We do have similar deployment but my question to you is Why do you have Active and standby Edge deployment if you have ECMP enabled.
As per my understand ECMP should be enabled if you have ACTIVE-ACTIVE Edge deployed. Correct me if i am wrong?
Since in the active edge gateway it has 2 equal cost path to the physical routers ecmp has been enabled
I would go forward with your first approach.
Is the below steps correct.
Step 1. Disable ECMP - Not sure doing this will have any impact
Step 2 : Change OSPF cost from 1 to 100 in both NSX side & R2 side for VL:AN 101
There should be no interruption during Step 1. I suppose you have configured the OSPF Hello/Dead timers for 1/3 thus the routing change should be very fast.
Thanks. But I have the below query.
If i disable the ECMP, only 1 path will be selected.
My understand is that it will be either through vlan 100 or vlan 101
Is there any way to control it. how to control that once ECMP is disabled my active route is via vlan 100, so that i can make the cost change in vlan 101 & do the required maintenance.
Why don't you simply disable the second Edge Uplink(20.x.x.x) and do the required change ?
That is one of the options i am looking at. But there will be impact doing that.
The live traffic flowing through that particular interface will be affected.
I just wanted to achieve uninterrupted traffic by doing that.
The live traffic flowing through that particular interface will be affected.I just wanted to achieve uninterrupted traffic by doing that.
maximum 30 seconds it will take traffic to failover. I'm saying maximum assuming your Edges are service provider Edge.With Great Regards,
vExpert 2012-2017 | VCP3-5 | VCAP5-DCD | VCP-NV | vSAN Specialist | VDI | Germany
Both the NSX Edges & the Physical devices are not service provider devices.
So u mean to say that , if i disable the interface in NSX edge there will be no impact.
From my understanding there will be impact. The reason is from NSX Edge -> Physical device the path may get changed but from the physical device - > NSX Edge it will take time to re converge . Because of this there will be down time.
Correct me if i am wrong.
You can monitor the rx/tx packet flow from host esxtop were the edge is running and check the VNIC counters , when there is no flow you can just flip the ECMP to disable state or simply disable the second interface -> This one way you can do the change with less outage
But this is practically not possible since it is a production environment.
The traffic volume will be high, so can expect to wait & watch.
So what is the best way or method to change from 2 equal cost paths to 1 path without traffic interruption.
1 way is to change the cost at both NSX side & physical router side.
But for doing this is it required to disable ECMP ?
Going via your steps and requirement it will no more be a ECMP,it will be unequal cost load balancing.So if ECMP is enabled and if you are changing the cost, as far as i know existing flows will not have any impact - because hash is already calculated and it will be stored in router memory(in this case edge), cost change should not trigger a new hash calculation ,however over a period of time for new flows new hash will be calculated and it will pass via optimized path which would be 10.10.x.x. network and it will take 20.x.x.x path whenever situation demands.