Kubernetes Container Policies: Enhancing Security and Efficiency
Tags: kubernetes, security, devsecops
Published: 2023-12-29 14:00:00

Microservices and cloud-native apps are all the rage these days. But
making the transition from a few containers in Docker to managing and
scaling containerized applications can be a real headache. Enter
Kubernetes (K8s). K8s is an open-source platform designed to take the
stress out of managing large-scale container deployments. In simple
terms, Kubernetes groups your application's containers into units called
**pods**. These pods make it easier to deploy and manage workloads
across multiple machines.

So then, what are K8s **container policies**? They're essentially a set
of rules that your Kubernetes pods and containers must follow. These
rules help you keep your configurations in check, beef up security, and
make the most out of your resources.

In this article, we'll dive into why container policies are a big deal
for the security and efficiency of your containerized apps. We'll also
touch on how cloud-native application protection platforms (CNAPPs) can
take your K8s security to the next level.

## What are K8s container policies, and why should you care?

Think of your K8s containers as cars zipping around a city. In this
scenario, container policies are like the traffic rules of that city.
They set the do's and don'ts for how containers behave within a
Kubernetes cluster. Container policies define who can go where, how fast
they can move around, and what they can carry. Without container
policies, your K8s cluster would have chaos, filled with resource
conflicts and security vulnerabilities.

So, it's safe to say that having container policies is non-negotiable if
you want to keep your containerized apps running smoothly.

### Types of container policies

What kinds of container policies are out there? Let’s break down the
most important ones to know about:

- **Network policies** control traffic flow, governing which pods can communicate. Want to keep some pods isolated? Network policies are your go-to solution.
- **Resource quotas** play the role of budget managers for your K8s cluster. They set limits on CPU and memory usage within namespaces, ensuring that no single application hogs all the resources.
- **Security policies** set rules on things like privilege escalation and access to host resources.

## Why are K8s container policies a big deal?

Alright. So, we have container policies in place. What’s the real
impact? Let’s see.

### Enhanced security

In today’s cloud-native landscape, security breaches are your worst
nightmare, and they’re a constant threat. Fortunately, container
policies act like your personal security detail. Let’s take network
policies, for example. Imagine a malicious container that attempts to
extract data from another container within the cluster. A network policy
can prevent this kind of breach by isolating containers and blocking
access.

### Resource optimization

What organization wouldn’t want to save money and boost performance?
Resource quotas help you do just that. They make sure no single pod hogs
all the resources. The result is predictable and efficient resource
allocation throughout your cluster, while preserving your application’s
full functionality. With properly tuned resource quotas, you’ll get cost
savings *and* optimized application performance.

## Getting started with K8s container policies

That’s pretty good for a foundational understanding of container
policies. Now, let’s walk through some concrete steps for how to get
started.

### Setting up a basic K8s cluster

To set up a K8s cluster, you can refer to a full [<u>step-by-step
guide</u>](https://www.cyberithub.com/setup-kubernetes-cluster-on-ec2-instance-using-kops/)
for creating a cluster on AWS. In summary, the key steps are:

- Provision the AWS resources, including a virtual private cloud (VPC), EC2 instances, and security groups.
- Use command-line tools like `kops` or `eksctl` to install K8s on your EC2 instances.
- Configure networking components like subnets and route tables to ensure communication within your cluster.
- Deploy a sample pod to verify that your cluster is up and running.

Setting up clusters on other cloud providers is equally straightforward.

### Examples of policy setup

Here are some examples of container policy implementation.

#### Network policy

Suppose you want to enforce a network policy that allows specific pods
to communicate with one another. Let’s look at the following definition
in YAML:

```yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-frontend-backend
spec:
  podSelector:
    matchLabels:
      role: frontend
  policyTypes:
  - Ingress
ingress:
  - from:
    - podSelector:
        matchLabels:
          role: backend
```

In this example, the network policy allows traffic from pods labeled
`backend` to reach pods labeled as `frontend`. This effectively isolates
certain pods, restricting which ones can access the frontend.

### Resource quota

Resource quotas ensure that your pods do not consume excessive
resources. Here's an example:

```yaml
apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-resources
spec:
  hard:
  pods: "10"
  requests.cpu: "4"
  requests.memory: 4Gi
  limits.cpu: "8"
  limits.memory: 8Gi
```

In this policy, we restrict the number of pods to 10. Then, we set
limitations on CPU and memory usage. This ensures the proper
distribution of resources and prevents any single pod from monopolizing
them.

### Security policy

Consider the following example of a security policy:

```yaml
apiVersion: security.k8s.io/v1
kind: PodSecurityPolicy
metadata:
  name: restricted
spec:
  privileged: false
  seLinux:
    rule: RunAsAny
  supplementalGroups:
    rule: RunAsAny
  runAsUser:
    rule: MustRunAsNonRoot
```

In this example, we implement measures such as:

- Prohibiting privileged containers (privileged: false)
- Enforcing SELinuxs runAsAny rule
- Ensuring that containers do not run as the root user

Just to be clear, you can also configure some security settings for pods
and containers through the securityContext for your pod specification.
This includes setting whether or not to allowPrivilegeEscalation. For
more information, you can reference the documentation here:
[<u>https://kubernetes.io/docs/tasks/configure-pod-container/security-context/</u>](https://kubernetes.io/docs/tasks/configure-pod-container/security-context/)

The above examples are a great starting point for developing your own
K8s container policies. Depending on your requirements and use case, you
can expand these policies to align with your security context and
permissions needs.

Remember to apply these policies. You’ll use tools like `kubectl` to
update the control plane through the Kubernetes API.

## How do CNAPPs step up your K8s security game?

You've got Kubernetes up and running, and you've set up some solid
policies. But what about the more general security risks associated with
cloud-native, containerized applications? You know—the ones that keep
you up at night. This is where CNAPPs come into play. CNAPPs are your
security command centers, designed specifically for the cloud-native
world. Let's dig into how they make your life easier.

### Role in K8s security

Kubernetes is complex, no doubt about it. And with complexity comes
risk. So, how do CNAPPs help?

- **Configuration management**: Are you ever worried that you (or more likely, one of the other engineers on your team) set things up the wrong way, leaving a gaping security hole? CNAPPs automatically flag any missteps in your Kubernetes setup that could be exploited.
- **Container runtime protection**: What is happening in your containers *right now*? CNAPPs monitor container activity, alerting you or taking predefined actions if something looks fishy.
- **Network segmentation**: Are you clear and confident about who is allowed to talk to whom within your K8s cluster? CNAPPs can help you establish rock-solid network policies.
- **Vulnerability management**: Do you know what’s in your containers?  From third-party dependencies to open-source libraries, CNAPPs scan your container images for vulnerabilities to protect you from deploying anything risky.

### Securing containerized applications

Let’s step back from K8s specifically to look more generally at
containerized applications. CNAPPs help you with security here, too.

- **Threat detection**: CNAPPs continuously monitor your apps, bringing real-time threat detection and mitigation.
- **Policy enforcement**: As you define security policies, CNAPPs ensure enforcement throughout the application lifecycle.
- **Visibility and monitoring**: Your DevSecOps team needs a bird’s-eye view of your app’s security. CNAPPs provide the insights and analytics to make this possible.
- **Integration with CI/CD**: As the industry moves toward “shift left security,” it makes sense if security checks are just part of the build process. CNAPPs fit right into your CI/CD pipeline, making sure that everything in your app is secure before it goes live.

### Why should you choose Panoptica for managing your K8s policies?

[<u>Panoptica</u>](https://www.panoptica.app/) (from
[<u>Outshift</u>](https://eti.cisco.com/)) is a CNAPP solution that
helps organizations gain the upper hand in container security and
efficiency. **Continuous monitoring** from Panoptica gives you 24/7,
360-degree **visibility** into what’s happening in your K8s clusters.
**Proactive security** measures help you identify vulnerabilities and
misconfigurations before they can be exploited. And Panoptica’s
**Kubernetes Security Posture Management (KSPM)** maps out how K8s
objects relate to one another, providing you with a complete view of
your cluster's security posture.

![Panoptica Dashboard](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/h4aevqvd3q2qdl33mtk7.png)

## Wrapping up

Managing large-scale, containerized applications can be chock full of
challenges. However, with the right K8s container policies and reliable
tools like Panoptica, you’re well-equipped to face them. You not only
get robust security measures but also an optimized container ecosystem.

So, what's next? If you're looking to dive deeper into Kubernetes and
container policies, [<u>sign up</u>](https://www.panoptica.app/sign-up)
to try out Panoptica for free today. We're here to guide you through the
complexities and help you fortify your native apps against emerging
threats.