Microsoft
MicrosoftGot it. So it sounds like you were using MPSJ while it was in preview. Before preview, you were not able to join multiple plans to the same subnet. So you were unknowingly using it and reaping the benefits 😀
While in preview, we were not enforcing the /26 subnet requirement. There was a note in this blog post calling out that we would be enforcing that at GA, which is why you only recently started having this issue. This post was updated when we went GA and now states that /26 minimum is required.
The only way around this is most likely to go back to the old way of doing things which was by doing one vnet integration per App Service plan. If you want to continue having multiple plans with the same subnet for new integrations, you must meet the /26 requirement.
Thanks! I guess that explains it. Why was there a decision to limit it to /26 ranges when it was working fine on /28s?
MicrosoftWe found that a /28 will not be big enough to support the majority of customers that will be using MPSJ. When you account for the additional IPs needed for things like upgrades and scaling, to be proactive and minimize the IP exhaustion issues customers may run into, we recommend and enforce a min of /26.
