PodDisruptionBudget minAvailable in Python

Simulate a Kubernetes PodDisruptionBudget check for minAvailable and maxUnavailable constraints with a Python class.

Easy Python 3.9+ Aug 9, 2026 Production deployment patterns 11 views 0 copies

kubernetes pdb simulation deployment

Python code

18 lines

Python 3.9+

class PodDisruptionBudget:
    def __init__(self, name, min_available=None, max_unavailable=None):
        self.name = name
        self.min_available = min_available
        self.max_unavailable = max_unavailable

    def check_availability(self, ready_pods):
        if self.min_available is not None:
            return ready_pods >= self.min_available
        if self.max_unavailable is not None:
            return ready_pods <= self.max_unavailable
        return True


if __name__ == "__main__":
    pdb = PodDisruptionBudget("web-pdb", min_available=3)
    print(f"PDB '{pdb.name}' with 2 ready pods: {pdb.check_availability(2)}")
    print(f"PDB '{pdb.name}' with 5 ready pods: {pdb.check_availability(5)}")

Output

stdout

PDB 'web-pdb' with 2 ready pods: False
PDB 'web-pdb' with 5 ready pods: True

How it works

The PodDisruptionBudget class models Kubernetes scheduling constraints. check_availability uses min_available to enforce a floor on ready pods; if min_available is set, readiness requires ready_pods >= min_available. When only max_unavailable is set, it uses ready_pods <= max_unavailable to cap disruptions. The if __name__ == "__main__" guard lets the class be imported without running the demo.

Common mistakes

Using `==` instead of `>=` or `<=` for threshold checks
Not handling the case where both min_available and max_unavailable are set simultaneously
Forgetting to return a boolean when neither constraint is set

Variations

Add a `check_availability` that considers total_pods to compute max_unavailable dynamically
Use a dataclass to reduce boilerplate for the budget definition

Real-world use cases

Validating rollout safety before draining nodes in a deployment automation script.
Simulating PDB logic in unit tests for controllers that manage Kubernetes workloads.
Building a dry-run scheduler that verifies node drains will not violate availability targets.

PodDisruptionBudget minAvailable in Python

Python code

Output

How it works

Common mistakes

Variations

Real-world use cases

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Real-world use cases

More from Production deployment patterns

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