AWS/EC2 template agent

[sjones4]

Adds a new AWS/EC2 template agent for use with deployments via CloudFormation that make use of an EC2 launch template when scaling (compute) resources.

This allows CloudFormation to create all network and identity/authorization resources, with the launch template providing indirection in the use of those resources and abstraction from any infrastructure concerns (ip address allocations, disk mounting, ssm agent setup, etc)

[sjones4]

Daily build no. 7022

[sjones4]

Daily build no. 7118

[sjones4]

Demo is that ec2t agent can be used in AWS for scaling compute instances:

# appscale status --verbose
----------------------------------------------------------------------------
PUBLIC IP      PRIVATE IP    I/L*    CPU%xCORES      MEMORY%  DISK%                                                                                                            LOADAVG      ROLES
18.144.64.108  10.4.31.21    +/+     6.1x2              14.7  "/var/tmp" => 96.3 "/snap/core/8268" => 100.0 "/tmp" => 96.3 "/snap/amazon-ssm-agent/1480" => 100.0 "/" => 96.3  0.5 0.2 0.1  load_balancer taskqueue shadow taskqueue_master
54.215.208.28  10.4.16.100   +/+     3.1x2              41.0  "/var/tmp" => 65.5 "/snap/core/8268" => 100.0 "/tmp" => 65.5 "/snap/amazon-ssm-agent/1480" => 100.0 "/" => 65.5  0.3 0.2 0.1  memcache compute
54.183.76.165  10.4.19.189   +/+     2.0x2              12.1  "/var/tmp" => 68.3 "/snap/core/8268" => 100.0 "/tmp" => 68.3 "/snap/amazon-ssm-agent/1480" => 100.0 "/" => 68.3  0.3 0.1 0.1  zookeeper db_master database
52.53.130.109  10.4.22.120   +/+     0.4x2              13.1  "/var/tmp" => 65.0 "/snap/core/8268" => 100.0 "/tmp" => 65.0 "/snap/amazon-ssm-agent/1480" => 100.0 "/" => 65.0  0.5 0.2 0.1  compute
* I/L means 'Is node Initialized'/'Is node Loaded'

ROLE                COUNT
load_balancer           1
compute                 2
taskqueue_master        1
zookeeper               1
db_master               1
taskqueue               1
memcache                1
database                1
shadow                  1

AppScale is up. All 4 nodes are loaded

PROJECT ID         SERVICE ID    HTTP/HTTPS    APPSERVERS/PENDING    REQS. ENQUEUED/TOTAL    STATE
appscaledashboard  default       1080/1443     1/0                   0/0                     Ready
guestbook          default       8080/4380     20/0                  0/0                     Ready

Some nodes are in alarm state:
PUBLIC IP      PRIVATE IP    ALERT MESSAGE
18.144.64.108  10.4.31.21    Only 3.7% of '/var/tmp' partition is free
54.183.76.165  10.4.19.189   Only 31.7% of '/var/tmp' partition at db node is free

View more about your AppScale deployment at http://18.144.64.108:1080/status

verified that scaled instances are terminated (after 15 minutes) when the guestbook application is undeployed.