Kubernetes on Bare Metal: Benefits & Evolution of Management Tools

Why are companies running Kubernetes on bare metal? How do you automate provisioning, load balancing, and networking on physical infrastructure? Let’s find out.

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Kubernetes on Bare Metal: Benefits & Evolution of Management Tools

The place where you run Kubernetes impacts how your containerized applications perform. And sometimes, companies need to deploy Kubernetes on bare metal servers to isolate their apps, improve their data security, and maximize performance.

You might remember how difficult it was to deploy and manage K8s on physical hardware just a few years ago. Thankfully, that has changed for the better. The open-source toolset for Kubernetes evolved with time, making installation and management a lot easier. 

So, why are companies running Kubernetes on bare metal instead of more popular public cloud or virtual machines? How do you automate provisioning, load balancing, and networking on physical infrastructure? Let’s find out. 

Reasons to run Kubernetes on bare metal

It's easy to disregard physical infrastructure as obsolete or overly expensive. According to Flexera's 2022 State of the Cloud report, 80% of companies use at least one public cloud environment for their workloads. Likewise, Accelerate's 2021 State of DevOps report says that 49% of IT professionals use virtual machines (VMs) to deploy their primary applications, while only 30% prefer bare metal servers.

However, the convenience of cloud-based services and VMs comes with certain compromises. So, let's see what advantages bare metal environments offer for Kubernetes clusters.

Enhanced data security and access control

Bare metal servers have a single-tenant architecture where each user has a dedicated database, computing resources, and supporting infrastructure. As a result, your Kubernetes cluster is isolated from other users, which reduces the risk of data breaches. 

Isolated architectures allow you to add more proprietary security tools. For instance, a certificate signing requests (CSRs) mechanism can process verification requests to ensure that only authorized devices access your network.

Installing K8s on bare metal is recommended for organizations dealing with lots of personally identifiable information. Their isolated architecture helps comply with common data security and privacy regulations (like GDPR, PCI DSS, HIPAA).

Eliminates the costs of migration

Physical servers are optimal for core business processes. According to Forrester Consulting’s 2020 study, 90% of responders find it critical to maintain on-premises infrastructures. Because of that, 85% of organizations plan to increase their investments in bare metal servers. 

On top of that, many enterprises have built their on-premise applications over the years or even decades. For companies like that, running Kubernetes on existing bare metal infrastructure is much more affordable than migrating to the cloud.

Additionally, bare metal servers don't have any hypervisor overhead like VMs. You can dedicate the system's resources to the actual K8s cluster instead of allocating them for each virtual machine. Notably, Ericsson's 2020 research estimates that deploying Kubernetes on bare metal can cut your total costs of ownership by up to 30% (depending on your apps).

Optimized performance and latency

Deploying your Kubernetes on bare metal allows your applications to access the hardware devices directly without hypervisors and virtualization layers. This improves your system's performance and can reduce network latency up to three times compared to VMs.

Bare metal servers are excellent for critical high-bandwidth workloads that require direct access to the kernel. For example, big data software, live video streaming services, and machine learning analytics platforms perform better without virtualization layers. Telecommunications providers also deploy their 5G stack on bare metal to minimize latency. How to solve limitations of bare metal Kubernetes

Modern IT teams have grown accustomed to deploying K8s on cloud-based environments and VMs. Although these options are easier to manage, a bare metal setup is not that complicated. 

In fact, open-source tools can help your team manage the cluster on physical infrastructure nearly as efficiently. Here's how today’s solutions can automate redundant processes and overcome technical limitations.

DNS server set up

Cloud providers usually configure DNS servers for you. That's not the case with bare metal setups, where it's up to your team to host servers for each node. The good news is that the community has developed tools to get the DNS server running in no time. 

CoreDNS acts as a modular DNS server for your K8s environment. It lets you configure custom stub domains and upstream nameservers or change how the DNS service behaves on specific clusters. In addition, you can add plugins for other functions, like K8s service discovery, query rewriting, and metrics monitoring. 

You may also integrate your DNS with Kubernetes resources responsible for routing and service discovery with ExternalDNS. This add-on lets your team configure the automated DNS management based on resource names, labels, and annotations 

Network configuration

Bare metal servers have fewer abstractions and better performance than virtualized infrastructures. Still, you have to manually configure all network communications, which can be laborious because of outdated interfaces and poor support.

A networking tool like Calico makes it easy to configure communications between applications on K8s and legacy workloads. It also features robust security mechanisms that enforce policy models to filter malicious traffic and block compromised workloads. Plus, Calico lets you create a new cluster and migrate existing workloads with a live migration tool.

You can configure a network fabric with flannel. This virtual network runs binary agents to allocate a subnet lease for each host and control how traffic is transported between hosts. So, you run flannel for networking and use Calico's network policy for extra security.

Data recovery

Kubernetes clusters on physical servers are stateless, meaning your data can be lost after the server restarts. Managing data is much more complicated on bare metal servers. You must store backup data outside your K8s environment while keeping it manageable by the cluster.

Storage orchestrators like Rook solve these issues by transforming your storage system into a set of self-managed services with automated deployments and disaster recovery features. You may also use Ceph to decouple your hardware storage with abstraction layers and maintain a correct storage type for each container. Companies often use Rook to handle the configuration of the Ceph software components on the K8s cluster.

Alternatively, the Longhorn platform can create a persistent and distributed storage system without a single point of failure. It takes regular snapshots of block storage and updates itself without disrupting your volumes. In contrast to many external solutions, it's highly granular. For example, you can configure it to replicate only specific directories instead of your entire storage (which affects your cluster's performance).

State backups

Unlike virtualization platforms, bare metal setups on Kubernetes don't take an automatic snapshot for your nodes. So it’s considerably harder to back up and recover data if your files get damaged or your hardware fails.

This problem is solvable with open-source tools like Velero that regularly back up your cluster state data. Storing backups is possible outside the cluster (for deployment metadata) or locally (for snapshots of the persistent storage data). Velero can also migrate Kubernetes resources between multiple clusters to speed up disaster recovery.

Load balancing

Kubernetes platform doesn't come with built-in load balancers. That's why cloud platforms like AWS, Microsoft Azure, and Google Cloud come with their own balancing solutions. But you'll need to use a virtual balancer to get your LoadBalancer up and running on bare metal without specialized hardware.

A virtual load balancer like MetalLB is the best option for bare metal architectures that rely on consistent access to applications. It integrates with standard network equipment, assigns an external IP address to your nodes, and directs traffic to a workload inside your cluster. kube-vip is another cost-efficient Kubernetes bare metal load balancer that works without external hardware, although it's still being developed.

These and many other services can help you run Kubernetes on bare metal nearly as conveniently as on cloud-based environments.


Is it difficult to deploy Kubernetes on bare metal?

Kubernetes installation on bare metal is easier than it was a couple of years ago. Many third-party tools for K8s have evolved from alpha versions into full-scale solutions. Take MetaLB as an example. It was still in alpha when first released in 2018, but now it's grown into an efficient and user-friendly virtual load balancer.

For your convenience, we recommend using a configuration management tool like Ansible. It provides mechanisms to configure servers, install services, add hosts, and provision resources with minimal hand-coding. Instead of creating shell scripts, you can tell the engine what to do, and it will bring your environment to the desired state.

You can use Kuberspray.io — a composition of Ansible's provisioning tools — to deploy your cluster on bare metal. This tool helps you: 

  • Set up configuration management 
  • Identify the optimal DNS configurations 
  • Pick the right plugins for network support 
  • Select the correct certificate generation strategy 
  • Verify your deployment connectivity

You would only need to enable IPv4 protocol for networking transactions and allow forwarding.

Some companies avoid all that hassle by setting up a managed bare metal server in the cloud. Metal-as-a-Service (MaaS) and Hardware Leasing (HaaS) platforms let you run and maintain secure physical hardware for your Kubernetes cluster. At the same time, the providers take care of the provisioning, load balancing, and maintenance.

With these tools, you can initialize Kubernetes on bare metal in 10 minutes. However, if that sounds challenging for your team, an experienced company can deploy, set up, and configure your cluster.


To sum up

Managing Kubernetes on virtual machines and public clouds is easy. However, nothing comes close to running Kubernetes on bare metal in terms of performance, cost, and data security. 

More importantly, the Kubernetes platform has a vibrant community with a fast-growing software ecosystem. It helps you set up K8s on bare metal servers without stress and automate most management processes just like on a cloud-based platform.

And if you need extra help — Alpacked got you covered. Our team of certified K8s administrators and engineers provides container orchestration management services on cloud platforms, virtual machines, and physical infrastructure. Don’t hesitate to reach us if you need help deploying and configuring your Kubernetes cluster.

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