Add this line in postinstall script: During Create Instance, > Management, > Automation

curl https://git.mailliet.ovh/Public/GCP-PostInstall/raw/branch/master/docker-install.sh | sh

Or using gcloud: List available OS Images:

gcloud compute images list | grep debian

deploy VM:

gcloud beta compute instances create instance-3 \
--zone=us-east1-b \
--machine-type=f1-micro \
--subnet=default \
--network-tier=PREMIUM \
--metadata=startup-script="curl https://git.mailliet.ovh/Public/GCP-PostInstall/raw/branch/master/docker-install.sh |sh" \
--maintenance-policy=MIGRATE \
--image=debian-10-buster-v20200521 \
--image-project=debian-cloud