Container security best practices in production are a hot topic. They have changed the whole approach to web development. They make the process faster, more predictable, and easier to scale. But convenience does not eliminate risks. In a production environment where every failure can cost money, time, reputation, and security issues come to the fore. So, ignoring them means taking risks.

The top problems are well-known and include dangerous dependencies in images, weak access policies, and a lack of basic monitoring. And now add to this the human factor, and even a well-configured cluster can become vulnerable. Many people think that installing Docker and Kubernetes is enough. But attacks don`t wait for someone to finish reading the documentation.

That is why the modern approach to security is no longer just DevOps. It isn`t a culture of responsibility. Instructions alone are not enough to work. The system needs tools, checks, automation, and, of course, control. We examined container security in real-world conditions.

How to Scan a Docker Image for Vulnerabilities?

Even a notice can create a Docker image today. It`s fast, convenient, and seems hassle-free. But that`s where the risk lies, as you easily include dangerous packages, old dependencies with known vulnerabilities, or simply leave behind something that definitely shouldn`t go into production.

Everything may look fine on the surface, but there are real threats inside. And if you don't check the image, you are essentially launching something into the cluster that could later become an entry point for an attack.

Here are some typical examples of problem areas:

• The image is built on Ubuntu: latest, which already has a known vulnerability (CVE).
• After compilation, dev dependencies remain, which open up unnecessary possibilities.
• The image is taken from the public Docker Hub and contains an .ssh key that was left behind by someone who forgot to remove it.

Therefore, the first rule is that scanning before deployment is mandatory. Many tools allow you to automate this check before the image enters the cluster.

Top Tools to Scan Docker Images and Detect Vulnerabilities

Trivy. A simple and fast scanner from Aqua Security. Works with Docker, Kubernetes, and IaC. Ideal for CI/CD.

1. Grype. A popular open-source scanner that works well with Syft, which generates a Software Bill of Materials (SBOM).
2. Docker Scout. A built-in tool that allows you to compare images, see changes, track dependencies, and get recommendations.
3. Anchore Engine. A solution for teams that want to implement security policies and automatically stop the build when critical vulnerabilities are detected.

Integrating such scanners into the pipeline takes a few minutes. For example, Trivy in GitHub Actions looks like this:

- name: Scan image for vulnerabilities

  run: trivy image myapp:latest

However, it is also important here not just to run the scanner, but to respond correctly to its results. If you find many vulnerabilities and still continue the build, then this is not control; it is a formality. The correct approach is to stop the build immediately if there is at least one critical problem.

For this to work in real conditions, follow a few simple rules:

• Make sure your vulnerability databases are always up to date. Without up-to-date data, even the most advanced scanner will miss critical issues because it simply won't know what to detect.
• Block the use of images that have not been validated or tested. This applies not only to production but also to internal development and testing environments, as untested containers are a common source of risk.
• Collect and store scan logs and reports over time. This allows you to see security trends, helps identify weaknesses in the process, and supports decision-making to improve infrastructure or workflows.

This approach not only identifies problems but also forms a habit of thinking about security before the code enters the repository. Over time, the team begins to control the quality of images at each stage independently.

Kubernetes Security Policies: How to Configure Them for Production

Installing Kubernetes is not a problem. It can be done in an hour. But making it secure for production is a completely different story. Here, it is not speed that is needed, but consistency, discipline, and attention to detail. In a cluster where everything is allowed by default, the risks grow with each new pod.

By default, Kubernetes provides a lot of freedom. Any pod can have root access, go beyond namespaces, use resources without restrictions, and leave no traces in the logs. If you don't restrict these capabilities, you are essentially opening your infrastructure to any threats. Security in Kubernetes should be prepared from the very beginning, right from when your first deployment hits production. It’s not something to add on afterwards, but a key part of your initial setup. The earlier you start, the fewer surprises you’ll have to deal with later. Here’s what to focus on first:

1. Enable Pod Security Standards (PSS)

This is a built-in Kubernetes feature that helps define what your Pods are allowed to do. It comes in three levels:

• Privileged. This level gives full access with no restrictions. It is acceptable for testing in isolated or controlled environments. It should never be used in production because it bypasses key security boundaries.
• Baseline. This option offers a balanced approach. It blocks the most common security risks while still allowing enough flexibility for standard workloads. It is suitable for most general-purpose use cases.
• Restricted. This is the most secure configuration. It removes root access, blocks hostPath usage, and limits container capabilities. It is the recommended choice for sensitive or high-risk environments.

2. Set up policies with OPA Gatekeeper or Kyverno

These tools let you enforce custom security rules in your cluster. For example, you can:

• Require resource limits for all containers.
• Only allow images pulled from your private registry.
• Block containers that try to run as root.

They’re flexible, production-ready, and work well in CI/CD pipelines.

3. Use RBAC to manage access carefully

Kubernetes gives you fine-grained control over who can do what, but only if you use it wisely. Avoid giving broad permissions “just in case.” It’s always safer to start with minimal access and expand as needed.

4. Apply NetworkPolicies to limit Pod-to-Pod traffic

By default, any Pod can talk to any other Pod. That’s a serious risk in production. NetworkPolicies let you lock this down and define which services can talk to which, reducing your exposure.

5. Monitor whether your policies are actually working

Policies don’t mean much if no one’s watching whether they’re being followed. Make sure you track policy violations and take action when needed. Tools like:

• Kubernetes Audit Logs. Help you see what was done, when it was done, and by whom.
• Kubewarden. An alternative to Gatekeeper that runs on WebAssembly and allows more advanced use cases.
• Kubernetes Dashboard. Can be configured with read-only access for safe visibility without risk of accidental changes.

Why Real-Time Container Security Monitoring Is Essential

Even if you have isolated the environment, scanned images, and configured policies, that is not enough. Without runtime monitoring, all of this is just passive protection. Attacks most often occur after containers are launched, when everything appears to be stable.

This is when an attacker can exploit a vulnerability in one of the components, gain access to the container, extract tokens from the environment, or penetrate internal services. Therefore, runtime security is a critically important part of the overall strategy.

You need tools that monitor what is happening inside containers in real time: analyze process behavior, listen to system calls, and respond to suspicious activity.

Here are the tools that work:

1. Falco. Monitors system calls (syscalls) and alerts you to suspicious behavior, such as shell launches or access to system files.
2. Sysdig Secure. A commercial platform based on Falco with additional features: security policies, deep integration with SIEM, and active responses.
3. Aqua Runtime Protection. A component of the Aqua platform that not only detects threats but also blocks them: stops Pods, runs automatic scripts.

These systems don't simply gather logs. They identify and prevent undesirable activities on the fly. However, their efficiency depends on how well they are set up. As a result, you should take specific measures, such as avoiding ignoring notifications, even if they appear to be trivial. One of these may prove to be important. In addition, you should update regulations and policies on a regular basis. This guarantees that the system does not overlook any potential weaknesses.

To ensure that runtime monitoring is not just somewhere on the side, but part of the flow, integrate it into what you use every day. For example:

• Prometheus + Grafana for visualizing events, load, and alert triggers.
• Alertmanager for flexible routing of notifications to Slack, email, or PagerDuty.
• Webhooks for automatic actions: stopping containers, blocking IPs, creating tasks in Jira.

There is no such thing as too much security in production. And even if everything has been done correctly, without real-time monitoring, the system remains open to attack.

Conclusion

Container security is an important component of today's infrastructure, where a single setup error may cost a corporation a lot of money. It is the cornerstone of stable functioning, not something to be added later. Containers offer convenience. However, they have no direct influence over anything. They don't know if the code within is safe or if the process with root access can be trusted. The entire accountability rests with the team. This is why it is critical to adopt a methodical approach. And for this system to operate continually, everything must be automated. The ideal scenario is as follows: you push the code, the image check starts, policies are applied, and monitoring is activated. And even if you don't push, all these processes still run in the background.