hello,

my app will keep a long connection with server, while server may push message to client, two levels nginx proxy for the upstream servers, does keepalive directive support this model?

the documentation of the keepalive directive said:
"For HTTP, the proxy_http_version directive should be set to '1.1' and the 'Connection' header field should be cleared."

why clear that header?

if client or server close the connection, will the connection between two nginx still keepalive?

will nginx creat connection with upstream servers even if there's no request received?
will nginx pass requests from different clients to upstream in one keep-alive connection?