Usage of ./dns-from-gce:
-dnsttl=300: TTL for any DNS records created
-dnsupdate=60: How many seconds to sleep between updating DNS records from the host-list
-domainname="domain.com.": The DNS domain to use (including trailing '.')
-environmentkey="environment": Instance metadata key to derive the 'environment' from
-hostupdate=60: How many seconds to sleep between updating the list of hosts from GCE
-rolekey="role": Instance metadata key to derive the 'role' from
-zonename="": The DNS zone-ID to use (defaults to the domain-name)
Credentials:
Credentials can either be derived from a credentials file, or from instance permissions:
Credentials-file should be '~/.config/gcloud/application_default_credentials.json'
Instance permissions required:
Host-inventory (to find the list of running instances): "Compute.Read"