[andydunstall]

When Pico server nodes are replaced, the upstreams will automatically reconnect to a new node, then that node will propagate the new routing information to the other nodes in the cluster

So if you have a single upstream for an endpoint, when the upstream reconnects there may be a second where it isn't connected but will recover quickly (planning to add retries in the future to handle this more gracefully)

Similarly if a server node fails the upstream can reconnect