Chicken and Andouille Smoked Sausage Gumbo

Name: Chicken and Andouille Smoked Sausage Gumbo
Ingredients: 1/4 cup garlic powder; 1 cup diced yellow onion; 1 cup diced green bell peppers; 3/4 cup diced celery; 1 teaspoon cayenne pepper; 7 cups chicken stock; 1/2 pound andouille sausage; 2 ounces canola oil; 2 tablespoons gumbo file; 2 teaspoons kosher salt; 2 tablespoons black pepper; 1/2 cup butter; 1/2 cup all purpose flour