How to update Google Cloud DNS with ephemeral IP for an instance

Question

I have couple of instances on GCE that I don\'t really need static addresses for, but I still need to make them accessible via dns name. Since ephemeral external ip addresse

Answer 1

I'm going to take a slight spin on the answer from @MaZe. Also, I'll show using systemd so this script starts automatically at startup if you're on Ubuntu or another distro that uses systemd.

#!/bin/bash

EXISTING=`gcloud dns record-sets list --zone="{your domain}" | grep xxx.yyyy.com | awk '{print $4}'`
NEW=`gcloud compute instances describe {your instance} --zone={your zone} | grep natIP | awk -F': ' '{print $2}'`
gcloud dns record-sets transaction start -z={your domain}
gcloud dns record-sets transaction remove -z={your domain} \
    --name="xxx.yyyy.com." \
    --type=A \
    --ttl=300 "$EXISTING"
gcloud dns record-sets transaction add -z={your domain} \
   --name="xxx.yyyy.com." \
   --type=A \
   --ttl=300 "$NEW"
gcloud dns record-sets transaction execute -z={your domain}

Save it to /path/to/script.sh and start it up in systemd:

[Unit]
Description=Set xxx.yyyy.com to the correct external ip address of this instance
After=network.target auditd.service

[Service]
ExecStart=/path/to/script.sh
Type=oneshot

[Install]
WantedBy=multi-user.target

Save it in /etc/systemd/system as filename.service and enabled it with:

sudo systemctl enable filename.service