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I have a dozen load balanced cloud servers all monitored by Munin.

I can track each one individually just fine. But I'm wondering if I can somehow bundle them up to see just how much collective CPU usage (for example) there is among the cloud cluster as a whole.

How can I do this?

The munin.conf file makes it easy enough to handle this for subdomains, but I'm not sure how to configure this for simple web nodes. Assume my web nodes are named, web_node_1 - web_node_10.

My conf looks something like this right now:

    use_node_name yes
    use_node_name yes

Your help is much appreciated.

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up vote 1 down vote accepted

Yes, Munin supports virtual nodes which can combine data from other defined nodes.

See here for a good example:

update: Actually that was a terrible example, considering it didn't work. Here's the official example, which ought to work a lot better. :-)

I guess that's what I get for firing off a poorly researched answer that kinda looked right late on a Friday afternoon. :-o

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Thanks Graeme. Can you put a little more meat on that for me? I added another "node" under my previous nodes as mentioned above and it "Failed to parse". Here's what I added: [comparisons] update no apaches_load.graph_title Cluster Load apaches_load.graph_order server1=web_node_1;server1:load.load server2=web_node_1;server2:load.load ... server10=web_node_10;server10:load.load apaches_load.category Apache – Ryan Jun 1 '12 at 14:52
I recall getting this to work was a bit tricky and I don't seem to have one on my current munin masters. I'll see if I can find an old config somewhere, else I'll make a working example and post it here for you. – ThatGraemeGuy Jun 4 '12 at 8:14
Wow, that would be above and beyond helpful. Thanks. – Ryan Jun 4 '12 at 14:23

You can use munin to pull data from other graphs and aggregate them to a new graph. Here is a basic example for a munin.conf that pulls data from the CPU usage from your nodes to display it into another aggregate graph:

update no
contacts no

web_cpu.graph_title Webnodes - CPU Usage
web_cpu.cpu.label Webnodes - CPU Usage
web_cpu.cpu.sum web_node_1:cpu.user web_node_2:cpu.user web_node_3:cpu.user
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Unfortunately this does not work - the graph generation fails unfortunately. Perhaps a change to recent munin broke this. – Asfand Yar Qazi Jul 21 '15 at 13:57

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