This uses 3.1 Here's an example of the output I generate when debugging is turned on:
I have a routine I pass 3 parameters to: name of the variable, its units and the value. I generate 2 packets, the first with a header and the second with the data, which looks like this: 13:41:45.014 Name: ctxint.ctx Units: switches/sec Val: 562 TTL: 60 sent 00 00 00 80 00 00 00 0c 63 61 67 2d 64 6c 35 38 35 2d 30 32 00 00 00 0a 63 74 78 69 6e 74 2e 69 6e 74 00 00 00 00 00 00 00 00 00 06 64 6f 75 62 6c 65 00 00 00 00 00 0a 63 74 78 69 6e 74 2e 69 6e 74 00 00 00 00 00 0b 69 6e 74 72 70 74 73 2f 73 65 63 00 00 00 00 03 00 00 00 3c 00 00 00 00 00 00 00 00 00 00 00 85 00 00 00 0c 63 61 67 2d 64 6c 35 38 35 2d 30 32 00 00 00 0a 63 74 78 69 6e 74 2e 69 6e 74 00 00 00 00 00 00 00 00 00 02 25 73 00 00 00 00 00 04 31 30 37 32 Not sure if seeing the binary is of much value without the mappings, but as I said a V3.1 gmond is very happy with what I'm sending. We actually did think of xdr, but that would but additional requirements on collectl and it feels like doing things in binary will help minimize overhead. -mark |-----Original Message----- |From: Brad Nicholes [mailto:bnicho...@novell.com] |Sent: Tuesday, March 31, 2009 1:13 PM |To: Seger, Mark; ganglia-developers@lists.sourceforge.net |Cc: Evan J Felix |Subject: Re: [Ganglia-developers] Building a ganglia interface into |collectl | |>>> On 3/31/2009 at 9:56 AM, in message <49d23d46.2090...@hp.com>, Mark |Seger |<mark.se...@hp.com> wrote: |> |> This then leads to my question, which is what is the best way to send |> data to ganglia. I want to keep my messages very dense and so we |chose |> to simply send out binary data in the same format gmond expects. In |the |> case of pnnl, where they have a monitoring hierarchy, we've completely |> replaced all the monitoring gmonds with a dozen that act only as |> aggregators. There are about 190 nodes running collectl sending UPD |> messages to each aggregator gmonds and it seems to run just fine. |Does |> this make sense? Is there anything to watch out for? |> |> If anyone else is interested in trying this out while we're shaking |out |> the code, I'd be happy to share some pre-release code with a few |people. |> | |Which version of Ganglia are you targeting (3.0.x or 3.1.x). Ganglia |uses XDR to pack and unpack the metric packets. However the actual |format changed significantly between 3.0.x and 3.1.x. You can see the |XDR packet layout in the file lib/protocol.x for 3.0.x or |lib/gm_protocol.x for 3.1.x. The 3.1.x version is a bit more complex |than the 3.0.x version. The 3.0.x version is a very simple XDR packet |that basically contains a metric ID and a value. Gmond 3.0.x can get |away with just sending an ID in the packet because every 3.0.x gmond |hardcodes the metric metadata. Gmond 3.1.x made this more flexible by |splitting the packets in to metadata and value packets. Probably the |easiest way to communicate directly with gmond is to use the message |creation and sending APIs that are part of the ganglia library. Take a |look at the gmetric utility code for an example of how to use these |APIs. Gmetric is basically doing what you want to do but as a |standalone utility. For Ganglia 3.0.x you will have to include |lib/ganglia.h, for Ganglia 3.1.x you will include include/ganglia.h. |The libraries for Ganglia 3.1.x version have been made a little more |developer friendly by putting the public headers in the include/ |directory and converting the library to be a .so rather than static. | |Brad | ------------------------------------------------------------------------------ _______________________________________________ Ganglia-developers mailing list Ganglia-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ganglia-developers
