Hi,
We have been facing this issues from quiet sometime now, metabase starts throwing 502’s randomly. We neither find error logs. Is there anything we are missing.?
The only error being 
2018/02/20 05:04:01 [error] 4002#0: *2660 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: x.x.x.x, server: , request: “GET /api/health HTTP/1.1”, upstream: “http://x.x.x.x:3000/api/health”, host: “x.x.x.x”
Please help.