Docker overlay DNS cant resolve Container Name

Docker Engine Swarm
1

Hey,
I have 2 Docker Hosts with identical Docker Version and Configs. Since yesterday i have a Problem with the Overlay Networks on one of the Hosts. What i did:

docker network create -d overlay --attachable test_network
docker run --rm -it --network=“test_network” --name test.DNS.name bash
wget test.DNS.name

On One Host the response is as expected:

bash-4.4# wget test.DNS.name
Connecting to test.DNS.name (10.0.1.6:80)
wget: can’t connect to remote host (10.0.1.6): Connection refused
On the other the response is:
bash-4.4# wget test.DNS.name
wget: bad address ‘test.DNS.name’

I have no idea where this could come from. And would be very happy for ideas.

There the output from docker info (identical on both machines):
Containers: 3
Running: 2
Paused: 0
Stopped: 1
Images: 156
Server Version: 18.03.0-ce
Storage Driver: devicemapper
Pool Name: vg01-docker–pool
Pool Blocksize: 524.3kB
Base Device Size: 10.74GB
Backing Filesystem: xfs
Udev Sync Supported: true
Data Space Used: 22.89GB
Data Space Total: 42.95GB
Data Space Available: 20.06GB
Metadata Space Used: 6.922MB
Metadata Space Total: 5.583GB
Metadata Space Available: 5.576GB
Thin Pool Minimum Free Space: 4.295GB
Deferred Removal Enabled: true
Deferred Deletion Enabled: true
Deferred Deleted Device Count: 0
Library Version: 1.02.140-RHEL7 (2017-05-03)
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: active
NodeID: m99xj3rhtk8ymabv1k78v4pur
Is Manager: true
ClusterID: of2g9dy3xbwj2jye6potfq5dq
Managers: 1
Nodes: 2
Orchestration:
Task History Retention Limit: 5
Raft:
Snapshot Interval: 10000
Number of Old Snapshots to Retain: 0
Heartbeat Tick: 1
Election Tick: 3
Dispatcher:
Heartbeat Period: 5 seconds
CA Configuration:
Expiry Duration: 3 months
Force Rotate: 0
Autolock Managers: false
Root Rotation In Progress: false
Node Address: 10.16.21.145
Manager Addresses:
10.16.21.145:2377
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: cfd04396dc68220d1cecbe686a6cc3aa5ce3667c
runc version: 4fc53a81fb7c994640722ac585fa9ca548971871
init version: 949e6fa
Security Options:
seccomp
Profile: default
Kernel Version: 3.10.0-693.21.1.el7.x86_64
Operating System: Red Hat Enterprise Linux Server 7.4 (Maipo)
OSType: linux
Architecture: x86_64
CPUs: 12
Total Memory: 62.74GiB
Name: gtunxlvd04346
ID: QPYZ:ZYLJ:DNXO:VCRC:Y2CG:LOEN:WSKN:52X5:JPNX:FLSB:GPIR:FY3U
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false

2

Sorry, i didn’t see the second request.
I have a similar issue with the 18.03 version. Could you upgrade to 18.03.1??

3

thanks for the quick feedback, we restartet the Host with the Problem and now it is working as expected.

So this Problem can be solved with a restart of the Host.

It would still be interesting to find the cause of this, but i think that if there is no relation between researching this issue and the chance this happens again.

4

check this issue: