowland,
> Am 12.12.2014 um 21:52 schrieb Michael Adam:
>> Hi Rowland,
>>
>> I am really sorry that you are frustrated. Pleas keep on!
>>
>> We do try to document stuff, but clusters with ctdb is still an
>> area that is not done by the average admin. And there are not so
>> many people working on the code, so as usual, documentation sadly
>> lacks behind.
>>
> I'm on the way writing a documentation for ADMINS ;-). As soon as I
> finished withe te german version (that will be if everything is
> working) I will translate it. Rowland, if you want, I can send you my
> german documentation if you want, at least you can get all the
> commands and config-file information out of it.

I quite willing to read any documentation, so yes please.

Rowland

>
>> Someone like you, who with the help of us devs finally gets to a
>> working system, might help us in the end to improve the docs! :-)
>>
> That's what I want.
>> Clustering also relies on a whole additional area which is the
>> corresponding cluster file systems used underneath, which makes it
>> difficult to have comprehensive documentation for a concrete
>> setup.
>>
> That wat I'm fighting with, no documentation or only
> developers-klingon-language ;-)
>> That being said, there is documentation out there, but not
>> necessarily terribly up to date, and not precisely what you want.
>>
>> On the samba wiki, there is the generic but somewhat superficial
>>
>> https://wiki.samba.org/index.php/CTDB_Setup
>>
>> and as a specific example the GFS/CTDB/Samba howto:
>>
>> https://wiki.samba.org/index.php/GFS_CTDB_HowTo
>>
>> which is of course redhat-cluster/gfs specific as far as the file
>> system is concerned.
>>
>> The manual pages of ctdb are also pretty good by now!
>>
> That' right, BUT the wiki not mentions how to get the cluster into a
> samba4 domain and how permissions work on a cluster-fs
>> It is true that Debian is especially rare in these clustered Samba
>> docs. This is due to the fact, that for a long time, there was no
>> big focus on cluster file systems in Debian.
>>
>> A couple of years ago, I have given a couple of talks and courses
>> about clustered Samba partly also using Debian and Gluster, but
>> also RedHat and GFS. My 2010 notes
>>
>> http://www.samba.org/~obnox/presentations/sambaXP-2010/sambaxp-2010-tutorial-ctdb-handout.pdf
>>
>>   even contain some note on what is different and needs to be
>> considered on a Debian systems. (The main difference is that
>> /etc/default is used instead of /etc/sysconfig by most packages.)
>>
>> At that time, OCFS2 was not yet ready for CTDB/Samba, and GlusterFS
>> was mainly available in Debian, but did not perform very well. Now
>> Gluster has been taken on by RedHat, and I think we can expect
>> updates from that corner in the nearer future.
>>
>> Here is a paper explaining some of the fundamentals of CTDB and the
>> basic configuration of CTDB and clustered samba on Top.
>>
>> http://www.samba.org/~obnox/presentations/sambaXP-2009/samba-and-ctdb.pdf
>>
>>   And a pretty similar article from Linux Magazine:
>>
>> http://www.linux-magazine.com/Issues/2009/105/Samba-for-Clusters
>>
>> and an accompanying one on registry configuration:
>>
>> http://www.linux-magazine.com/Issues/2009/105/Samba-s-Registry
>>
>> Some of the details need to be checked because the info is 4-5
>> years old, but the basics are still correct.
>>
>> As a last but possibly important remark (for those who have not
>> fallen asleep by now ;-) let me mention that as far as I know,
>> Stefan Kania (whom I have copied in this reply, since I am not
>> certain that he is subscribed to the list) is currently working on
>> a reproducible setup with Debian/Gluster/CTDB/Samba. Maybe he can
>> give some insight on the specialities of a CTDB setup on current
>> Debian.
>>
> I'm reading the samba-mailinglist. Is there another one?
>
>> I apologize for having pointed mainly to my own writings, but at
>> the time I have undertaken some considerable efforts to create some
>> documentation and explanations, so I hope this is of any use. :-)
>>
> Regards
>
> Stefan
>
>> Cheers - Michael
>>
>> PS: Also, you are asking why Ronnie suggests a single node
>> cluster. Because it is always good to start out with a simple
>> case. And once you mastered that, move on to more complicated
>> things. And you can even see most config points in that 1-node
>> cluster.
>>
>>
>> On 2014-12-12 at 10:36 +0000, Rowland Penny wrote:
>>> On 11/12/14 18:32, ronnie sahlberg wrote:
>>>> I just tried building a single-node "cluster" on debian with
>>>> ctdb.
>>> Why a single node ????
>>>
>>>> I can check building a 4 node cluster next week when I am home
>>>> from my travels.
>>> Try it with two nodes
>>>
>>>> To get ctdb running on ubuntu 14.10, as root:
>>> Hang on, you said 'debian' above
>>>
>>>> 1, Install the ctdb package: apt-get install ctdb
>>>>
>>>> 2, create a missing directory mkdir -p /var/lib/run/ctdb
>>> Why is there a missing directory, sounds like a bug to me.
>>>
>>>> 3, remove the reclock file vi /etc/default/ctdb and comment out
>>>> CTDB_RECOVERY_LOCK
>>> But I want the lock.
>>>
>>>> 4, create a nodes file vi /etc/ctdb/nodes and add the line
>>>> 127.0.0.1
>>> Yes, but why '127.0.0.1' ???
>>>
>>>> 5, create a public addresses file vi
>>>> /etc/ctdb/public_addresses and add the two lines 127.0.0.2/8
>>>> lo 127.0.0.3/8 lo
>>> Do you have to create these ipaddresses, if so where and how
>>>
>>>> 6, start ctdb service ctdb start
>>>>
>>> That is this first part I really understood.
>>>
>>>> then check everything looks fine with 'ctbb status' and 'tail
>>>> /var/log/ctdb/log.ctdb'
>>>>
>>>>
>>>> That will not really create a very interesting cluster, just
>>>> one node, two public addresses and all on loopback. But this
>>>> should at least verify that ctdbd will start and run. Then you
>>>> can just shut it down and edit /etc/ctdb/nodes|public_addresses
>>>> and make them more interesting.
>>> Again, why just one node. ??
>>>
>>>> I personally suggest never running anything smaller than 4
>>>> node clusters for real data.
>>> Yes, but I am testing, so where is the documentation for people
>>> like me, who just want to get a couple of nodes up and running
>>> ???
>>>
>>> Rowland
>>>
>>>> Please see man ctdb man ctdbd less /etc/default/ctdb
>>>> http://ctdb.samba.org/configuring.html
>>>>
>>>> it should contain most to get started with ctdb.
>>>>
>>>>
>>>> regards ronnie sahlberg.
>>>>
>>>>
>>>>
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