@Override
  public void setAlertLevel(AlertLevel level) {
    if (isConnected()) {
      gfManagerAgent.setAlertLevel(level.getSeverity());
    }

    alertLevel = level;
  }
Checks to make sure that {@link #connect()} has been called.

@throws IllegalStateException If {@link #connect()} has not been called.
geode-core/src/main/java/org/apache/geode/admin/internal/AdminDistributedSystemImpl.java