1. Chef Fundamentals

2. Chef Client Run and Expanding
Our Cookbook
Chef Fundamentals Webinar Series - Module 4
training@opscode.com

3. Nathen Harvey
• Technical Community Manager at Opscode
• Co-host of the Food Fight Show Podcast
• @nathenharvey
• nharvey@opscode.com

4. Quick Recap

5. Checkpoint
• In the last module we
• bootstrapped a node using knife bootstrap
• wrote a simple cookbook to deploy a simple
webpage

6. Where'd my Node go?
• You still need an Ubuntu 10.04+ machine to manage
• Launch a new instance in the training lab
• Fire up a new Vagrant
• Launch an new AMI Instance

7. But it might not have worked
• In some instances, the apt-cache was out of date
• You can fix this!
• sudo apt-get update

8. Fix it the Chef way!
• Create an apt cookboook
• Use an execute resource
• Add to the run list

9. Dissecting your first chef-client run
The Anatomy of a Chef run

10. Objectives
• Describe the steps of a chef-client run
• Describe the basic security model of Chef

11. chef-client

12. chef-client
build node

13. chef-client
build node
Ohai!
node_name
platform
platform_version

14. chef-client
build node
authenticate

15. chef-client
build node
expanded run list
(recipes)
authenticate
sync
cookbooks

16. chef-client
build node
authenticate
load
cookbooks
sync
cookbooks

17. chef-client
build node
authenticate
converge
load
cookbooks
sync
cookbooks

18. chef-client
build node
authenticate
converge
load
cookbooks
sync
cookbooks
success?

19. chef-client
build node
authenticate
converge
load
cookbooks
sync
cookbooks
Yes
success?
node.save

20. chef-client
build node
authenticate
converge
load
cookbooks
sync
cookbooks
Yes
node.save
No
exception
success?

21. chef-client
build node
authenticate
converge
load
cookbooks
sync
cookbooks
Yes
node.save
notification
handlers
success?
No
exception

22. Private Keys
• Chef Server requires keys to authenticate.
• client.pem - private key for API client
• validation.pem - private key for ORGNAMEvalidator
• Next, let’s see how those are used...

23. /etc/chef/
client.pem?

24. /etc/chef/
client.pem?
Yes
Sign Requests

25. No
/etc/chef/
client.pem?
Yes
Sign Requests
/etc/chef/
validation.pem?

26. No
/etc/chef/
client.pem?
Yes
Sign Requests
No
/etc/chef/
validation.pem?
401!

27. No
/etc/chef/
client.pem?
No
/etc/chef/
validation.pem?
Yes
Yes
Sign Requests
Request API
Client
401!

28. No
/etc/chef/
client.pem?
No
/etc/chef/
validation.pem?
Yes
Yes
Sign Requests
Request API
Client
client.pem
401!

29. No
/etc/chef/
client.pem?
No
/etc/chef/
validation.pem?
Yes
Yes
Sign Requests
Request API
Client
client.pem
401!

30. Compile and Execute
• Compile a Resource Collection
• Execute the Resources in that Collection

31. Introducing the Node object
Attributes & Search

32. Lesson Objectives
• After completing the lesson, you will be able to
• Explain what the Node object represents in Chef
• List the Nodes in an organization
• Show details about a Node
• Describe what Node Attributes are
• Retrieve a node attribute directly, and via search

33. What is the Node object
• A node is any physical, virtual, or cloud machines
that is configured to be maintained by a Chef
• When you are writing Recipes, the Node object is
always available to you.

34. Exercise: List nodes
$ knife node list
target1

35. Exercise: List clients
$ knife client list
ORGNAME-validator
target1

36. Each node must have a unique name
• Every node must have a unique name within an
organization
• Chef defaults to the Fully Qualified Domain Name of
the server, i.e. in the format server.domain.com
• We overrode it to "target1" to make typing easier

37. Exercise: Show node details
$ knife node show target1
Node Name:
Environment:
FQDN:
IP:
Run List:
Roles:
Recipes:
Platform:
Tags:
target1
_default
ip-10-154-155-107.ec2.internal
54.242.35.165
ubuntu 12.04

38. What is the Node object
• Nodes are made up of Attributes
• Many are discovered automatically (platform, ip
address, number of CPUs)
• Many other objects in Chef can also add Node
attributes (Cookbooks, Roles and Environments,
Recipes, Attribute Files)
• Nodes are stored and indexed on the Chef Server

39. Exercise: Run Ohai on node
opscode@target1:~$ sudo ohai | less
{
"languages": {
"ruby": {
},
"python": {
"version": "2.7.3",
"builddate": "Apr 10 2013, 06:20:15"
},
"perl": {
"version": "5.14.2",
"archname": "x86_64-linux-gnu-thread-multi"
}
},
"kernel": {

40. Exercise: Show all the node attributes
$ knife node show target1 -l
Node Name:
Environment:
FQDN:
IP:
Run List:
Roles:
Recipes:
Platform:
Tags:
Attributes:
tags:
target1
_default
ip-10-154-155-107.ec2.internal
54.242.35.165
ubuntu 12.04
Default Attributes:
Override Attributes:
Automatic Attributes (Ohai Data):
block_device:
loop0:
removable: 0
size:
0

41. Exercise: Show the raw node object
$ knife node show target1 -Fj
{
"name": "target1",
"chef_environment": "_default",
"run_list": [],
"normal": {"tags":[]}
}

42. Exercise: Show only the fqdn attribute
$ knife node show target1 -a fqdn
target1:
fqdn: ip-10-154-155-107.ec2.internal

43. Exercise: Use search to find the same data
$ knife search node "*:*" -a fqdn
1 items found
target1:
fqdn: ip-10-154-155-107.ec2.internal

44. Templates and Cross-platform
Revisit the Apache Cookbook