1. Create LB with autoscaling capability as we'll use the LB sessions autoscaling method

2. Optional, but to see Haproxy stats you need to allow access to port 8081 of the respective's public IP address firewall, then access "http://$IP:8081/admin?stats",
to login use this user/passwd combo: admin1:AdMiN123

3. Also open port 80.

4. Start Autoscaling group with template Macchinina and userdata macchinina-webserv-cgi - make sure to use a tiny compute offering, 128 MB RAM more than sufficient

ScaleUp duration: 5
Quiet time: 5
Condition: LB avg conns per vm greater than 1

ScaleDown duration: 5
Quiet time: 5
Condition: LB avg conns per VM less than 1

Min members: 1
Max members: 10 
Polling interval: 1
Expunge grace period: 15

5. Load-test the respective public IP with ab as follows:
ab -n 500 -s 120 -c 20 http://{IP}/cgi-bin/test.cgi

6. Watch the group scale