Rocks Cluster Distribution
Rocks Cluster Distribution, commonly known as Rocks, is an open-source Linux distribution tailored for high-performance computing (HPC) environments, enabling users to deploy and manage computational clusters, grid endpoints, and visualization tiled-display walls on commodity hardware without requiring specialized expertise.[1] Based on CentOS, it provides a streamlined "cluster on a CD/DVD" installation process that automates node provisioning, networking, and software configuration, making it accessible for scientific and research applications.[1][2] Development of Rocks began in May 2000 under the Rocks Cluster Group at the San Diego Supercomputer Center (SDSC) at the University of California, San Diego, with the primary goal of addressing the complexities of cluster deployment and management.[1][3] The project was supported by funding from the National Science Foundation (NSF), including grants OCI-1032778 and OCI-0721623, which facilitated its evolution into a robust tool for scalable computing.[1] Key innovations include the use of "rolls"—modular software packages that allow customization for specific needs, such as parallel processing libraries or storage solutions—enhancing flexibility while maintaining ease of use.[1] The latest stable release, Rocks 7.0 "Manzanita," was issued on December 1, 2017, and is exclusively 64-bit, built on CentOS 7.4 (which reached end-of-life in June 2024) with integrated security updates including those for Spectre and Meltdown vulnerabilities.[1] Although official active development has been dormant since 2017, community efforts provided updates and unofficial releases (such as 7.2.0-UCR in 2023 based on CentOS 7.9) through 2024, with major repositories archived by September 2025; the distribution remains available via its official repository and GitHub, continuing to serve the scientific community for building reliable HPC infrastructures.[1][4] Its source code and documentation are openly accessible, supporting ongoing use and potential extensions through community contributions.[1]Overview
Definition and Purpose
Rocks Cluster Distribution, originally known as NPACI Rocks, is an open-source Linux distribution specifically designed for deploying and managing high-performance computing (HPC) clusters, grid endpoints, and visualization walls.[1] It was initiated in May 2000 by the Rocks Group at the San Diego Supercomputer Center (SDSC) to address the challenges associated with cluster deployment and management in scientific computing environments.[5] The primary purpose of Rocks is to automate the installation, configuration, and scaling of clusters, enabling users to build and maintain HPC systems without requiring deep expertise in system administration.[1] This approach democratizes access to parallel computing resources, supporting a wide range of scientific research applications by simplifying the setup of complex, multi-node infrastructures.[6] Rocks has achieved significant global adoption, with over 1,300 registered clusters as of 2008.[7] The distribution is derived from CentOS/Red Hat Enterprise Linux, with the latest version (7.0 Manzanita) based on CentOS 7.4.[8] It supports customization via modular add-ons called Rolls.[1] Official development has been dormant since the 2017 release of version 7.0, though community updates, such as update rolls in 2024 and installation images in 2025, continue to provide extended support.[9]Key Features
Rocks Cluster Distribution facilitates automated cluster provisioning through a modified version of the Anaconda installer, which supports PXE-based network booting and kickstart configurations to enable rapid deployment of compute nodes across the network.[10] This approach minimizes manual intervention, allowing administrators to install and configure entire clusters from a single frontend machine.[1] A core strength lies in its modular "rolls" system, which permits users to incorporate specialized software stacks—such as those for job scheduling or monitoring—through a straightforward checkbox selection during the installation process.[10] Rolls are self-contained packages that integrate seamlessly, enabling customization without altering the base distribution.[1] The distribution accommodates heterogeneous hardware environments; while earlier versions supported both x86 and x86_64 architectures, version 7.0 is exclusively 64-bit (x86_64) for enhanced performance on modern systems.[10][11] Built-in management tools further simplify operations, including Ganglia for real-time cluster monitoring and integrated DHCP/TFTP services for automatic node discovery and booting.[10] Scalability is a defining attribute, with Rocks capable of managing clusters ranging from small laboratory setups to installations comprising thousands of nodes, supported by roll-based software distribution that streamlines upgrades and maintenance.[10] As an open-source project released under various open-source licenses, including the GNU GPL v2, BSD, and others, it fosters community contributions through its GitHub repository, promoting ongoing development and adaptation.[10][12][13] It is based on CentOS for stability.[11]History
Origins and Development
The Rocks Cluster Distribution was founded in May 2000 by the Rocks Group at the San Diego Supercomputer Center (SDSC), as part of the National Partnership for Advanced Computational Infrastructure (NPACI).[12] The initiative emerged in response to the burgeoning demands of high-performance computing (HPC) in the early 2000s, particularly the challenges associated with deploying and managing Beowulf-style clusters using commodity hardware.[14] These clusters, while cost-effective, often required extensive manual configuration, leading to software inconsistencies and administrative burdens that hindered scalability for scientific applications.[15] Leadership of the project was provided by Philip M. Papadopoulos, then Associate Director of Distributed Computing at SDSC, with significant contributions from Greg Bruno and Mason J. Katz, both affiliated with the University of California, San Diego (UCSD) and SDSC.[16] The first release, known as NPACI Rocks, appeared in 2000 and quickly transitioned to a fully open-source model under the Rocks Cluster Group, emphasizing community accessibility and reproducibility.[17] Around 2002-2003, the team introduced the "rolls" concept to enhance modularity, allowing users to add specialized software packages without altering the core distribution, which marked a pivotal evolution toward customizable HPC environments.[18] Subsequent development addressed base operating system stability by shifting from Red Hat Linux to CentOS in later iterations, prioritizing community-driven updates for long-term reliability in enterprise-like deployments.[17] By the 2010s, the project migrated its codebase to GitHub at github.com/rocksclusters, facilitating collaborative contributions, though updates became less frequent after 2017 as the focus shifted to maintenance of existing installations.[13] This evolution reflected the Rocks Group's ongoing commitment to simplifying cluster lifecycle management, supported briefly by National Science Foundation funding.[19]Funding and Milestones
The development of Rocks Cluster Distribution received primary financial support from the U.S. National Science Foundation (NSF), with initial grants spanning from 2000 to 2007 focused on establishing the toolkit for high-performance computing clusters.[1] A follow-up NSF grant, OCI-0721623 titled "SDCI: NMI: Improvement: The Rocks Cluster Toolkit and Extensions to Build User-Defined Cyberenvironments," provided funding from 2007 to 2010 for core enhancements, including support for grid computing and visualization features.[20] An additional NSF grant, OCI-1032778, extended support through 2011 to sustain development and maintenance efforts at the University of California, San Diego (UCSD).[1] Key milestones in Rocks' evolution include its 2007 integration with the Intel Cluster Ready program, which certified Rocks as compatible with Intel hardware to streamline high-performance computing deployments.[21] By 2010, Rocks achieved peak adoption with 1,376 registered clusters worldwide, demonstrating its widespread utility in academic and research environments.[22] In 2017, the release of version 7.0 (Manzanita) marked a significant shift to a fully 64-bit architecture based on CentOS 7.4, aligning with modern hardware requirements and dropping legacy 32-bit support.[1] Rocks was developed through institutional partnerships at UCSD and the San Diego Supercomputer Center (SDSC), with international collaborations including deployment at GridKa, Germany's Tier-1 center for high-energy physics computing, which hosted one of the largest registered Rocks clusters.[1] These efforts extended to educational settings, where Rocks facilitated hands-on teaching of high-performance computing concepts in university courses and workshops.[23] Following the conclusion of major NSF funding in 2011, Rocks transitioned to community-driven maintenance, with contributors providing minor updates such as security patches for vulnerabilities like Spectre and Meltdown in January 2018. As of 2025, active development remains dormant since 2017, with the project sustained through existing repositories for legacy support.[1] This approach enabled non-experts to deploy and manage clusters efficiently, influencing subsequent open-source HPC tools like OpenHPC by emphasizing simplified installation and modular extensions.[24]Architecture
Core Components
The Rocks Cluster Distribution employs a frontend-backend model as its foundational architecture, where the frontend, or head node, functions as the central server responsible for cluster orchestration. It handles automated installation processes through services such as DHCP for IP address allocation to compute nodes, TFTP for serving PXE boot files like pxelinux.0, and HTTP for distributing Kickstart files and enabling web-based access during booting.[10][25] These services ensure seamless provisioning of compute nodes via network booting, with the frontend requiring essential daemons like dhcpd, httpd, and autofs to support the process.[10] Backend services integrate automated operating system deployment and state management to maintain cluster integrity. Kickstart, based on Red Hat's automation tool, generates dynamic installation profiles via CGI scripts on the frontend, facilitating unattended OS setups for nodes.[25] Complementing this is an XML-based configuration database stored in SQL (typically MySQL), which manages cluster-wide attributes, network settings, and node-specific parameters through a graph-based inheritance model with nearly 100 modules for heterogeneous environments.[10][25] This database enables precise control over appliance types, such as compute or login nodes, by referencing XML variables for customized configurations. Software distribution in Rocks relies on RPM packages managed through Yum repositories, allowing efficient updates and dependency resolution across the cluster.[10] Rolls, which extend core functionality, are packaged as ISO add-ons containing RPMs, XML definitions, and integration scripts, deployable via CD, DVD, or network installation.[10] Monitoring is provided by default through Ganglia, which tracks resource utilization across nodes with versions such as 3.6.0 integrated into the base distribution.[10] Networking supports public and private interfaces, VLANs, and channel bonding, with MySQL handling backend database operations isolated under /opt/rocks.[10] Security features include built-in firewall rules configurable via command-line tools, automated SSH key distribution for host-based authentication, and appliance-based access controls that enforce role-specific permissions, such as random root passwords for backend nodes.[10] The base operating system layer consists of a CentOS kernel with Rocks-specific patches optimized for clustering, supporting standard Linux networking protocols without custom derivations.[10] This foundation, derived from Red Hat Enterprise Linux via CentOS (versions including 5, 6, and 7), ensures compatibility and stability for high-performance computing environments.[25][10]Node Configuration
In a Rocks cluster, the frontend serves as the single master node responsible for managing the entire system, including service orchestration, persistent storage for the cluster database, and distribution of configurations to other nodes. It runs essential services such as DHCP, DNS, and the Kickstart server for node provisioning, requiring a minimum of 30 GB disk space, 1 GB RAM, and two Gigabit Ethernet ports for public and private networks.[26][10] Compute nodes function as worker nodes dedicated to executing parallel computational jobs, typically provisioned through network booting via PXE and supporting bare-metal deployments or virtualization environments like KVM or Xen when enabled through specific rolls. These nodes connect primarily via a single private Ethernet interface and synchronize configurations from the frontend, with hardware needs including at least 30 GB disk and 1 GB RAM to handle job execution efficiently.[27][10] Specialized appliances extend the cluster's functionality, such as login nodes that provide user access points for interactive sessions and storage nodes that manage shared filesystems like Lustre when integrated via corresponding rolls. These nodes inherit base hardware requirements but may require additional resources, such as expanded storage for fileservers or multi-core processors for user loads, to fulfill their roles without impacting core compute performance.[27][28] Node configuration begins with defining hosts in the Rocks MySQL database using their MAC addresses, captured via theinsert-ethers command during initial DHCP requests, enabling automated assignment of hostnames, IP addresses, and appliance types. While Rocks supports heterogeneous hardware including varied CPUs and GPUs across nodes through cross-kickstarting mechanisms, uniform configurations are recommended to optimize parallel job performance and avoid compatibility issues in MPI-based workloads.[27][28]
For scalability, Rocks clusters can expand to thousands of nodes leveraging multicast-based discovery protocols in tools like Ganglia for monitoring and efficient PXE booting for provisioning, with power management facilitated through IPMI integration to enable remote control of node states across large deployments. Hardware compatibility emphasizes x86_64 architectures since version 7.0, which is based on CentOS 7, while older releases provide backward support for x86 via cross-architecture kickstarts.[10]
Rolls
Base Rolls
The Base Rolls form the foundational layer of the Rocks Cluster Distribution, comprising the essential components required for any basic cluster deployment. These rolls—Base, Kernel, OS, Web Server, and Boot—provide the operating system infrastructure, customized kernel, booting mechanisms, and initial management tools, ensuring a functional frontend and compute node provisioning without optional extensions. They are always included in installations and integrate via a modular structure to support automated configuration and scalability. The Base Roll delivers core operating system packages, Rocks-specific command-line tools (e.g.,rocks add host for adding nodes, rocks sync config for propagating changes), and XML-based configuration files for cluster-wide settings. It incorporates utilities like cfengine for automated configuration management, MySQL for storing cluster data such as host attributes, and scripts for secure information distribution (e.g., 411 service). This roll includes over 100 administrative commands (e.g., list host, set host attr, report host) and supports features like PXE booting, DNS/DHCP setup, IPMI integration, VLANs, and firewall rules, all built on CentOS or compatible distributions. The Base Roll contains RPM packages for core utilities (e.g., coreutils under GNU GPL v2, wget), development tools (e.g., Perl, Python), and networking services (e.g., NTP for time synchronization), along with spec files for package building and insert-ethers scripts that populate the database with node details during provisioning.[10]
The Kernel Roll supplies a customized Linux kernel with patches optimized for clustering environments, including support for high-speed interconnects like Infiniband via loadable modules. It is tightly version-matched to the OS Roll's base (e.g., CentOS 7.4 kernel for Rocks 7.0) to ensure compatibility and includes boot loader components such as GRUB configurations. Key contents encompass kernel images (vmlinuz), initial ramdisks (initrd.img), and RPMs for kernel modules, along with spec files and insert-ethers scripts for seamless integration into the cluster database. This roll enables UEFI and legacy BIOS booting, facilitating the initial frontend startup and node provisioning.[29][30]
The OS Roll furnishes distro-specific operating system packages tailored for Rocks, such as CentOS 7.4 in Rocks 7.0, encompassing base system libraries, the GNOME desktop environment, and development toolsets (e.g., GCC, JDK). It bundles over 9,000 RPMs for essential functionalities like file systems (Autofs), security (SSH, SSL), and utilities (e.g., Python 2.7.5 and 3.6.2, Perl 5.16.3), ensuring a complete runtime environment for both frontend and compute nodes. The roll includes spec files for custom builds and insert-ethers scripts to automate OS-specific node registration in the MySQL database, with support for architectures like x86_64 and i386.[30][10]
The Web Server Roll establishes an Apache-based web interface for cluster administration, integrating PHP for dynamic scripting and MySQL as the backend database to power the Rocks portal. This enables browser-based management of nodes, rolls, and configurations, with RPMs for HTTPD server components, secure SSL support, and related libraries (e.g., libxml2). It includes spec files for packaging and insert-ethers scripts to link web services with the cluster's node database, providing a centralized dashboard for tasks like monitoring and updates.[31][10]
The Boot Roll, often combined with the Kernel Roll, manages PXE and TFTP services for automated node installation, supplying initial ramdisk images, boot loaders, and network boot configurations (e.g., pxelinux setups in /tftpboot). It contains RPMs for boot utilities (e.g., rocks-boot), spec files for kernel integration, and insert-ethers scripts that detect and register node MAC addresses via DHCP during provisioning. This roll ensures stateless compute node imaging over the network, supporting features like device driver loading and partition schemes.[29][27]
All Base Rolls share a common structure: directories of RPM packages for installation, spec files defining build parameters, and insert-ethers scripts that interface with the cluster's MySQL database to handle node discovery and configuration. These rolls are added to the frontend during initial setup using commands like rocks add roll <roll.iso>, rebuilding the distribution for deployment. Community efforts have continued post-2017, including an unofficial 7.2.0-UCR release (2023) with refreshed base components based on CentOS 7.9.2009.[10][4]
Extension Rolls
Extension rolls are optional software packages in the Rocks Cluster Distribution that enable customization for specialized domains, such as high-performance computing (HPC), grid computing, and visualization, by adding domain-specific tools and configurations without altering the core system. These rolls are designed to integrate seamlessly during cluster installation or post-deployment, allowing users to tailor the cluster to particular workloads while maintaining the simplicity of Rocks' appliance-based approach. Unlike base rolls, which provide essential operating system and networking components, extension rolls focus on enhancing functionality for advanced applications. The HPC Roll equips clusters for parallel computing workloads by installing pre-configured tools, including MPI implementations such as OpenMPI for Ethernet-based parallelism and MPICH for distributed applications, along with parallel virtual machine (PVM) support and cluster-fork for running commands in parallel. Compilers like GCC are available via the OS Roll, while optimized options such as Intel compilers require a separate roll.[32] The Condor Roll incorporates HTCondor, an open-source job scheduler for high-throughput distributed computing, providing integration for resource discovery, matching, and job submission across heterogeneous nodes in the cluster. It enables efficient workload distribution by leveraging Condor's matchmaking capabilities to allocate tasks based on resource availability and requirements, making it suitable for non-dedicated or opportunistic computing scenarios.[33] The Grid Roll extends Rocks for grid computing environments by including the Globus Toolkit for secure data transfer and resource management, WS-GRAM for web services-based grid resource allocation, and utilities for certificate management using tools like the Simple Certificate Authority. This setup supports federated resource sharing and authentication in distributed grid infrastructures, allowing clusters to function as grid endpoints.[34] The Viz Roll supports the creation of visualization clusters, particularly for tiled display walls, by providing tools such as SAGE (Scalable Adaptive Graphics Environment) for collaborative, multi-application visualization across multiple screens. It configures nodes as display drivers, enabling high-resolution, immersive environments for scientific data rendering and interaction.[35] Additional examples of extension rolls include the ZFS Roll, which integrates zfs-linux-0.7.3 to provide advanced file system features like snapshots, compression, and RAID-Z for scalable storage management on cluster nodes. The ZFS roll was updated in 2017 for compatibility with Rocks 7.0. Another is the Intel Cluster Ready Roll, released in 2008, which certifies hardware compatibility and automates the installation of Intel compilers, libraries, and tools to ensure optimized performance on Intel-based clusters.[36][21] Users can create custom extension rolls using the Rocks toolkit, which involves packaging software RPMs with dependencies into a structured directory, defining installation graphs and node configurations via XML files, and including post-install scripts for automated setup. This process ensures the roll adheres to Rocks' distribution model for easy integration.[37] Extension rolls are versioned to align with specific base releases of Rocks, ensuring compatibility; for instance, rolls like the ZFS update are tailored for Rocks 7.0 to match its kernel and OS components.[36]Installation and Management
Deployment Process
The deployment of a Rocks Cluster Distribution begins with preparation of the installation media for the latest stable release, Rocks 7.0 "Manzanita" (based on CentOS 7.4, released December 1, 2017). Administrators download the necessary ISO images from the official Rocks repository, including the Kernel Roll and other required rolls such as Base, Core, CentOS, and Updates-CentOS, which provide the foundational software stack. These ISOs are used to create bootable USB drives or CDs for the frontend, while compute nodes rely on PXE network booting. Rocks 7.0 supports network-only installation, requiring all rolls to be hosted on an accessible roll server. Compatible hardware is assembled, with the frontend node recommended to have at least 30 GB disk space, 1 GB RAM, and two Ethernet ports (one private, one public), while compute nodes require 30 GB disk, 1 GB RAM, and one Ethernet port connected to the private network, with BIOS/UEFI settings prioritizing PXE boot.[38][30] The frontend installation serves as the central management node for the cluster. The frontend machine is booted from the Kernel Roll media (USB or CD). At the boot menu, select "Install Rocks 7.0" to start the Anaconda installer. Network configuration follows: assign a static IPv4 address to the public interface (e.g., eth1) and set IPv6 to "link-local only" if needed; for the private network (e.g., eth0), select the interface and ensure no overlap with public subnets. In the roll selection screen, access available rolls from the network server and add required ones (e.g., Base, Core, Kernel, CentOS, Updates-CentOS) via the "Add Selected Rolls" option; additional rolls like Ganglia or HPC can be included for specific needs. System settings include hostname, gateway, DNS, root password, and timezone. For disk partitioning, use manual mode in the "Installation Destination" to allocate space, ensuring at least 10 GB for /export/rocks on a separate partition for scalability (e.g., 8 GB for /, 4 GB for /var, 1 GB swap, remainder to /export). The installer downloads packages from the rolls, initializes the MySQL database for cluster metadata, and reboots upon completion. Note that this process differs from earlier versions by emphasizing network access for rolls rather than physical media insertion.[30] Once the frontend is operational, compute nodes are provisioned to expand the cluster. As root on the frontend, execute theinsert-ethers command to listen for PXE requests from new nodes, selecting the "Compute" profile. Compute nodes are powered on, triggering PXE boot over the private Ethernet network connected to the frontend's private port (eth0). Upon detecting a node's MAC address, the frontend assigns a hostname (e.g., compute-0-0), an IP from the defined range, and serves a customized Kickstart file via HTTPS, automating OS installation, package deployment from selected rolls, and configuration. The process is monitored using rocks-console <[hostname](/page/Hostname)> to view progress, with insert-ethers marking success with an asterisk (*) next to the node. For larger setups, use the --cabinet option. Customization is possible through XML profiles or commands like rocks set host geom before provisioning. Since Rocks 7.0 requires PXE for compute nodes, hardware without PXE support may need initial configuration or alternatives like temporary USB booting to enable it.[39][40]
Verification confirms successful deployment. Run rocks list host on the frontend to list provisioned hosts, profiles, and status. The Ganglia web interface, accessible at the frontend's IP (port 80), displays real-time metrics like CPU load and memory usage; active nodes show heartbeats, with issues flagged visually. Test connectivity with pdsh -w compute-* uptime. Deployment times are approximately 30 minutes for the frontend and 10-20 minutes per compute node, varying by hardware and network.[41]
Cluster Administration
Cluster administration in Rocks Cluster Distribution involves command-line tools and practices to maintain, monitor, and scale HPC environments post-deployment. The Rocks CLI provides control over the configuration database for propagating changes and managing nodes.[42] Key tools includerocks sync config to rebuild and distribute configuration files from the database after changes. For remote execution, rocks run host runs commands on groups like compute nodes (e.g., rocks run host compute "ls /tmp"). Node management uses add host and remove host to integrate or decommission nodes, updating the database.[43][44][45]
Monitoring uses the Ganglia web interface for cluster metrics, with daemons reporting CPU, memory, and network data. Integration with Nagios is possible via rolls and plugins like check_rocks_nodes for health alerts.[41][46]
Upgrades use the roll architecture, but are limited since Rocks 7.0's base OS, CentOS 7, reached end-of-life on June 30, 2024. Previously, yum update applied roll-based updates on the frontend, propagated to nodes; kernel updates required reboots and potential reinstalls. As of 2025, no new official updates are available; use archived repositories for critical fixes or consider migrating to a supported distribution. Custom update rolls can still be inserted for specific needs.[47]
Scaling adds nodes via PXE booting, integrating them through the database. Virtual scaling uses rolls like KVM for VM compute nodes, managed with rocks start host vm.[27][48]
Troubleshooting involves logs in /var/log/rocks-install for kickstart errors and rocks report host for configuration reports. Best practices include regular backups of /var/rocks using mysqldump and enabling SELinux in enforcing mode for security, compatible with cluster services. Note that due to the project's dormancy since 2017 and base OS EOL, long-term support may require community extensions or alternatives.[49][50][51][5]