DownUnderCTF 2020 Infrastructure

CTFd on appengine flex setup so that you can get the sp00dy autoscaling.

1. Create a memorystore and cloud sql instances on google cloud and set up the connection information into the env vars
2. Create an account with an email provider such as mailgun or amazon ses, and set the details into the env vars
3. Make sure memorystore and cloudsql are on the same VPC, and change the setting under network.name to your VPC
4. Set up the Google Cloud Storage bucket for hosting the challenge files. You need to first enable Interoperability mode in order to get the S3 compatible key.
   • Make sure the permissions for the bucket are also public. Grant Storage Legacy Object Reader to allUsers on the bucket settings page.
5. Run the below command

gcloud app deploy

Extras

You can place this setup behind a Google Cloud load balancer and CDN for caching of static files, which is what we did in our setup.

# create the serverless network endpoint group (NEG)
gcloud beta compute network-endpoint-groups create ctfd-gae-neg --network-endpoint-type serverless \
    --app-engine-service=default --region australia-southeast1

# create the backend
gcloud beta compute backend-services add-backend ctfd-gae-backend \
    --global \
    --network-endpoint-group=ctfd-gae-neg \
    --network-endpoint-group-region=australia-southeast1

We then used the GUI to create our load balancer with the above backend. Check out https://cloud.google.com/iap/docs/load-balancer-howto for more information.