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Mastering Kubernetes in on-premises environments

Mastering Kubernetes in on-premises environments

Jan 16, 2024

Oshrat Nir
Developer Advocate

In the era of cloud computing, Kubernetes has emerged as a true cornerstone of cloud-native technologies. It’s an orchestration powerhouse for application containers, automating their deployment, scaling, and operations across multiple clusters. Kubernetes isn’t just a buzzword; it’s a paradigm shift that underpins the scalability and agility of modern software.

While Kubernetes is often associated with the cloud, its adaptability for on-premises infrastructures is a testament to its versatility. Companies that prefer or require on-premises deployments for regulatory, security, or data sovereignty reasons increasingly turn to Kubernetes to leverage cloud-native capabilities within their controlled environments.

Kubernetes has proven to be more than capable of bridging the gap between traditional setups and the dynamic, micro-service architecture that cloud-native practices advocate for. The CNCF Annual Survey 2022 provides a glance into this trend, highlighting the growing adoption of Kubernetes in on-premises settings. For startup-level organizations, 22% use private cloud for their Kubernetes infrastructure, while for larger organizations, with more than 5,000 employees, this figure is 15%.

Data center and cloud architecture by organization size
Figure 1: Data center and cloud architecture by organization size (Source: CNCF Annual Survey 2022)

This blog post seeks to inform and equip technical practitioners with deep insights into securing Kubernetes in an on-premises context. 

So, let’s embark on this journey together through Kubernetes, from cloud to core.

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Kubernetes: bridging on-premises and cloud-native worlds

At its core, Kubernetes is a platform-agnostic container orchestration system. It’s designed to run anywhere—from your local development machine to high-scale production environments in the cloud and, crucially, on-premises data centers. On-premises Kubernetes is not a mere transplant of its cloud counterpart; it’s a specialized incarnation tailored to address the unique constraints and possibilities of an organization’s private infrastructure.

Kubernetes is a convergence point for traditional practices and cloud-native innovation in these environments. It offers on-premises infrastructures the flexibility to deploy applications with the speed and agility typically associated with the cloud while maintaining the governance, compliance, and security requirements that characterize on-premises solutions.

Benefits of a cloud-native approach for on-premises users

There are many benefits of adopting Kubernetes on-premises. It enables teams to:

  • Deploy applications faster by leveraging containerization and Kubernetes’ powerful orchestration capabilities
  • Scale resources dynamically in response to application demands, just as they would in the cloud
  • Streamline operations with Kubernetes’ self-healing features, such as automatically restarting failed containers and distributing loads to maintain service continuity
  • Improve resource utilization by managing underlying infrastructure more efficiently, ensuring that applications use the optimal amount of resources

These advantages are not merely theoretical. They represent tangible gains in productivity, cost-efficiency, and agility that can significantly impact an organization’s operational dynamics.

Challenges faced by on-premises infrastructures in adopting cloud-native practices

Adopting Kubernetes on-premises comes with a unique set of challenges.

Lack of cloud vendor management

Unlike cloud-hosted solutions, many on-premises setups are not directly managed by cloud vendors. This means that setting up a Kubernetes cluster often involves a more hands-on, vanilla approach that requires in-depth knowledge and manual configuration.

Hardware management 

In contrast to cloud environments, on-premises infrastructures require manual hardware provisioning and management; this can be both time-consuming and resource-intensive.

Networking complexity 

Setting up networking for Kubernetes on-premises is more complex, frequently requiring deep integration with existing network infrastructure; organizations must also address challenges such as overlay networking and ingress control. 

While ingress control is a common aspect across cloud-native environments, its implementation in on-premises setups poses specific challenges. In these environments, ingress must be carefully configured to work seamlessly with the existing network architecture, which often includes legacy systems and custom configurations.

Storage considerations

Persistent storage in on-premises environments must be carefully managed to provide stateful applications with the robustness they need; this often necessitates integration with existing SAN/NAS solutions or distributed storage systems.

These challenges underscore the need for a nuanced approach to Kubernetes on-premises, one that respects existing investments in infrastructure and expertise while navigating toward a more agile and automated future.

How Kubernetes addresses specific on-premises requirements

Kubernetes is not a static entity; it’s a continuously evolving ecosystem that adapts to the needs of its users. To address the specific requirements of on-premises environments, Kubernetes has grown to support a variety of add-ons and integrations, including:

  • Customizable networking solutions: Tools such as Calico, Flannel, and Weave provide flexible networking options that can be tailored to the specific needs of an on-premises deployment.
  • Storage orchestration: Kubernetes supports a range of storage solutions, including local storage, Network File System (NFS), and more sophisticated dynamic provisioning options through the Container Storage Interface (CSI).
  • Extensibility and customization: Operators and Custom Resource Definitions (CRDs) enable organizations to extend Kubernetes with custom resources and management logic, providing the control necessary for on-premises deployments.

Through these capabilities and more, Kubernetes not only bridges the gap between on-premises and cloud environments but also enables a new paradigm of infrastructure management that is resilient and adaptable to change.

In the next section, we will explore the difficulties in managing Kubernetes in an on-premises setting, looking at the role of various Kubernetes providers and the shared responsibility model in these deployments.

Managed Kubernetes Services: a gateway to simplified on-premises management

Kubernetes has been adopted in on-premises data centers through the support of a growing ecosystem of service providers. While cloud service providers (CSPs) offer managed Kubernetes solutions, the on-premises landscape is enriched by specialized entities such as Rancher/SUSE, VMware vSphere, and Red Hat OpenShift. These providers extend Kubernetes’ reach beyond the cloud, bringing its benefits into the data center.

A multitude of smaller, cloud-agnostic companies such as Giant Swarm and Platform9 also contribute to this diversity, offering fully managed experiences tailored to on-premises needs. These solutions are designed to ease the operational burden, providing a Kubernetes experience that balances the control of on-premises with the convenience of the cloud.

Additionally, the major CSPs also provide managed offerings on-premises, namely, Google Cloud Anthos, Azure Arc, and Amazon EKS Anywhere. These solutions are very attractive for organizations that run on CSP-managed Kubernetes in the cloud and can extend it to on-premises, effectively creating a hybrid cloud solution. However, these will not be the best solutions for air-gapped environments.

Navigating the complexities of on-premises Kubernetes

Managed Kubernetes services are increasingly becoming the gateway for organizations to adopt Kubernetes on-premises without the complexity of setting up and maintaining the entire stack. These services typically provide:

  • Streamlined installation and upgrades to simplify the setup and maintenance of Kubernetes clusters with automated processes
  • Enhanced security features that offer robust security configurations out of the box, which is critical for on-premises deployments
  • Support for multi-cluster operations, which enables governance and operational efficiency across multiple clusters, whether on-premises or in the cloud
  • Access to expertise and support to guide organizations through the intricacies of Kubernetes operations

Key security aspects in on-premises Kubernetes

Securing an on-premises Kubernetes environment entails protecting various system components. Let’s review the crucial areas that need strict security measures and the best practices to safeguard your Kubernetes infrastructure.

etcd encryption: a cornerstone of Kubernetes security

The etcd database is the heart of a Kubernetes cluster, storing all of the system and service states. Securing etcd is not optional; it’s imperative. Encryption of etcd data at rest prevents unauthorized access to this sensitive information and is a fundamental security practice.

Guidelines for setting up etcd encryption and pitfalls to avoid

  • Utilize Kubernetes’ built-in support for data encryption at rest to encrypt sensitive resources before they are saved.
  • Employ strong encryption standards, such as AES-CBC or AES-GCM algorithms, to ensure the confidentiality of the data.
  • Avoid using the same encryption key for an extended period. Regularly rotate keys to minimize risks associated with key compromise.
  • Ensure that backups of the etcd database are also encrypted. An unsecured backup can be as vulnerable as an unencrypted database.

Securing the API server: beyond the basics

The Kubernetes API Server acts as the front door to your cluster, making its security configuration a top priority.

Guidelines for a hardened API server configuration

  • Enforce authentication and authorization mechanisms and add the native RBAC (role-based access control) layer, ensuring that only permitted users and services can access and perform operations on the cluster.
  • Enable audit logging to keep a comprehensive record of all requests made to the API server, which is crucial for post-incident analysis.
  • Implement monitoring solutions to watch for suspicious activities or configuration anomalies.
  • Regularly audit API server logs and use tools such as Falco or kube-bench for ongoing security assessments.

kubelet configuration: ensuring node integrity

The kubelet serves as the primary node agent. It manages the state of each node, making sure your containers are running properly.

Best practices for kubelet security configurations

  • Secure the kubelet’s communication with the API server using TLS encryption.
  • Restrict kubelet permissions by minimizing the use of privileged containers and Pod Security Admission.
  • Implement automated update processes for the kubelet to make sure it is running the most recent and most secure versions.
  • Use tools like kured or a robust CI/CD pipeline to manage these updates automatically.

Inter-component communication: safeguarding with TLS

Securing communication between Kubernetes components is crucial to prevent man-in-the-middle attacks and unauthorized data access.

Components (API server, scheduler, controller manager, etc.) must communicate over secure channels to ensure the integrity and confidentiality of their interactions.

Implementing TLS for inter-component communication

  • Employ TLS for all communication paths within the cluster. Ensure that all components validate the TLS certificates of the components they communicate with.
  • Use strong cipher suites and the latest version of TLS (currently 1.3) to ensure the most robust encryption.
  • Deploy mutual TLS (mTLS) for all service-to-service communications to enforce bidirectional verification of communications.
  • Automate the rotation of TLS certificates to reduce the risk of compromise.
  • Utilize tools like cert-manager for managing certificate issuance and rotation within the cluster.

Let’s extend our discussion to advanced security measures that can further bolster the security posture of an on-premises Kubernetes cluster. We will discuss implementing robust TLS protocols, key rotation practices, and maintaining high-security standards in a dynamic environment.

Advanced security measures for Kubernetes

A dynamic environment like Kubernetes, where containers are constantly created and destroyed, requires continuous vigilance to maintain high-security standards.

Strategies for staying ahead of security vulnerabilities

  • Implement a continuous security monitoring solution that can detect vulnerabilities in real-time.
  • Subscribe to security bulletins and keep abreast of new vulnerabilities and patches related to Kubernetes and container technologies.

Using admission controllers to enforce security policies

  • Admission controllers in Kubernetes allow organizations to define and enforce governance and best practices throughout the cluster lifecycle.
  • They can restrict actions that don’t comply with the organization’s security policies, such as preventing the creation of containers with elevated privileges.

Continuous security assessment: tools and practices for regular audits

  • Conduct regular security assessments with tools like Kubescape or ARMO Platform, which can scan for vulnerabilities, misconfigurations, and compliance with security policies.
  • Perform penetration testing and security audits regularly to uncover potential weaknesses that automated tools might miss.

Conclusion: making the most of Kubernetes on on-premises

Organizations must see Kubernetes as a strategic asset. On-premises users benefit from the agility, scalability, and resilience that Kubernetes offers, enabling them to compete in a digital economy while meeting stringent security and compliance requirements. It facilitates a cloud-native approach that is seamlessly integrated with existing infrastructure, bridging the gap between the old and the new, the traditional and the innovative.

Embracing Kubernetes on-premises can be transformative for organizations willing to invest in its potential. With the right approach, tools, and mindset, Kubernetes can drive your on-premises infrastructure into the future of cloud-native computing.

For those ready to take their on-prem installations to the cloud-native world, don’t forget the importance of securing their Kubernetes infrastrcuture. ARMO Platform offers an end-to-end Kubernetes security solution that cuts through the noise and brings you the insights and guidance you need, whether on-prem or in the cloud. Join the ranks of security-minded enterprises and start your ARMO experience today.

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