v1.2 Miner&Worker using Http should have some problems

[Xib1uvXi]

Describe the bug

In our big cluster, we can often find in the log that the worker cannot connect to the miner

2020-11-24T14:22:11.520+0800    ^[[33mWARN^[[0m auth    auth/handler.go:39      JWT Verification failed (originating from 10.0.8.101:34388): RPC client error: sendRequest failed: Post "http://10.0.8.101:2345/rpc/v0": dial tcp 10.0.8.101:2345: connect: connection refused
2020-11-24T14:26:40.953+0800    ^[[33mWARN^[[0m auth    auth/handler.go:39      JWT Verification failed (originating from 10.0.8.101:46968): RPC client error: sendRequest failed: Post "http://10.0.8.101:2345/rpc/v0": dial tcp 10.0.8.101:2345: connect: connection refused
2020-11-24T14:26:40.953+0800    ^[[33mWARN^[[0m auth    auth/handler.go:39      JWT Verification failed (originating from 10.0.8.101:47060): RPC client error: sendRequest failed: Post "http://10.0.8.101:2345/rpc/v0": dial tcp 10.0.8.101:2345: connect: connection refused
2020-11-24T14:26:43.926+0800    ^[[33mWARN^[[0m auth    auth/handler.go:39      JWT Verification failed (originating from 10.0.8.101:48918): RPC client error: sendRequest failed: Post "http://10.0.8.101:2345/rpc/v0": dial tcp 10.0.8.101:2345: connect: connection refused

We have checked the network connection between worker and miner, The network connection is no problem

# in our worker 
telnet 10.0.8.101 2345

# output
Trying 10.0.8.101...
Connected to 10.0.8.101.
Escape character is '^]'.
^C
Connection closed by foreign host.

Then I realized that the TCP-Backlog queue may be full

# in our miner
   netstat -s | grep LISTEN
    193 SYNs to LISTEN sockets dropped

# in our miner
   netstat -s | grep TCPBacklogDrop
    TCPBacklogDrop: 81

At the same time, I also found that there will be a large number of TIME_WAIT

   netstat -na |grep TIME_WAIT | wc -l
89542

I review the code of go-jsonrpc about httpClient, I found that connection pool is not used, Why not use go http Transport, I think it should be able to improve the problem of excessive http connections