10 AKS Networking Best Practices

Azure Kubernetes Service (AKS) is a managed Kubernetes service that makes it easy to deploy and manage containerized applications. AKS simplifies the process of setting up and managing a Kubernetes cluster, allowing you to focus on building and running your applications.

However, setting up and managing a Kubernetes cluster can be complex, and there are many networking best practices that should be followed to ensure that your cluster is secure and efficient. In this article, we will discuss 10 AKS networking best practices that you should consider when setting up and managing your AKS cluster.

1. Use a dedicated virtual network for AKS

A dedicated virtual network for AKS ensures that the resources in your cluster are isolated from other services and applications running on Azure. This helps to reduce the attack surface of your environment, as well as providing better control over traffic flow between different components. Additionally, it allows you to configure more granular access control policies, such as restricting access to specific ports or IP addresses.

Using a dedicated virtual network also makes it easier to manage networking configurations, such as setting up DNS records, configuring load balancers, and creating private endpoints. All of these features help to ensure that your AKS cluster is secure and properly configured.

2. Create subnets to isolate pods and services

Creating subnets allows you to segment your network into different logical areas, which helps improve security and performance. By isolating pods and services in their own subnet, you can control access to them more easily and prevent malicious traffic from reaching them. Additionally, by creating separate subnets for each type of service or pod, you can ensure that they have the resources they need without competing with other services or pods. This will help keep your AKS cluster running smoothly and efficiently.

3. Use Azure CNI instead of kubenet

Azure CNI is a container networking interface that provides advanced features such as network policy enforcement, service discovery, and load balancing. It also allows for more efficient use of IP addresses by using an overlay network instead of assigning each pod its own IP address. This makes it easier to scale your cluster without worrying about running out of IPs.

Kubenet, on the other hand, does not provide these advanced features and can be difficult to manage at scale. Therefore, if you are looking for a reliable and scalable AKS networking solution, Azure CNI is the way to go.

4. Enable IP forwarding on the nodes

IP forwarding allows the nodes in your AKS cluster to route traffic between different subnets. This is important because it enables communication between services running on different nodes, as well as allowing external access to applications running inside the cluster.

To enable IP forwarding, you’ll need to edit the /etc/sysctl.conf file and add the following line: net.ipv4.ip_forward=1. Once this is done, you can then run the command sysctl -p to apply the changes. After that, IP forwarding should be enabled and working correctly.

5. Configure your own DNS server

By default, AKS uses Azure’s DNS server for name resolution. This is fine in most cases, but if you need to access resources outside of the cluster (e.g., databases or other services), then you’ll need to configure your own DNS server.

Configuring your own DNS server allows you to control how names are resolved and gives you more flexibility when it comes to accessing external resources. It also ensures that all nodes within the cluster can communicate with each other without any issues. To do this, you’ll need to set up a DNS server on an existing VM or create a new one using Azure’s Virtual Machine service. Once you have your DNS server configured, you can then point your AKS cluster to use it.

6. Disable outbound internet access for nodes

By default, nodes in an AKS cluster have outbound internet access. This means that any malicious code running on a node can potentially communicate with external systems and exfiltrate data or download additional malware.

To prevent this from happening, you should disable outbound internet access for all nodes in the cluster. You can do this by using network policies to restrict traffic between pods and services within the cluster. Additionally, you can use Azure Firewall to control outbound traffic from the cluster. By disabling outbound internet access, you can ensure that your nodes are secure and protected from potential threats.

7. Use private endpoints for public services

Private endpoints allow you to control access to your services, ensuring that only authorized users can access them. This is especially important for public-facing services like web applications and APIs, as it helps protect against malicious actors trying to gain unauthorized access.

Additionally, private endpoints help improve performance by reducing the number of hops between the client and the service. By using a private endpoint, traffic does not have to traverse the public internet, which can reduce latency and increase throughput.

8. Connect your cluster to an existing VNet

When you connect your AKS cluster to an existing VNet, it allows for secure communication between the nodes in the cluster and other resources within the same network. This is especially important if you have sensitive data or applications that need to be kept private. Additionally, connecting your cluster to a VNet also gives you more control over how traffic flows into and out of the cluster, allowing you to better manage security policies and access controls.

9. Limit pod traffic with Network Policies

Network Policies allow you to control the traffic between pods in your cluster, which is essential for security and compliance. By limiting pod traffic, you can ensure that only authorized services are able to communicate with each other, reducing the risk of malicious attacks or data leakage.

Network Policies also help improve performance by ensuring that only necessary traffic is allowed through. This reduces the amount of unnecessary network traffic, allowing applications to run more efficiently.

Finally, Network Policies provide an additional layer of visibility into your AKS environment. By monitoring the traffic between pods, you can gain insight into how your applications are communicating and identify any potential issues.

10. Use Calico for advanced networking features

Calico is an open source networking and network security solution that provides a highly scalable, secure, and reliable way to connect Kubernetes clusters. It offers features such as policy-based routing, service mesh integration, and advanced traffic management capabilities.

Calico also supports multi-cluster deployments, allowing you to easily manage multiple AKS clusters from one central location. This makes it easier to deploy applications across multiple clusters, while still maintaining the same level of security and control. Additionally, Calico’s built-in support for Network Policy allows you to define rules for how different services can communicate with each other, providing an extra layer of security.