Unable to Create a CloudWatch Healthcheck via Ansible - boto

Question

I have a inventory file which has a RDS endpoint as :
[ems_db]
syd01-devops.ce4l9ofvbl4z.ap-southeast-2.rds.amazonaws.com
I wrote the following play book to create a Cloudwatch ALARM :
---
- name: Get instance ec2 facts
debug: var=groups.ems_db[0].split('.')[0]
register: ems_db_name
- name: Display
debug: var=ems_db_name
- name: Create CPU utilization metric alarm
ec2_metric_alarm:
state: present
region: "{{aws_region}}"
name: "{{ems_db_name}}-cpu-util"
metric: "CPUUtilization"
namespace: "AWS/RDS"
statistic: Average
comparison: ">="
unit: "Percent"
period: 300
description: "It will be triggered when CPU utilization is more than 80% for 5 minutes"
dimensions: { 'DBInstanceIdentifier' : ems_db_name }
alarm_actions: arn:aws:sns:ap-southeast-2:493552970418:cloudwatch_test
ok_actions: arn:aws:sns:ap-southeast-2:493552970418:cloudwatch_test
But this results in
TASK: [cloudwatch | Get instance ec2 facts] ***********************************
ok: [127.0.0.1] => {
"var": {
"groups.ems_db[0].split('.')[0]": "syd01-devops"
}
}
TASK: [cloudwatch | Display] **************************************************
ok: [127.0.0.1] => {
"var": {
"ems_db_name": {
"invocation": {
"module_args": "var=groups.ems_db[0].split('.')[0]",
"module_complex_args": {},
"module_name": "debug"
},
"var": {
"groups.ems_db[0].split('.')[0]": "syd01-devops"
},
"verbose_always": true
}
}
}
TASK: [cloudwatch | Create CPU utilization metric alarm] **********************
failed: [127.0.0.1] => {"failed": true}
msg: BotoServerError: 400 Bad Request
<ErrorResponse xmlns="http://monitoring.amazonaws.com/doc/2010-08-01/">
<Error>
<Type>Sender</Type>
<Code>MalformedInput</Code>
</Error>
<RequestId>f30470a3-2d65-11e6-b7cb-cdbbbb30b60b</RequestId>
</ErrorResponse>
FATAL: all hosts have already failed -- aborting
What is wrong here? What can i do to solve this ? I am new to this but surely this seems some syntax issue with me or the way i am picking up the inventory endpoint split.

Answer 1

The variable from debug isn't being assigned in the first debug statement, though you may be able to if you change it to a message and enclose it with quotes and double braces (untested):
- name: Get instance ec2 facts
debug: msg="{{groups.ems_db[0].split('.')[0]}}"
register: ems_db_name
However, I would use the set_fact module in that task (instead of debug) and assign that value to it. That way, you can reuse it in this and subsequent calls to a play.
- name: Get instance ec2 facts
set_fact: ems_db_name="{{groups.ems_db[0].split('.')[0]}}"
UPDATE: Add a threshold: 80.0 to the last task, and the dimensions needs to use the instance id encapsulated with double braces.