private Optional<Mutex> tryLock(ApplicationId application, NodeRepository nodeRepository) {
        try {
            return Optional.of(nodeRepository.applications().lockMaintenance(application));
        } catch (UncheckedTimeoutException e) {
            log.log(Level.INFO, () -> "Could not lock " + application + " for maintenance deployment within timeout");
            return Optional.empty();
        }
    }
Attempts to activate this deployment

@return the application config generation resulting from this deployment, or empty if it was not successful
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/MaintenanceDeployment.java