I'm designing a infrastructure to monitor websites and applications. The idea is to build an application which checks the user website/application with a certain interval (30 sec, 1 min, 5 min, etc.). It's important that the website check is close to the given interval. The goal of the infrastructure is to have a scalable infrastructure with a high uptime without a single point of failure (if that's possible). A monitor which is 99% online of the time online isn't acceptable.
So after some brainstorming I came up with the following infrastructure.
This diagram contains all the different parts/applications of the infrastructure. Each application runs on its own machine.
At this moment the manager delegator application is a high risk. If that application is down, it cannot move websites to another delegator if one of the worker delegators is down.
So my question is if this infrastructure is reliable and scalable enough for monitoring thousands of websites. Assuming there are enough workers to do all the monitoring. Recommendations are welcome!