[ClusterLabs] Observed Difference Between ldirectord and keepalived

[Timo Schöler]

On 1/4/21 3:11 AM, Eric Robinson wrote:
>> -----Original Message----- From: Users
>> <users-bounces at clusterlabs.org> On Behalf Of Timo Schöler Sent:
>> Saturday, January 2, 2021 4:27 AM To: users at clusterlabs.org 
>> Subject: Re: [ClusterLabs] Observed Difference Between ldirectord
>> and keepalived
>> 
>> On 1/2/21 10:11 AM, Eric Robinson wrote:
>> 
>>> We recently switched from ldirectord to keepalived. We noticed
>>> that, after the switch, LVS behaves a bit differently with
>>> respect to "down" services.
>>> 
>>> On ldirectord, a virtual service with 2 realservers displays
>>> "Masq    0" when one of them is down.
>>> 
>>> TCP  192.168.5.100:3002 wlc persistent 50
>>> 
>>> -> 192.168.8.53:3002            Masq    1      0          0
>>> 
>>> -> 192.168.8.55:3002            Masq    0      0          4
>>> 
>>> On keepalived, it does not shown the down server at all...
>>> 
>>> TCP  192.168.5.100:3002 wlc persistent 50
>>> 
>>> -> 192.168.8.53:3002            Masq    1      0          0
>>> 
>>> Why is that? It makes it impossible to see when services are
>>> down.
>> 
>> Hi Eric,
>> 
>> I think you're showing the output of ``ipvsadm -Ln'' here, right?
>> 
>> If so, what OS are you using? I observed similar behaviour when
>> moving from CentOS 6 to CentOS 7 (i.e. Kernel 2.6.x to Kernel
>> 3.10.x), so there may have changed default values of displaying
>> stuff or APIs.
>> 
>> Timo
> 
> Hi Timo,
> 
> That is exactly the case! The old load balancer is on CentOS 6 and
> the new one is on CentOS 7. (I'm aware of the recent announcement
> regarding CentOS, but 7 will not be end-of-life for another 4
> years.)
> 
> Did you ever come up with a solution? We have scripts that rely on
> the old behavior to alert admins of down services.
> 
> -Eric

Hi Eric,

world's moving on (regarding CentOS)...

I had the same issue, icinga2 was in the game. I modified the custom
made NRPE checks making them differentiate between OS versions.

Timo