Author Topic: tiered core / multiple servers  (Read 2125 times)

dutler

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tiered core / multiple servers
« on: July 01, 2008, 09:26:02 am »
Hello: I do not quite understand the need for ONE super server as the core. (besides I have a handful of dual p3 i want to use) :)
Has anyone set up the core services crossed several machines? I would rather have my LinuxMCE talk to my asterisk/freepbx and to my nas. This seems simple enough with the nature of Linux, but what about distributing encoding and decoding, dvd ripping, DTV sources, and what not?

Thanks, tom

royw

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Re: tiered core / multiple servers
« Reply #1 on: July 01, 2008, 09:30:59 pm »
The core is intended to be a firewall between your internal LAN and the external world.  The core then provides network services to the internal LAN. This allows the core to support a lot of plug and play devices on the internal LAN.  Currently the core services are tightly bound into the core.  Feel free to explore decoupling them as that is a long term goal of the project.

In the mean time, you can use all of those other computers as NAS or Media Directors (MD).  Basically you place an MD where ever you want to play media.  Now all of your media is available at each of the MDs.  If an MD has a DVD player, then you can rip from that MD, and yes, this means you can perform simultaneous rips.

I read on the wiki the other day that LinuxMCE supports multiple house setups where you can have multiple cores that connect via VPN across the external LAN.  I'm still trying to figure out an excuse (think wife) for playing with it.  :)

Have fun,
Roy

tschak909

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Re: tiered core / multiple servers
« Reply #2 on: July 01, 2008, 09:39:40 pm »
While there is such a concept in the database of multiple installations, a lot of coding work needs to be done to facilitate it.

Initially, Pluto intended for Device IDs to be globally Unique. This is evident when you load the build database, and look at the device #s for the earliest installations (you see device #s like 4000, 8120, etc.), however, it became evident that this wouldn't scale, so everybody has their own device root, tied to a particular installation..however, while the installation #s are unique, and the devices are tied to a given installation, the logic modules themselves do not have a concept of Device 1 in Installation #120533, and Device 1 in Installation #123064.... If multiple-house installation is to be a priority, this needs to be rectified by an ambitious developer.

-Thom

colinjones

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Re: tiered core / multiple servers
« Reply #3 on: July 02, 2008, 12:46:12 am »
I read on the wiki the other day that LinuxMCE supports multiple house setups where you can have multiple cores that connect via VPN across the external LAN.  I'm still trying to figure out an excuse (think wife) for playing with it.  :)


Roy - I assume you aren't trying to justify to your wife buying a second house just to play with this :) if so, I'm in awe of your ambition (and daring!)

dutler

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Re: tiered core / multiple servers
« Reply #4 on: July 02, 2008, 06:44:36 am »
Thanks for the help thus far. This question is just about use some of my old computers (20 headless 1U servers != MD), but about understand the the archetechture.

I dont understand what makes it so tightly coupled. Take Asterisk for an example. For LinuxMCE to make a phone call it should speak with Asterisk over and AMI via IP address right? FreePBX can even run on a different server than Asterisk and it has a lot of business logic (not just a GUI).

I would rather keep my m0n0wall firewall, dhcp and dns cache .... I know for the MD's to work diskless they need the proper tftp server, but lots of dhcp servers can serve up a different ip address for the tftp server.

So is it really that tight or is that just the rule of thumb?
thanks, tom

colinjones

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Re: tiered core / multiple servers
« Reply #5 on: July 02, 2008, 07:21:03 am »
whatever else is true, forget trying to replace the DHCP system. It is MUCH more than for just giving IP addresses, it relates to the pnp system, and identifying individual devices (ie it isn't just a DHCP server), so don't try to remove/replace/move it or you will break LMCE. Suggest you type DHCP into the search box before commenting on this any further - you will see it has been discussed to death, there isn't anything you can't find out about why by doing that search.

totallymaxed

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Re: tiered core / multiple servers
« Reply #6 on: July 02, 2008, 07:24:57 am »
Thanks for the help thus far. This question is just about use some of my old computers (20 headless 1U servers != MD), but about understand the the archetechture.

I dont understand what makes it so tightly coupled. Take Asterisk for an example. For LinuxMCE to make a phone call it should speak with Asterisk over and AMI via IP address right? FreePBX can even run on a different server than Asterisk and it has a lot of business logic (not just a GUI).

I would rather keep my m0n0wall firewall, dhcp and dns cache .... I know for the MD's to work diskless they need the proper tftp server, but lots of dhcp servers can serve up a different ip address for the tftp server.

So is it really that tight or is that just the rule of thumb?
thanks, tom

Believe us... LinuxMCE is very tightly coupled. We have had this kind of discussion numerous times now here... sure its possible (as in anything is 'possible') but its not trivial. but hey this is an FOSS project so your welcome to go and give it a try ;-)

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dutler

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Re: tiered core / multiple servers
« Reply #7 on: July 02, 2008, 07:34:06 am »
Quote
before commenting on this any further
right, this isnt about the DHCP, but about decentralizing the core services to multiple servers. DHCP/PXE booting was just an example.

I appreciate the replies - especially standing on the shoulders of giants, but colinjones, "because I said so" doesnt do any one any good.

Maybe the proper way to go is to start a wiki page and invite the more experienced users to participate with the documentation? Just seems like a bad plan for someone like me to have to RE it.

Andrew, can you point me to some threads... I must be searching for the wrong stuff.

dutler

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Re: tiered core / multiple servers
« Reply #8 on: July 02, 2008, 08:26:45 am »
Heres my confusion -
Documentation says that the DCE is socket based messaging system, well then the diff software shouldn't have to be on the same machine.  It still may not scale to a service provider fashion, but should be limited to one machine.

Maybe most of the software such as Asterisk doesn't use the DCE and uses wrappers instead?
-tom

colinjones

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Re: tiered core / multiple servers
« Reply #9 on: July 02, 2008, 08:47:01 am »
Dutler

I realise that DHCP was just an example, which is why I said "whatever else is true...", I was responding to that specific example.

Also, I never anything like "because I said so", please don't put words in my mouth. I said it relates to pnp and identifying devices ... it wasn't my intention to detail exactly why, because as I said ... search on DHCP, you will get much better information than me regurgitating it here for you. I just did, it came back with 16 pages of results. On the first page alone at least 9 threads relate directly to that subject.

I wasn't commenting on the other stuff. But I will now - the architecture is already highly distributed around a central message router on the core ... its just that the partitioning, so far, has concentrated on the media functionality by allowing you to spin out Media Directors, HA, etc, rather than on distributing the processing functionality. And IMO placing priority on having the media functionality decoupled is definitely the right way. Of course, ideally all of it would be decoupled in time, but not as yet - as Andrew (a commercial integrator of LMCE products) and Thom (one of the Devs) pointed out, this an undertaking not for the faint-hearted (and is probably fair to say that there are even higher priorities at the moment).

Either way, it is unlikely that the DHCP function will ever be decoupled to the point where you can replace it with a generic DHCP server, because as I said, it isn't just a DHCP server.

tschak909

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Re: tiered core / multiple servers
« Reply #10 on: July 02, 2008, 01:19:23 pm »
I would highly suggest spending some serious time with the source code. The monumental size of your task will become apparent.

-Thom

dutler

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Re: tiered core / multiple servers
« Reply #11 on: July 02, 2008, 05:30:22 pm »
Well, thank you. There still seems to be logical steps missing, but he the explanation of its a big deal is taken - just doesnt make since.

-tom

hari

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Re: tiered core / multiple servers
« Reply #12 on: July 02, 2008, 09:32:02 pm »
Well, thank you. There still seems to be logical steps missing, but he the explanation of its a big deal is taken - just doesnt make since.
Asterisk is one of the more complicated examples as it not only uses dce but also agi scripts, configuration scripts and whatnot. Start with an easy dce device and relocate it on another machine. You maybe want to add a new device "Computer" for that other machine and set proper controlled by device data. Usually devices are started by AppServer, either run it on that other machine, too, or figure out some other startup mechanism. Devices exit and are restarted by AppServer on the dcerouter reload.

best regards,
Hari
rock your home - http://www.agocontrol.com home automation

dutler

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Re: tiered core / multiple servers
« Reply #13 on: October 28, 2008, 11:35:15 am »
Hi, I never set up a LinuxMCE system. If it has has to be master of the users world and is so fragile and with so many wrappers... i deiced it was not compatible with me and stuck with my mythtv get up.

But, I recently have done some work with DHCP and thought I would report my new knowledge since is different than what I was told here and because it bothered me to be shut down by a community.

So, LMCE needs to run a DHCP:
Services could be relayed by a DHCP proxy, thus allowing my DHCP/DNS combo to function the way I wanted. But may not be good enough for LMCE for what ever reasoning or quircks of LMCE.

DHCP servers - such as the one in LMCE can be configured to operated on a non-standard port and clients can listen on non-standard port either mod the boot rom, chain ether boot.... what ever your hardware needs. Some extra work, but scalable.

DHCP server - such as the one in LMCE can be configured to only service certain MACs - aaah since my household (and likely many others) have a finite number of LMCE devices this is prob the easiest. Just do static entries (mac + ip) for your dhcpd.conf.

-tom


hari

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Re: tiered core / multiple servers
« Reply #14 on: October 28, 2008, 12:21:52 pm »
maybe, but this is not exactly plug and play :-)
rock your home - http://www.agocontrol.com home automation