98e122c7e2
In #12112 and #12113 we solved for the problem of races in releasing volume claims, but there was a case that we missed. During a node drain with a controller attach/detach, we can hit a race where we call controller publish before the unpublish has completed. This is discouraged in the spec but plugins are supposed to handle it safely. But if the storage provider's API is slow enough and the plugin doesn't handle the case safely, the volume can get "locked" into a state where the provider's API won't detach it cleanly. Check the claim before making any external controller publish RPC calls so that Nomad is responsible for the canonical information about whether a volume is currently claimed. This has a couple side-effects that also had to get fixed here: * Changing the order means that the volume will have a past claim without a valid external node ID because it came from the client, and this uncovered a separate bug where we didn't assert the external node ID was valid before returning it. Fallthrough to getting the ID from the plugins in the state store in this case. We avoided this originally because of concerns around plugins getting lost during node drain but now that we've fixed that we may want to revisit it in future work. * We should make sure we're handling `FailedPrecondition` cases from the controller plugin the same way we handle other retryable cases. * Several tests had to be updated because they were assuming we fail in a particular order that we're no longer doing.
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
- Mailing List: Google Groups
- Gitter: hashicorp-nomad
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.
Contributing
See the contributing directory for more developer documentation.