gte-lte-operators.md

GTE and LTE Operators for Requirements

Overview

Karpenter currently supports Gt (greater than) and Lt (less than) operators for numeric requirements. These are strict inequalities, which creates an awkward user experience. For example, to require a minimum of 2 CPUs, users must specify Gt 1 instead of the more intuitive Gte 2.

Motivation

Users frequently need to express inclusive bounds on numeric requirements like CPU count, memory, or GPU count. The current off-by-one interface is confusing and error-prone:

User Intent	Current Syntax	Proposed Syntax
At least 2 CPUs	Gt 1	Gte 2
At most 8 CPUs	Lt 9	Lte 8

Proposal

Add two new operators to Karpenter's requirement system:

• Gte - Greater than or equal to
• Lte - Less than or equal to

API Changes

apiVersion: karpenter.sh/v1
kind: NodePool
spec:
  template:
    spec:
      requirements:
        - key: karpenter.k8s.aws/instance-cpu
          operator: Gte  # New operator
          values: ["2"]
        - key: karpenter.k8s.io/instance-memory
          operator: Lte  # New operator
          values: ["64"]

Implementation

1. Define new operator constants in pkg/apis/v1/
2. Add greaterThanOrEqual and lessThanOrEqual fields to the Requirement struct
3. Update NewRequirementWithFlexibility to handle Gte and Lte
4. Update validation to accept the new operators
5. Update intersection and comparison logic

Backward Compatibility

• Existing Gt and Lt operators remain unchanged
• New operators are additive; no breaking changes

Alternatives Considered

1. Automatic conversion: Convert Gte N to Gt N-1 internally. Rejected because it loses semantic meaning and complicates debugging.
2. Documentation only: Document the off-by-one pattern. Rejected because it doesn't solve the UX problem.