9ed75e1f72
When client nodes are restarted, all allocations that have been scheduled on the node have their modify index updated, including terminal allocations. There are several contributing factors: * The `allocSync` method that updates the servers isn't gated on first contact with the servers. This means that if a server updates the desired state while the client is down, the `allocSync` races with the `Node.ClientGetAlloc` RPC. This will typically result in the client updating the server with "running" and then immediately thereafter "complete". * The `allocSync` method unconditionally sends the `Node.UpdateAlloc` RPC even if it's possible to assert that the server has definitely seen the client state. The allocrunner may queue-up updates even if we gate sending them. So then we end up with a race between the allocrunner updating its internal state to overwrite the previous update and `allocSync` sending the bogus or duplicate update. This changeset adds tracking of server-acknowledged state to the allocrunner. This state gets checked in the `allocSync` before adding the update to the batch, and updated when `Node.UpdateAlloc` returns successfully. To implement this we need to be able to equality-check the updates against the last acknowledged state. We also need to add the last acknowledged state to the client state DB, otherwise we'd drop unacknowledged updates across restarts. The client restart test has been expanded to cover a variety of allocation states, including allocs stopped before shutdown, allocs stopped by the server while the client is down, and allocs that have been completely GC'd on the server while the client is down. I've also bench tested scenarios where the task workload is killed while the client is down, resulting in a failed restore. Fixes #16381 |
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README.md
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.