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Re: Strategy for "one-off" tasks


From: Daniel Pittman
Subject: Re: Strategy for "one-off" tasks
Date: Fri, 11 Jul 2003 10:57:02 +1000
User-agent: Gnus/5.090016 (Oort Gnus v0.16) XEmacs/21.5 (cassava)

On Thu, 10 Jul 2003, Frank Smith wrote:
> --On Thursday, July 10, 2003 15:34:06 -0700 Darren Dunham
> <address@hidden> wrote:

[...]

>> I think the idea is "why would you need to perform a one-time-only
>> task"? Can you give an example of what this would be? 

[...]

> One example:
> 
>    We have a bunch of web servers that connect to a farm of database
>    servers on the same private subnet, and the connection goes through
>    a load balancer. The database servers need a static route set for
>    each web server pointing to the load balancer, so the web server
>    will get the reply back from the same IP it sent the request to
>    (the load balancer). When we add a new web server, we need to add a
>    route to each database server. Using "AppendIfNoSuchLine" works
>    fine for adding to the init script, but we also need to run a
>    shellcomand one-time-only to add the route now instead of on the
>    next reboot (which is probably many months from now).

...but you can achieve the same thing in a convergent fashion by having
cfengine define a class when the file is changed, and then executing a
shell command (or whatever) that will ensure the routes are correctly
installed.

I do this for management of the /etc/aliases file, and it works just
fine.

        Daniel

-- 
Youth is happy because it has the capacity to see beauty. Anyone who keeps the
ability to see beauty never grows old.
        -- Franz Kafka




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