spinifex/docs/terraform-workbooks/s3-webapp

title, description, category, tags, resources

title	description	category	tags	resources
S3-Backed Web App	Deploy a Flask file-sharing web application backed by S3 (Predastore) using Terraform on Spinifex.	Terraform Workbooks	terraform s3 predastore flask webapp workbook	title url Terraform AWS Provider https://registry.terraform.io/providers/hashicorp/aws/latest title url Spinifex Repository https://github.com/mulgadc/spinifex title url Predastore (S3) https://github.com/mulgadc/predastore title url OpenTofu https://opentofu.org/

Terraform: S3-Backed Web App

Deploy a Flask file-sharing web application backed by S3 (Predastore) using Terraform on Spinifex.

Table of Contents

• Overview
• Instructions
• Troubleshooting

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Overview

Deploy an EC2 instance running a Flask file-sharing web application backed by S3 (Predastore). Users can upload files through a web form and browse uploaded content — demonstrating Terraform managing both compute and object storage together.

Architecture:

What you'll learn:

• Configuring the AWS provider with both Spinifex and Predastore endpoints
• Creating S3 buckets on Predastore via Terraform
• Deploying a Python webapp with cloud-init that talks to S3
• Passing credentials and configuration to instances via user-data

Prerequisites:

• Spinifex installed and running (see Installing Spinifex)
• Predastore running (S3 API on port 8443)
• An Ubuntu 26.04 AMI imported (see Setting Up Your Cluster)
• OpenTofu or Terraform installed
• The EC2 instance must be able to reach Predastore — use the host's br-wan IP, not localhost

Instructions

Step 1. Get the Template

Clone the Terraform examples from the Spinifex repository:

git clone --depth 1 --filter=blob:none --sparse https://github.com/mulgadc/spinifex.git spinifex-tf
cd spinifex-tf
git sparse-checkout set docs/terraform
cd docs/terraform/s3-webapp

Or create the files manually and paste the full configuration below.

Step 2. Create terraform.tfvars

Before deploying, create a terraform.tfvars with your Predastore credentials. The predastore_host must be reachable from inside the VPC — use the host's br-wan or LAN IP, not localhost.

Step 3. Create main.tf

Step 4. Deploy

The workbook defaults to t3.small (2 vCPU, 2 GiB). On clusters without that type registered, override with TF_VAR_instance_type — query what's available with aws ec2 describe-instance-types.

export AWS_PROFILE=spinifex
tofu init
tofu apply

Step 5. Test the Application

Note: EC2 instances can take 30+ seconds to boot after apply. If SSH or HTTP is unreachable, wait and retry.

Open the web_url output in your browser. You should see the file browser UI. Upload a file and verify it appears in the list.

# Verify via CLI
curl http://<public_ip>

# Check the S3 bucket directly
aws s3 ls s3://webapp-uploads/ --profile spinifex --endpoint-url https://localhost:8443

Clean Up

tofu destroy

Troubleshooting

Predastore Connection Refused from Instance

The EC2 instance cannot reach localhost on the host. Set predastore_host to the host's br-wan or LAN IP address:

predastore_host = "192.168.1.10:8443"

S3 Bucket Creation Fails

Verify Predastore is running and accessible:

curl -k https://localhost:8443/
aws s3 ls --profile spinifex --endpoint-url https://localhost:8443

Flask App Not Starting

SSH into the instance and check the service:

ssh -i s3-webapp-demo.pem ec2-user@<public_ip>
sudo systemctl status s3-webapp
sudo journalctl -u s3-webapp --no-pager -n 50

Upload Fails or Files Not Appearing

Check that the S3 credentials in /opt/webapp/.env are correct and that the bucket exists:

ssh -i s3-webapp-demo.pem ec2-user@<public_ip>
cat /opt/webapp/.env
/opt/webapp/venv/bin/python -c "import boto3; print('boto3 OK')"

AMI Not Found

Ensure you have imported an Ubuntu 26.04 image:

aws ec2 describe-images --owners 000000000000 --profile spinifex