Introduction to Infrastructure as Code & Automation / Introduction to Chef

Chef Fundamentals by Chef Software, Inc. is licensed under a
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Intro to Infrastructure as Code
Introduction to Chef
All Things Open – October 2014
https://github.com/nathenharvey/ato-2014

Nathen Harvey
• Community Director at Chef
• Co-host of the Food Fight Show
• Co-organizer of DevOpsDC meetup
• Occasional farmer – http://bit.ly/farmer-nathen
• @nathenharvey
• nharvey@getchef.com

Hello!
• System Administrator?

Hello!
• Developer?

Hello!
• Developer?
• Ruby developer?

Hello!
• Developer?
• DevOp?

Hello!
• Developer?
• DevOp?
• Business Person?

Are you experienced?
• Experience with Infrastructure as Code or
Configuration Management?

Are you experienced?
• Experience with Infrastructure as Code or
Configuration Management?
• Experience with Chef?

Which version control system do your use?

• cp foo foo.bak

• cp foo{,.`date +%Y%m%d%H%M`}

• cp foo{,.`date +%Y%m%d%H%M`}
• cp foo{,.`date +%Y%m%d%H%M`-`$USER`}

The Sys Admin’s Journey
• ssh

• ssh
• Store notes in ~/server.txt

• ssh
• Move notes to the wiki

• ssh
• Write some scripts (setup.sh, fixit.sh, etc.)

• ssh
• Golden images and snapshots

• ssh
• Golden images and snapshots
• Policy-driven configuration management

Automation Platform
• Creates a dependable view of your entire network’s
state.
• Can handle complex dependencies among the
nodes of your network.
• Is fault tolerant.
• Is secure.
• Can handle multiple platforms
• Can manage cloud resources
• Provides a foundation for innovation

Infrastructure as Code
• Programmatically
provision and configure
components

• Treat like any other
code base

• Reconstruct business
from code repository,
data backup, and
compute resources

• Programmatically
provision and configure
components
• Treat like any other
code base
• Reconstruct business
from code repository,
data backup, and
compute resources

Policy-based
• You capture the policy for your infrastructure in
code
• A program ensures each node in your
infrastructure complies with the policy
• A control loop keeps the system stable and
allows for change when policy is updated

Sample Infrastructure
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master

New Compliance Mandate!
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master

New Compliance Mandate!
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master
•  Move SSH off of port 22
•  Let’s put it on 2022

6 Golden Images to Update
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master
1
3
4
5
6
2
/etc/ssh/sshd_config
--- a/sshd_config
+++ b/sshd_config
-Port 22
+Port 2202

12 Instances to replace
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master
1
3
2
5 6 74
8
10
9
11
12
•  Launch
•  Delete
•  Repeat
•  Typically manually

Done in maintenance window
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master
1
3
2
5 6 74
8
10
9
11
12
•  High stakes
•  Late hours
•  Risky change

New configurations required?
Graphite Nagios
JBoss
Memcache
Postgres Slaves
Postgres Master
Do the new instances
have new IP Addresses?
* Not all connections shown

Chef
Fast, scalable, flexible IT automation

What is Chef
• Open source framework for managing
complexity in your infrastructure through policy-
driven automation code
• A community of professionals
• A company

Chef
https://www.getchef.com/chef/

Chef Server – Policy & State

Desired Configuration
Node
Chef
Server
chef-client
What policy should I follow?

Node
Chef
Server
chef-client
"recipe[ntp::client]"
"recipe[users]"
"role[webserver]"

Chef
Server
chef-client
"recipe[ntp::client]"
"recipe[users]"
"role[webserver]"

HA Proxy Configuration
Webservers
HA Proxy

Webservers
HA ProxyChef
Server

Webservers
HA ProxyChef
Server
Webservers?

Webservers
HA ProxyChef
Server
Webservers?
{
"web01" : {
"hostname" : "web01",
"ipaddress" : "10.1.1.1"
},
"web02" : {
"ipaddress" : "10.1.1.2"
},
"web03" : {
"ipaddress" : "10.1.1.3"
},
"web04" : {
"ipaddress" : "10.1.1.4"
}

Webservers
HA ProxyChef
Server
Webservers?
{
"web01" : {
"ipaddress" : "10.1.1.1"
},
"web02" : {
"ipaddress" : "10.1.1.2"
},
"web03" : {
"ipaddress" : "10.1.1.3"
},
"web04" : {
"ipaddress" : "10.1.1.4"
}
pool_members
{
"web01" : {
"ipaddress" : "10.1.1.1"
},
"web02" : {
"ipaddress" : "10.1.1.2"
},
"web03" : {
"ipaddress" : "10.1.1.3"
},
"web04" : {
"ipaddress" : "10.1.1.4"
}

Webservers
HA Proxy
haproxy.cfg
server web01 10.1.1.1 weight 1 maxconn 1 check
pool_members
{
"web01" : {
"ipaddress" : "10.1.1.1"
},
"web02" : {
"ipaddress" : "10.1.1.2"
},
"web03" : {
"ipaddress" : "10.1.1.3"
},
"web04" : {
"ipaddress" : "10.1.1.4"
}

Building your policy
Resources and Recipes

Resources
• Piece of the system and its desired state
• Package that should be installed
• Service that should be running
• File that should be generated
• Cron job that should be configured
• User that should be managed
• And more
• docs.getchef.com/chef/resources.html

OPEN IN EDITOR:
SAVE FILE!
Hello, Chef!
file "/tmp/hello_chef.txt" do
content "Hello, Chef"
mode "0777"
end
~/hello_chef.rb

$
Recipe: (chef-apply cookbook)::(chef-apply recipe)
* file[/tmp/hello_chef.txt] action create
- create new file /tmp/hello_chef.txt
- update content in file /tmp/hello_chef.txt from none to 79c290
--- /tmp/hello_chef.txt 2014-10-22 19:59:04.000000000 -0400
+++ /tmp/.hello_chef.txt20141022-23075-19aelx1 2014-10-22
19:59:04.000000000 -0400
@@ -1 +1,2 @@
+Hello, Chef
- change mode from '' to '0777'
Apply the policy
sudo chef-apply hello_chef.rb

Resources
• Describe the desired state
• Do not need to tell Chef how to get there
• What happens when you re-apply the policy?

$
* file[/tmp/hello_chef.txt] action create (up to date)
Apply the policy

Resources
• A piece of the system
• Its desired state
file "/tmp/hello_chef.txt" do
content "Hello, Chef"
mode "0777"
end

$
Change the state of the system
echo “Hello, #ato2014” > /tmp/hello_chef.txt

$
* file[/tmp/hello_chef.txt] action create
- update content in file /tmp/hello_chef.txt from e453df to 79c290
--- /tmp/hello_chef.txt 2014-10-22 20:00:20.000000000 -0400
+++ /tmp/.hello_chef.txt20141022-23340-17a7m5t 2014-10-22
20:00:50.000000000 -0400
@@ -1,2 +1,2 @@
-“Hello, #ato2014”
+Hello, Chef
Apply the policy

Resources – Test and Repair
• Resources use a test and repair model
• Resource currently in the desired state?
• Yes – Do nothing
• No – Bring the resource into the desired state (repair)

Built-in Resources
• package
• template
• service
• cron
• directory
• mount
• user
• group
• registry_key
• remote_directory
• route
• and many more…
docs.getchef.com/chef/resources.html

Recipes
• Policy is defined as a collection of resources in
recipes. There are lots of abstractions on top of
this but resources are the basic building blocks.

Sample Recipe
package "httpd"
template "/etc/httpd/conf/httpd.conf" do
source "httpd.conf.erb"
owner "root"
group "root"
mode "0644"
notifies :restart, "service[httpd]"
end
service "httpd" do
action [:start, :enable]
end
file "/var/www/html/index.html" do
content "Hello, ATO!"
end

Test-driven Infrastructure
Change policy with confidence

New policy mandate
• Apache should listen on port 81, not the default
port!
• Verify policy changes BEFORE applying the
changes to production

Questions to ask when testing
• Did chef-client complete successfully?
• Did the recipe put the node in the desired state?
• Are the resources properly defined?
• Does the code following our style guide?

Chef client success status
• Requirements to verify chef-client success:
• A place to store the cookbook artifact

• A chef-client with access to the cookbook

• A chef-client with access to the cookbook
• A target server running the same OS as production

Test Kitchen
• Test harness to execute code on one
or more platforms
• Driver plugins to allow your code to
run on various cloud and virtualization
providers
• Includes support for many testing
frameworks
• Included with ChefDK

Test Kitchen Lifecycle
• kitchen create
• kitchen list
• kitchen converge
• kitchen login
• kitchen destroy

ü  Did chef-client complete successfully?
• Did the recipe put the node in the desired state?

$
kitchen@localhost's password:
Manually Inspect with kitchen login
kitchen login

$
kitchen login
kitchen

$
Last login: Wed Sep 24 04:30:29 2014 from 172.17.42.1
kitchen login
kitchen

$
Hello, ATO!
curl http://localhost

Serverspec
• Write RSpec tests to verify your servers
• Not dependent on Chef
• Defines many resource types
• package, service, user, etc.
• Works well with Test Kitchen
• http://serverspec.org/

OPEN IN EDITOR:
SAVE FILE!
Serverspec Test
require 'serverspec'
set :backend, :exec
describe "apahce" do
it "has httpd package installed" do
expect(package('httpd')).to be_installed
end
it "is listening on port 80" do
expect(port(80)).to be_listening
end
it "displays our home page" do
expect(command("curl http://localhost").stdout).to match /ATO/
end
end
test/integration/default/serverspec/default_spec.rb

$
-----> Setting up Busser
Creating BUSSER_ROOT in /tmp/busser
Creating busser binstub
Plugin serverspec installed (version 0.2.6)
-----> Running postinstall for serverspec plugin
Finished setting up <default-centos-64> (0m32.59s).
-----> Verifying <default-centos-64>...
Suite path directory /tmp/busser/suites does not exist, skipping.
Uploading /tmp/busser/suites/serverspec/default_spec.rb (mode=0664)
-----> Running serverspec test suite
/opt/chef/embedded/bin/ruby -I/tmp/busser/suites/serverspec -S /opt/chef/embedded/bin/rspec /tmp/busser/suites/serverspec/default_spec.rb
--color --format documentation
apache
is installed
Finished in 0.29547 seconds
1 example, 0 failures
Finished verifying <default-centos-64> (0m4.44s).
-----> Kitchen is finished. (1m25.74s)
Verify the kitchen
kitchen verify

ü  Did chef-client complete successfully?
ü  Did the recipe put the node in the desired
state?

Now for our new mandate
• Update the tests
• Watch them fail
• Update the policy
• See tests pass
• Roll-out changes to production

We’ve only scratched the surface
https://www.getchef.com/chef/

Build Anything
• Simple internal applications
• Complex external
applications
• Workstations
• Hadoop clusters
• IaaS infrastructure
• PaaS infrastructure
• SaaS applications
• Storage systems
• You name it
http://www.flickr.com/photos/hyku/245010680/

And Manage it Simply
• Automatically
reconfigure everything
• Linux, Windows, Unixes,
BSDs
• Load balancers
• Metrics collection
systems
• Monitoring systems
• Cloud migrations
become trivial
http://www.flickr.com/photos/helico/404640681/

What questions do you have?
• Ask me anything!
• @nathenharvey
• nharvey@getchef.com
• Thank you!

Introduction to Infrastructure as Code & Automation / Introduction to Chef

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