Mismatch Between Docker and Machine Hostnames

There is a limitation in Docker runtime which prevents running containers from being notified when Docker updates the hostname.

To correct this mismatch:

1. Find the current Docker hostname.

   hostname
   Example output

   coreos-1122.3.0

2. Update the hostname in the Docker host.

   sudo hostname new-coreos-1122.3.0

3. Find the Linux process id of the Lacework datacollector container.

   sudo docker ps -a
   Example output

   0123ae6c9bd9 lacework/datacollector:latest “/var/lib/backup/data” 2 hours ago Up 2 hours datacollector

4. Find the PID of the Lacework datacollector container.

   sudo docker inspect 0123ae6c9bd9 | grep Pid
   Example output

   “Pid”: 2897,
   “PidMode”: “host”,
   “PidsLimit”: 0,

5. Edit the UTS namespace of the Lacework datacollector container and update it with the new hostname, where nsenter is part of the util-linux package.

   sudo nsenter --target 2897 --uts hostname new-coreos-1122.3.0

6. Log in to the Lacework agent container and verify that the new hostname is visible.

   sudo docker exec -it 0123ae6c9bd9 /bin/bash   

   root@new-coreos-1122:/# hostname  
   new-coreos-1122.3.0 12

You should not have to restart the Lacework agent container to display the new hostname.