KAI Scheduler vs OpenPBS

KAI Scheduler is a self-hosted, open-source Kubernetes scheduler for allocating GPUs to AI workloads such as data processing, training, and inference. It supports interactive notebooks through multi-node distributed training in one cluster and is designed for large GPU clusters and high-throughput workloads. Hierarchical queue trees provide quotas, limits, priorities, and borrowing between teams. Gang scheduling places distributed workloads together when resources are available, while elastic workloads change replica counts within configured minimum and maximum values. GPU sharing includes time slicing, MPS, and MIG. Other scheduling controls include topology-aware placement, time-based fairshare, and priority-based preemption. KAI documents integrations with Ray on Kubernetes and Grove. It runs on cloud or on-premises infrastructure, including Karpenter environments. Installation uses a production Helm chart, source builds, or ArgoCD, with a running Kubernetes cluster, Helm CLI, and NVIDIA GPU Operator required for GPU requests. The Apache-2.0 project is also a CNCF sandbox project.

OpenPBS schedules jobs and manages workloads in high-performance computing environments, including clusters, clouds, and supercomputers. Its policy-driven scheduling balances job turnaround time and system utilization while selecting job placements. The system is designed for millions of cores and has been tested beyond 50,000 nodes. A plugin framework provides administration visibility and supports customized extensions. Health checks monitor faults and can mitigate them automatically; the fail-over architecture is designed to avoid a single point of failure and keep jobs running through failures. OpenPBS is self-hosted and free under the AGPL 3.0 open-source license, while PBS Pro is also dual licensed commercially. Public-sector organizations such as academic and research facilities generally choose the open-source license. Community help comes through a volunteer forum, without a guarantee of answers or bug fixes. OpenPBS is integrated into the OpenHPC software stack. The installation guide states that SELinux is not supported, and critical and high security fixes are delivered in the next major release.