@Override
        public void require(ConfigChangeAction action) {
            if (action instanceof VespaRestartAction && action.getServices().isEmpty())
                throw new IllegalStateException("restart actions must have services specified");

            actions.add(action);
            action.validationId().ifPresent(id -> invalid(id, action.getMessage()));
        }
Report an action the user must take to change to the new configuration.
If the action has a {@link ValidationId}, {@link #invalid} is also called for this id, and the action's message.
config-model/src/main/java/com/yahoo/vespa/model/application/validation/Validation.java