What is Kubernetes?

Kubernetes (known as K8s) automates containerized application deployment, scaling and management. 

It orchestrates containers across clusters of machines everywhere — on-prem, the cloud or in a hybrid environment.

Kubernetes builds resilience, scalability and security into your infrastructure. 

However, it's dynamic, and its distributed architecture introduces unique security complexities that need specialized management and continuous visibility.

Even still, Kubernetes is the de facto standard for container orchestration. 

Whether managing microservices, running batch jobs or building cloud-native apps, Kubernetes helps you control complexity while scaling your infrastructure.

You can use Kubernetes to run containerized workloads across distributed infrastructure. That includes everything from simple web applications to complex, multi-service platforms. 

K8s gives you the power to deploy and scale applications for every environment, without manual configuration.

With Kubernetes, you can:

• Automate deployment pipelines in your CI/CD workflow
• Scale microservices based on demand and resource usage
• Manage infrastructure costs by optimizing container density
• Run hybrid and multi-cloud environments without vendor lock-in
• Reduce downtime using built-in failover and self-healing

Kubernetes is widely adopted in modern application development and security, making it a critical component for your technology stack and for building and securing cloud-native applications.

Ready to align your Kubernetes usage with cloud risk strategy? Learn how to prioritize security in your deployment model.

A Kubernetes cluster is the foundation of how Kubernetes works. 

It includes:

• A control plane, which makes global decisions like scheduling workloads and responding to cluster events.
• One or more worker nodes, which run the pods that hold your containers.

Your cluster is what lets you deploy once and run anywhere. 

But it's also where most misconfigurations happen, especially when you have exposed API servers, over-permissioned nodes or your role-based access control (RBAC) rules are too broad. 

Identifying and remediating these configuration flaws requires continuous assessment of the cluster's deployed state and security posture.

Tenable Cloud Risk Report 2024 found that 78 percent of organizations have publicly accessible Kubernetes API servers. 

Sometimes, attackers only need a few minutes to exploit these exposures and move laterally into your cloud infrastructure.

Kubernetes follows a modular, distributed architecture. 

Its components work together to orchestrate containers. 

K8’s core building blocks include:

• Pods, the smallest deployable units in Kubernetes
• Services, which expose pods to traffic inside or outside the cluster
• Ingress, which manages external access to services
• etcd, a key-value store that holds cluster configuration and state
• Kubelet, which runs on each node and communicates with the control plane
• Kube-scheduler and kube-controller-manager, which automate workload management

You can scale and update workloads declaratively using YAML manifests and let Kubernetes maintain the desired state, even if parts of your environment are offline.

Kubernetes architecture gives you declarative automation, but it's also where your attack surface grows as your clusters scale.

Kubernetes works by constantly comparing the current state of your workloads to the desired state you've defined in your configuration files. 

When the two don't match, it takes automated actions to fix the difference.

For example, if a node fails, Kubernetes schedules the affected pods onto healthy nodes. 

If a new version of your application is available, Kubernetes rolls out the update without downtime, using strategies like rolling updates or blue-green deployments.

Kubernetes also integrates with your monitoring, logging and policy tools. It is ideal for shift-left security, especially when paired with CI/CD pipelines. You can embed security checks directly into development and deployment workflows to prevent issues before they reach production.

Want to enforce policies before deployment? See how Tenable integrates security into every stage of your development lifecycle.

A container is a lightweight, standalone software package that includes everything you need to run a process: code, runtime, libraries and dependencies. 

In Kubernetes, containers run inside pods, which group them for deployment and networking.

Containers make your workloads portable and consistent, but also introduce new risks, especially when:

• Containers run in privileged mode, giving them full access to the host
• Workloads lack runtime isolation
• Containers pull from unverified images

Tenable Cloud Risk Report 2024 shows that 44 percent of organizations run containers in privileged mode. That dramatically increases the risk of privilege escalation, especially when attackers already have access to vulnerable APIs or service accounts.

Docker and Kubernetes work closely together in many environments.

Docker is a container engine. It packages your applications and runs them as containers. 

Kubernetes is a container orchestration system. It deploys and manages those containers across a cluster.

Although Kubernetes formerly depended on Docker as its runtime, it now supports other engines like containerd through the Container Runtime Interface (CRI).

As of Kubernetes 1.24, the Kubernetes community and project maintainers removed Docker Engine's direct integration as a container runtime. The most current version of Kubernetes is 1.33.

Just remember, you should always monitor for:

• Excessive container permissions
• API misconfigurations
• Unverified image sources
• Outdated runtime components

To address these interconnected risks, you need a unified view that encompasses both the container image layer and the orchestration layer.

If you're new to Kubernetes, the fastest way to get started is to deploy a local cluster with Minikube or kind. 

These tools run K8s locally, so you can test deployments before pushing to production.

Basic steps:

1. Install Minikube or kind.
2. Write a deployment manifest in YAML.
3. Use kubectl to apply the deployment.
4. Expose the application as a service.
5. Scale pods up or down to simulate real-world loads.

Use this hands-on workflow to learn how Kubernetes schedules pods, enforces configurations and responds to failures. It's the foundation for automating at scale and securing your environment before production.

Ready to test Kubernetes security? Try Request a demo of Tenable Cloud Security.

Kubernetes is powerful, but it's not the only way to run containers. 

You may use alternatives like:

• Docker Swarm, for simpler orchestration
• Nomad, for mixed workload types
• K3s, a lightweight Kubernetes distribution
• Managed services

Each has tradeoffs in performance, portability and security. If you're struggling to manage Kubernetes complexity, consider whether a managed solution could better meet your use case, especially for smaller teams.

Managing vulnerabilities in Kubernetes goes far beyond traditional image scanning. 

Containers are just one layer. The Kubernetes control plane, the cluster configuration and workload runtime behavior all introduce different risks.

While tools may flag CVEs in container images, they often miss excessive cluster-admin bindings, exposed kubelet APIs or workloads running in privileged mode. These are the exact risks attackers use to escalate privileges.

A complete Kubernetes vulnerability management strategy includes:

• Real-time visibility across the cluster.
  • Kubernetes workloads are often ephemeral. Pods spin up and disappear in seconds. If you don’t directly integrate your vulnerability scanner with your Kubernetes environment, it will miss critical risks.
  • A Kubernetes-native approach provides continuous visibility into both static configurations and dynamic live workloads.
• Continuous scanning across layers.
  • You're not just scanning application code. You're assessing:
    • Base image vulnerabilities
    • Runtime misconfigurations
    • Control plane components (like etcd and the API server)
    • RBAC rules and service account tokens
    • Policy enforcement using trusted benchmarks
• Security checks with frameworks like the CIS Kubernetes Benchmark and Pod Security Standards.
  • These establish guardrails across environments for consistent vulnerability posture from dev to prod.
• Shift left with CI/CD integration.
  • Modern Kubernetes environments are automated. Your vulnerability checks should be too. Tenable integrates security into CI/CD pipelines to help you block misconfigured YAML files, vulnerable images or over-permissive settings before they ever reach a cluster.
• Risk-based prioritization.
  • Tools like Tenable Cloud Security score risks based on the live environment by correlating configuration flaws with active network exposure and potential attack paths. That means prioritizing a known exploit path with active exposure over a low-severity CVE in an isolated container.

With Kubernetes, vulnerability management is as much about configuration as it is about code. You need a platform that combines static analysis with live context and remediation guidance, tailored to how your clusters actually behave.

Want to operationalize Kubernetes vulnerability management? See how Tenable delivers unified visibility and risk-based prioritization.

As you scale Kubernetes across environments, you also scale your attack surface. 

Clusters are dynamic. Pods, namespaces and services constantly change. 

Without centralized visibility, it's nearly impossible to understand your full exposure.

Exposure management in Kubernetes starts with identifying the places where attackers gain initial access. 

According to the Tenable Cloud Risk Report 2024, of the 78 percent of organizations with Kubernetes API servers exposed to the public internet, 41 percent allow inbound access. 

These exposures are rarely intentional, but they're exactly what attackers exploit.

Kubernetes creates unique exposure layers, including:

• Public-facing API servers with weak or missing access controls.
• Misconfigured ingress controllers that forward external traffic to internal services.
• Overused public groups like system:authenticated that expand trust boundaries.
• Rarely segmented open internal traffic paths between pods and nodes.

These issues are challenging to find if you’re using traditional tools. That's why exposure management for Kubernetes depends on visibility into both infrastructure and orchestration layers.

You need to see how you’ve configured a Kubernetes cluster, where you’ve exposed workloads and how network policies either reduce or amplify risk. 

It's not enough to scan static resources. You also need context-aware discovery that continuously maps new exposures as clusters scale and workloads shift. This gives you insight into potential attack paths from external exposure to internal resource vulnerabilities.

Effective tooling integrates directly with the Kubernetes API, monitors for policy violations and flags toxic combinations, like over-permissive roles combined with a reachable API endpoint.

If you're running containers in production, you've probably already felt the pain of trying to keep everything secure. 

Kubernetes is powerful, but it can get messy fast. 

One day, you're cruising along, and the next, someone points out that your pod has way too many permissions or your network policies have holes you could drive a truck through.

That's basically why Kubernetes security posture management exists. 

Here's what usually happens without KSPM: 

• Your developers move fast, spinning up new services, tweaking configurations.
• Security reviews happen later, if at all.
• Meanwhile, misconfigurations pile up. Some are harmless, but others make headlines when someone, like an attacker, finds them.

KSPM flips this around. 

Instead of applying security after the fact, you get continuous visibility into what's actually happening in your clusters. 

It's like having a security expert constantly looking over your shoulder, but without the awkward breathing down your neck.

KSPM process

First, KSPM figures out what you actually have running, even apps and services you don’t know about. 

Then, it compares your real configurations against security best practices and your internal rules. 

The smart part is how it prioritizes findings. Not every misconfiguration is a critical issue, so it helps you focus on what actually matters.

Good KSPM tools help you understand why a security issue is a problem and what you should do about it. 

Plus, they track whether you're actually getting better over time or just treading water.

This isn't the same thing as regular cloud security tools, like cloud security posture management (CSPM). Those look at your broader AWS or Azure setup, like IAM roles, network configs, etc. 

KSPM gets granular into Kubernetes specifically. It understands how pods talk to each other, what cluster-level policies mean and ways Kubernetes can surprise you.

When looking for a KSPM solution, skip anything requiring you to install agents everywhere. You've got enough moving parts already. 

Look for a KSPM platform that integrates with your teams’ workflows instead of forcing workarounds.

The real win happens when KSPM becomes part of your regular development process. 

Instead of security being something that happens somewhere else, after the fact, developers get feedback right in their pull requests. 

The reality is, container security isn't going away. If anything, it's getting more complex as these environments grow. 

You can either stay ahead of it with something like KSPM or keep playing catch-up every time something goes wrong.

What is Kubernetes in simple terms?
Kubernetes, in simple terms, is a platform that automates how you run applications in containers. Also known as K8s, Kubernetes helps you scale and manage containers across cloud or on-prem systems.

Can Kubernetes run without Docker?
Yes. Kubernetes can run without Docker. It now uses containerd or other runtimes by default. Docker is no longer a required dependency.

What's the difference between containers and Kubernetes?
Containers package your code. Kubernetes manages how and where those containers run.

Is Kubernetes hard to learn?
Kubernetes has a learning curve, but tools like Minikube and tutorials help you get started quickly.

Does Kubernetes work on Windows?
Yes. You can run Kubernetes on Windows using tools like Docker Desktop or WSL 2.

Kubernetes unlocks scalability and automation, but only when you properly configure and secure it. Missteps in RBAC, network policies or runtime permissions can expose your business to serious threats.

Simplify Kubernetes security with confidence. Get started with Tenable Cloud Security.