Re: Spread for dynamic cluster with nodes entering and leaving at any time

Hi Luis,

Sorry for the delay, but I wanted to check with my colleagues about this is=
sue first.

You basically have the right idea that you need to list the full potential =
membership in the configuration file ahead of time.  However, I don=92t thi=
nk the configuration system will currently accept you listing out an entire=
 /24 network (i.e. - 255 daemons) the way you proposed.  By default, Spread=
 only allows up to 128 daemons in a ring and I think the configuration file=
 is similarly limiting.

In the past, however, we wrote a modification for a client that allowed the=
m to specify wildcard address matching in the configuration file that did a=
llow you to specify, for example, an entire /24 network as part of the pote=
ntial membership.  The system still had the limitation that only up to 128 =
daemons could ever be online and connected at any given moment, but they co=
uld be from the full address space.

If you are interested, I=92ll dig into that old version some and send you m=
ore details

Cheers!

-----
John Lane Schultz
Spread Concepts LLC
Cell: 443 838 2200

On Jun 16, 2014, at 10:55 AM, Luis Rodero-Merino <[email protected]> wro=
te:

Hello,

I'm a newbie to spread, we are evaluating if it can fit in our scenario. We=
 have a dynamic cluster of hosts, where nodes can appear (e.g. I add one mo=
re host to increase capacity) and disappear (e.g. some host fails) at any m=
oment. In this scenario we cannot know in advance which nodes will be runni=
ng at any given time, we only know the network they share. We need nodes to=
 be able to auto-discover each other (i.e., they realize through spread abo=
ut other nodes entering or leaving the cluster without any intervention fro=
m administrators), so at all times any given node is aware of who else is '=
alive'.

Given spread documentation, I assume that we need to include in the spread.=
conf file a 'Spread_Segment' section where all possible nodes are defined b=
efore-hand, so for network a.b.c.* we could have something like :

Spread_Segment 224.0.2.2:4803 {
    node1            a.b.c.1
    node2            a.b.c.2
    node3            a.b.c.3
    ...
    node255        a.b.c.255
}

Is that so? Thank you very much for your help.

Best,
Luis
 =


-- =


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