OpenPanel vs Panelica: Per-User Docker vs 5-Layer Kernel Isolation

Why operators are looking at OpenPanel alternatives in 2026

OpenPanel emerged as one of the more technically interesting entries in the post-cPanel panel landscape. Its core proposition -- spinning up a Docker container per user, each with isolated MySQL, PHP, and Redis -- is a genuinely novel approach to multi-tenant isolation. Stefan Pejcic and the Amsterdam-based team deserve credit for taking container-per-user seriously when most panels still rely on Unix permissions and PHP pool segregation.

But operators running OpenPanel at scale start encountering a specific problem: container-per-user architecture trades isolation clarity for resource efficiency. Each Docker container carries overhead. Memory consumption grows linearly per user. On a server with 50 accounts, the container orchestration layer itself becomes a meaningful fraction of your available RAM. That is the point where operators start asking whether there is a cPanel alternative that provides equivalent or stronger isolation without the per-container overhead model.

That is where the Panelica comparison becomes practically relevant.

What OpenPanel is best at

OpenPanel's container-per-user model delivers clear, auditable isolation. Each user's environment is a discrete Docker container -- their MySQL instance runs inside their container, their PHP version is set per container, their Redis is separate. For a hosting operator who wants isolation that is architecturally visible and easy to explain to customers, that model has real appeal.

The feature set is broad for a panel at its price point. The Community edition is free for up to 3 users and 50 websites. The web server choice is wide: Nginx, Apache, OpenLitespeed, OpenResty, and Varnish are all options. The 100+ OpenCLI terminal commands give operators scripting capability that many panels do not offer at the command line. Resource limiting by CPU, memory, disk, inodes, and ports is built in. Custom branding is available. The Enterprise edition at 14.95 euros per month adds removal of limits and priority support.

For a small hosting operation willing to accept the container overhead model, OpenPanel is a well-thought-out panel with a genuine community and active development.

The architectural fork: OpenPanel's container model vs Panelica's kernel approach

The fundamental architectural question is: where do you draw the isolation boundary? OpenPanel draws it at the container wall -- each user is a Docker container, and Docker's own network, filesystem, and process namespaces provide the separation. Panelica draws the boundary at the kernel resource scheduler -- cgroups v2 slices enforce limits at the CPU scheduler and memory manager level, while Linux namespaces provide filesystem and process separation without the runtime overhead of a full container daemon per user.

The practical result: on a server with 100 hosting accounts, Panelica's shared service model (one MySQL instance, one Redis, shared Nginx worker pool with per-user routing) uses significantly less RAM than a model where each user runs their own MySQL, Redis, and PHP stack inside an isolated container. Shared services with kernel-level tenant separation is the architecture that enterprise Linux distributions have used for years. Container-per-tenant is a newer approach that trades efficiency for architectural clarity.

OS and stack support side-by-side

OpenPanel supports Debian and Ubuntu distributions on x86 hardware. The per-user Docker containers can run various web server configurations including Nginx, Apache, OpenLitespeed, OpenResty, and Varnish -- giving administrators flexibility in the server stack each user gets.

Panelica covers Debian 12/13, Ubuntu 22.04/24.04/26.04, and extends to AlmaLinux 9/10 and Rocky Linux 9/10. The RHEL family support is relevant for enterprise deployments and operators whose customers or procurement requirements favor Red Hat ecosystem compatibility. Panelica's control plane is a compiled Go binary with no runtime interpreter dependency -- it does not run inside Docker, it manages Docker as one of 20 services it orchestrates.

Both panels handle PHP-FPM, SSL via Let's Encrypt, MySQL, and Git-based workflows. Panelica adds PostgreSQL 17, native BIND 9 DNS, Postfix/Dovecot email, ProFTPD, and an integrated WordPress manager covering installation, staging, plugin management, and WP-CLI. These are stack layers that OpenPanel delegates to third-party tools or does not include.

Isolation model: per-user Docker vs Panelica's 5-layer kernel approach

OpenPanel's Docker-per-user model provides genuine isolation. Containers have their own filesystem view, their own process namespace, and their own network stack. A compromised PHP process inside one container cannot directly reach files in another container's filesystem. That is a real security property.

Panelica's isolation model operates at five layers simultaneously, all at the kernel level rather than the container runtime level. Cgroups v2 enforce CPU, memory, I/O, and PID limits per user independently of what that user's processes are doing -- a user cannot escape their resource allocation by spawning processes that bypass the container model, because there is no container model to bypass. Linux namespaces provide the same PID and mount isolation that Docker provides, but without the daemon overhead. SSH chroot jails, per-user PHP-FPM pools, and UID/GID isolation complete the five layers.

A key operational difference: OpenPanel's container model requires Docker to be running and healthy for customer sites to function. Panelica's cgroups-based isolation operates at the kernel level -- there is no container daemon in the data path between an HTTP request and a PHP-FPM worker. That means one fewer service that can fail or introduce latency into the critical path.

What is free, what is paid: pricing reality

OpenPanel's Community edition is free for up to 3 users and 50 websites -- a meaningful ceiling for small operations but a hard limit. The Enterprise edition is EUR 14.95 per month, which removes the user and website limits and adds priority support. For EU operators, that pricing is relatively predictable and straightforward.

Panelica's Free Starter covers 1 domain with full platform features. The Professional plan at $4.99 per month supports 30 domains and 5 users. The Business plan at $9.99 per month has no domain or user cap and includes multi-admin, remote backups, and Docker management. At the Business tier, running 100 customer accounts on Panelica costs $9.99 per month plus the server cost. Running 100 accounts on OpenPanel's per-user container model requires a server large enough to hold 100 MySQL instances -- which is a hardware cost that scales with the architecture.

Feature coverage matrix

When OpenPanel still fits

OpenPanel's container-per-user model is architecturally compelling for a specific type of hosting operation: one where you want the isolation boundary to be a visible, discrete container that you can inspect, pause, migrate, and snapshot independently. If your operations team thinks in terms of containers rather than kernel namespaces, OpenPanel's mental model maps cleanly to your workflow.

The free Community tier covering 3 users and 50 websites is a reasonable entry point for a very small operation or for a pilot before committing to a paid plan. The web server flexibility -- particularly OpenLitespeed for WordPress-heavy workloads -- is a feature Panelica does not currently match for customers who specifically need LiteSpeed caching.

If your workload is primarily PHP web hosting and you have the server memory to accommodate per-user containers, OpenPanel delivers solid isolation at a manageable price point for small account counts.

Migrating from OpenPanel to Panelica

OpenPanel stores site files in conventional home directories even within the container model. Panelica's migration pipeline connects to the source server over SSH, discovers user accounts and domain configurations, transfers files via rsync, imports MySQL databases while preserving user credential hashes, and re-provisions DNS records and SSL certificates. The same pipeline approach described in the cPanel to Panelica migration walkthrough applies to OpenPanel sources, since the underlying data structures -- home directories, MySQL dumps, zone files -- follow standard conventions. Post-migration, each user account on Panelica gets the full 5-layer kernel isolation applied automatically at account creation time.

Choosing the right cPanel alternative for your scale

Both OpenPanel and Panelica are legitimate answers to the "we need a modern cPanel alternative with real isolation" question. Where they diverge is in how they implement that isolation and what it costs to run at scale.

OpenPanel's container model is clear, auditable, and architecturally interesting. Panelica's kernel-level model is more resource-efficient at scale, carries a full email and DNS stack, and extends to RHEL-family operating systems that matter in enterprise environments. For hosting operators whose account count is growing beyond the point where per-user container overhead is comfortably absorbed by available hardware, the architecture comparison below is worth working through in detail.

The full OpenPanel vs Panelica comparison covers the isolation architectures in technical detail. For a broader view of how the panel market looks in 2026, the 2026 panel overview and the comparison hub cover the full panel landscape. For context on the EU data residency angle relevant to both EU-based vendors, the EU hosting companies replacing US-built panels post covers the regulatory picture that is driving a lot of the panel re-evaluation currently happening in the market.