Script to diff un-updatebale Statefulsets fiesl

README.md

List un-updatabale file Kubernetes Statefulset

https://kubernetes.io/docs/tutorials/stateful-application/basic-stateful-set/#updating-statefulsets

There are some cases that you might be trying to update a statefulset and you get this error:

Error: cannot patch "my-statefulset" with kind StatefulSet: StatefulSet.apps "my-statefulset" is invalid: spec: Forbidden: updates to statefulset spec for fields other than 'replicas', 'ordinals', 'template', 'updateStrategy', 'persistentVolumeClaimRetentionPolicy' and 'minReadySeconds' are forbidden && cannot patch "my-statefulset-tracking" with kind StatefulSet: StatefulSet.apps "my-statefulset-tracking" is invalid: spec: Forbidden: updates to statefulset spec for fields other than 'replicas', 'ordinals', 'template', 'updateStrategy', 'persistentVolumeClaimRetentionPolicy' and 'minReadySeconds' are forbidden

And while you can diff a file manually beteween you update and the yaml that you can fecth: kubectl -n my-ns get sts my-statefulset -o yaml

So I makde the scritp that diff that also excluding the options, this will help you be faster on the system.

-> % k8s-diff-sts-upgrade.py template.yaml onserver.yaml
Differences in the 'spec' block:
- Field: revisionHistoryLimit
  - template: None
  - template: 10
- Field: serviceName
  - template: my-statefulset-v1
  - template: my-statefulset-v1-svc
- Field: podManagementPolicy
  - template: None
  - template: OrderedReady

k8s-diff-sts-upgrade.py

#!/usr/bin/env python3

## This script compares two Kubernetes StatefulSet YAML files and prints the differences spec block
# This is useful for
import argparse
from pathlib import Path

import yaml


def get_file_path(file_path):
    return Path(file_path).stem


def load_yaml(file_path):
    with open(file_path, "r") as stream:
        return yaml.safe_load(stream)


def compare_spec_blocks(yaml1, yaml2):
    spec1 = yaml1.get("spec", {})
    spec2 = yaml2.get("spec", {})

    excluded_fields = {
        "replicas",
        "ordinals",
        "template",
        "updateStrategy",
        "persistentVolumeClaimRetentionPolicy",
        "minReadySeconds",
    }

    differences = {}

    all_keys = set(spec1.keys()).union(set(spec2.keys()))
    for key in all_keys:
        if key in excluded_fields:
            continue

        value1 = spec1.get(key, None)
        value2 = spec2.get(key, None)

        if value1 != value2:
            differences[key] = {"file1": value1, "file2": value2}

    return differences


def main(file1, file2):
    yaml1 = load_yaml(file1)
    yaml2 = load_yaml(file2)
    yaml1_name = get_file_path(file1)
    yaml2_name = get_file_path(file1)

    differences = compare_spec_blocks(yaml1, yaml2)

    if differences:
        print("Differences in the 'spec' block:")
        for key, diff in differences.items():
            print(f"- Field: {key}")
            print(f"  - {yaml1_name}: {diff['file1']}")
            print(f"  - {yaml2_name}: {diff['file2']}")
    else:
        print("No differences found in the 'spec' block (excluding specified fields).")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Compare 'spec' blocks of two YAML files, excluding specific fields."
    )
    parser.add_argument("file1", type=str, help="Path to the first YAML file")
    parser.add_argument("file2", type=str, help="Path to the second YAML file")
    args = parser.parse_args()

    main(args.file1, args.file2)