Kubernetes has emerged as the de facto leader in container orchestration, revolutionizing how we deploy, scale, and manage containerized applications. As businesses increasingly adopt microservices architectures and containerized applications, Kubernetes has become an indispensable tool in modern infrastructure.

As with any system, the more widely it’s adopted, the more it becomes a target for malicious actors. Kubernetes clusters, given their importance in application deployment, are no exception. A compromised Kubernetes cluster can lead to unauthorized access to sensitive data, disruption of application services, and potential misuse of resources for nefarious activities like cryptomining.

Despite the flexibility and numerous advantages Kubernetes brings with it, it also presents security challenges that cannot be overlooked. In this blog post, I introduce Kubernetes security fundamentals and best practices to secure your cluster effectively.

Kubernetes Security 101

Securing a Kubernetes cluster first requires understanding its multifaceted nature and the potential risks associated with each layer. At its core, Kubernetes is a system of multiple interconnected components, each with its specific function and potential vulnerabilities. These components range from the control plane, which manages the cluster, to the worker nodes that run the containers. Each component communicates over the network, accesses storage resources, and interacts with the Kubernetes API.

Securing your cluster effectively requires adopting a layered approach.

Kubernetes Security Best Practices

Node Security

Nodes are the workers for containerized applications of a Kubernetes cluster. They host the pods that run your containerized applications and services. Given their pivotal role, ensuring the security of nodes is paramount to the overall safety of the entire cluster. In 2018, Tesla’s Kubernetes dashboard, which was not password protected, was the victim of a cryptomining malware attack. This unauthorized access could have been prevented by ensuring node security and removing extra packages:

# Minimizing and hardening the base OS

sudo apt-get remove –purge unnecessary-package-name

Best practices for securing nodes include:

  • Minimizing and hardening the base OS
  • Removing unnecessary applications
  • Eliminating unnecessary user accounts
  • Deploying OS-hardening frameworks
  • Collecting and analyzing OS logs
  • Regularly updating and patching

Kubernetes API Security

The Kubernetes API server plays a central role in managing and operating a Kubernetes cluster. It serves as the entry point for commands sent via the kubectl command-line tool, interacts with other components, and maintains the desired state of the cluster. Securing the Kubernetes API is therefore essential.

Best practices for securing the Kubernetes API include:

  • Using role-based access control (RBAC) authorization by implementing least-privilege access:

# Using RBAC authorization for only reading pods


kind: Role


namespace: default

name: pod-reader


– apiGroups: [“”]

resources: [“pods”]

verbs: [“get”, “watch”, “list”]

  • Using admission controllers
  • Using third-party API authentication and API authorization integrations
  • Implementing network-level security for API requests
  • Collecting and analyzing audit logs

Kubernetes Network Security

In a Kubernetes cluster, the network enables interactions between pods, services, and external entities. Ensuring robust network security is crucial to safeguarding your cluster and its applications. By default, all network access is enabled within Kubernetes clusters, so implementing a deny-all network policy is a good starting point:

# Implementing deny-all network policy


kind: NetworkPolicy


name: deny-all


podSelector: {}


– Ingress

– Egress

Best practices for network security in Kubernetes include:

  • Implementing network policies
  • Securing cluster ingress and egress
  • Isolating workloads using namespaces
  • Using a trusted Container Network Interface (CNI) plugin
  • Monitoring and analyzing network traffic
  • Encrypting data in transit
  • Regularly reviewing and updating network configurations

Kubernetes Pod Security

Pods are the smallest building block in a Kubernetes cluster, encapsulating one or more containers. Ensuring their security is vital to the overall health and safety of your cluster. For instance, even if the following frontend pod is breached, attackers will be limited within the CPU and memory limits set:

# Pod with resource requests and limits

apiVersion: v1

kind: Pod


name: frontend



– name: app

image: my-frontend:v1



memory: “64Mi”

cpu: “250m”


memory: “128Mi”

cpu: “500m”

Best practices for Kubernetes pod security include:

  • Scanning container images
  • Implementing pod security policies (PSP)
  • Implementing pod security contexts
  • Using network policies for pod communication
  • Limiting resource usage with quotas
  • Regularly monitoring and auditing pod activities

Kubernetes Data Security

Data is the lifeblood of applications. In a Kubernetes environment, data can be found in various forms, from configuration data to application databases. Ensuring the confidentiality, integrity, and availability of this data is paramount to the security and functionality of the applications running within the cluster.

Best practices for securing data associated with Kubernetes include:

  • Encrypting data at rest such as secrets and configmaps:

# Example EncryptionConfiguration for secrets and configmaps


kind: EncryptionConfiguration


– resources:

– secrets

– configmaps


– identity: {}

– aesgcm:


– name: key1

secret: c2VjcmV0IGlzIHNlY3VyZA==

– name: key2

secret: dGhpcyBpcyBwYXNzd29yZY==

  • Securing data in transit
  • Using access control for data
  • Rotating and managing secrets
  • Backing up data regularly
  • Limiting exposure to sensitive data
  • Monitoring data access and anomalies

Additional Kubernetes Security Resources

While the foundational security measures for Kubernetes revolve around nodes, the API, network, pods, and data, additional tools and resources can further enhance your cluster’s security posture. These resources provide deeper insights, finer controls, and advanced protection mechanisms.

Audit Logs

Audit logs in Kubernetes provide a chronological record of security-relevant administrative actions taken on objects in a cluster. Ensure audit logging is enabled and configured on your Kubernetes API server:

# Enabling audit logging

kube-apiserver \

–audit-log-path=/var/log/kubernetes/audit.log \


In addition, regularly review these logs to track user activity, performed operations, and the source of each request to protect your Kubernetes cluster.

Namespaces for Workload Isolation

Namespaces allow for the segmentation of workloads in a cluster, providing a level of isolation between them:

# Creating a namespace for team-a

apiVersion: v1

kind: Namespace


name: team-a

This not only helps in organizing your workloads but also limits the impact of a security breach to a specific namespace. For example, a SaaS company could leverage namespaces to isolate workloads of different development teams, ensuring that a potential breach in one namespace doesn’t affect the others, thereby limiting the impact of security incidents.

Regularly Update and Patch

While a recurring theme in security, it’s worth emphasizing: Regularly update all components of your Kubernetes cluster, including worker nodes, the control plane, and any installed extensions or tools. This ensures protection against known vulnerabilities.

Training and Awareness

Make sure your team receives regular training on Kubernetes security best practices. Awareness is the first line of defense. Encourage a security culture of sharing best practices and communicating potential threats.

Disaster Recovery and Incident Response

Have a clearly defined disaster recovery plan in place. This should include backups, recovery steps, and communication plans. It’s easy to get started backing up Kubernetes resources:

# Backup script

kubectl get all –all-namespaces -o yaml > backup.yaml

Similarly, have an incident response plan detailing steps to take in the event of a security breach, including investigation, mitigation, communication, and post-incident analysis.


While the journey to securing your K8s cluster might seem challenging, it’s achievable with the proper practices, tools, and mindset. Remember, security is as much about the technology as it is about the people and processes. Equip yourself with knowledge, arm your cluster with the best tools, and always stay vigilant. Your Kubernetes cluster, applications, and organization will be all the better for it.