public static DistributionDiff computeDiff(DistributionConfigBundle oldCfg, DistributionConfigBundle newCfg) {
        return new DistributionDiff(
                computeGroupDiff(oldCfg, newCfg),
                IntegerDiff.of(oldCfg.totalLeafGroupCount(), newCfg.totalLeafGroupCount()),
                IntegerDiff.of(oldCfg.redundancy(), newCfg.redundancy()),
                IntegerDiff.of(oldCfg.searchableCopies(), newCfg.searchableCopies()));
    }
Utility for computing a "minimal" diff between two arbitrary distribution configs.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/DistributionDiffCalculator.java