ZeroMQ Client Lose Connection

Question

I have a client (PULL) connect to the server (PUSH). At first they work just fine. But later the connection is broken, and client-side ZeroMQ doesn't try to reconnect to server.

One mysterious thing is that if I do netstat in client side and server side, the client side shows the connection is still ESTABLISHED, while the server side doesn't have the corresponding entry. I suppose this is the reason why client-side doesn't do reconnecting.

PS: client and server are in differenct IDC, and there is a band limit between them. But when the disconnection happens, our monitor shows it does not hit the band limit.

And, when I do netstat in server side (when the connection is fine), sometimes the Send-Q column is very big, and then drop down to 0.

That's all the information I have. If you need more details please tell me.

Answer 1

I realize this is a very old question, but I ran into almost the exact same issue and found this while trying to find a fix. I believe I have fixed my issue so hopefully this helps someone at some point.

I had the same scenario but with ROUTER -> ROUTER. Everything worked great at first but after ~15 minutes of not sending any messages, messages would no longer make it. Then I found: http://api.zeromq.org/3-2:zmq-setsockopt. The three socket options that worked for me were ( using pyzmq ):

# self.client is my socket here
self.client.setsockopt(zmq.TCP_KEEPALIVE, 1)
self.client.setsockopt(zmq.TCP_KEEPALIVE_IDLE, 300)
self.client.setsockopt(zmq.TCP_KEEPALIVE_INTVL, 300)

These override the OS settings and I'm no longer seeing the connection timeout or drop.