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Azure Kubernetes Service on Azure Stack HCI (AKS-HCI) is an on-premises implementation of the popular Azure Kubernetes Service (AKS) orchestrator, which automates running containerized applications at scale. AKS on Azure Stack HCI enables developers and admins to deploy and manage Linux and Windows containerized apps on Azure Stack HCI.


With AKS-HCI, enterprises can take advantage of consistent AKS experience across cloud and on-premises environments, extend to Azure with hybrid capabilities, run apps with confidence through built-in security, and use familiar tools to modernize Windows apps. For a more detailed overview of AKS-HCI capabilities, refer to this blog.


One of the core strengths of AKS-HCI is using security-first approach. At Microsoft, we believe that leading with strong security posture is table stakes for an enterprise-grade offering. Our security roadmap is comprehensive, starting with a mindset of placing strong protection guardrails and bolstering that with industry-hardened threat detection, and remediation and recovery. The protection-related hardening is built into AKS-HCI. To bring threat detection and remediation, and we integrate with security management systems such as Azure Security Center.



Figure 1. Securing AKS-HCI Deployment


In this blog, we will describe the security capabilities in AKS-HCI. These security features are not available in the current public preview version, but these and more will be released in the lead-up to general availability.


Secure image baseline and container protection


Microsoft provides a secure baseline for Windows and Linux container host images and services the updates of those images to maintain consistency and standards.




Figure 2. AKS-HCI implemented with hypervisor isolation


AKS-HCI is designed such that every layer is secure. The container host is deployed as a virtual machine. Each tenant cluster runs on its dedicated set of container hosts and uses the same strong Hyper-V-based isolation used in Azure which provides the strong kernel isolation among the container hosts.  


In addition, AKS-HCI has multiple layers of protection built in. The first cluster to be bootstrapped is the management cluster, which is then used to bootstrap other tenant clusters. The container pods are run within Hyper-V virtual machines, enforcing strong isolation guarantees wherein the impact of a compromised container or pod is contained within the Hyper-V VM itself.


Identity and access management (IAM)


AKS-HCI integrates with Active Directory (AD), providing strong identity and facilitating seamless single sign-on (SSO) to manage the AKS-HCI environment and deploy the container workloads. Additionally, there is provision for Windows containerized application workloads to be bootstrapped with group Managed Service Account (gMSA) identity. gMSA is an AD-managed service account for which the passwords are automatically rotated.


Secure communication and secrets Management


Communication between the control plane components is protected by Transport Layer Security (TLS). AKS-HCI comes with zero-touch, out-of-the-box provisioning, and management of certificates for the infrastructure and Kubernetes built-in components. Additionally, the Kubernetes secrets are encrypted at rest using strong Advanced Encryption Standard (AES), with the ability to rotate the key encryption keys (KEK).


Integration with Azure security assets


AKS-HCI is integrated into the Microsoft security ecosystem, which allows extending Azure security constructs such as Azure Container Registry and Azure policies. In the future, integration with Azure assets like Azure Security Center will provide customers the ability to monitor for threats and offer pre- and post-runtime security assessments for both the infrastructure fabric and the Kubernetes cluster. This helps in monitoring for threats and keeping a strong security posture.


Join us in this journey


Security is a journey, not a destination. These are just some of the security features that we are working on and making generally available (GA) soon. AKS-HCI is going to be continually updated like a service. We will add more security features and continue to further harden the platform. Join us in this journey: we would love to hear feedback, experience, and insights on security. Be part of discussions in our Github repository.


Brought to you by Dr. Ware, Microsoft Office 365 Silver Partner, Charleston SC.