Agent Control v1.18.0

Features

• Added exponential backoff and jitter retries to OCI artifact fetches using a new BackoffPolicy (configured under self_update.download_retry), replacing the previous with_retries(usize, Duration) API.
• Added post-download script support for OCI packages.
• Hardened service restart policies on Linux and Windows platforms (implementing systemd rate limiting: maximum of 5 restarts within 60 seconds) to prevent crash-looping from saturating CPU capacity.
• Added support for retrieving remote agent type definitions directly from OCI registries.
• Configured agent type definitions to tolerate unknown fields to ensure forward compatibility.
• Added support for creating on-host agents without defining a health check, which disables health reporting for that agent.
• Streamlined version tracking for on-host agents by deriving versions directly from OCI package metadata. This eliminates command-based version checking and removes the need for the deployment.version configuration in agent type definitions.
• Replaced the filesystem configuration in on-host agent type definitions with an explicit, recursive, tagged-kind tree structure where every entry declares kind: file | dir | dir_content_from_map and dir entries nest using entries:.
• Introduced a persistent flag (default value is set to false) for on-host filesystem entries; ephemeral entries are deleted when a sub-agent stops, while persistent entries remain until the agent is removed from the fleet.Reconciliation across writes is driven by a .ac-managed-paths.json manifest (reserved filename — agent types must not declare it) so paths Agent Control no longer owns are deleted while sub-agent-created files are preserved.
• Introduced the shared-filesystem-dir variable for agent type configurations.
• Extended the internal fs crate to support file copy operations.
• Removed the filesystem manifest-based prune mechanism; Agent Control no longer deletes previously-declared paths dropped by subsequent configurations; agent-managed files are now reclaimed only when the agent is removed from the fleet.

Fixes

• Fixed an on-host self-update issue where pushing an empty version: "" string from Fleet Control incorrectly triggered an image pull of the :latest OCI tag. It now correctly treats an empty string as a no-op (), matching the behavior of an absent version field.

For a detailed description of changes, see the release notes.