User-Level Socket-Based Checkpointing for Distributed and Parallel Computation

We present a preliminary description of a user-level checkpointing package, DMTCP, for Linux. The socket-based approach presents a novel method for checkpointing distributed processes. This includes checkpointing of any dynamically created POSIX threads and forked child processes. It also includes checkpointing of remotel y spawned processes via ssh and other mechanisms. As with all user-level checkpointing, no modification of the kernel is needed, and the application code is not modified. The package also checkpoints signal handlers, ordinary file descriptors, socket descriptors, and c ertain other types of file descriptors. Each checkpointed process has an associated checkpoint file . Hence, process migration, and even migration of an entire computation to a new cluster, are achieved through the simple expedient of copying checkpoint files to a new host. However, process migration adds the additional restriction that the source and destination hos t must be homogeneous.