ACME cookbook

Automatically get/renew free and trusted certificates from Let's Encrypt (letsencrypt.org). ACME is the Automated Certificate Management Environment protocol used by Let's Encrypt.

Attributes

Attribute	Description	Default
contact	Contact information, default empty. Set to mailto:[email protected]	[]
endpoint	ACME server endpoint, Set to https://acme-staging.api.letsencrypt.org if you want to use the Let's Encrypt staging environment and corresponding certificates.	https://acme-v01.api.letsencrypt.org
renew	Days before the certificate expires at which the certificate will be renewed	30
source_ips	IP addresses used by Let's Encrypt to verify the TLS certificates, it will change over time. This attribute is for firewall purposes. Allow these IPs for HTTP (tcp/80).	['66.133.109.36']
private_key	Private key content of registered account. Private keys identify the ACME client with the endpoint and are not transferable between staging and production endpoints.	nil
key_size	Default private key size used when resource property is not. Must be one out of: 2048, 3072, 4096.	2048

Recipes

default

Installs the required acme-client rubygem.

Usage

Use the acme_certificate resource to request a certificate with the http-01 challange. The webserver for the domain for which you are requesting a certificate must be running on the local server. This resource only supports the http validation method. To use the tls-sni-01 challange, please see the resource below. Provide the path to your wwwroot for the specified domain.

acme_certificate 'test.example.com' do
  crt               '/etc/ssl/test.example.com.crt'
  chain             '/etc/ssl/test.example.com-chain.crt'
  key               '/etc/ssl/test.example.com.key'
  wwwroot           '/var/www'
end

Use the acme_ssl_certificate resource to request a certificate using the tls-sni-01 challange. By default an nginx server is expected to be running on the machine that will be configured to complete the challange. Using a different webserver is possible by specifying a different provider for the resource, but by default only the nginx provider is implemented (see libraries/ssl_certificate/nginx.rb on how to port the resource for another webserver).

acme_ssl_certificate '/etc/ssl/test.example.com.crt' do
  cn                'test.example.com'
  alt_names         ['foo.example.com', 'bar.example.com']
  output            :crt # or :fullchain
  key               '/etc/ssl/private/test.example.key.pem'
  min_validity      30 #Renew certificate if expiry is closed than this many days

  webserver         :nginx
end

In case your webserver needs an already existing certificate when installing a new server you will have a bootstrap problem. Webserver cannot start without certificate, but the certificate cannot be requested without the running webserver. To overcome this a self-signed certificate can be generated with the acme_selfsigned resource.

acme_selfsigned 'test.example.com' do
  crt     '/etc/ssl/test.example.com.crt'
  chain   '/etc/ssl/test.example.com-chain.crt'
  key     '/etc/ssl/test.example.com.key'
end

A working example can be found in the included acme_client test cookbook.

Providers

certificate

Property	Type	Default	Description
cn	string	name	The common name for the certificate
alt_names	array	[]	The common name for the certificate
crt	string	nil	File path to place the certificate
key	string	nil	File path to place the private key
key_size	integer	2048	Private key size. Must be one out of: 2048, 3072, 4096
chain	string	nil	File path to place the certificate chain
fullchain	string	nil	File path to place the certificate including the chain
owner	string	root	Owner of the created files
group	string	root	Group of the created files
wwwroot	string	/var/www	Path to the wwwroot of the domain
ignore_failure	boolean	false	Whether to continue chef run if issuance fails
retries	integer	0	Number of times to catch exceptions and retry
retry_delay	integer	2	Number of seconds to wait between retries
endpoint	string	nil	The Let's Encrypt endpoint to use
contact	array	[]	The contact to use

selfsigned

Property	Type	Default	Description
cn	string	name	The common name for the certificate
crt	string	nil	File path to place the certificate
key	string	nil	File path to place the private key
key_size	integer	2048	Private key size. Must be one out of: 2048, 3072, 4096
chain	string	nil	File path to place the certificate chain
owner	string	root	Owner of the created files
group	string	root	Group of the created files

Example

To generate a certificate for an apache2 website you can use code like this:

# Include the recipe to install the gems
include_recipe 'acme'

# Set up contact information. Note the mailto: notation
node.set['acme']['contact'] = ['mailto:[email protected]']
# Real certificates please...
node.set['acme']['endpoint'] = 'https://acme-v01.api.letsencrypt.org'

site = "example.com"
sans = ["www.#{site}"]

# Generate a self-signed if we don't have a cert to prevent bootstrap problems
acme_selfsigned "#{site}" do
  crt     "/etc/httpd/ssl/#{site}.crt"
  key     "/etc/httpd/ssl/#{site}.key"
  chain    "/etc/httpd/ssl/#{site}.pem"
  owner   "apache"
  group   "apache"
  notifies :restart, "service[apache2]", :immediate
end

# Set up your webserver here...

# Get and auto-renew the certificate from Let's Encrypt
acme_certificate "#{site}" do
  crt               "/etc/httpd/ssl/#{site}.crt"
  key               "/etc/httpd/ssl/#{site}.key"
  chain             "/etc/httpd/ssl/#{site}.pem"
  wwwroot           "/var/www/#{site}/htdocs/"
  notifies :restart, "service[apache2]"
  alt_names sans
end

Testing

The kitchen includes a boulder server to run the integration tests with, so testing can run locally without interaction with the online API's.

Contributing

1. Fork the repository on Github
2. Create a named feature branch (like add_component_x)
3. Write your change
4. Write tests for your change (if applicable)
5. Run the tests, ensuring they all pass
6. Submit a Pull Request using Github

License and Authors

Authors: Thijs Houtenbos [email protected]

Credits

Let’s Encrypt is a trademark of the Internet Security Research Group. All rights reserved.