MultiBird on L2 - A crazy idea for Fail Over y and Load Balancing

[Grant Taylor]

On 1/19/21 6:48 AM, Alexander Zubkov wrote:
> You can use VRRP or alike protocol on L2

VRRP (and HSRP) are traditionally / inherently an Active / Passive 
configuration for any given instance.  Conversely, GLBP is Active / 
Active.  So, VRRP (HSRP) isn't a direct comparison for GLBP.

Note:  I'm eliding any fancy SDN breaking the rules and pretending to be 
a first hop redundancy protocol.

The Linux Virtual Server is akin to more traditional load balances and 
can be a SPOF in and of themselves.

I believe the IPTables "CLUSTERIP" is somewhat akin to MS-NLB in that 
multiple systems will have the cluster IP bound and will apply an 
algorithm to see which is answering the Active / Active IP for any given 
client.  Perhaps this can be leveraged as part of a solution for what 
the OP is wanting.

I don't know how the routing protocols would work in such an Active / 
Active configuration.  As I see it, an A/A configuration would 
effectively be akin to anycasting in that multiple systems would think 
and behave as if they were the given IP.  Meaning that they would each 
have their own sessions and state, which would significantly differ from 
each other.  E.g. A/A(1) would connect to peer B and A/A(2) would 
connect to peer C.  Thus both B and C would think they are connected to 
A/A, though they would be different A/As.  B and C would probably be 
okay with this in a stable state.  But I don't know what's going to 
happen to an established connection when A/A transitions.  I expect that 
B & C connections will end up falling apart and need to be 
re-established anew.  There is also the issue of how do you exchange B & 
C state between A/A(1) and A/A(2)?

I suspect that CLUSTERIP is something worth exploring / thought 
experiment.  I just don't know if it will pan out or not.



-- 
Grant. . . .
unix || die

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