I am trying to understand the role of overseer and solrCloud stateChange mechanism. I tried finding resources on web, but with not much luck. Can someone point me to some relevant doc or explain. Few doubts i have: 1. In doc, it says overseer updates clusterstate.json when a new node joins. How does overseer node knows when a new node joins. Even overseer is one independent node. 2. There is an overseer queue znode in zookeeper. Do all solr servers update its state in overseer queue? what type of events are published to the queue? is this queue maintained inside zookeeper? 3. when a node goes down and loose connection with zookeeper, does zookeeper updates its state in clusterstate.json or it lets overseer know about lost connection and let it update clusterstate.json? 4. in docs it says that when a node is in down state, it can not cater to read or write request. I have tried issuing a get request on one node which is showing down in solr cloud panel and i did get response ( with all relevant documents). How is this happening? When a node goes to down state, does it not block its request handlers or notify it not to cater to any get requests?
Thanks in advance for helping me understand solrCloud intern state change mechanism. --
