PKI in Containerised CI/CD Pipelines

Public Key Infrastructure (PKI) is key to securing containerised CI/CD pipelines, which are often vulnerable due to their dynamic and fast-paced nature. By automating certificate management and enforcing cryptographic verification at every stage, PKI ensures secure software delivery. Here's how PKI strengthens these pipelines:

• Build Phase: Certificates sign container images and binaries, verifying identities.
• Verification: Tools like Kubernetes admission controllers block unverified or expired signatures.
• Registry: Signed images and metadata ensure traceability.
• Trust Management: Automates key rotation and updates cryptographic standards without disruptions.

Traditional PKI systems struggle with the short lifecycles and high volume of certificates in containerised setups. Automating certificate provisioning, renewal, and revocation using tools like ACME, HashiCorp Vault, or Sectigo simplifies management and reduces risks. For Kubernetes environments, solutions like cert-manager and EJBCA streamline certificate handling for workloads and service meshes.

To avoid common errors:

• Never store keys on build servers - use secure key vaults.
• Automate certificate lifecycle management.
• Enforce signature verification during deployments.
• Apply consistent security policies across environments.

Understanding PKI in DevOps Environments

What is PKI?

Public Key Infrastructure (PKI) is a system designed to manage digital certificates and cryptographic keys, ensuring secure communication and verifying identities across networks. At its core, PKI relies on three key components: digital certificates, Certificate Authorities (CAs), and effective key management.

The system uses asymmetric cryptography, where each entity is assigned a pair of keys: a private key (kept secret) and a public key (shared openly). These keys work together to encrypt data and validate digital signatures, forming the backbone of secure communication.

In DevOps environments, PKI plays a critical role in establishing trust between services, containers, and pipeline components. Instead of depending on passwords or static credentials, PKI leverages certificates to enable automatic workload authentication. This is particularly useful in containerised setups, where numerous short-lived services need to interact securely without requiring manual intervention.

Understanding this framework highlights the unique challenges posed by dynamic, containerised environments.

PKI Challenges in Containerised Infrastructure

Traditional PKI systems were built for relatively static infrastructures with long-lived servers and infrequent certificate updates. However, containerised environments introduce a new level of complexity. Containers are often short-lived, requiring certificates for brief periods, making manual certificate management impractical.

The dynamic nature of containerised systems adds to the complexity. For example, Kubernetes orchestrates container lifecycles, meaning each workload may need its own certificate for secure communication. Static certificate configurations can quickly become outdated in such fast-changing environments. Additionally, managing thousands of certificates across a microservices architecture becomes an overwhelming task if handled manually.

Shorter certificate lifespans further complicate management. Certificates in these environments often need to be valid for only a few days - or even hours - to maintain security. This demands instant provisioning, frequent rotations to minimise risks, and immediate revocation when a workload ends. Any delays or errors in this process can lead to security vulnerabilities or disruptions.

Visibility and compliance present another hurdle. With containers constantly coming and going, keeping an accurate inventory of active certificates is challenging. Organisations may struggle to track which certificates are in use, their expiration dates, or the workloads they are tied to. This lack of oversight can lead to compliance issues and make auditing difficult.

Lastly, the distributed nature of containerised setups often involves multiple layers of Certificate Authorities. For instance, Kubernetes clusters may use internal CAs for cluster certificates, service meshes may deploy separate CAs for workload identities, and enterprise CAs might handle external-facing services. Coordinating trust relationships and certificate chains across these layers is a delicate task, and any mismanagement can result in trust failures.

To address these challenges effectively, PKI must be tightly integrated into CI/CD workflows, a concept explored further in the context of DevSecOps.

PKI in DevSecOps

To tackle the complexities of modern environments, DevSecOps incorporates PKI to automate secure verification processes from build to deployment. DevSecOps extends the principles of DevOps by embedding security into every stage of the development lifecycle, rather than treating it as an afterthought. When applied to PKI, this means integrating cryptographic validation directly into CI/CD workflows, making it a seamless part of development.

A shift-left approach brings security testing and validation earlier in the pipeline, ideally during the build stage. This allows code signing certificates to be introduced early, enabling developers to sign code and containers before they advance through the pipeline. By addressing certificate requirements during the build process, organisations can identify and resolve issues before they reach production, reducing risks and vulnerabilities.

Integrating code signing certificates with an enterprise PKI framework adds an extra layer of security and accountability. This replaces unmanaged keys that might otherwise be stored on build servers. Automated systems can validate certificates, flag expirations, and enforce standards across the pipeline. For instance, Kubernetes admission controllers can automatically verify image signatures during pod scheduling, rejecting deployments with missing or outdated certificates.

PKI in DevOps How to Deploy Certificate Automation within CI CD

Implementing PKI in CI/CD Pipelines

Integrating Public Key Infrastructure (PKI) into containerised CI/CD workflows can streamline security by automating certificate management based on predefined policies. This ensures the principles of PKI are applied consistently throughout the deployment process.

Automating Certificate Management

Managing certificates manually in containerised environments is neither practical nor efficient, especially at scale. Automation tools simplify this process, ensuring certificates are issued, renewed, and maintained without disrupting workflows. This is particularly important for dynamic environments where services frequently start and stop.

The ACME protocol offers a standardised method for automating certificate provisioning. It handles requests, validation, and renewals seamlessly, making it an ideal choice for CI/CD pipelines. Certificates can be automatically integrated into build, test, and deployment stages, ensuring the pipeline runs smoothly without manual intervention [2].

HashiCorp Vault provides a comprehensive solution, combining certificate management with secrets handling. It supports fast TLS certificate provisioning while enforcing policies to maintain security compliance. Keys can be securely stored in hardware security modules (HSMs) or cloud-based key vaults, with automatic rotation to adhere to PKI best practices [2].

Venafi focuses on enterprise-level certificate lifecycle management, offering deep integration with tools like Docker, Kubernetes, and configuration platforms such as Ansible and Chef. This approach ensures certificates are managed directly within existing DevSecOps pipelines, providing consistent oversight across all infrastructure [2].

Sectigo integrates with popular containerisation and automation tools like Docker, Terraform, and Jenkins. By embedding PKI processes into CI/CD pipelines and orchestration platforms like Kubernetes, Sectigo's Certificate Manager efficiently handles the high volume and short lifecycle of certificates required for ephemeral infrastructure [3].

Depending on your needs, you might choose ACME for streamlined provisioning, Vault for combined secrets and certificate management, or Venafi and Sectigo for enterprise-grade lifecycle oversight.

Securing Pipeline Stages with PKI

To ensure robust security, PKI principles should be applied across every stage of the CI/CD pipeline, from code commits to production deployment. Certificates play a crucial role in securing these stages.

Build and signing are critical early steps. Code signing certificates, issued through enterprise PKI, replace unmanaged keys and provide auditable identities for builds. By automating the request for signing identities tied to enterprise PKI policies, every signed container image and binary becomes part of a traceable workflow. This ensures that each build is linked to a verifiable identity, creating a clear audit trail [1].

Keys stored in HSMs or cloud key vaults can be rotated automatically and revoked if compromised. This ensures workflows remain secure and tied to auditable identities throughout the pipeline [1].

Before workloads reach production, verification and enforcement steps ensure only trusted images are deployed. Kubernetes admission controllers verify image signatures, rejecting any unsigned, expired, or untrusted images. This policy-driven enforcement scales consistently across clusters without relying on ad hoc scripts [1].

During the registry and storage stages, signed container images and their metadata remain linked, ensuring provenance is preserved. This allows verification to occur at any point in the deployment process, maintaining trust throughout the artefact lifecycle [1].

Finally, trust distribution and lifecycle management ensure certificates remain valid and synchronised across environments. Updates to trust bundles and key rotations must be carefully coordinated to prevent interruptions in multi-cluster deployments. This requires close collaboration between certificate authorities, orchestration platforms, and deployment tools [1].

Example: PKI in Kubernetes-Based Pipelines

Kubernetes-based environments showcase the effectiveness of PKI strategies. Tools like cert-manager and EJBCA work together to provide policy-driven PKI management, particularly for Istio service meshes that require large-scale certificate handling [5].

Cert-manager acts as a Kubernetes-native certificate controller, automating certificate provisioning and renewal through custom resource definitions. When paired with EJBCA, it forms a complete PKI solution integrated into Kubernetes workflows. This setup manages certificates for service-to-service communication, external traffic ingress, and individual pod workloads.

Here’s how it works: when a new service is deployed, cert-manager detects it and requests a certificate from EJBCA based on predefined policies. EJBCA validates the request, issues the certificate, and returns it to cert-manager. The certificate is then mounted into the pod as a Kubernetes secret, ready for immediate use.

As certificates near expiration, cert-manager renews them automatically without disrupting services. If a pod is deleted, the associated certificate is revoked, maintaining security hygiene. This process also extends to Istio service meshes, where cert-manager provisions certificates for mutual TLS between services. Istio handles TLS handshakes and verification, ensuring secure, authenticated connections without manual certificate management.

For more comprehensive supply chain security, integrate certificate-based signing with tools like in-toto, SigStore, and SLSA [5].

The key to success is integrating PKI directly into orchestration frameworks and configuration tools. When certificate management becomes part of the infrastructure-as-code model, it scales naturally with the environment, ensuring consistency across clusters and regions [3] [4].

Best Practices for PKI in Containerised CI/CD Workflows

Securing your pipeline stages is just the beginning. To truly optimise Public Key Infrastructure (PKI) in containerised environments, you need to go beyond deploying tools. The key lies in following practices that tackle challenges like scalability, compliance, and common pitfalls in implementation.

Scalability and Key Lifecycle Management

Managing certificates in large-scale environments can be tricky. With high certificate volumes and short lifespans, a manual approach simply won’t cut it. Instead, adopt policy-based issuance to streamline the process. By integrating certificate issuance into your enterprise PKI framework, you can automate the creation of auditable signing identities - no manual approvals needed.

Automating key rotation is equally important. Store keys in hardware security modules (HSMs) or cloud key vaults and set them to rotate automatically based on predefined policies. If a key is compromised, you should have mechanisms in place to revoke and replace it immediately, ensuring your pipeline keeps running smoothly.

Another critical element is trust bundle synchronisation. When certificates expire or cryptographic standards change, updates should automatically propagate across distributed clusters. This prevents security lapses and ensures your infrastructure stays up to date.

Taking a shift-left DevSecOps approach can also help. By embedding PKI into development workflows, you ensure that certificate management scales alongside your infrastructure without becoming a bottleneck. This proactive strategy also simplifies compliance and audit processes.

Compliance and Auditing

Building audit capabilities directly into your PKI workflows is a must. For example, Kubernetes admission controllers can verify image signatures before scheduling pods. These checks automatically generate audit trails, detailing what was deployed, who signed it, and whether it met policy requirements.

Provenance tracking is another cornerstone of compliance. By linking signed images with their metadata as they move through registries and environments, you can verify their authenticity at any stage of the deployment process. Tools like in‑toto attestations, SigStore, and SLSA frameworks provide additional layers of security and transparency for the software supply chain.

To maintain compliance, define clear certificate policies. These should cover everything from validity periods and key sizes to approved certificate authorities and renewal procedures. Tools like HashiCorp Vault can simplify the provisioning of TLS certificates while ensuring adherence to these policies. Additionally, comprehensive logging of certificate activities - such as issuance, renewal, and revocation - should integrate with your existing SIEM systems. This setup not only streamlines compliance reporting but also helps you avoid common implementation errors.

Common Mistakes in PKI Implementation

Even the most well-designed environments can fall victim to predictable PKI mistakes. Here are some to watch out for:

• Storing keys on build servers: This is a security risk. Always use HSMs or cloud key vaults for secure storage and automated key rotation and revocation.
• Skipping verification: Signing container images is only half the battle. Without enforcing verification during deployment - using tools like Kubernetes admission controllers or policy engines - the signing process does little to improve security.
• Relying on manual processes: Manual certificate management slows down containerised CI/CD pipelines. Instead, adopt protocols like ACME to automate certificate provisioning, validation, and renewal.
• Inconsistent security policies: Applying different security standards across development, staging, and production environments creates vulnerabilities. A unified PKI governance framework is essential to enforce consistent policies.
• Neglecting the full certificate lifecycle: Failing to plan for issuance, renewal, and revocation can lead to preventable outages.
• Isolating PKI from toolchains: PKI solutions should integrate seamlessly with tools like Docker, Kubernetes, Jenkins, Terraform, and Ansible. This reduces friction and ensures smoother workflows.

Conclusion

Integrating PKI into containerised CI/CD pipelines is a critical step for securing modern DevSecOps workflows. Transitioning from manual certificate management to automated, policy-driven methods fundamentally changes how organisations safeguard their software supply chains. With enterprise PKI governance, cryptographic verification of container images ensures that your deployments are not just assumed to be secure but are proven secure through robust validation [1].

Seamlessly embed PKI into your DevOps tools - whether it's Docker, Kubernetes, Jenkins, Terraform, or Ansible - to create a tightly integrated security framework [3]. Automation is key: streamline certificate issuance, rotation, revocation, and trust bundle updates to eliminate the inefficiencies of manual processes while maintaining the speed and flexibility required in containerised environments.

Protocols like ACME make automating certificate provisioning straightforward, integrating directly into CI/CD pipelines [2]. Combine this with Kubernetes admission controllers to enforce image signature verification automatically, rejecting any unsigned or untrusted images before they can compromise your pipeline. These measures build a strong PKI governance model that enhances security without disrupting development workflows.

DevSecOps takes traditional DevOps a step further by embedding security into every stage of the pipeline [2]. At scale, Certificate Lifecycle Management becomes essential, managing the sheer volume of certificates and their shorter lifecycles in modern environments [3]. By leveraging the right PKI tools and automation, you close critical security gaps, protect your infrastructure, and enable your teams to focus on innovation. This integration isn’t just about security - it’s about enabling operational excellence.

A well-executed PKI strategy doesn’t just protect your pipelines - it also boosts efficiency. For tailored solutions that align security with agility, Hokstad Consulting offers expertise in DevOps transformation and automation. Their customised approaches help reduce operational risk while optimising deployment cycles, ensuring your PKI strategy supports both your security and business goals.

Act now. Unmanaged certificates can lead to costly outages and cybersecurity breaches [3]. By adopting the practices outlined here - such as policy-driven issuance and comprehensive audit trails - you’ll create a scalable foundation that keeps your containerised pipelines secure and your organisation ready for the challenges of tomorrow.

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