i have an reoccurring issue with connection from inside an container to ping an host outside of the docker host.
The containers running for a while without issues but out of the sudden the communication stops. Checking the containers shows that they are running. Following situations
- I can ping from host to container via the bridge
- i can ping from container to docker0 bridge ip
- containers are running
- containers can ping each other
- container cannot ping any external ip (same host or other)
- this problem affects all bridge networks
- this problem does not affect host network
- i cannot see any obvious issues in ‘iptables -l’
I observed this issue with docker 1.8.0 and also with 1.13.1. In most cases i can try to fix it by
- restarting docker engine
- stopping docker engine and removing the docker0 bridge and start the engine again
- restart the server
most likely the 1. point goes well.
This behavior is happening for sure if i play with the hosts network but may also happen something else happen in the network. I cannot really tell whats the cause here.
Does anybody know why this happen, how to avoid it and how to fix this issue while the containers are running?