location /hls {
error_page 404 = @hls;
keepalive_requests 1000;
}

location @hls {
# Serve HLS fragments
types {
application/vnd.apple.mpegurl m3u8;
video/mp2t ts;
}
root /tmp;
add_header Cache-Control no-cache;
keepalive_requests 1000;
}

keepalive_requests must be large enough in this two location meanwhile
if set keepalive_requests to 0 or 1 in /hls or @hls, keepalive_requests would not work in the other location