balanced pool problem??

[Bob Harold]

On Thu, Sep 13, 2018 at 11:29 AM project722 <project722 at gmail.com> wrote:

> Hey guys I just established a new failover relationship between 2 rhel 6
> servers running dhcp 4.1.1. I created the relationship about 10 hours ago.
> I'm doing some checking and I'm seeing the following in the logs from each
> server:
>
> server A - (primary)
> Sep 13 09:45:54 serverA dhcpd: balanced pool 55ab409d8790 <poolname>
> total 884  free 151  backup 150  lts 0  max-misbal 45
>
> Server B - (secondary)
> Sep 13 09:45:53 serverB dhcpd: balanced pool 5654c47474a0 <poolname>
> total 884  free 157  backup 144  lts -6  max-misbal 45
>
> The ultimate plan is to decom server A and sync B with a new Primary once
> I verify all lease data from A has synced to B. But, my concern here is the
> discrepency I see in the "free" and "backup" numbers from each server. If
> the pools are balanced, shouldn't these numbers be the same?
>

That looks normal to me.
I am running:
DHCP Server 4.3.6-P1

And here are some sample log lines from the failover pair:

Sep 14 10:34:31 adonis3 dhcpd: balancing pool 206cf30 35.0.120.0/23 total
470 free 157 backup 236 lts -39 max-own (+/-)39
Sep 14 10:24:11 adonis4 dhcpd: balancing pool 1a88870 35.0.120.0/23 total
470 free 165 backup 238 lts 36 max-own (+/-)40
Sep 14 10:34:31 adonis3 dhcpd: balancing pool 2097490 35.0.122.0/23 total
469 free 184 backup 156 lts 14 max-own (+/-)34
Sep 14 10:24:11 adonis4 dhcpd: balancing pool 1ab2dd0 35.0.122.0/23 total
469 free 183 backup 166 lts -8 max-own (+/-)35
Sep 14 10:34:31 adonis3 dhcpd: balancing pool 20c08d0 35.0.124.0/23 total
501 free 230 backup 231 lts 0 max-own (+/-)46
Sep 14 10:24:11 adonis4 dhcpd: balancing pool 1adc210 35.0.124.0/23 total
501 free 228 backup 236 lts 4 max-own (+/-)46

As long as they are balanced within "max-own", it should be ok.

What you don't want to see is "requesting peer rebalance" lasting more than
a few minutes at a time:

Aug  8 07:59:09 adonis8 dhcpd: balanced pool 54334b0 35.0.118.0/25  total
107  free 83  backup 19  lts -32  max-misbal 15
Aug  8 07:59:09 adonis8 dhcpd: balancing pool 54334b0 35.0.118.0/25  total
107  free 83  backup 19  lts -32  max-own (+/-)10  (requesting peer
rebalance!)
Aug  8 07:59:09 adonis7 dhcpd: balanced pool 51e0d50 35.0.118.0/25  total
107  free 41  backup 61  lts -10  max-misbal 15
Aug  8 07:59:09 adonis7 dhcpd: balancing pool 51e0d50 35.0.118.0/25  total
107  free 41  backup 61  lts -10  max-own (+/-)10

I have seen it stuck in that state, and one of the servers run out of
IP's.  Had to remove failover and put it back, in order to clear the
condition.  Have not figured out what causes it.

-- 
Bob Harold
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