Kubernetes vs Docker isn't a fight between alternatives. Docker builds and runs containers; Kubernetes schedules them across many machines. The real choice is between Compose on one host, Docker's Swarm mode, and Kubernetes, and each one implies a different hire.
This piece is part of our series Hire developers by tech stack: rates, vetting and interview guides. Everything below is dated October 2026.
Kubernetes vs Docker: the short answer
Docker is the tool most developers meet first. You describe an application in a Dockerfile, build an image, and run it as a container on a single machine. Docker Compose adds a file that defines several containers (an app, a database, a cache) and starts them together.
Kubernetes starts where one machine stops. It takes containers, wraps them in pods, and decides which node in a cluster runs each one. If a node dies, it moves the work. You tell it what you want running, and it keeps reality matching that description.
They don't compete, because they work together. Kubernetes' own dockershim FAQ says images built with docker build work with all CRI implementations. An image you build with Docker today runs on a Kubernetes cluster unchanged.
What changed: Kubernetes stopped talking to Docker directly
The "Kubernetes dropped Docker" headline was half right. Kubernetes deprecated its built-in Docker integration, called dockershim, with release 1.20 and removed it in 1.24. What went away was the plumbing between the kubelet and Docker Engine. The images stayed valid.
The current rule is simple. Kubernetes 1.37 requires a CRI-conformant runtime, and the container runtimes page documents containerd, CRI-O, Docker Engine through cri-dockerd, and Mirantis Container Runtime. Teams on managed clusters often never pick a runtime.
Here's where each project stands today. The Kubernetes releases page lists 1.37.1 as the latest patch, with 1.36 and 1.35 also supported, all with patches dated 15 September 2026. The project maintains release branches for the three most recent minors and gives about a year of patch support. Docker Engine's latest is 29.8.2, dated 30 September 2026, according to Docker's Engine release notes.
That support window is a cost of choosing Kubernetes. Minor versions arrive on a cadence and old ones drop out, so someone has to upgrade, and upgrades sometimes remove things. The kubelet flags removed in Kubernetes 1.37 are a typical example: small, documented, and breaking if nobody read the notes.
When Docker alone is enough
More often than the "Docker is for local development" line suggests. Docker's own guidance on running Compose in production calls a single server the easiest path. It recommends a separate production Compose file, restart policies, and no bind mounts of your code.
Our judgment, not a sourced figure: Compose is enough if you run on one host, have a handful of services, and can tolerate downtime while the host is replaced. A B2B tool with a few hundred users and one maintenance window a week fits that description. So does most early-stage software.
Docker can't spread containers over several machines on its own, which is the point where people start asking about Kubernetes. Before you do, there's a middle step.
Swarm mode: the middle option
Swarm mode is built into Docker Engine. Docker's Swarm documentation lists scaling, self-healing, rolling updates and mutual TLS, and Docker's Compose production guide says Compose apps can run on a Swarm cluster. If you already use Compose and want a few machines instead of one, it's the smallest jump.
Don't confuse it with Docker Classic Swarm, the older standalone project, which the same docs call no longer actively developed. Swarm mode itself is maintained: the 29.8.0 release notes include Swarm fixes. In our view its ecosystem is much smaller than Kubernetes', so if you expect to need managed services, autoscaling add-ons or a large pool of engineers who know it, factor that in.
When you need Kubernetes
Kubernetes adds scheduling across nodes, self-healing, declarative rollouts and autoscaling. You reach for it when one host or a small Swarm no longer fits: many services owned by several teams, workloads that must survive node failures without a person involved, or traffic that swings enough to need automatic scaling.
It's also the mainstream choice among teams that run containers. The CNCF's 2025 survey found 82% of container users running Kubernetes in production, up from 66% in 2023. The same survey lists the price: lack of training (36%) and complexity (34%) among the challenges of cloud native adoption.
So the cost isn't licence fees. It's the upgrade cadence above plus skills. Whether to run clusters yourself or use a managed service is its own decision, covered in what to check before hiring a Kubernetes engineer. We have no sourced figure for what Kubernetes costs to run compared with Compose, so we won't print one.
Comparison table
| Criterion | Docker (Engine + Compose) | Kubernetes |
|---|---|---|
| What it does | Builds images, runs containers | Schedules and manages containers across machines |
| Unit of work | Container | Pod |
| Scope | One host, or a cluster via Swarm mode | A cluster |
| Config style | Compose file, declarative | Manifests, declarative |
| Runtime | Docker Engine, which uses containerd (runc by default) | Any CRI runtime |
| Current version (Oct 2026) | 29.8.2 | 1.37.1 |
| Release support | No published Engine policy found | Three minors, about 1 year of patches |
| Extensive work in past year, professional devs (Stack Overflow 2025) | 73.8% | 30.1% |
| Who typically operates it (our judgment) | Any backend developer | DevOps or platform engineer |
Docker doesn't publish an Engine support window we could find, so there's no number to give.
Who you need to hire for each setup
Docker is close to a universal developer skill. In Stack Overflow's 2025 developer survey, 73.8% of professional developers reported extensive development work with Docker over the past year, and 30.1% with Kubernetes. That's roughly 2.5 times as many for Docker, a ratio we derived from those two figures.
Read that carefully. It's a self-selected, global survey of what people use. It says nothing about how many are available to hire, at what seniority, or in your country and timezone.
The direction is still useful. For Compose on one host, you need a backend developer with good container habits, and you probably already employ one. Screening Docker developers with a build review is the way to confirm it.
For Kubernetes, you need a DevOps or platform engineer, because someone has to own upgrades, networking, and what happens at 3 a.m. when a node fails. The pool is narrower, which is consistent with CNCF respondents citing lack of training (36%). In our view, a team that adopts Kubernetes without that person can end up with a cluster nobody wants to touch.
Hiring DevOps engineers through HighCircl
HighCircl covers DevOps among its stacks and places engineers from seven European countries. DevOps engineers through HighCircl pass four vetting stages run by senior engineers, and about 1 in 10 applicants get through. A shortlist of 3-5 candidates arrives within 72 hours. The margin is 20%, capped and disclosed, there's no minimum hour commitment, and a replacement guarantee applies if an engagement isn't working.
FAQ
Is Kubernetes replacing Docker?
No. They do different jobs. Kubernetes removed its built-in Docker integration in 1.24, but images built with Docker still run on it, and Docker is the most widely used container tool among developers in Stack Overflow's 2025 survey.
Do I need Docker to use Kubernetes?
No. Kubernetes needs a CRI-conformant runtime such as containerd or CRI-O, and you can build images with other tools. Docker is the most widely used tool for building them.
Is Docker Compose enough for production?
For one server, yes. Docker's own documentation treats a single server as the easiest production path for Compose. Once you need to survive a host failure without downtime, or run across several machines, look at Swarm mode or Kubernetes.
Is Docker Swarm dead?
Classic Swarm, the standalone project, is no longer actively developed. Swarm mode, built into Docker Engine, is maintained: the 29.8.0 release notes include Swarm fixes. Its ecosystem looks small next to Kubernetes' (our view), but it's not abandoned.
Should a small team start with Kubernetes?
Usually not. Start with Compose on one host and move when a specific limit hurts: downtime on host failure, too many services to manage by hand, or load that needs autoscaling. Adopting Kubernetes first means paying for the upgrade cadence and the skills before you have the problem they solve.