Kron Documentation
Start here for installation and day-to-day usage, then use the specification set for formal contracts.
Getting Started
Specifications
- HELLOKRON.md
- SPEC.md
- Scope
- Terminology
- Time Model
- Inputs
- Outputs
- Periods
- Window Semantics
- Distribution Semantics
- Seed Semantics
- Constraint Semantics
- Decision Computation
- Handling and Outcomes
- Execution Trigger Semantics
- Deadline Semantics
- Concurrency Semantics
- Idempotency Semantics
- State Machine
- Spec Change Semantics
- Clock Change Semantics
- Observability Contract
- Invariants
- Compatibility
- CORE-SPEC.md
- Scope
- Design Constraints
- Versioning
- Core Concepts
- Primary Interfaces
- Determinism Requirements
- PeriodID
- Window Computation
- Seed Derivation
- Seed Hash
- PRNG Requirements
- Distribution Specification
- Distribution Contract
- Constraint Specification
- Candidate Selection Algorithm
- Constraint Evaluation Rules
- Error Handling
- Timezone Handling
- Precision Rules
- Unschedulable Semantics
- Stability Guarantees
- Performance Requirements
- Prohibited Behaviors
- Conformance
- SYNTAX.md
- KRONTAB File Format Specification
- EXECUTION.md
- Scope
- Process Model Overview
- krond Lifecycle
- Scheduler Loop
- Job Identity
- Fork and Exec Model
- Execution Environment
- Concurrency Handling
- Timeout Handling
- State Persistence
- Missed Period Handling
- Output Handling
- Signal Handling
- Locking Model
- Isolation and Security
- Resource Limits
- Crash Recovery
- Determinism Guarantee
- Performance Model
- Failure Guarantees
- Summary
- STATE.md
- Scope
- Goals
- Storage Location
- State File Schema
- Field Definitions
- State Transitions
- Write Semantics
- Idempotency Rules
- Crash Recovery
- Period Advancement Rules
- Deadline Interaction
- Unschedulable Period
- Concurrency Interaction
- State Corruption Handling
- Migration Rules
- File Permissions
- Locking
- Invariants
- Non-Goals
- ERROR-MODEL.md
- Scope
- Design Principles
- Error Categories
- ConfigurationError
- ValidationError
- SchedulingError
- ConstraintError
- Unschedulable Condition
- ExecutionError
- PersistenceError
- SystemError
- IncompatibleStateError
- Deadline Interaction
- Concurrency Conflicts
- Clock Anomalies
- Partial Failure Handling
- Retry Rules
- Error Logging Contract
- Fatal Conditions
- Non-Fatal Conditions
- Invariants Under Error
- Adapter-Specific Notes
- Summary
- LOGS.md
- SECURITY.md
- Scope
- Threat Model
- Trust Boundaries
- Principle of Least Privilege
- Configuration Security
- Command Execution Security
- Privilege Dropping
- Environment Isolation
- State File Security
- Symlink and Path Safety
- PID Validation
- Denial of Service Mitigation
- Resource Limits
- Timezone and Locale Safety
- Supply Chain Security
- Logging Safety
- Kubernetes-Specific Security
- Upgrade and Migration Security
- Auditability
- Cryptographic Requirements
- Non-Goals
- Security Invariants
- COMPAT.md
- Scope
- Cron Drop-in Profile (Next Stage)
- Cron Expression Compatibility
- Day-of-Month and Day-of-Week Semantics
- Timezone Semantics
- DST Handling
- anacron Comparison
- systemd Timers Comparison
- Kubernetes CronJob Comparison
- Behavior Differences from Cron
- Backward Compatibility Rules
- Forward Compatibility
- Migration from Cron
- Migration from systemd Timers
- Migration from Kubernetes CronJob
- Precision Differences
- Reproducibility Guarantee
- Unsupported Cron Features
- Interoperability Expectations
- Compatibility Invariants
- Summary
- CRON-DROPIN.md
- TEST-VECTORS.md
- CRD-SPEC.md
- Scope
- API Group
- Resource Structure
- Spec
- schedule
- timezone
- window
- distribution
- seed
- constraints
- policy
- jobTemplate
- Status
- lastOutcome
- next* Fields
- Conditions
- Defaulting Rules
- Immutability Rules
- Reconciliation Semantics
- Idempotency Rules
- Suspension
- Deadline Handling
- Deletion Semantics
- Upgrade Rules
- Validation Guarantees
- Compatibility Guarantees
- Naming of Jobs
- Invariants
- Non-Goals
- CLI-SPEC.md
- krontab
- krond
- kronctl (Kubernetes helper)
- Output Formats
- Exit Codes
- Determinism Requirements
- Logging Interaction
- Backward Compatibility
- Security Rules
- Non-Goals
- Kron manifesto (project principles)
- Product shape (what Kron is) — superseded by SPEC.md and HELLOKRON.md
- Roadmap — superseded by top-level ROADMAP.md
- Repository layout suggestion — superseded by STRUCTURE.md