[Pacemaker] Making utilizations dynamic

[Michael Schwartzkopff]

On Thursday 20 January 2011 23:02:25 Michael Schwartzkopff wrote:
> Hi,
> 
> I read about the utilization feature in beekhofs blog. Really nice. But why
> do not take the next step and make the utilization in resources dynamic
> since RAM or CPU usage will change with time.
> 
> For a demonstration I used a cluster node with utilization of 100 ticks
> (normal one core machine):
> 
> node node1 \
>         utilization ticks="100"
> 
> Next I configured a slightly modified Dummy resource starting with 10 ticks
> utilization:
> 
> primitive resDummy1 ocf:misch:Dummy \
>         op monitor interval="10s" \
>         utilization ticks="10"
> 
> To test the whole feature I used placement-strategy="minimal", of course.
> 
> In the monitor part of my Dummy-RA I added:
> 
>         old=$(crm resource utilization $OCF_RESOURCE_INSTANCE show ticks)
>         actual=$(cat /tmp/new.data)
>         new=$(( (4*$old + $actual)/5 ))
>         ocf_log info "old = "$old" actual = "$actual" new = "$new
>         crm resource utilization $OCF_RESOURCE_INSTANCE set ticks $new
> 
> 
> Please note that there is a kind of hysteresis feature included in the
> lines above. Changes in the utilization will not instantaneous appear in
> the resource but gradually.
> 
> Measuring the actual utilization of time ticks I use the file /tmp/new.data
> where I can enter numbers for testing. I real life I would do something
> like
> 
> PID=$( get the pid to the process in question)
> new=$(top -n1 -p $PID -b | awk '/$PID/ {print $9}')
> 
> Testing my dynamic utilization feature you can write "200" into the
> /tmp/new.data file. The utilization value of the resource will gradually
> increase with every monitoring and when the value reaches the limit of
> "100" the resource will stop working on the node.
> 
> writing back "10" into the file you can watch the utilization fall again
> and finally being started on the node again.
> 
> Imagine the consequences for a cloud cluster consisting of 30 nodes hosting
> 100 virtual machines. All machines would be migrated to the least possible
> number of real machines during the night when there no work to do. In the
> next morning when work starts virtual machines would be migrated to free
> machines when the work load gradually increases.
> 
> The only thing to do that remains would be a daemon that switches off
> unused machines to save energy. But this could be done using STONITH
> agents.
> 
> Basically this would be an option to make cloud computing really green!
> 
> Please mail me your comments about this idea. Thanks.
> 
> Cheers,


No reply, no comments? Nothing at all?

-- 
Dr. Michael Schwartzkopff
Guardinistr. 63
81375 München

Tel: (0163) 172 50 98
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