use_identity agent config (#18592)
The initial intention behind the `vault.use_identity` configuration was to indicate to Nomad servers that they would need to sign a workload identities for allocs with a `vault` block. But in order to support identity renewal, #18262 and #18431 moved the token signing logic to the alloc runner since a new token needs to be signed prior to the TTL expiring. So #18343 implemented `use_identity` as a flag to indicate that the workload identity JWT flow should be used when deriving Vault tokens for tasks. But this configuration value is set on servers so it is not available to clients at the time of token derivation, making its meaning not clear: a job may end up using the identity-based flow even when `use_identity` is `false`. The only reliable signal available to clients at token derivation time is the presence of an `identity` block for Vault, and this is already configured with the `vault.default_identity` configuration block, making `vault.use_identity` redundant. This commit removes the `vault.use_identity` configuration and simplifies the logic on when an implicit Vault identity is injected into tasks.
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.