The issue with Google Compute Engine VM instances being allocated duplicate external IP addresses has been resolved for all affected projects as of Saturday, 2018-06-16 12:59 US/Pacific. Customers with VMs having duplicate internal IP addresses should follow the workaround described earlier, which is to delete (without deleting the boot disk), and recreate the affected VM instances. We will conduct an internal investigation of this issue and make appropriate improvements to our systems to help prevent or minimize future recurrence.

Mitigation work is currently underway by our Engineering Team. GCE VMs that have an internal IP that is not assigned to another VM within the same project, region and network should no longer see this issue occurring, however instances where another VM is using their internal IP may fail to start with networking. We will provide another status update by Saturday, 2018-06-16 15:00 US/Pacific with current details.

Detailed Description We are investigating an issue with Google Compute Engine VM instances failing to start with networking after being stopped, or new instances being allocated with the same IP address as a VM instance which was stopped within the past 24 hours. Our Engineering Team is evaluating a fix in a test environment. We will provide another status update by Saturday, 2018-06-16 03:30 US/Pacific with current details.

Diagnosis Instances that were stopped at any time between 2018-06-14 08:42 and 2018-06-15 13:40 US/Pacific may fail to start with networking. A newly allocated VM instance has the same IP address as a VM instance which was stopped within the mentioned time period.

Workaround As an immediate mitigation to fix instances for which networking is not working, instances should be recreated, that is a delete (without deleting the boot disk), and a create. e.g:

gcloud compute instances describe instance-1 --zone us-central1-a

gcloud compute instances delete instance-1 --zone us-central1-a --keep-disks=all

gcloud compute instances create instance-1 --zone-us-central1-a --disk='boot=yes,name=instance-1'

To prevent new instances from coming up with duplicate IP addresses we suggest creating f1-micros until new ip addresses are allocated, and then stopping the instances to stop incurring charges. Alternatively new instances can be brought up with a static internal ip address.

Our Engineering Team continues to evaluate the fix in a test environment. We believe that customers can work around the issue by launching then stopping f1 micro instances until no more duplicate IP addresses are obtained. We are awaiting confirmation that the provided workaround works for customers. We will provide another status update by Friday, 2018-06-15 20:00 US/Pacific with current details.

Our Engineering Team is evaluating a fix in a test environment. We will provide another status update by Friday, 2018-06-15 17:30 US/Pacific with current details.

Investigation continues by our Engineering Team. We are investigating workarounds as well as a method to resolve the issue for all affected projects. We will provide another status update by Friday, 2018-06-15 17:30 US/Pacific with current details.

Google Compute Engine VM instances allocated with duplicate internal IP addresses