title: Microservices for job/cron tasks
body: <p>For example I want to have a microservice to send notifications(email, sms, push notification). Everything is ok for few users. After some time our application have a lot of users, so, this microservice doe not manage, and email a sent after 1 hour. </p>
  
  <p>So, how to handle this situation? Deploy another instance of microservice, but how to handle that only one microservice process one email and user don't receive multiple emails?</p>