Re: manual vip assignment / rescheduling

Hi Gerald,

How long are you waiting for the other node to get a vip when you bring 
it NIC back up?  I would give it as long as 30 seconds, because it 
requires the Spread membership to complete, and a balance timeout as 
well.  You can watch the Spread daemon membership take place by looking 
at the tail on your spread log.  If you are waiting that long, I think 
the source of your problem is in the last paragraph of my email, but I 
answered your questions first.

At this stage, administrative control to grab/release IPs is not 
implemented in Wackamole, though it has been discussed and likely will 
happen whenever we decide to do a bit of an overhaul.

Balance timeout is relevant to you: if the vips become allocated 
unevenly (due to the "minimum disruption" strategy, as you're seeing in 
your system), vips should be moved to restore a "balanced" allocation 
based on the notion that any given machine should have at most one more 
vip than any other.  The timeout is the length of time between rounds of 
balancing, and the AquisitionsPerRound is the number of vips that can be 
moved during a given round of balancing.  Depending on how stable your 
network is, you might wish to change these parameters from the default.

Maturity timeout is what you might call a setup period.  It specifies a 
time interval during which a newly started Wackamole daemon will not 
actually aquire or release IP addresses, unless it hears from another 
daemon that the cluster is already mature.  So, if you start 5 daemons, 
the first daemon started will "turn mature" after his maturity timeout 
is up, and notify all other daemons to start moving vips for real.  This 
is just there to avoid disrupting a network too much when you bring a 
cluster up.  The time of 5 seconds specified in the sample config is 
really way too short, it is an artifact of our testing.

Also, from looking at your spread.conf, I noticed you have a line:
  Spread_Segment  127.0.0.255:4803 {
 
                                   localhost               127.0.0.1
  }
You shouldn't include a localhost segment if you have more than 1 Spread 
daemon or more than 1 Spread segment.  Its a common misconfiguration 
that stems from the sample.spread.conf (which is designed to let someone 
run a single Spread daemon without doing any work at all).  This seems 
to me to be the likely reason that IP addresses aren't being balanced in 
your cluster.

Cheers,
Ryan


Gerald Leier wrote:

> hi again,
> 
> i want to build a vpn-"fullcluster" where i got 2 nodes and 2 vips
> which get shared between them. if i set one nodes networkinterface
> down. the other node sets the 2nd vip up.
> now... when i put the first nodes nic up again it doesnt get another
> vip. the second node keeps both vips. well thats nice behavior.
> for example if one node is flapping he shouldnt get any new connections.
> 
> is there a way to tell wackamole that it should move one vip to a node ?
> (yeah i know, i could stop and start wackamole on that node and the vips
> get rescheduled)
> 
> also i would like to know what mature and balance intervals are for.
> 
> 
> thanx in advance
>  gerald
> 
> 
> p.s.: i included my configs below
> 
>   
> 
> #[wackamole.conf]
> Spread = 4803
> SpreadRetryInterval = 5s
> Group = my-vpn
> Control = /var/run/my-vpn.it
> VirtualInterfaces {
>         { eth0:192.168.1.50/24 }
>         { eth0:192.168.1.51/24 }
> }
> Arp-Cache = 90s
> Notify {
>         eth0:192.168.1.100/24
> }
> balance {
>         AcquisitionsPerRound = all
>         interval = 4s
> }
> mature = 5s
> #[wackamole.conf]
>                                                                                                     
> 
> #[spread.conf]
> Spread_Segment  127.0.0.255:4803 {
>                                                                                                     
>         localhost               127.0.0.1
> }
>                                                                                                     
> Spread_Segment  192.168.1.255:4803 {
>         vpn-uno     192.168.1.99
>         vpn-due     192.168.1.98
> }
> DebugFlags = { PRINT EXIT }
> EventLogFile = /var/log/spread.log
> EventTimeStamp = "[%a %d %b %Y %H:%M:%S]"
> RequiredAuthMethods = "NULL"
> AllowedAuthMethods = "NULL"
> #[spread.conf]
> 
> 
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> 

-- 
Ryan W. Caudy
Center for Networking and Distributed Systems
Department of Computer Science
Johns Hopkins University