AC Hosting Environment

AC Hosting Environment Documentation
  • 1 Release Notes
    • 1.1 End-Of-Life (EOL) Notice
    • 1.2 Support Policy
    • 1.3 Differences to CentOS
  • 2 Deployment
    • 2.1 Prerequisites
    • 2.2 Preparing to Install
    • 2.3 Installation
    • 2.4 Post Installation Steps
  • 3 AC Tools
    • 3.1 AC Configure Syslog
      • 3.1.1 Introduction
      • 3.1.2 Un/Installation
      • 3.1.3 Usage
    • 3.2 AC Firewall
      • 3.2.1 Introduction
      • 3.2.2 Un/Installation
      • 3.2.3 Usage
    • 3.3 AC Integrity
      • 3.3.1 Introduction
      • 3.3.2 Un/Installation
      • 3.3.3 Usage
      • 3.3.4 Integration Tips
    • 3.4 Make Bash Installer
      • 3.4.1 Introduction
      • 3.4.2 Un/Installation
      • 3.4.3 Usage
    • 3.5 AC X509 Authority
      • 3.5.1 Introduction
      • 3.5.2 Un/Installation
      • 3.5.3 Command Reference
      • 3.5.4 Certificates For Beginners
      • 3.5.5 CA Management
      • 3.5.6 Server, Client, and User Certificate Management
      • 3.5.7 Reporting Commands
      • 3.5.8 Troubleshooting

1.3 Differences to CentOS

December 15th, 2025

ACHE is not simply a rebranded and trimmed down version of CentOS. Specific to the intended deployment use cases, a number of important configuration changes have been pre-applied to both reduce workload for the system administrator and proactively reduce problems associated with the out-of-the-box configuration that ships with CentOS.

These changes are categorized below.

1.3.1 Security

  • Selinux has been disabled.
    The overhead impact on performance and added complexity of running Selinux can have a significant negative impact overall. In the use case scenarios that ACHE is deployed, Selinux should not be required.
  • Root SSH access has been disabled.
    No one should be logging in directly as the root user.
  • Firewall frontend interface has been replaced with AC Firewall.
    This is not a replacement of netfilter or the iptables command. Those still exist and are in fact used. However, the configuration frontend for the firewall (if used) is now via the new ac_firewall service.

1.3.2 Installation

  • Installation is hands-off fully automated. There are absolutely no user configuration installation options.
  • Installation relies on one (and only) one hard disk to be attached at installation time. ACHE is expected to be a lightweight single disk system or, a multi-disk system with removeable hot-swap drive bays.

1.3.3 Tuning

  • Kernel parameter nvm.swappiness=1 has been set. This is recommended by most commercial RDBMS releases (MariaDB, Oracle, Postgresql etc.)
  • Non required services are fully disabled (not just stopped).

1.3.4 Storage

  • The primary file system is XFS.
  • Installation will automatically configure a single disk to use XFS and LVM.

1.3.5 Software

  • Most packages included with CentOS have been omitted from the release. The remaining packages should leave a fully functioning system with all the expected command-line tools that a system administrator actually uses day-to-day.
  • No desktop UI related packages are included.
  • Basic Enterprise Application Realm (BEAR) is included with the ACHE distribution but not installed. BEAR can be located in the /root/BEAR/ directory.
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