Core 4 Remote Workers

[Daniel Wittenberg]

Maybe I misunderstood, but it sounds like you are going to have the workers listen for work coming from core, rather than the workers going and fetching work?  If that is the case it would concern me a bit as far as being robust, in that if a server goes away, or can't talk to a worker anymore, you have to deal with timeouts, and potentially cause slow-downs in getting work processed.  So I always liked the idea better that the workers check in and get work from the core, then you remove the need for any listening sockets.  I think you'll also need to consider security in that when a worker does check in, how do you know it's not a malicious worker, shared key or something, and then of course there's transport security, so ssl or payload-level encryption.

Dan


On Feb 2, 2013, at 8:12 AM, Eric Stanley wrote:

> All,
> 
> I've been giving some thought to remote workers for core 4 and wanted to 
> run those thoughts by this list. I see remote workers as a very useful 
> extension to the worker concept in core 4.
> 
> To implement remote workers, I think there are about 4 basic things that 
> would need to be done.
> 1. Implement the ability to listen to multiple query handler interfaces 
> (precursor to #2)
> 2. Implement the ability to create and listen on TCP socket query 
> handler interfaces.
> 3. Add a host key to the worker registration to allow workers to specify 
> the host(s) for which it will handle checks.
> 4. Write a stand-alone remote worker that can connect to the core 
> instance via TCP.
> 
> The reason I have steps 1 and 2, instead of combining them is first, 
> because a generalized solution is more extensible and second, I think 
> having multiple TCP listeners is a reasonable use case where you have a 
> multi-homed system, but you may not want to listen on all interfaces.
> 
> The host key should be allowed to specify one or more IP addresses, IP 
> subnets, contiguous IP address ranges, host names and host name 
> patterns/wildcards (i.e. *.example.com). If multiple workers register 
> for the same host, some sort of distribution mechanism should be used to 
> load balance the workers.
> 
> Using the second criteria of host to determine which worker gets the 
> check raises the question of the order of precedence for the criteria. 
> Initially, I think the host should have precedence over plugin, but I 
> can see implementing and order of precedence option in the core 
> configuration file. This would be more important if additional worker 
> selection criteria were added.
> 
> The communication between the remote worker and the core process should 
> be able to be protected by SSL. The remote worker will need a mechanism 
> to retry the connection in the event the network drops the connection.
> 
> I realize this is a sizable change and we may not want it to happen 
> before the release of 4.0. Thoughts on this are welcome.
> 
> Further down the road, I can see developing a remote worker proxy, whose 
> sole job is to broker the communication between core and even more 
> remote workers. This would enable a tree-shaped worker hierarchy for 
> monitoring environments that are both large and dispersed geographically 
> and/or topologically. This would require a re-registration process so 
> the proxy workers could keep core updated with their abilities as 
> leaf-node workers connected and disconnected.
> 
> Thoughts?
> 
> -- 
> Eric Stanley
> ___
> Developer
> Nagios Enterprises, LLC
> Email:estanley at nagios.com
> Web:www.nagios.com  
> 
> 
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_jan
> _______________________________________________
> Nagios-devel mailing list
> Nagios-devel at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/nagios-devel


------------------------------------------------------------------------------
Everyone hates slow websites. So do we.
Make your web apps faster with AppDynamics
Download AppDynamics Lite for free today:
http://p.sf.net/sfu/appdyn_d2d_jan