By Ian Lumb | September 25, 2013 | workload manager, HPC cluster management, cluster management shell, node provisioning, CMGUI, Software image, HPC, node categories, Cluster Management, HPC Cluster, Linux Cluster, Linux Cluster Management, Bright Cluster Manager, cluster testing, GUI, adding nodes, HPC job schedulers, User authentication, Power Distribution Units, head node, linux cluster configuration, HPC cluster configuration, CMSH, login nodes, interactive sessions, access services, access control
Whether it’s force of habit, or from actual need, users of HPC environments crave interactivity. Because the impact of unmanaged interactive sessions can be significant, there exists the potential for concern. Is it possible to meet users’ need for interactivity while managing the potential for impact? In this first part of a two-part series on managing interactive impact, attention focuses on the introduction of login nodes to a cluster managed by Bright Cluster Manager. The second part in this series will focus on use of workload managers as a complementary means for managing the interactive impact on the compute nodes of a cluster.
In the simplest case, clusters are comprised of a head node plus multiple compute nodes. As the names suggest, the head node manages all the resources within its control, whereas compute nodes are those resources focused on executing computational workloads. (In addition to compute nodes, and even in the simplest of cases, head nodes typically manage network, power-distribution and potentially other devices.) As the only dual-home node within a cluster, the head node provides services both internally (i.e., to the resources it manages such compute nodes, network switches, PDUs, etc.) and externally to the cluster. In this simplest of configurations, access is one of the key services provided by the head node for the entire cluster.
The purpose of this post is to introduce a solution for managing interactive impact. More specifically, the burden of delivering a user-facing access service, is shifted from the head node to another managed resource in the cluster. Typically identified as a login node, configuration considerations for this user-facing access service might include:
Bright Cluster Manager allows login nodes to be created, subject to the configuration considerations outlined above. The process is as follows:
Bright Cluster Manager includes a Command-Line Interface (CLI) as well as a GUI. It is noteworthy that each of the above steps can be applied through use of either the CMSH CLI or CMGUI.
The intent of the above was only to provide an overview of the steps involved in the creation of login nodes for a cluster managed by Bright Cluster Manager. The details of these steps can be found in the Bright Knowledge Base article “How do I add a login node?”. This article on login nodes is the second most popular FAQ in the Bright Cluster Manager Knowledge Base. (To view the other nine FAQs in this top 10 list, go to the FAQ Home area of The Bright Knowledge Base and look for the “Most popular FAQs” column on the right.) The Bright Knowledge Base is a substantial and authoritative resource for assistance in managing clusters via the Bright Cluster Manager. With numerous contributions from Bright users as well as Bright Computing, this Knowledge Base complements resources like the extensive and comprehensive Bright Administrator Manual.
In this first part of a two-part series on managing the impact of interactive use, attention focused on the introduction of login nodes to a cluster managed by Bright Cluster Manager. By introducing login nodes using Bright, the head node of a cluster is completely relieved of the burden of delivering a user-facing service for interactive use.