ANSIBLE&

AWS ASSUMED ROLESA SHORT EXAMPLE

WHO AM I ?

• JAMES MORGAN ( @BIGJIMMYNZ, JIMMY@DRIVENBYDEVOPS.IO )

• DEVOPS TECHNICAL CONSULTANT FOR OPEN SYSTEMS SPECIALISTS

• CLOUD INFRASTRUCTURE, AUTOMATION, CI/CD PROCESSES• BACKGROUND AS SYSADMIN/NOC FOR SAAS

INFRASTRUCTURE AND PLATFORMS

WHAT PROBLEM ARE WE SOLVING?

• INCREASINGLY COMMON TO HAVE MULTIPLE AWS ACCOUNTS• USER ACCESS CONTROLLED FROM CENTRAL ACCOUNT• ROLES ALLOW USERS TO ASSUME PRIVILEGES ACROSS ROLES

WITH TEMP CREDS• ANSIBLE, IN GENERAL, GRABS THE LOCAL DEFAULT CREDS• MANUAL SETUP OF ASSUMED CREDS TO MAKE PLAYBOOKS

WORK

SETUP THE AWS CLI

• ADD PROFILES TO THE ~/.AWS/CONFIG AND ~/AWS/CREDENTIALS FILES

• TEST ACCOUNT OPERATION WITH AWS CLI COMMANDS AND ‘—PROFILE’• USEFUL TOOL: HTTPS://GITHUB.COM/DONNEMARTIN/SAWS

• MFA NOT REQUIRED BUT DEPENDENT ON IAM ROLE CONFIGURATION

AWS SECURITY TOKEN SERVICE• ALLOWS REQUESTS FOR TEMPORARY, LIMITED-PRIVILEGE

CREDENTIALS FOR AWS IDENTITY AND ACCESS MANAGEMENT (IAM)

• REQUIRES• EXISTING CREDENTIALS FOR PRIMARY ACCOUNT• THE ROLE ARN TO BECOME• PROFILE NAME• MFA DEVICE ARN IS MFA IS TO BE USED

THE ANSIBLE PART

• VARIABLE DEFINITIONS TO HOLD MULTIPLE CREDENTIALS• VARIABLES CONTAINING STS REQUIRED INFORMATION• PLAYBOOK IMPORTS VARS IN STANDARD ANSIBLE SYNTAX• USE THE STS_ASSUME_ROLE MODULE

• IT RETURNS THE NEW CREDS IN THE TASK OUTPUTS• SET THESE VALUES INTO FACTS• USE THE NEW FACTS AS INPUTS FOR FURTHER TASKS (OR YOU CAN SET

ENVIRONMENT VARS FOR TASKS)

WITH AND WITHOUT STS

• EXAMPLE USES A VAR FLAG THAT TURNS STS FUNCTIONALITY ON/OFF• WHEN CONDITIONAL CAN THEN DISABLE TASKS

• USE “| DEFAULT(OMIT)” IN CREDENTIAL ASSIGNMENTS• THIS WILL ALLOW THE USE OF DEFAULT CREDS WHEN STS=OFF

MFA FUNCTIONALITY

• MFA REQUIREMENTS ARE DETERMINED BY IAM SETUP AND ROLES• NEED TO ACQUIRE THE MFA SERIAL ARN WHICH WILL BE

LOCATED IN YOUR IAM ACCOUNT• IN THE EXAMPLE IT CAN BE TURNED OFF LIKE STS

• REMOVE MFA ARN FROM ~/.AWS/CONFIG• REMOVE MFA ARN FROM ANSIBLE STS VARS (NOT JUST SETTING IT BLANK)• THE TASK WILL THEN OMIT THAT OPTION FROM STS_ASSUME_ROLE

• PLAYBOOK ARGUMENT OR PROMPT FOR TOKEN VALUE INTERACTIVELY

PROBLEMS/LIMITATIONS

• BEEN USING THE LATEST BRANCH OF ANSIBLE• AS CHANGES HAPPEN IN ANSIBLE DEVELOPMENT, THIS CAN CAUSE

ABBERANT EFFECTS IN YOUR CODE• MUST USE LATEST DYNAMIC EC2 INVENTORY SCRIPT

• THE INVENTORY SCRIPT HAS ISSUES WITH MFA REQUIREMENTS

INFO AND EXAMPLE CODE

• BLOG: HTTP://WWW.DRIVENBYDEVOPS.IO/AWS-ANSIBLE-AND-ASSUMED-ROLES

• GITHUB: HTTPS://GITHUB.COM/DARKNESSNZ/ANSIBLE_STS_ASSUME_ROLE

• INVENTORY SCRIPT: HTTPS://RAW.GITHUBUSERCONTENT.COM/ANSIBLE/ANSIBLE/DEVEL/CONTRIB/INVENTORY/EC2.PY

• STS_ASSUME_ROLE: HTTP://DOCS.ANSIBLE.COM/ANSIBLE/STS_ASSUME_ROLE_MODULE.HTML