0ba7d0036b
When claiming a CSI volume, we need to ensure the CSI node plugin is running before we send any CSI RPCs. This extends even to the controller publish RPC because it requires the storage provider's "external node ID" for the client. This primarily impacts client restarts but also is a problem if the node plugin exits (and fingerprints) while the allocation that needs a CSI volume claim is being placed. Unfortunately there's no mapping of volume to plugin ID available in the jobspec, so we don't have enough information to wait on plugins until we either get the volume from the server or retrieve the plugin ID from data we've persisted on the client. If we always require getting the volume from the server before making the claim, a client restart for disconnected clients will cause all the allocations that need CSI volumes to fail. Even while connected, checking in with the server to verify the volume's plugin before trying to make a claim RPC is inherently racy, so we'll leave that case as-is and it will fail the claim if the node plugin needed to support a newly-placed allocation is flapping such that the node fingerprint is changing. This changeset persists a minimum subset of data about the volume and its plugin in the client state DB, and retrieves that data during the CSI hook's prerun to avoid re-claiming and remounting the volume unnecessarily. This changeset also updates the RPC handler to use the external node ID from the claim whenever it is available. Fixes: #13028
Nomad
Nomad is a simple and flexible workload orchestrator to deploy and manage containers (docker, podman), non-containerized applications (executable, Java), and virtual machines (qemu) across on-prem and clouds at scale.
Nomad is supported on Linux, Windows, and macOS. A commercial version of Nomad, Nomad Enterprise, is also available.
- Website: https://nomadproject.io
- Tutorials: HashiCorp Learn
- Forum: Discuss
Nomad provides several key features:
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Deploy Containers and Legacy Applications: Nomad’s flexibility as an orchestrator enables an organization to run containers, legacy, and batch applications together on the same infrastructure. Nomad brings core orchestration benefits to legacy applications without needing to containerize via pluggable task drivers.
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Simple & Reliable: Nomad runs as a single binary and is entirely self contained - combining resource management and scheduling into a single system. Nomad does not require any external services for storage or coordination. Nomad automatically handles application, node, and driver failures. Nomad is distributed and resilient, using leader election and state replication to provide high availability in the event of failures.
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Device Plugins & GPU Support: Nomad offers built-in support for GPU workloads such as machine learning (ML) and artificial intelligence (AI). Nomad uses device plugins to automatically detect and utilize resources from hardware devices such as GPU, FPGAs, and TPUs.
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Federation for Multi-Region, Multi-Cloud: Nomad was designed to support infrastructure at a global scale. Nomad supports federation out-of-the-box and can deploy applications across multiple regions and clouds.
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Proven Scalability: Nomad is optimistically concurrent, which increases throughput and reduces latency for workloads. Nomad has been proven to scale to clusters of 10K+ nodes in real-world production environments.
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HashiCorp Ecosystem: Nomad integrates seamlessly with Terraform, Consul, Vault for provisioning, service discovery, and secrets management.
Quick Start
Testing
See Learn: Getting Started for instructions on setting up a local Nomad cluster for non-production use.
Optionally, find Terraform manifests for bringing up a development Nomad cluster on a public cloud in the terraform directory.
Production
See Learn: Nomad Reference Architecture for recommended practices and a reference architecture for production deployments.
Documentation
Full, comprehensive documentation is available on the Nomad website: https://www.nomadproject.io/docs
Guides are available on HashiCorp Learn.
Roadmap
A timeline of major features expected for the next release or two can be found in the Public Roadmap.
This roadmap is a best guess at any given point, and both release dates and projects in each release are subject to change. Do not take any of these items as commitments, especially ones later than one major release away.
Contributing
See the contributing directory for more developer documentation.