Puppet users - Mar 2010 - Using puppet to automate tasks (ex: mysql slave setup)

I''m not sure if puppet can be coerced to do something like this, but I
wanted
to throw it out there as it''s a process that seems fairly easy to
automate.

To create new mysql slaves my process goes something like this:

1) run innobackupex [1] on mysql master
2a) copy data from master to slave (takes a decent amount of time depending on
wire speed and database size; usually on the order of 6-24 hrs)
2b) setup mysql slave w/ data from mysql master to start replicating binary log
3) import backup using innobackupex

The problem here seems to be that I need to do things on two different hosts
and only once certain things have happened.

I figured I could easily specify the node that is the master and the slave in
the manifests, but I''m not sure how far this gets me.  I imagine
through the
creative use of exec''s and "onlyif"s this should be doable,
but I wanted to
get other people''s experiences with automating processes like this.

-Doug

[1]
http://www.percona.com/docs/wiki/percona-xtrabackup:xtrabackup_manual#setting_up_a_new_slave_from_a_backup_in_replication

Hi Doug,

On 10 mrt, 14:18, Doug Warner <d...@warner.fm>
wrote:
> I''m not sure if puppet can be coerced to do something like this,
but I wanted
> to throw it out there as it''s a process that seems fairly easy to
automate.
>
> To create new mysql slaves my process goes something like this:
<snip>
> I figured I could easily specify the node that is the master and the slave
in
> the manifests, but I''m not sure how far this gets me.  I imagine
through the
> creative use of exec''s and "onlyif"s this should be
doable, but I wanted to
> get other people''s experiences with automating processes like
this.
Although the idea is cool and I''d love to see the module once you have
created it, I doubt this is something you really want to do with
puppet. I see puppet more as a "this is what my machine should look
like" kinda tool. Pushing data for several hours really shouldn''t
be
part of that, I think. I can imagine it triggering a script in the
background that fetches like the daily backup from a server and builds
the slave the next time puppet runs and it detects the download being
completed, though. But that would still give you puppet errors for
several hours (dependencies not being satisfied), which would indicate
to me it''s not the right tool for the job. But maybe that''s
just me.

--
Kind regards,
Tim

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On 03/10/2010 08:39 AM, Tim Stoop wrote:
> Although the idea is cool and I''d love to see the module once you
have
> created it, I doubt this is something you really want to do with
> puppet. I see puppet more as a "this is what my machine should look
> like" kinda tool. Pushing data for several hours really
shouldn''t be
> part of that, I think. I can imagine it triggering a script in the
> background that fetches like the daily backup from a server and builds
> the slave the next time puppet runs and it detects the download being
> completed, though. But that would still give you puppet errors for
> several hours (dependencies not being satisfied), which would indicate
> to me it''s not the right tool for the job. But maybe
that''s just me.
That''s kinda my impression as well.  The manifests would have to be
carefully
crafted for "if this is here, do this now" which is going to be very
trick
across systems.

I haven''t used Capistrano yet, but would a tool like that be better
suited for
this type of job?

-Doug

In my environment I''d probably do something like this with Func
(https://fedorahosted.org/func/).  It''s primarily used with RedHat
based systems.  If that''s not a problem for you, then you can write
scripts on your "overlord" that run commands on any systems running
the func daemon and reporting to your "overlord".  Your specific issue
could be solved mostly with the "Command" and "CopyFile"
module or, with a little Python experience, you could write your own module
using the available api.

It takes some work getting Func implemented but can be done quite easily with an
existing puppet infrastructure or with something like Cobbler.


byron

-----Original Message-----
From: puppet-users@googlegroups.com [mailto:puppet-users@googlegroups.com] On
Behalf Of Doug Warner
Sent: Wednesday, March 10, 2010 8:19 AM
To: puppet-users@googlegroups.com
Subject: [Puppet Users] Using puppet to automate tasks (ex: mysql slave setup)

I''m not sure if puppet can be coerced to do something like this, but I
wanted to throw it out there as it''s a process that seems fairly easy
to automate.

To create new mysql slaves my process goes something like this:

1) run innobackupex [1] on mysql master
2a) copy data from master to slave (takes a decent amount of time depending on
wire speed and database size; usually on the order of 6-24 hrs)
2b) setup mysql slave w/ data from mysql master to start replicating binary log
3) import backup using innobackupex

The problem here seems to be that I need to do things on two different hosts and
only once certain things have happened.

I figured I could easily specify the node that is the master and the slave in
the manifests, but I''m not sure how far this gets me.  I imagine
through the creative use of exec''s and "onlyif"s this should
be doable, but I wanted to get other people''s experiences with
automating processes like this.

-Doug

[1]
http://www.percona.com/docs/wiki/percona-xtrabackup:xtrabackup_manual#setting_up_a_new_slave_from_a_backup_in_replication

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On Mar 10, 2010, at 5:18 AM, Doug Warner wrote:
> I''m not sure if puppet can be coerced to do something like this,
but
> I wanted
> to throw it out there as it''s a process that seems fairly easy to
> automate.
>
> To create new mysql slaves my process goes something like this:
>
> 1) run innobackupex [1] on mysql master
> 2a) copy data from master to slave (takes a decent amount of time  
> depending on
> wire speed and database size; usually on the order of 6-24 hrs)
> 2b) setup mysql slave w/ data from mysql master to start replicating  
> binary log
> 3) import backup using innobackupex
>
> The problem here seems to be that I need to do things on two  
> different hosts
> and only once certain things have happened.
>
> I figured I could easily specify the node that is the master and the  
> slave in
> the manifests, but I''m not sure how far this gets me.  I imagine  
> through the
> creative use of exec''s and "onlyif"s this should be
doable, but I
> wanted to
> get other people''s experiences with automating processes like
this.
Hi Doug,

I, um, don''t know if this is a good idea, but this might work for you:

http://github.com/reductivelabs/puppet-external-resource

Basically, I''ve created a simple resource that functions as a kind of  
gate for exactly that situation.  I''ve tested it in very simplistic  
situations, but you should consider this to be experimental code and  
by no means a complete solution.  I just made this repo public five  
minutes ago and wrote it for a customer last week.

For long delays -- 12 hours -- this will likely be pretty spammy,  
because you''ll get a lot of ''skipped because of failed
dependencies''
reports, and you''ll likely want to run it with a timeout of 0 and  
verify that it works correctly in that case.

With this, your slave would have something like:

class dbslave {
   external_resource { db-backup:  check => "..script to verify backup  
is complete..." }
   db::import { mydb: ...., require => External_resource[db-backup] }
}

By default, it''ll run the external resource check every 10 seconds,  
and if it doesn''t complete within five minutes then it fails, causing  
all dependent resources (in this case, your import) to be skipped.   
You can tune both the frequency and timeout, but I haven''t tested it  
with a timeout of 0; it might just sleep infinitely in that case.

-- 
There is only one success - to be able to spend your life in your own
way. -- Christopher Morley
---------------------------------------------------------------------
Luke Kanies  -|-   http://reductivelabs.com   -|-   +1(615)594-8199

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