Check_AWS_EC2_instance_status

Using Amazon EC2 API, this is possible to retrieve the status of an instance without installing any agent or configuring SNMP daemon.
Moreover, this requires only read-only credentials that could be easily generated using Amazon IAM. For security reasons, we use encrypted credentials that are decrypted by this plugin.

Here is a command line sample of use:
debian-secludit # RUBYOPT=rubygems ruby check_ec2_status.rb -v -a ec2-XXX-XXX-XXX-XXX.compute-1.amazonaws.com -i i-XXXXXXXX -f ec2_credentials_1.cfg
** Launching EC2 status retrieval on instance ID: i-XXXXXXXX on Amazon Server: $ec2.us-east-1.amazonaws.com
Amazon Server: ec2.us-east-1.amazonaws.com
EC2 Status Check: OK - State Name: running, State Code: 16|running=1

The ec2_credentials_1.cfg files contains the encrypted credentials as follow:
[blank_space]ec2_access_id[blank_space]B64_encoding(BF-CBC-Cipher_encoding(Access Key ID)
[blank_space]ec2_access_key[blank_space]B64_encoding(BF-CBC-Cipher_encoding(Secret Access Key)
You can use the encrypt_credentials.rb ruby script that does that as follow:
debian-secludit # RUBYOPT=rubygems ruby encrypt_credentials.rb -A XXXXXXXXXXXXXXXXXXXX -S XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX -f ec2_credentials.cfg

Here is a sample configuration file for nagios.
define host {
name Amazon_EC2_Instance_Name
use generic-host
address ec2-XXX-XXX-XXX-XXX.compute-1.amazonaws.com
check_command check_ec2_status!i-XXXXXXXX!/etc/nagios3/credentials/ec2_credentials_1.cfg
max_check_attempts 3
}