How to settings CNI overlay in Azure Container App

Marcus Martins Leite 40

I need to know if is possible settings Azure Container App with CNI overlay like AKS. If not, please, can you solve IP exhaution in replicas. I can't see where is the IP address information is. I know that IP address is assigned to replicas, but I don't know how many IP's are available to my containers.

navba-MSFT 19,735 Reputation points Microsoft Employee

2023-06-28T06:27:12.3766667+00:00
@Marcus Martins Leite

@Marcus Martins Leite Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

I see that your question is specific to setting the CNI overlay in Azure Container App to avoid the IP exhaustion in replicas.

When setting up Container Apps, you need to have a Container App environment which is a Kubernetes Cluster (AKS) with a predefined Azure CNI network setup.

Regarding IP exhaustion in replicas, ACA automatically assigns IP addresses to each container instance when it is created. The IP address is assigned from a pool of available IP addresses that is managed by Azure.

How IP addresses are allocated in a subnet and what subnet sizes are supported depends on which plan you're using in Azure Container Apps.

Selecting an appropriately sized subnet for the scale of your Container Apps is important as subnet sizes can't be modified post creation in Azure.

Consumption only environment:

/23 is the minimum subnet size required for virtual network integration.

Container Apps reserves a minimum of 60 IPs for infrastructure in your VNet, and the amount may increase up to 256 addresses as your container environment scales.

As your app scales, a new IP address is allocated for each new replica.

Workload profiles environment:

/27 is the minimum subnet size required for virtual network integration.

The subnet you're integrating your container app with must be delegated to Microsoft.App/environments.

11 IP addresses are automatically reserved for integration with the subnet. When your apps are running on workload profiles, the number of IP addresses required for infrastructure integration doesn't vary based on the scale of your container apps.

More IP addresses are allocated depending on your Container App's workload profile:

When you're using Consumption workload profiles for your container app, IP address assignment behaves the same as when running on the Consumption only environment. As your app scales, a new IP address is allocated for each new replica.

When you're using the Dedicated workload profile for your container app, each node has 1 IP address assigned.

More Info here.
Marcus Martins Leite 40 Reputation points

2023-06-28T15:17:38.1933333+00:00

1 - The use of the Subnet ips is usued on which component: Replicas or Revision or Containers?

2 - If I use a /27 subnet I have 21 Ips available. How will these IPs be consumed? For example: With 21 Ip's I can limit myself to using which amount of which resource?

3 - I want to test uploading Containers Apps and see when I no longer have the possibility to upload new apps, since the number of containers is unlimited. Are there some tests that I can do see this limitation with the minimum range of ips?
navba-MSFT 19,735 Reputation points Microsoft Employee

2023-06-29T17:22:34.6566667+00:00

@Marcus Martins Leite Thanks for getting back. Please find below my answers inline to your question.

1 - The use of the Subnet ips is usued on which component: Replicas or Revision or Containers?
Answer: Replicas.

2 - If I use a /27 subnet I have 21 Ips available. How will these IPs be consumed? For example: With 21 Ip's I can limit myself to using which amount of which resource?
Answer: No we don’t allow customers to define/control the number of Ips getting used. This is primarily due to the ACA Platform multiplexing these IPs across replicas. For instance, in the Dedicated plan, only a dedicated node receives an IP from the customer's VNET, while individual pods receive an IP from an internal logical IP range. You may observe a larger number of pods assigned per customer IP in the Consumption Plan as well. Please note this multiplexing factor especially for the Consumption Plane may change in the future. Our documentation provides the exact numbers that the customers should expect: https://video2.skills-academy.com/en-us/azure/container-apps/networking#subnet

3 - I want to test uploading Containers Apps and see when I no longer have the possibility to upload new apps, since the number of containers is unlimited. Are there some tests that I can do see this limitation with the minimum range of ips?
Answer: If you want to test and simulate an IP exhaustion issue then you could try with increasing the replicas count. If using a Dedicated Workload Profile then you would see a Validation Error indicating that the environment doesn’t have enough Ips on the creation of Workload Profile itself. We are working on adding a System Events support for the Consumption Workload Profile which would exactly indicate if there was a failure to reserve an IP for an instance. The tentative ETA for this is in couple of month.

Hope this answers.
Marcus Martins Leite 40 Reputation points

2023-06-30T11:24:33.9733333+00:00

For me yet not clear about a rule for count the number of available ip's. Do you have any formula for this? I understand about /27 or /23, but I need a real test. I believe that the Azure Container Apps structure is a little confuse for me. For example, my client demand to know me about the numbers of container app I can create in the envinroment in consuption plan. I can't answer. Another thing is about the Azure Container App concept like:

1 - Azure Container Envinroment = Cluster

2 - Container App = Microservice

3 - Revision = Versions of microservice

4 - Replicas = POD

Can you if I am correct about these definitions?

Accepted answer

navba-MSFT 19,735 Reputation points Microsoft Employee

2023-06-30T12:51:08.9566667+00:00

@Marcus Martins Leite Thanks for getting back.

Yes, you are correct about these definitions. Here is some additional information to help you understand these concepts better:

Azure Container Environment: An Azure Container Environment is a managed Kubernetes cluster that provides a platform to deploy and run containerized applications. It is a fully managed service that abstracts the underlying infrastructure and provides a scalable, secure, and reliable environment to run your applications.

Container App: A Container App is a containerized application that can be deployed to an Azure Container Environment. It is a lightweight, portable, and self-contained unit that encapsulates all the dependencies and configurations required to run the application.

Revision: A Revision is a version of a Container App that is deployed to an Azure Container Environment. It represents a specific configuration of the application, including the container image, environment variables, and other settings. Revisions allow you to deploy and manage multiple versions of your application simultaneously.

Replicas: A Replica is a copy of a Pod that runs a Container App. Pods are the smallest deployable units in Kubernetes, and they can contain one or more containers. Replicas allow you to scale your application horizontally by creating multiple instances of the same Pod. Each Replica is identical to the others and runs the same version of the Container App.

I hope this information helps you better understand the Azure Container App concepts.

Question: How many container app I can create in the container app environment in consumption plan ?
Answer: In Azure Container Apps, the number of container apps that you can create in a container app environment in the consumption plan is unlimited. However, there are some quotas and limits that you should be aware of.

For example, the maximum number of revisions per container app is 100, and the maximum number of replicas per revision is 300. Additionally, the total CPU and memory allocations requested for all the containers in a container app must add up to one of the predefined combinations. You can find more information about these quotas and limits in the Azure documentation.

If you need to request an increase in quota amounts for your container app, you can learn how to do so by visiting the Quotas for Azure Container Apps documentation page. Hope this answers.

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navba-MSFT 19,735 Reputation points Microsoft Employee

2023-07-03T04:50:05.5066667+00:00

@Marcus Martins Leite Just following up to check if the below answer helped. If that answers your query, do click "Accept the answer” for the same, which might be beneficial to other community members reading this thread. And, if you have any further query do let us know. I would be happy to help.
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How to settings CNI overlay in Azure Container App

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