[FIXED] nslookup: isc_socket_bind: address in use - can't resolve dns in docker container (phusion image)

Issue

I am running a AWS instance with 2CPUs, 8GB Ram, 450Mbps Bandwidth, with a docker container that holds python application.

The container load average is almost ~6.0 during the day when Python is running, and after container is up in about 10 hours, host machine and container are still running but it fails to connect with any domain, but still can connect by IP address. Also the host machine DNS stills working fine.

Here is the detail:

`nslookup google.com` results:
`nslookup: isc_socket_bind: address in use`

I aware that running under ~6.0 load average can leads to many problems, but in my case the DNS problem keep happens over time, thus I need to understand why before upgrading the AWS instance.

Solution

This is solved.

wc -l /proc/net/udp #result in ~16000 hanging connections.

Then I must stop the Python application from establishing too many UDP connections. It's a log component with SyslogHander, which implicitly opens UDP sockets.

Answered By - ThangTD