public OsVersionChange readOsVersionChange() {
        return read(osVersionsPath, OsVersionChangeSerializer::fromJson).orElse(OsVersionChange.NONE);
    }
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