Azure Container Apps - Scale Set Instances consuming 58 IP Addresses

Scott Tomlin 21 Reputation points
2022-10-27T00:33:16.363+00:00

In our Container Apps environment with a VNET we have noticed that a Scale set instance will consume 58 IP Addresses. Why would that be the case when the container app is provisioned with only a single max replica? What happens in the background when we provision a new Container App?

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  1. Chris Bellée 76 Reputation points Microsoft Employee
    2022-11-10T03:25:08.237+00:00

    The Azure Container App infrastructure uses Azure CNI for network connectivity in order for each container to receive an IP from the underlying virtual network/subnet. As such, the Azure CNI driver reserves IP addresses for each underlying node, the number of IPs reserved is dependent on the ACA team's settings for how many pods are able to be scheduled per node, which I don't believe has been shared publicly.

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  1. Scott Tomlin 21 Reputation points
    2022-11-10T09:46:38.87+00:00

    Thanks, I should have posted the answer, I was given the same information on a support ticket I had opened. By using a /16 subnet instead of /23, we seem to have gotten past the issue.

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