Frequently Asked Questions

General

What is Simuzo?

Simuzo is a hosting utility that provides resource management and isolation using native Linux technologies. It enables hosting providers to offer secure, isolated hosting environments with per-user resource limits.

What panels does Simuzo integrate with?

Simuzo currently supports Webuzo, cPanel, Plesk, DirectAdmin, InterWorx, and ISPmanager.

What are the minimum system requirements?

Linux with kernel 4.18+, 2GB RAM, 1 CPU core, 5GB free disk space, and cGroups v2 support.

Installation

How do I install Simuzo?

Run the universal installer script as root. It automatically detects your control panel and configures all components: wget -O simuzo.sh https://a.simuzo.com/install.sh && chmod +x simuzo.sh && ./simuzo.sh

Do I need cGroups v2?

Yes, cGroups v2 is required for resource limits. Most modern Linux distributions have this enabled by default.

Is manual configuration required?

No, the installer automates the setup of Apache, PAM, and SimuzoFS isolation.

SimuzoFS

What is SimuzoFS?

SimuzoFS provides SimuzoFS Jail isolation that creates a private filesystem view for each user, preventing access to other users' files.

Does SimuzoFS affect performance?

No, SimuzoFS adds minimal overhead. Most users won't notice any performance impact.

Can users access system files?

Users can access a limited set of system files via the fallback mechanism (__FALLBACK__), but cannot access other users' data.

Resource Limits

How do resource limits work?

Simuzo uses Linux cGroups v2 to apply CPU, memory, IO, and process limits. Limits are applied hierarchically: custom user limits → plan limits → default limits.

What is the difference between Memory Max and Memory High?

Memory Max is a hard limit - processes are killed if exceeded. Memory High is a soft limit that triggers throttling before reaching the hard limit.

Can I change limits without rebooting?

Yes, limits are applied immediately via cGroups without requiring reboot.

What happens when a user exceeds their limits?

Depending on the resource, either throttling occurs (CPU, IO) or processes are killed (memory). Events are logged in Statistics and Audit Trail.

MySQL Governor

What does MySQL Governor do?

MySQL Governor monitors database resource usage per user and can throttle or terminate queries that exceed resource limits.

Does it work with MariaDB?

Yes, MySQL Governor works with both MySQL and MariaDB.

How does user-database mapping work?

The database map (/var/run/simuzo/dbmap) maps MySQL users and databases to system users.

Podman Manager

What is Podman?

Podman is a container runtime (Docker alternative) that runs containers rootless by default, making it more secure.

Can users run Docker images?

Yes, Podman is compatible with Docker images. Users can deploy any Docker Hub image.

How do containers persist data?

Containers should use volumes to persist data on the host. Without volumes, data is lost when the container is deleted.

Security

Is SimuzoFS secure?

Yes, SimuzoFS provides strong isolation between users. Each user has their own filesystem namespace.

Can users see each other's processes?

No, process information is isolated per user via cGroups and namespaces.

How is authentication handled?

PAM (Pluggable Authentication Modules) handles authentication, integrated with the host system.

Troubleshooting

Why aren't resource limits working?

Check: cGroups v2 enabled, limits assigned to users, cGroup hierarchy exists at /sys/fs/cgroup/simuzo/

How do I debug issues?

Enable debug_level=3 in Settings, check logs in /var/simuzo/logs/, and verify service status.

Where can I get support?

Visit https://simuzo.com/ for documentation, support tickets, and community forums.