Dear Yedidyah, We are actually seeing collisions, which is why I reached out in first place. Strange is that is did not happen since few weeks ago, and since then I saw it multiple times. For now I am simply going to create new mac pool for each of the clusters and switch to it, hoping it's not going to affect existing VMs. Regarding planning, if I would have known, that same mac pool is created across datacenters/clusters, I would have taken it into account. Relying on common sense, I just did not expect this to be the case, but to my fault I should have applied trust-but-verify approach. ----- kind regards/met vriendelijke groeten Marko Vrgotic Sr. System Engineer ActiveVideo e: m.vrgotic@activevideo.com On 26/01/2020, 07:45, "Yedidyah Bar David" <didi@redhat.com> wrote: On Thu, Jan 23, 2020 at 2:30 PM Vrgotic, Marko <M.Vrgotic@activevideo.com> wrote: > > Hi Yedidyah, > > Thank you for you update. > > This platform started with 4.3 deployment. > The Default mac address pool, apparently on all Clusters (5) is: > from_mac | to_mac > -------------------+------------------- > 56:6f:ef:88:00:00 | 56:6f:ef:88:ff:ff > I think I misled you, or for some reason didn't understand your original post. The default pool is for "everything". I thought you refer to different setups - separate engines - and the bug I mentioned about changing the default was addressed at this scenario. Inside a single engine, there is only one default. You should not see collisions *inside* it. Do you? The engine should know no to allocated the same mac to two different NICs. > Interestingly enough, I am alos not able to add another mac pool to Default. I can only create new one, Correct. > let's say MacPool2 and also create only single pool inside. Option to add second mac range under same name is grayed out, whether I login as SuperUser or Admin to Aministration Portal. Indeed. You can only change it, not add a new one with the same name. > > Never mind, it is as so, but I am still not "happiest" with: > > Question2: Would there be an harming effect on existing VMs if the default mac pool would be changed? > => I am pretty certain it's harmless, but didn't try that myself. > Reason is that I have 600VMs on 5 cluster setup in production - If I make the change where currently required and we are wrong, its going to affect almost half of those existing VMs. I did test the change on the staging, and it did not seem to have any harmful effect but that one has like 5VMs atm. > > I will run some additional tests on staging to see if I can get more comfortable before making change in production, but if anyone else can contribute boosting the confidence, please let me know. Ccing Dominik from the network team. I am pretty certain that people do change/add pools live, but guess not often - I guess most people plan ahead and then don't touch. Groetjes, -- Didi