Installation

Install SHM on a verified AlmaLinux 9 server with the one-time, license-bound command generated in Client Area.

Where to find it: Documentation > Hosting Manager > Installation.

Available to: Anyone may read this guide. Generating the command requires access to the SHM license in Client Area, and installation requires root on the target server.

What this page does

This guide separates server eligibility from the installation steps. The current SHM installer validates the operating system, rejects an unsafe fresh-install target, installs its runtime dependencies, prepares the service baseline, activates the selected license, and reports the panel address.

Requirements

Do not use the fresh-install command to overwrite an existing SHM server. Preserve the server and its backups, then use the supported repair path with Synconix Support.

Virtualization and container support

SHM supports bare-metal servers, KVM virtual machines, LXC and OpenVZ system containers, and Virtuozzo containers running on a modern kernel. The virtualization product name is only the first clue. What matters is whether that server can use the Linux kernel features required by each optional SHM capability.

A KVM virtual machine has its own kernel. An LXC, OpenVZ, or Virtuozzo system container shares the physical host's kernel. The hosting provider therefore controls low-level features such as cgroup controllers, namespaces, nested mounts, subordinate user-ID mappings, and /dev/fuse. SHM can detect and use these features, but it cannot create or grant a kernel permission that the host has blocked. This is why two containers with the same amount of CPU and RAM can offer different SHM capabilities.

What cgroup v2 does

Think of cgroup v2 as the Linux resource-control layer. SHM asks systemd to place work performed by each hosting account into that account's own controlled group. The kernel can then enforce a ceiling for that account without applying the same ceiling to the whole server.

• cpu enforces the account's CPU percentage.
• memory enforces its RAM limit.
• pids limits how many processes or tasks it can run.
• io enforces disk bandwidth and IOPS limits.

Disk-space and inode quotas are separate. They depend on quota support in the filesystem that stores the account, not on cgroup v2.

Container permissions by feature

• Core SHM and hosting services: The panel and independent web, PHP, DNS, mail, and database services are not disabled merely because cgroup v2 is missing. Each service must still pass its own installation prerequisite and health check.
• Managed Podman: Requires systemd as PID 1, a working systemd user manager, delegated cpu, memory, and pids controllers, unprivileged user and network namespaces, subordinate UID/GID mappings, and working rootless storage and networking. A container host may also need to expose /dev/fuse and allow nesting.
• JailShell: Base JailShell does not require cgroup v2. In a system container it does require systemd as PID 1, a filesystem that permits its protected setuid launcher, nesting or mount namespaces, and permission for the isolated bind, proc, and devpts mounts. The container profile commonly grants the required mount operations through CAP_SYS_ADMIN. Enabling Podman inside JailShell also requires every Podman capability listed above.
• Per-account resource limits: CPU, RAM, process/task, disk-bandwidth, and IOPS limits are available only for the controllers exposed by the host. If one controller is missing, the related fields remain unlimited and SHM does not pretend that an unenforceable limit was applied.

Why a restricted container cannot enable these features

The host kernel creates the cgroup hierarchy and decides which namespaces, devices, capabilities, and mount operations enter the container before SHM starts. Installing another package or changing a file inside the guest cannot replace a missing host-kernel feature, convert a legacy cgroup v1 host to cgroup v2, or delegate a permission from outside the guest. When one of these checks fails, the cause is the container's virtualization profile rather than an SHM setting.

What to confirm with your VPS provider

• systemd runs as PID 1 inside the container.
• A unified cgroup v2 hierarchy is delegated with cpu, memory, and pids; request io when account disk-bandwidth or IOPS limits are required.
• Nesting or mount namespaces and the bind, proc, and devpts mount operations required by JailShell are allowed.
• For Podman, unprivileged user/network namespaces, subordinate UID/GID mappings, rootless networking, and /dev/fuse are available.

If the provider cannot supply these capabilities, use KVM or bare metal for the complete feature set. A restricted LXC, OpenVZ, or Virtuozzo container can still be a valid SHM server for the independent features it supports; unavailable optional capabilities should be treated as a known platform limit, not as a failed SHM installation.

Install SHM

Installation command: Open Client Area > Licenses.

1. Sign in to Client Area and open Licenses.
2. Select the SHM license intended for this server, choose Generate install token, and confirm.
3. Keep Stable selected unless Synconix Support has asked you to use another release channel.
4. Copy the complete command while the token countdown is active. Client Area displays the command in this format:

curl -fsSL 'https://download.synconix.com/YOUR_INSTALL_TOKEN' | bash

YOUR_INSTALL_TOKEN is a non-working placeholder. Use only the command generated for the selected license. The real token is one-time and expires; never save or share it in scripts, screenshots, tickets, or logs.

5. Paste the generated command into the root shell of the intended server and run it exactly as shown.
6. Let the installer finish. Do not bypass an operating-system, existing-panel, or existing-SHM safety refusal.

Verify the installation

• Confirm that the installer reports completion and prints an HTTPS address on port 882.
• Open the printed address and confirm that the SHM sign-in page responds.
• Sign in and verify that the selected license is recognized before configuring customer services.
• If the installer stops, read /var/log/synconix-shm/install.log. Generate a new token only when the previous token expired; do not reuse another license's command.

Result and next check

SHM is installed only when the installer completes, the panel opens on the intended server, and the correct license is active. Continue with Quick Start to configure services, security, packages, a test account, DNS, mail, and backups.