With Font Awesome icons:
<!-- Controls -->
<a class="carousel-control-prev" href="#carousel-example-generic" role="button" data-slide="prev">
<span class="fa fa-chevron-left fa-lg" style="color:red;"></span>
<span class="sr-only">Previous</span>
</a>
<a class="carousel-control-next" href="#carousel-example-generic" role="button" data-slide="next">
<span class="fa fa-chevron-right fa-lg" style="color:red;"></span>
<span class="sr-only">Next</span>
</a>