Top Kubernetes Security Best Practices
Since its first release, Kubernetes adoption has grown exponentially. As it helps improve efficiency and agility, it's now one of the popular ways to deploy applications.
However, Kubernetes is insecure by design. The cloud also adds another layer of complexity. But the good news is that developers and engineers can follow security best practices to boost their security posture.
For example, they can shift security left and enforce policy-as-code to fortify their Kubernetes environment. This approach helps automate continuous monitoring to achieve robust security.
Enforcing policy as code also helps DevOps teams apply governance standards across clusters with a single click. You can also seamlessly deploy enterprise policy checks across cloud environments with rules that meet your specific requirements.
At Magalix, we're serious about containers and security. So we put together a list of our top 8 security best practices for Kubernetes development.
1- Use Policy-as-Code to Enforce Resource Management
When it comes to Kubernetes best practices, efficient and proactive resource management is vital. This approach helps establish predefined limits on resources used by both pods and containers. It's the best way for DevOps teams to manage the production environment and enhance both operations and security.
In this scenario, you can use policy-as-code tools to scan configurations and identify any that don't comply with your codified policies. These policies help ensure that pods specify how much CPU resources are needed and define a limit for CPU consumption (in worst-case scenarios). In this case, the scheduler will place the workload on an appropriate node and circumvent starving tenants.
The container runtime and Linux offer a variety of capabilities for processes to use, but these should be established with fine-grained permissions. Just like limiting the containers' resources, it's also important to limit the containers' capabilities at runtime. This is because it can increase access to the container runtime daemon and host system. By limiting capabilities, you essentially contain workloads within the container.
If a Kubernetes application manages to break out of a container, it may enable workloads to access the node upon which it runs. This enables access to Kubernetes secrets that can allow entry into the control pane and other nodes.
2- Never Assume Security by Default
When it comes to technology, you should never take security for granted. The same is true for Kubernetes. Even if your containers are hosted and managed on one of the leading cloud provider's environments, you must take a proactive approach to stay on top of potential vulnerabilities.
Managed services providers often provide default security controls when you sign up. But securing the default platform by itself isn't enough. This is because individual applications and their configurations increase your exposure to risk.
In different sectors like finance and healthcare, security is also tied closely with regulatory compliance protocols. In this scenario, you can also use policy-as-code to ensure that your use cases are within the required parameters defined by the governing body.
3- Deploy Proper Controls
Companies that put Kubernetes into production must always deploy additional security controls. So, when you change your default security settings, it's crucial to understand what types of controls are available and implement those that best suit your project.
However, proper controls over your environment demand complete visibility into the deployment environment and the applications that run there. This is critical when deploying business-critical applications to avoid potential downtime. You must know how each pod communicates with others over the network. You must also know what's going on within each pod.
Disable Public Access
To avoid exposure over the internet, try to work with private nodes whenever possible. If you're running Kubernetes in the cloud, make sure to disable public access to the API control pane.
If you haven't already done this, do it immediately. This is because a hacker with access to the API will have complete access to sensitive data stored within the cluster. So, it's best to use a direct connection to access the nodes and other infrastructure resources. Alternatively, you can also configure a VPN tunnel or use a bastion host.
Enforce Role-Based Access Control
Consistently implement the least privileged principle and close all entry points by default. Whenever you must expose a service to the internet, use an API gateway or a load balancer with only the required ports.
Plan according to your workload permission needs and enforce RBAC. With RBAC, everything is denied by default. However, you can enable API access, granting granular permissions to specific users.
4- Validate Images
You can also use the access controller to add an extra layer of protection through validation. As your application scales, it's critical to automate enforcement-specific security policies in the clusters. This approach will help ensure that containers always pull images from authorized repositories.
DevOps teams must always scan images and lock things down. They should also go through them and ensure that each image they pull does what it's supposed to do. As hackers have become increasingly stealthy at embedding malware, especially cryptojacking software, it's imperative to validate images before loading applications.
5- Segregate Sensitive Workloads
It's also a good idea to leverage features like namespaces, taints, and tolerations in Kubernetes to segregate sensitive workloads. Once segregated, you can further apply highly restrictive policies and best practices to those workloads.
As security incidents hog the headlines almost daily, organizations must also adopt a proactive security culture by embracing a multi-layered security approach whenever possible.
6- Take Multi-Layered Security Approach
Cloud-native applications have a myriad of components and elements. As such, Kubernetes and container deployments are often complicated.
Like traditional software development architectures, there's no uniform security protocol that covers all potential scenarios. As a result, always take the security by default approach and improve defenses by following best practices.
While it's certainly challenging, you should always use different tools to secure and protect each layer. This makes it vital to understand how each layer works and apply proper security protocols.
7- Enforce Network Policies
You can use network policies and have them work like admission controllers or internal firewalls. You can configure your network access policies at the networking layer of the pod. Through label selectors, you can limit access to pods.
When setting up network policies, you must configure the label and value requirements to enable seamless communication with a service. This approach can also be leveraged to prevent egress traffic to all containers and pods (except the DNS registry). This approach also helps limit access to the instance metadata API.
8- Shift Security Left
You can also programmatically enforce security by integrating policy-as-code within DevOps workflows. This approach helps create developer-centric experiences and the continuous deployment for cloud-native applications.
For example, DevOps teams can establish "automated operators" within your cloud infrastructure or Kubernetes cluster to continuously monitor the repositories for changes. Whenever there's a change, an automatic update is triggered.
Whenever you shift security left and enforce policy-as-code, you normalize hybrid environments and achieve exceptional governance levels in all clusters from a single source of truth.
It's also best to create a centralized playbook to enact and enforce security protocols across the software development lifecycle. This approach helps accelerate innovation while maintaining a robust security posture.
By shifting left and improving transparency between teams, you can build a sustainable governance framework. This approach helps DevOps teams receive timely inputs, help developers get automated feedback on their code and ascertain your overall security posture.
At Magalix, we help enterprises define, manage, and deploy custom governance policies as policy-as-code using a robust OPA policy execution engine. We also help DevOps teams implement proper workflows and playbooks to ensure security and compliance.