Render controller action from another controller

Try render 'posts/show' or render :template => 'posts/show'

Just render the template

def index
  render 'posts/show'
end

This one also works

def index
  render template: 'posts/show'
end

If you want to render in some other layout

def index
  render template: 'posts/show', layout: 'different_layout' 
end