Installation prechecks

Understand the environment checks the CAST Imaging installer runs before an installation starts, and how to resolve a blocked installation

Overview

Available in ≥ 3.6.6-funcrel

Before it makes any change to your machine, the CAST Imaging installer validates the environment it is about to install into: the operating system, the software it depends on, the hardware resources available, the ports it needs, and the endpoints it must reach.

These checks run automatically every time you launch the installer and cannot be skipped. The results are grouped by area and reported in the installer output.

An example report can be found here and a snippet is shown below:

+-- PRECHECK REPORT - CAST IMAGING 3.x.x --------------------------------------+
| Host: ubuntu-2404-testing  |  Component: all  |  Config: precheck.ini        |
| Platform: LINUX | Date: 2026-07-29 10:52:33                                  |
| Engine: docker                                                               |
+------------------------------------------------------------------------------+

+-- SYSTEM --------------------------------------------------------------------+
| WARN Java JDK 17-21 present (Linux) Java not found (PATH or JAVA_HOME)       |
|   -> Optional on Linux: only to decrypt encrypted (CRYPTED2) passwords.      |
|      Plain-text install works without Java.                                  |
+------------------------------------------------------------------------------+
| OK   CPU architecture x86_64                  x86_64                         |
|   -> ARM64 / aarch64 is not supported: CAST Imaging ships no ARM64 images.   |
+------------------------------------------------------------------------------+
| OK   Supported Linux OS                       ubuntu24.04                    |
|   -> Validated only on RHEL/Rocky/Alma 8-9, Debian 11-12, Ubuntu             |
|      22.04/24.04.                                                            |
+------------------------------------------------------------------------------+
| OK   glibc >= 2.28                            2.39                           |
|   -> Required by CAST containers. An older glibc means an OS too old         |
|      (RHEL/CentOS 7).                                                        |
+------------------------------------------------------------------------------+

The checks are scoped to the components you are installing, so a dashboards installation is not blocked by a requirement that only applies to imaging-viewer.
Where a check reads a value from your own configuration - a port, for example - the configured value is tested rather than the default.

Blocking failures and warnings

Each check reports one of two outcomes when it does not pass:

Outcome	Effect on the installation
Blocking failure	The installation does not start. Nothing on the machine has been changed, so resolve the reported condition and launch the installer again.
Warning	The installation continues. The capability associated with the check may not work, so review the message and decide whether to act before or after installing.

What is validated

System

The operating system and its edition, the CPU architecture, and the runtime prerequisites:

Only the x86_64 architecture is supported. ARM64/AArch64 hosts are rejected - no ARM64 images are shipped.
On Linux, glibc must be recent enough. A glibc older than the supported level indicates an operating system release that is too old.
On Microsoft Windows, a 64-bit JDK with JAVA_HOME set is mandatory, because CAST Imaging uses it to encrypt and decrypt passwords. On Linux the same JDK is optional and produces only a warning - it is needed there solely to decrypt encrypted passwords, and an installation using plain-text passwords does not require it.
Windows Server Core is not supported.

For the supported operating system releases and Java versions, see Software requirements.

Software

The tools the installer depends on:

On Linux, the container engine you have chosen - Docker or Podman - must be installed, running and usable by the current user. Docker requires the Compose v2 plugin; the standalone docker-compose v1 command is not supported. Podman must be able to reach a compose provider.
The command-line tools the installer calls: curl is required on both platforms, while tar, unzip and ss produce warnings on Linux when missing.

For the supported engine releases, see Software requirements.

Filesystem and rights

On Linux, the installer verifies that it can write and execute where it needs to:

Check	Outcome if it fails
`INSTALL_DIR` is writable, directly or through `sudo`	Blocking
`INSTALL_DIR` is not mounted `noexec` - the installer runs helper binaries from it	Blocking
`/etc/cast-imaging` is writable - it holds the installation state and secrets	Warning, because it is created during installation where it does not exist
The installation package itself is complete	Blocking

Hardware

The CPU, memory and free disk space available for the components being installed. Disk space is measured on /opt on Linux and on the system drive on Windows.

Memory and disk failures are blocking. CPU produces a warning only, so an under-provisioned processor does not prevent installation.

See Hardware requirements and Disk space for the values.

Ports

Every port needed by the components being installed must be free on that host. Where you have changed a port in your own configuration, the installer tests your configured value rather than the default.

A port already in use is a blocking failure: either free the port, or install the component on a different host.

Once CAST Imaging is installed, service port numbers cannot be changed. See TCP ports for the full list of ports per component.

Network

The endpoints the installer and the installed product need to reach:

Target	Outcome if unreachable	Purpose
CAST Extend	Blocking	Downloading and synchronizing CAST extensions
The Control Panel of the central machine	Blocking	Allows `analysis-node`, `imaging-viewer` and `dashboards` to register with the Control Panel when they are installed on separate machines. Not checked for a single-machine installation
Docker Hub	Warning	Pulling the container images on Linux
The default Maven repositories - Maven Central, Jenkins, JBoss, Eclipse and Apache	Warning	Resolving build dependencies during analysis

Restricted and air-gapped environments

The network checks describe endpoints that a restricted environment is not expected to reach, and unreachable endpoints are normal there:

Where access to CAST Extend is not permitted, install the Extend Local Server to manage extensions on-premises.
Where the machine has no internet access, transfer the container images to it before installing - the air-gapped installation instructions are part of each Linux installation guide.
Where your organization mirrors the Maven repositories internally, the warning about the public repositories can be disregarded.

Hardware - CPU, RAM, disk and TCP ports
Software - operating systems, Java, container engines and browsers
Database - PostgreSQL releases and configuration
Disk space - per-component disk usage and storage locations