public void writeOsVersionChange(OsVersionChange change) {
        NestedTransaction transaction = new NestedTransaction();
        CuratorTransaction curatorTransaction = db.newCuratorTransactionIn(transaction);
        curatorTransaction.add(CuratorOperations.setData(osVersionsPath.getAbsolute(),
                                                         OsVersionChangeSerializer.toJson(change)));
        transaction.commit();
    }
Acquires the single cluster-global, reentrant lock with the specified timeout for active nodes of this application
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/CuratorDb.java