Volume 2 - Chapter 24: Understanding Ansible and Terraform

Question 1

Describe what the term “Configuration Drift” means.

Answer 1

Configuration drift is an unintended effect where a networking device’s configuration slowing changes from the standard configuration over time.

Question 2

The following figure is an example of?

Answer 2

Centralized Configuration Management

Question 3

Describe the benefit of using configuration monitoring/enforcement

Answer 3

Even when company uses centralized configuration management configuration drift is still possible because technicians still have access to the network device CLI to make changes.

Configuration monitoring/enforcement can be used to detect if a device’s configuration drifts from the ideal configuration or unauthorized changes are made.

Question 4

What term best describes the following?

The way that configuration changes are deployed to a networking device once they are managed in a configuration management system?

Answer 4

Configuration Provisioning.

Question 5

Describe the function of templates and variables in regards to centralized configuration management

Answer 5

Some networking devices will share identical commands (for example, DNS servers or VLANs), but may need configurations that are unique to that device such as IP addresses and hostnames.

A standard template can be created and pushed to networking devices that includes the common configurations (DNS servers and VLANs), and variables that are unique to each device (IP addresses and hostnames)

Question 6

An engineer wants to create a Jinja2 template for a Cisco router that contains the following:
* a hostname
* 2 common DNS servers: 192.168.72.6 and 172.16.31.2
* a common domain name of mylab.local
* an IP address for interface Gi0/0/0

What would you expect to the output of this template to be?

Answer 6

hostname {{hostname}}
!
ip name-server 192.168.72.6 172.16.31.2
ip domain name mylab.local

interface GigabitEthernet0/0
  ip address {{address1}} {{mask1}}

Question 7

An engineer wants to create a YAML variables for the Jinja2 template created in the previous question:
* The hostname of the router is L2-RT1
* The IP address is 192.168.40.5/24

What would you expect to the output of this YAML file to be?

Answer 7

.
~~~
___
hostname: L2-RT1
address1: 192.168.40.5
mask1: 255.255.255.0
~~~

Question 8

Describe the function of a “Playbook” in regards to Ansible.

Answer 8

To provide actions that Ansible can take and logic for its decisions

Question 9

Describe the function of an “Inventory” in regards to Ansible.

Answer 9

The inventory contains the list of devices that Ansible is managing, including the devices names, IP address, roles, etc….

Question 10

Describe the function of a “Template” in regards to Ansible.

Answer 10

Template represents a network device’s configuration including variables

Question 11

What type of language is used to write templates with Ansible?

Answer 11

Jinja2

Question 12

Describe the function of “Variables” in regards to Ansible.

Answer 12

A file that contains the values for the variables in the template.

Question 13

What type of language is used to write variables with Ansible?

Answer 13

YAML.

Question 14

True or False:

Ansible relies on an agent on the network device to read/write the device’s configuration.

Answer 14

False; Ansible uses an agentless architecture

Question 15

If Ansible utilizes an agentless architecture, how does Ansible read/write configurations to/from a network device?

Answer 15

Using SSH or NETCONF

Question 16

What is the default model used by Ansible?

Answer 16

Ansible uses a push model by default, but also supports a pull model.

Question 17

True or False:

Terraform uses an Infrastructure as a Service (Iaas) model?.

Answer 17

False; Terraform is Infrastructure as Code (IaS).

Question 18

True or False:

Terraform is compatible with various cloud services providers.

Answer 18

True; Terraform can work with cloud services using the cloud provider’s APIs.

Question 19

What language is used by Terraform?

Answer 19

HashiCorp Configuration Language (HCL).

Question 20

Describe the difference in use case for Ansible versus Terraform.

Answer 20

Ansible is used for device configurations
Terraform is used for infrastructure provisioning

Question 21

What are the 3 stages to Terraform’s core workflow?

Answer 21

1. Write: Define the resources that will be used
2. Plan: The specific steps for creating, updating, or decoming the infrastructure
3. Apply: Completeing the plan in a specific order of operations

Question 22

True or False:

Terraform uses an agentless model similar to Ansible.

Answer 22

False; Terraform uses a client/server model

Question 23

What type of push/pull model is used by Terraform?

Answer 23

Push