Toddler hitting at childcare — how did you handle it?

Got a call from my son's childcare (he's 22 months) that he's been hitting other children. He's never done this at home. The teachers say it's usually when someone takes his toy. I feel mortified and worried at the same time. Is this a normal toddler phase? What strategies did you use at home to address hitting? And how did you work with the childcare teachers on a consistent approach? I want to handle this before it becomes a pattern.