BCFG: A Configuration Management Tool for Heterogeneous Environments

Since clusters were first introduced[5], node counts have increased rapidly. Currently, a variety of clusters with more than one thousand nodes are listed on the TOP500 list. In the next three years, clusters with more than four thousand nodes are expected. Cluster management functionality has lagged behind all areas of system software. In order to effectively manage the clusters of today and tomorrow, the basic cluster management software model must change. Current techniques focus on the management of single nodes, as opposed to complete cluster configurations. This approach typically leads to automatic management of compute nodes, while using ad-hoc techniques to manage service nodes. Configuration management is the process where software configurations on clients are installed, updated and verified. Scalability in this context applies not only to node count, but also to numbers of administrators and discrete configurations. Another important area is that of cluster-aware configuration description languages. We believe these concerns will impact large cluster operations greatly if not addressed. To address these issues, we have begun development of BCFG, a symbolic configuration management tools for heterogeneous clusters. It uses a multi-tiered configuration description, allowing high levels of reuse among differing configurations. BCFG is intended as a vehicle for research into system management problems, and experimentation with new techniques. This effort was also motivated by our experiences on Chiba City[2], our testbed cluster. Testbed users can specify the software configuration for nodes; this allows the automatic replacement of any portion of the default cluster OS. Chiba City’s configuration management requirements are complex, due to this testbed usage model. However, we feel that these problems translate to large scale computational clusters as well; as the size of these clusters grows, the numbers of discreet configurations employed will grow as well.