# FreeBSD Jails vs Docker: Container Isolation Compared
Containerization is not a new idea. FreeBSD jails have been isolating workloads since the year 2000, more than a decade before Docker shipped its first release. Yet Docker dominates modern infrastructure conversations, and for good reason: its ecosystem is enormous. That does not make jails obsolete. The two technologies solve overlapping problems with fundamentally different architectures, trade-offs, and strengths.
This guide provides a fair, technically deep comparison of FreeBSD jails and Docker containers. No cheerleading for either side. Just the facts you need to pick the right tool.
TL;DR
**FreeBSD jails** provide OS-level isolation with a 25-year track record. They give you a full FreeBSD environment inside a lightweight partition of the kernel. Architecture is simple, security defaults are strong, and ZFS integration is first-class.
**Docker** provides application-level packaging with a massive ecosystem. Dockerfiles, Docker Hub, and orchestration tooling (Kubernetes, Swarm) make it trivially easy to build, ship, and run applications across any Linux host.
If you need rock-solid isolation on FreeBSD infrastructure, jails are the natural choice. If you need cross-platform portability and access to thousands of pre-built images, Docker wins. If you need both, there are hybrid paths covered later in this article.
A Brief History
FreeBSD Jails (2000)
Jails were introduced in FreeBSD 4.0, released on March 14, 2000. The original implementation was created by Poul-Henning Kamp for a shared hosting provider that needed stronger isolation than chroot could offer. The key insight was simple: give each isolated environment its own root filesystem, network address, and process space, all enforced by the kernel.
Over the following decades, jails gained VNET networking (per-jail network stacks), hierarchical jails (jails inside jails), resource limits via RCTL, and deep ZFS integration. Tools like ezjail, iocage, cbsd, and more recently Bastille and pot emerged to manage jail lifecycles.
For more on setting up jails from scratch, see our [FreeBSD jails guide](/blog/freebsd-jails-guide/).
Docker (2013)
Docker was released at PyCon in March 2013 by Solomon Hykes at dotCloud. It built on existing Linux kernel features -- namespaces (introduced in Linux 2.6.24, 2008) and cgroups (merged in Linux 2.6.24, 2008) -- but wrapped them in a developer-friendly interface with Dockerfiles, a layered image format, and a public registry (Docker Hub).
Docker did not invent Linux containers. LXC predated it. But Docker made containers accessible to application developers, not just sysadmins. That distinction drove explosive adoption. By 2015, container orchestration platforms like Kubernetes had emerged, and Docker became the default unit of deployment for cloud-native applications.
Architecture Comparison
How Jails Work
A FreeBSD jail is a partitioned view of the host kernel. When you create a jail, you provide:
- A **root filesystem** (typically a directory tree or ZFS dataset containing a FreeBSD base system)
- A **hostname**
- One or more **IP addresses** (or a full VNET network stack)
- **Security restrictions** enforced by the kernel (no raw sockets by default, no kernel module loading, no device access)
The jail runs the same FreeBSD kernel as the host. Processes inside the jail see only their own process tree. The filesystem is constrained to the jail root. Network access is limited to assigned addresses.
There is no image layering, no union filesystem, no daemon. A jail is simply a set of kernel-enforced constraints applied to a subtree of the system. You start it with jail(8) or a management tool, and it runs until you stop it.
Host Kernel (FreeBSD)
|
+-- Jail A (own root FS, IP, process space)
|
+-- Jail B (own root FS, IP, process space)
|
+-- Jail C (own root FS, VNET stack)
How Docker Works
A Docker container is built from a layered image. Each layer is a read-only filesystem diff created by a Dockerfile instruction. At runtime, a writable layer is added on top using an overlay filesystem (typically OverlayFS).
The container runtime (containerd, or historically the Docker daemon) creates Linux namespaces for the container: PID, mount, network, UTS, IPC, and user namespaces. Cgroups enforce resource limits (CPU, memory, I/O). Seccomp profiles restrict system calls.
Docker Engine / containerd
|
+-- Container A (namespaces + cgroups + layered image)
|
+-- Container B (namespaces + cgroups + layered image)
The image format is the key differentiator. Docker images are portable, versioned, and distributable through registries. A Dockerfile is a reproducible build script. This makes Docker fundamentally an **application packaging** tool, not just an isolation tool.
Key Architectural Difference
Jails give you an **isolated OS environment**. You get a full FreeBSD userland and manage it like a lightweight machine. You install packages with pkg, configure services, and treat it as a server.
Docker gives you an **isolated application process**. The container runs one application (or a small number of tightly coupled processes). The image contains only what the application needs. You build it once and run it anywhere.
This is not a better/worse distinction. It is a different mental model with different trade-offs.
Isolation Model
FreeBSD Jails
Jail isolation is enforced directly by the FreeBSD kernel through the prison structure. Every process is associated with a jail (including the host, which is jail 0). The kernel checks jail membership on every relevant system call.
Key isolation properties:
- **Filesystem**: Processes cannot see or access anything outside the jail root. No chroot escape is possible because the kernel enforces the boundary at a lower level.
- **Process visibility**: Processes in a jail see only other processes in the same jail. The host can see all processes.
- **Network**: By default, a jail is assigned specific IP addresses and cannot bind to or communicate on other addresses. With VNET, each jail gets its own full network stack including routing table, firewall rules, and interfaces.
- **System restrictions**: Jails cannot load kernel modules, mount filesystems (unless explicitly allowed), access raw sockets (unless allowed), or modify the host's network configuration. The security.jail.enforce_statfs sysctl controls what mount information is visible.
- **Superuser restrictions**: Root inside a jail is not root on the host. The kernel restricts privileged operations even for UID 0 within a jail. This is enforced by default, not as an opt-in feature.
Docker Containers
Docker isolation relies on a combination of Linux kernel features:
- **Namespaces**: PID namespace (isolated process tree), mount namespace (isolated filesystem view), network namespace (isolated network stack), UTS namespace (isolated hostname), IPC namespace (isolated inter-process communication), user namespace (optional UID remapping).
- **Cgroups**: Enforce resource limits on CPU, memory, I/O, and PIDs.
- **Seccomp**: System call filtering. Docker's default seccomp profile blocks approximately 44 of the 300+ Linux system calls.
- **AppArmor/SELinux**: Mandatory access control policies add another layer.
- **Capabilities**: Docker drops most Linux capabilities by default, retaining only a minimal set.
Comparison
Jails use a single, purpose-built isolation mechanism: the kernel's jail subsystem. Docker stacks multiple independent mechanisms (namespaces, cgroups, seccomp, LSMs) to achieve comparable isolation.
The jail model is simpler and has fewer moving parts. The Docker model is more granular -- you can tune each mechanism independently. In practice, both provide strong isolation when properly configured. The difference lies in defaults and attack surface, which we cover in the security section.
Networking
Jail Networking
Jails support two networking modes:
**IP-based (traditional)**: The jail is assigned one or more IP addresses on the host's existing interfaces. The jail can only bind to those addresses. The host manages the network stack (routing, firewall). This is simple and lightweight.
sh
jail -c name=myjail path=/jails/myjail \
ip4.addr="192.168.1.10" \
command=/bin/sh
**VNET (virtualized network stack)**: Each jail gets its own network stack with its own interfaces, routing table, and firewall. Typically uses epair virtual interfaces -- one end in the jail, one end on the host bridge. This allows the jail to run its own DHCP client, configure its own firewall with PF or IPFW, and behave like a fully networked machine.
sh
jail -c name=myjail path=/jails/myjail \
vnet=new \
vnet.interface=epair0b \
command=/bin/sh
VNET jails can participate in complex network topologies. Combined with PF on the host, you can build sophisticated multi-tier architectures entirely within one FreeBSD server.
Docker Networking
Docker provides multiple network drivers:
- **bridge** (default): Containers connect to a virtual bridge on the host. Docker manages NAT and port mapping. Simple for single-host setups.
- **host**: Container shares the host's network namespace. No isolation, maximum performance.
- **overlay**: Multi-host networking via VXLAN. Used with Docker Swarm and Kubernetes. Enables container-to-container communication across hosts.
- **macvlan**: Containers get their own MAC address and appear as physical devices on the network. Similar in concept to VNET jails with bridge attachment.
- **none**: No networking.
Docker's networking story is stronger for multi-host deployments thanks to overlay networking and service discovery built into Swarm and Kubernetes. Jail networking is more transparent -- there is no hidden NAT or iptables rules, just standard FreeBSD networking constructs.
Image and Template Management
Docker Images
Docker's image system is arguably its greatest innovation. A Dockerfile defines a reproducible build process:
dockerfile
FROM python:3.12-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "app.py"]
Images are layered and cached. If your requirements.txt has not changed, the pip install layer is reused from cache. Images are pushed to registries (Docker Hub, GitHub Container Registry, private registries) and pulled on demand.
Docker Hub hosts over 100,000 official and community images. Need PostgreSQL? docker pull postgres. Need Redis? docker pull redis. This is a massive productivity advantage.
Jail Templates
Jails do not have a standardized image format. Instead, there are several approaches:
- **Manual setup**: Extract a FreeBSD base tarball, install packages, configure. Repeatable via shell scripts.
- **ZFS clones**: Create a golden jail on a ZFS dataset, snapshot it, and clone new jails instantly. Copy-on-write means clones use almost no additional disk space until they diverge. This is fast and space-efficient.
- **Bastille templates**: Bastille provides a Dockerfile-like template system for jails. Templates can install packages, copy files, enable services, and configure the jail.
- **Pot flavours**: The pot jail manager supports flavours -- scripts that customize a jail at creation time.
sh
# Bastille template example
bastille create myjail 14.1-RELEASE 192.168.1.10
bastille template myjail project/webserver
ZFS clones deserve special mention. They are instantaneous and free until modification. A fleet of 50 identical jails backed by ZFS clones starts faster and uses less disk than 50 Docker containers with shared image layers. But the tooling is not as polished as docker build and docker push.
Orchestration
Docker Orchestration
Docker's orchestration ecosystem is its strongest competitive advantage:
- **Docker Compose**: Define multi-container applications in a YAML file. Start everything with docker compose up. Excellent for development and small deployments.
- **Docker Swarm**: Built-in cluster management. Simple to set up, production-ready for moderate scale.
- **Kubernetes**: The industry standard for container orchestration. Handles scheduling, scaling, service discovery, rolling updates, and self-healing across clusters of any size. Kubernetes assumes OCI-compatible containers, which means Docker images.
Thousands of tools integrate with Docker: CI/CD pipelines (GitHub Actions, GitLab CI, CircleCI), monitoring (Prometheus, Datadog), service meshes (Istio, Linkerd), and more.
Jail Orchestration
Jail orchestration is more manual but options exist:
- **Bastille**: The most Docker-like jail manager. Supports templates, networking, and basic lifecycle management. Growing community.
- **cbsd**: Feature-rich jail and bhyve manager with clustering support, web UI, and cloud integration.
- **pot + Nomad**: HashiCorp Nomad can schedule pot jails as a workload type. This gives you cluster-level orchestration with FreeBSD jails.
- **Custom scripts**: Many FreeBSD administrators manage jails with shell scripts and configuration management tools (Ansible, Puppet).
The honest assessment: Docker's orchestration ecosystem is years ahead. If you need Kubernetes-level orchestration, Docker (or OCI containers) is the only practical choice today. If you are running a single server or a small cluster, jail management tools are perfectly adequate.
Performance Overhead
Both jails and Docker containers run at near-native performance. Neither uses hardware virtualization. Processes execute directly on the host kernel with thin isolation wrappers.
Jails
Jail overhead is negligible. The kernel checks jail membership on system calls, but the cost is a few CPU cycles per call. Network performance with IP-based jails is identical to host performance. VNET jails add a small overhead for the virtualized network stack, comparable to a virtual switch.
Filesystem performance depends on the backing store. ZFS datasets provide native performance. NullFS mounts (which expose host directories inside a jail) have near-zero overhead.
Docker
Docker overhead comes primarily from:
- **Overlay filesystem**: OverlayFS adds latency to filesystem operations, particularly metadata-heavy workloads. For I/O-intensive applications, bind mounts or volume drivers are recommended.
- **NAT traversal**: Bridge networking with NAT adds overhead to every network packet. Host networking eliminates this at the cost of isolation.
- **Daemon overhead**: The Docker daemon (and containerd) consume resources for image management, logging, and health checks.
In CPU-bound and memory-bound benchmarks, both technologies show less than 1% overhead compared to bare metal. The differences emerge in I/O and networking edge cases.
Benchmark Context
Direct benchmarks are difficult because jails and Docker run on different operating systems (FreeBSD and Linux). A fair comparison would require identical hardware and workloads. Published benchmarks generally agree that both are "near-native" and that the choice should be driven by features, ecosystem, and operational requirements rather than raw performance.
Security
Jails: Secure by Default
FreeBSD jails were designed for security from the beginning. The jail primitive was created specifically to isolate untrusted workloads on shared hosting servers.
Key security properties:
- **Root in a jail is not root on the host.** The kernel enforces this at the system call level. There is no configuration required to enable this -- it is the default behavior.
- **Minimal attack surface.** Jails use one isolation mechanism (the kernel jail subsystem) with a small, well-audited codebase.
- **No daemon required.** Jails are a kernel feature. There is no privileged daemon that, if compromised, grants access to all containers (unlike the Docker daemon).
- **25 years of hardening.** Jails have been in production since 2000. The attack surface has been audited, fuzzed, and battle-tested for over two decades.
- **Jail escapes are exceedingly rare.** Publicly known jail escape vulnerabilities are few and have been patched quickly.
Docker: Improving but Complex
Docker's security has improved dramatically since its early days, but the stacked architecture creates a larger attack surface:
- **Docker daemon runs as root.** A compromise of the Docker daemon grants full host access. Rootless Docker mitigates this but is not the default in all deployments and has functional limitations.
- **Historical CVEs.** Docker has had significant vulnerabilities: CVE-2019-5736 (runc container escape), CVE-2020-15257 (containerd host file access), CVE-2024-21626 (runc file descriptor leak). Each exploited a different component in the container stack.
- **Namespace complexity.** Stacking namespaces, cgroups, seccomp, and LSMs creates interaction complexity. Misconfigurations can weaken isolation. Running containers with --privileged disables most protections.
- **User namespaces** (rootless containers) are powerful but not universally used. When enabled, they provide strong UID remapping that prevents container root from being host root.
Verdict
Jails have stronger isolation defaults and a simpler security model. Docker has more configuration options and a larger attack surface, but with proper hardening (rootless mode, user namespaces, seccomp profiles, no --privileged), it achieves comparable security. The difference is that jails are secure out of the box, while Docker requires deliberate hardening.
Developer Experience
Docker wins on developer experience. This is not controversial.
**Docker advantages:**
- Dockerfile is a simple, well-documented format anyone can learn in an afternoon.
- docker build, docker run, docker push -- three commands cover 90% of workflows.
- Docker Desktop provides a GUI for macOS and Windows developers who do not run Linux.
- Docker Compose defines multi-service applications in one file.
- VS Code, JetBrains, and other IDEs have deep Docker integration.
- CI/CD pipelines assume Docker. GitHub Actions, GitLab CI, CircleCI all run Docker natively.
**Jail advantages:**
- If you already know FreeBSD, jails feel natural. They are just a FreeBSD system with extra boundaries.
- ZFS snapshots and clones make experimentation safe and fast. Roll back a jail to a previous state in seconds.
- No abstraction layers. You understand exactly what is running and how.
- Bastille is closing the DX gap with Dockerfile-like templates.
For teams that do not already run FreeBSD, Docker's learning curve is significantly lower. For FreeBSD administrators, jails are straightforward and integrated into the OS they already know.
Ecosystem
Docker's ecosystem advantage is its defining competitive moat. Consider:
- **Docker Hub**: Over 100,000 images. Every major database, web server, programming language runtime, and development tool has an official Docker image.
- **OCI standard**: Docker images follow the Open Container Initiative specification. Any OCI-compatible runtime can run them.
- **Kubernetes**: The dominant orchestration platform assumes OCI containers. The entire cloud-native ecosystem (Helm charts, operators, service meshes) is built around this assumption.
- **Cloud providers**: AWS ECS/EKS, Google GKE, Azure AKS all provide managed Docker/Kubernetes hosting.
FreeBSD jails have:
- **FreeBSD packages**: Anything in the FreeBSD ports tree (over 30,000 packages) can be installed in a jail.
- **Community templates**: Bastille and cbsd provide community-maintained templates, but the selection is orders of magnitude smaller than Docker Hub.
- **No equivalent to Docker Hub**: There is no centralized registry for jail images.
If you need a specific application packaged and ready to run, Docker is almost certainly faster. If you are building from source or using FreeBSD-native software, jails have everything you need.
Running Docker on FreeBSD
FreeBSD does not run Docker natively. Docker depends on Linux kernel features (namespaces, cgroups) that do not exist in the FreeBSD kernel. However, there are workarounds:
Linux Binary Compatibility (Linuxulator)
FreeBSD's Linux compatibility layer can run some Linux binaries. However, the Docker daemon requires Linux kernel features that the compatibility layer does not emulate. Running Docker directly via Linuxulator is not currently possible.
bhyve Virtual Machine
The practical approach is to run a Linux VM on FreeBSD using bhyve:
1. Create a Linux VM with bhyve (see our [bhyve guide](/blog/bhyve-freebsd-guide/))
2. Install Docker inside the Linux VM
3. Use Docker normally within the VM
This adds the overhead of a full VM but gives you complete Docker compatibility. Tools like vm-bhyve and cbsd simplify VM management.
Podman Exploration
There has been community work on porting Podman (a daemonless, Docker-compatible container runtime) to FreeBSD. As of 2026, experimental FreeBSD support exists in Podman, allowing it to use FreeBSD jails as a container backend. This is the most promising path toward Docker-compatible tooling on FreeBSD, though it is not yet production-ready for all workloads.
For guidance on setting up FreeBSD on virtual infrastructure, see our [FreeBSD VPS setup guide](/blog/freebsd-vps-setup/).
Comparison Table
| Feature | FreeBSD Jails | Docker |
|---|---|---|
| **First released** | 2000 (FreeBSD 4.0) | 2013 |
| **Host OS** | FreeBSD only | Linux (primary), Windows |
| **Isolation mechanism** | Kernel jail subsystem | Namespaces + cgroups + seccomp |
| **Architecture** | Full OS environment | Application-centric process |
| **Image format** | ZFS clones, tarballs | OCI layered images |
| **Image registry** | None (community templates) | Docker Hub (100k+ images) |
| **Networking** | IP alias, VNET | bridge, overlay, host, macvlan |
| **Multi-host networking** | Manual / VPN | Overlay (built-in) |
| **Orchestration** | Bastille, cbsd, pot+Nomad | Kubernetes, Swarm, Compose |
| **Filesystem** | ZFS (native), UFS, NullFS | OverlayFS, bind mounts, volumes |
| **Resource limits** | RCTL | cgroups |
| **Root isolation** | Default (root is jailed) | Opt-in (rootless mode) |
| **Daemon required** | No | Yes (dockerd/containerd) |
| **Startup time** | Sub-second | Sub-second |
| **Performance** | Near-native | Near-native |
| **Security track record** | Very few escapes in 25 years | Multiple CVEs, improving |
| **Developer tooling** | Bastille, manual scripts | Dockerfile, Compose, IDE plugins |
| **CI/CD integration** | Limited | Ubiquitous |
| **Learning curve** | Moderate (requires FreeBSD knowledge) | Low (cross-platform) |
| **Community size** | Small, dedicated | Massive |
When to Use FreeBSD Jails
Choose jails when:
- **You already run FreeBSD.** Jails are a native feature. No additional software to install, no daemon to manage, no compatibility layers.
- **Security is paramount.** Jails provide strong default isolation without requiring manual hardening. If you are isolating untrusted workloads, jails have a proven track record.
- **You want ZFS integration.** ZFS clones, snapshots, and replication integrate seamlessly with jails. Backup, migration, and rollback are built into the filesystem.
- **You need stable, long-running services.** Jails excel at running services that are configured once and run for months or years. FreeBSD's focus on stability aligns well with this use case.
- **You prefer simplicity.** Jails are a kernel feature. No overlay filesystems, no daemon, no orchestration platform required for basic use.
- **You run network infrastructure.** FreeBSD's networking stack is exceptional. VNET jails with PF firewalling are a powerful combination for routers, firewalls, VPN gateways, and DNS servers.
For a deeper comparison of the underlying operating systems, see [FreeBSD vs Linux](/blog/freebsd-vs-linux/).
When to Use Docker
Choose Docker when:
- **You need cross-platform portability.** Docker images run on any Linux host, any major cloud provider, and (via Docker Desktop) on developer machines running macOS or Windows.
- **You need pre-built images.** If your stack includes common software (PostgreSQL, Redis, Nginx, Node.js), Docker Hub has production-ready images maintained by the upstream projects.
- **You need Kubernetes.** If your organization uses Kubernetes or plans to, Docker (OCI) images are required. There is no practical Kubernetes path for jails.
- **You want fast onboarding.** New developers can run docker compose up and have a complete development environment in minutes, regardless of their host OS.
- **You need microservices orchestration.** Docker Compose, Swarm, and Kubernetes provide service discovery, load balancing, rolling updates, and self-healing out of the box.
- **Your CI/CD pipeline assumes containers.** Most CI/CD platforms run pipelines inside Docker containers. Fighting this assumption is counterproductive.
Hybrid Approaches
You do not have to choose exclusively. Some architectures combine both:
- **Jails for infrastructure, Docker (in bhyve) for applications.** Run DNS, firewalls, and monitoring in jails. Run web applications in Docker inside a Linux VM managed by bhyve.
- **Jails for production, Docker for development.** Developers use Docker Compose locally. Production runs on FreeBSD with jails. Deployment scripts translate between the two.
- **Podman on FreeBSD.** As Podman's FreeBSD support matures, it may become possible to run OCI images using jails as the backend, combining Docker's image format with jail isolation.
Frequently Asked Questions
Are FreeBSD jails containers?
Yes, by the modern definition. Containers are OS-level virtualization that isolates processes using kernel features without the overhead of a full virtual machine. Jails meet this definition. They predate the term "container" by over a decade.
Can I run Docker inside a FreeBSD jail?
No. Docker requires Linux kernel features (namespaces, cgroups) that are not available inside a FreeBSD jail. To run Docker on FreeBSD, use a Linux VM via bhyve. See our [bhyve guide](/blog/bhyve-freebsd-guide/) for setup instructions.
Which is faster, jails or Docker?
Both run at near-native performance. Neither uses hardware virtualization. In micro-benchmarks, differences are negligible (under 1% for CPU and memory workloads). Filesystem and networking performance vary depending on configuration (ZFS vs OverlayFS, VNET vs bridge networking). For practical purposes, performance should not be the deciding factor.
Are jails more secure than Docker containers?
Jails have stronger security defaults. Root inside a jail cannot escalate to host root without a kernel vulnerability. Docker historically required root daemon access and had more publicly disclosed escape vulnerabilities. With rootless Docker, user namespaces, and proper seccomp profiles, Docker can achieve comparable security, but it requires deliberate configuration. Jails are secure by default.
Can Kubernetes manage FreeBSD jails?
Not directly. Kubernetes expects OCI-compatible container runtimes. HashiCorp Nomad, however, can manage jails via the pot driver. This gives you cluster-level scheduling and orchestration for jail workloads, though with a smaller ecosystem than Kubernetes.
Is there a Docker Hub equivalent for jails?
No. The FreeBSD community has not built a centralized image registry for jails. Bastille templates, ZFS snapshots, and manual provisioning scripts are the primary distribution mechanisms. This is one of the areas where jails are at the greatest disadvantage compared to Docker.
Should I migrate from jails to Docker?
Not necessarily. If your infrastructure runs on FreeBSD and jails serve your needs, there is no technical reason to migrate. Docker's advantages are ecosystem and portability. If you do not need those, jails offer a simpler, more secure, and equally performant alternative. Evaluate based on your specific requirements, not industry trends.
Can I convert a Docker image to a jail?
Not directly, since Docker images contain Linux binaries and jails run FreeBSD. However, you can replicate the concept: examine a Dockerfile, install the equivalent FreeBSD packages in a jail, and configure the service similarly. For Linux-specific software with no FreeBSD port, a bhyve VM with Docker is the practical path.
Conclusion
FreeBSD jails and Docker are both excellent containerization technologies. They emerged from different traditions, serve different audiences, and optimize for different priorities.
Jails are for operators who value simplicity, security, and deep OS integration. Docker is for developers and organizations who value portability, ecosystem breadth, and tooling convenience.
Neither is universally better. The right choice depends on your operating system, your team's expertise, your deployment targets, and whether you need the massive ecosystem that Docker provides. For many FreeBSD shops, jails remain the superior option. For organizations building cloud-native, multi-platform applications, Docker is the pragmatic choice.
The best infrastructure decisions come from understanding both options clearly, not from choosing the most popular one.