Create a CloudFormation stack and use Rolling Updates to update the application version deployed to your EC2 instances.

1. Create a CloudFormation stack based on an existing template.

1. Open CloudFormation in AWS Management Console.
2. Click Create Stack button.
3. Select Upload a template to Amazon S3.
4. Choose file learn-cloudformation/lab9-rolling-update/demo.yaml.
5. Click Next button.
6. Insert lab9-$usernameas stack name. Replace $usernamewith your username (e.g. lab9-awittig).
7. Select two random subnets and the only available VPC as Parameters.
8. Insert 1 as VersionParameter.
9. Click Next button.
10. Skip next step by clicking on Next button.
11. Review your input and click Create button.
12. Wait until your stack reaches status CREATE_COMPLETE.
13. Select your stack by clicking on row of the table.
14. Switch to the Outputs tab.
15. Search for *ELB and click on the URL.
16. A website showing Version 1 should appear.
17. Select your stack by clicking on row of the table again.
18. Select Update Stack from the Actions menu.
19. Select Use current template and click Next.
20. Insert 2 as VersionParameter.
21. Click Next.
22. Click Next.
23. Click Update.
24. Wait until your stack reaches status UPDATE_COMPLETE.
25. Select your stack by clicking on row of the table.
26. Switch to the Outputs tab.
27. Search for ELB and click on the URL.
28. A website showing Version 2 should appear.
29. Select your stack by clicking on row of the table again.
30. Select Delete Stack from the Actions menu.
31. Confirm the deletion of your stack.
32. Congratulations! You are done with the lab!