The decision to adopt a purpose-built container operating system (OS) versus maintaining a standard OS across legacy and cloud-native systems depends on your organization’s risk tolerance, compliance requirements, and visibility needs. Below is a structured approach you can take to evaluate the trade-offs and select the right strategy.

Why to Use a Purpose-Built Container OS

Purpose-built container operating systems (container OSes) are designed specifically to host containers, offering a streamlined, secure, and efficient environment for running containerized workloads. Deciding when to use a purpose-built container OS depends on your operational needs, application architecture, and management priorities.

High Security/High Risk Environments

• Minimalist OS options like Bottlerocket or Flatcar Linux remove unnecessary packages, greatly reducing your overall attack surface, particularly compared to using general-purpose Linux.
• By running only essential services (often as containers themselves), these OSes make it easier to enforce security best practices and compliance requirements.
• Features such as immutable, read-only root filesystems and atomic updates help prevent configuration drift and support compliance with important frameworks, including Federal Risk and Authorization Management Program (FedRAMP) and the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule.
• Automated patching (for example, Bottlerocket’s node rotation) supports patch management standards, such as the National Institute of Standards and Technology (NIST) Special Publication (SP) 800-53, which outlines security and privacy controls for information systems and organizations.

Cloud-Native Workloads

• Purpose-built OS distributions are optimized for Kubernetes, often including preconfigured kubelet and Container Network Interface (CNI) integrations, which reduces the complexity of set up.
• These OSes are optimized for minimal resource consumption, resulting in faster boot times and lower overhead.
• Smaller OS footprints help minimize resource overhead, which is especially important for Artificial Intelligence (AI), Machine Learning (ML), and edge workloads.

Regulatory Compliance

• Many purpose-built OSes are designed to align with Center for Internet Security, Inc. (CIS®) Kubernetes Benchmarks and other standards out of the box.
• Immutable operating systems simplify compliance evidence collection for audits and frameworks, including Systems and Organization Controls 2 (SOC 2).

Fleet Management at Scale

If you are managing a large number of container hosts, purpose-built container OSes dramatically simplify fleet management. They minimize the diversity of software on each host, reduce the risk of configuration drift, and enable rapid, consistent updates across the fleet through image-based deployments. This is especially valuable in environments where consistency, automation, and rapid scaling are critical.

Immutable Infrastructure and Automation

Purpose-built container OSes are designed for immutable infrastructure patterns. Updates and configuration changes are typically handled by replacing entire images rather than patching individual packages, reducing the risk of untested or inconsistent states.

Homogeneous Workloads

If your server’s sole purpose is to host containers (with no need for traditional applications or services outside containers), a container OS is ideal. This is common in Kubernetes clusters, microservices architectures, and edge computing scenarios where uniformity and simplicity are desired.

Visibility and Security Considerations for Container OSes

If you’re on the cloud, you’ve already sacrificed visibility into a lot of underlying systems, particularly compared to running your own datacenter. So perhaps sacrificing some visibility by moving to a container OS is worth the tradeoff for a more secure base system. Only you can decide which approach makes the most sense for your use case and organization. Here are a few things to consider when making your decisions:

• Are you comfortable having a system that’s so “locked down” that it’s hard for you to see what’s happening in it? It is much harder to access, or add traditional security tools to, container OS-based nodes because of how locked down they are. It may also not allow you to align with compliance requirements, particularly if the use of specific tools is mandated.
• Does it make sense to have a system that’s not as locked down but provides you with greater visibility into what’s happening in your containers? In those environments, it’s much easier to see if there’s a problem and act on it quickly.
• What would happen if there were to be a breach? What are the implications of that? The implications of a breach could be very different if you’re a healthcare or government organization compared to the implications for a company that doesn’t handle confidential client data.

Why Standardize on a General-Purpose OS

Standardizing on a general purpose or non-container OS is a strategic decision that can simplify IT environments, improve efficiency, and support a broad range of workloads. While container OSes are optimized for hosting containers, non-container OSes (such as Red Hat Enterprise Linux, Ubuntu, or Windows Server) remain essential in many scenarios.

Diverse Application Requirements

When your infrastructure needs to support both containerized and non-containerized (traditional) applications, a non-container OS provides the flexibility needed to run a wide variety of workloads, including legacy, GUI-based, or specialized software that can’t be containerized easily.

Heterogeneous and Mixed Environments

Organizations with a mix of virtual machines (VMs), physical servers, and container platforms benefit from a standardized OS to ensure compatibility, reduce complexity, and streamline management across all environments.

Operational Simplicity and Efficiency

Standardizing on a single OS reduces the learning curve for IT staff, lowers maintenance overhead, and enables automation of provisioning, patching, and monitoring tasks. This leads to fewer errors, faster troubleshooting, and improved uptime.

Security and Compliance

In mixed environments, a standardized OS allows for consistent application of security policies, patch management, and compliance controls, making it easier to enforce organizational standards and regulatory requirements.

Cost Control and Predictability

Reducing the number of OSes in use can lower licensing, support, and maintenance costs. Bulk purchasing and centralized administration can also reduce expenses and enable predictable budgeting.

Support for Legacy and Specialized Workloads

Some workloads, especially legacy applications or those that require specific drivers or hardware integrations, may only run reliably on a traditional OS. Standardizing ensures continued support for these critical systems.

Ease of Integration and Vendor Supports

Many enterprise software vendors certify their products on specific general-purpose OSes. Standardizing simplifies integration, support, and troubleshooting with third-party vendors.

When to Change Tooling

Change your tooling when there is a clear need to improve compliance and visibility across your IT environment. Enhanced visibility is important for maintaining compliance, because it allows your organization to detect issues proactively and address them before they escalate into larger problems, such as security breaches or compliance violations. For example, real-time monitoring and comprehensive auditing tools help organizations immediately identify misconfigurations or vulnerabilities, rather than discovering them after the announcement of a critical or severe CVE, which could expose your business to unnecessary risk.

Uniformity in tooling, such as standardizing on a custom Amazon Machine Image (AMI) across the organization, brings significant benefits. It ensures that all environments are consistent, making it easier to apply security policies, automate compliance checks, and streamline updates across your infrastructure. This uniform approach reduces configuration drift, simplifies troubleshooting, and provides a single source of truth for system state, which is especially valuable in complex cloud environments with multiple layers of abstraction.

Even with the abstraction layers that platforms like Amazon provide, focusing on uniform tooling at the infrastructure layer remains important because it guarantees that compliance and security controls are consistently enforced, regardless of how higher-level services evolve.

Indeed, many organizations choose to change tooling not only to address gaps in compliance and visibility but also to enable proactive detection and response. By adopting tools that provide immediate feedback and alerting, teams can respond to issues as they arise, rather than relying on periodic audits or external disclosures to reveal problems. This proactive stance is a positive shift that empowers teams to maintain a secure and compliant environment continuously, reducing the risk of material incidents and regulatory penalties.

Keep in mind that there may be some limitations based on which cloud providers you use.

• AWS EKS supports custom AMIs and minimalist OS options, making it easier to meet compliance requirements, such as FedRAMP.
• Azure AKS is limited to Azure Linux; custom AMIs are not supported, you can apply kubelet customization and DaemonSets for node customization.
• Google GKE supports Container-Optimized OS and Ubuntu and offers integrated security tooling.

Build Your Own Adventure

The decision to choose between a purpose-built container operating system (OS) and a traditional OS is shaped by your company’s specific needs, existing infrastructure, and long-term strategy. The decision will depend on what your organization values most—whether that’s operational efficiency, flexibility, compatibility, or scalability. Here are a few of your options:

Build A Custom AMI

This option gives you full control over preinstalled security and monitoring tools. It also increases your maintenance overhead due to the need for regular updates and testing. It’s a common choice in industries with strict compliance or unique tooling needs.

Use Hybrid Approach

Use purpose-built OS for production Kubernetes clusters and a standard OS for your legacy systems. For example, deploy Bottlerocket in AWS EKS while maintaining Ubuntu AMIs for on-premises VMs.

Adopt Container-Native Tooling

Rely on your purpose-built container OS and implement the tools designed to scan them natively. You may need to redefine your compliance workflows and do some education with auditors to understand how you’re handling security and compliance. If you’re already in the cloud, you’ve already sacrificed visibility compared to running your own datacenter, so sacrificing some visibility may well be worth the tradeoff for a more secure base system.

Insecure About Container OS Security?

Purpose-built container OSes are ideal for high-compliance, cloud-native environments but often require new tooling and operational changes. Standard OSes remain practical for hybrid or legacy-heavy environments, or where existing tools and workflows are deeply entrenched.

To make the right choice, consider these pros and cons on when to split the containerized host OS vs. adopting a standard company-wide AMI:

• Do you plan on keeping static VMs around for a long time in the future?
• Does part of your organization plan on fully adopting a containerized workflow in the near future?
• Are you already using Kubernetes? Or are you 100% sure you’re moving in that direction?
• What is the proportion of legacy instances vs microservices?
• Is your security team empowered and agile? If you are going to have two workflows, can they adapt? Do they have the resources?
• Are you signing your custom AMI?
• How much effort is required to make this migration, and does your team have the bandwidth to execute on it effectively?

At Fairwinds, we work with a wide range of patterns and solutions for our clients, tailoring our approach to fit your specific needs and objectives. Our flexibility comes from the diverse directions and requirements we receive from our clients, allowing us to support every option available in the market.

If you are considering a move to Kubernetes but are unsure about the best path forward, or if you are evaluating newer container OSes and trying to determine which is right for your environment, we are here to help. These are exactly the kinds of challenges we address with our clients every day, guiding you through decision-making and implementation to ensure the solution aligns with your goals and technical requirements.

Book a strategy call to explore our fully managed Kubernetes services.

*** This is a Security Bloggers Network syndicated blog from Fairwinds | Blog authored by Brian Bensky. Read the original post at: https://www.fairwinds.com/blog/container-os-insecurity-k8s-infrastructure