I am trying to conceptually understand the backend architecture of a Sentinel and the details seem to be a little light. From what I understand, the only way to invoke a Autotask/Relayer script via a smart contract is through a Sentinel (is this correct?). Is the Sentinel just a scanner of sorts (ie. event listener) that scans the chosen blockchain every block?
Is AWS the single common point of failure for all (Autotask/Relayer/Sentinel)? Are there redundancies in place (ie. different AWS servers in different continents?)
If I am heading in the wrong direction here, is there a better method to invoke an autotask via a smart contract (ie. requesting data from an external api via a smart contract). I know that external adapters in Chainlink are very similar, but I need a permissioned style api call.