openvpn Cookbook

Installs OpenVPN and sets up a fairly basic configuration. Since OpenVPN is very complex, we provide a baseline, but your site will need probably need to customize.

Requirements

OpenSSL 0.9.7 or later and OpenSSL bindings for Ruby

Platform

• Debian 6.0
• Ubuntu 10.04+
• RHEL 5.x and RHEL 6.x w/ EPEL enabled.

Cookbooks

The yum cookbook by Opscode provides recipe[yum::epel] that can be used on RHEL-family systems to enable the EPEL repository containing the openvpn RPM. See Usage below.

Not Supported

This cookbook is designed to set up a basic installation of OpenVPN that will work for many common use cases. The following configurations are not supported by default with this cookbook:

• setting up routers and other network devices
• ethernet-bridging (tap interfaces)
• dual-factor authentication
• many other advanced OpenVPN configurations

For further modification of the cookbook see Usage below.

For more information about OpenVPN, see the official site.

Attributes

These attributes are set by the cookbook by default.

• node["openvpn"]["local"] - IP to listen on, defaults to node[:ipaddress]
• node["openvpn"]["proto"] - Valid values are 'udp' or 'tcp', defaults to 'udp'.
• node["openvpn"]["port"] - Port to listen on, defaults to '1194'.
• node["openvpn"]["type"] - Valid values are 'server' or 'server-bridge'. Default is 'server' and it will create a routed IP tunnel, and use the 'tun' device. 'server-bridge' will create an ethernet bridge and requires a tap0 device bridged with the ethernet interface, and is beyond the scope of this cookbook.
• node["openvpn"]["subnet"] - Used for server mode to configure a VPN subnet to draw client addresses. Default is 10.8.0.0, which is what the sample OpenVPN config package uses.
• node["openvpn"]["netmask"] - Netmask for the subnet, default is 255.255.0.0.
• node["openvpn"]["gateway"] - FQDN for the VPN gateway server. Default is node["fqdn"].
• node["openvpn"]["log"] - Server log file. Default /var/log/openvpn.log
• node["openvpn"]["key_dir"] - Location to store keys, certificates and related files. Default /etc/openvpn/keys.
• node["openvpn"]["signing_ca_cert"] - CA certificate for signing, default /etc/openvpn/keys/ca.crt
• node["openvpn"]["signing_ca_key"] - CA key for signing, default /etc/openvpn/keys/ca.key
• node["openvpn"]["routes"] - Array of routes to add as push statements in the server.conf. Default is empty.
• node["openvpn"]["script_security"] - Script Security setting to use in server config. Default is 1. The "up" script will not be included in the configuration if this is 0 or 1. Set it to 2 to use the "up" script.
• node["openvpn"]["push"] - DEPRECATED: Use routes above. If you're still using this in your roles, the recipe will append to routes attribute.

The following attributes are used to populate the easy-rsa vars file. Defaults are the same as the vars file that ships with OpenVPN.

• node["openvpn"]["key"]["ca_expire"] - In how many days should the root CA key expire - CA_EXPIRE.
• node["openvpn"]["key"]["expire"] - In how many days should certificates expire - KEY_EXPIRE.
• node["openvpn"]["key"]["size"] - Default key size, set to 2048 if paranoid but will slow down TLS negotiation performance - KEY_SIZE.

The following are for the default values for fields place in the certificate from the vars file. Do not leave these blank.

• node["openvpn"]["key"]["country"] - KEY_COUNTRY
• node["openvpn"]["key"]["province"] - KEY_PROVINCE
• node["openvpn"]["key"]["city"] - KEY_CITY
• node["openvpn"]["key"]["org"] - KEY_ORG
• node["openvpn"]["key"]["email"] - KEY_EMAIL

Recipes

default

Sets up an OpenVPN server.

users

Utilizes a data bag called users to generate OpenVPN keys for each user.

Usage

Create a role for the OpenVPN server. See above for attributes that can be entered here.

name "openvpn"
description "The server that runs OpenVPN"
run_list("recipe[openvpn]")
override_attributes(
  "openvpn" => {
    "gateway" => "vpn.example.com",
    "subnet" => "10.8.0.0",
    "netmask" => "255.255.0.0",
    "key" => {
      "country" => "US",
      "province" => "CA",
      "city" => "SanFrancisco",
      "org" => "Fort-Funston",
      "email" => "[email protected]"
    }
  }
)

Note: If you are using a Red Hat EL distribution, you may need the EPEL repository enabled to install the openvpn package. You can use Opscode's recipe[yum::epel] for this. Either add it to the run list in the openvpn role above, or add to a base role used by all your RHEL-family systems.

To push routes to clients, add node['openvpn']['routes] as an array attribute, e.g. if the internal network is 192.168.100.0/24:

override_attributes(
  "openvpn" => {
    "routes => [
      "push 'route 192.168.100.0 255.255.255.0'"
    ]
  }
)

To automatically create new certificates and configurations for users, create data bags for each user. The only content required is the id, but this can be used in conjunction with other cookbooks by Opscode such as users or samba. See SSL Certificates below for more about generating client certificate sets.

{
  "id": "jtimberman"
}

This cookbook also provides an 'up' script that runs when OpenVPN is started. This script is for setting up firewall rules and kernel networking parameters as needed for your environment. Modify to suit your needs, upload the cookbook and re-run chef on the openvpn server. For example, you'll probably want to enable IP forwarding (sample Linux setting is commented out). The attribute node["openvpn"]["script_security"] must be set to 2 or higher to use this otherwise openvpn server startup will fail.

Customizing Server Configuration

To further customize the server configuration, there are two templates that can be modified in this cookbook.

• templates/default/server.conf.erb
• templates/default/server.up.sh.erb

The first is the OpenVPN server configuration file. Modify to suit your needs for more advanced features of OpenVPN. The second is an up script run when OpenVPN starts. This is where you can add firewall rules, enable IP forwarding and other OS network settings required for OpenVPN. Attributes in the cookbook are provided as defaults, you can add more via the openvpn role if you need them.

SSL Certificates

Some of the easy-rsa tools are copied to /etc/openvpn/easy-rsa to provide the minimum to generate the certificates using the default and users recipes. We provide a Rakefile to make it easier to generate client certificate sets if you're not using the data bags above. To generate new client certificates you will need rake installed (either as a gem or a package), then run:

cd /etc/openvpn/easy-rsa
source ./vars
rake client name="CLIENT_NAME" gateway="vpn.example.com"

Replace CLIENT_NAME and vpn.example.com with your desired values. The rake task will generate a tar.gz file with the configuration and certificates for the client.

License & Authors

• Author:: Joshua Timberman ([email protected])

Copyright:: 2009-2010, Opscode, Inc

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.