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Nagios check for AWS Cloudwatch statistics/metrics

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Nagios Cloudwatch is a set of scripts to help with the Nagios (and derivates) monitoring of Amazon Cloud resources. Features includes:


3 simple steps


Either download the lastest stable release as a tar-ball or zip-file, or clone the git repository.
mkdir /path/to/your/plugins
cd /path/to/your/plugins
wget -O nagios-cloudwatch.latest.tar.gz
tar xvzf nagios-cloudwatch.latest.tar.gz

mkdir /path/to/your/plugins
cd /path/to/your/plugins
git clone
cd nagios-cloudwatch
git checkout stable


  #--- authentication
  access_key_id: YOUR_ACCESS_KEY
  secret_access_key: YOUR_SECRET_KEY

  #--- default region, unless overridden on the command line
  #--- possible regions us-west-1 us-west-2 eu-west-1, etc...
  region: us-west-2

  #--- Proxy config
  #proxy_uri: http://user:passwd@IP:PORT


Here are a couple of examples on how to run the script:

$ ./check_cloudwatch.rb --ec2 --list-instances
Name: vpn-v001ec2          Id: i-91f62199     privateIp:       State: Zone: running
Name: kmg-test002ec2       Id: i-7ef62176     privateIp:      State: Zone: running
Name: win-test003ec2       Id: i-9956e691     privateIp:      State: Zone: stopped

$ ./check_cloudwatch.rb --ec2 --instance=i-7ef62176 --list-metrics

$ ./check_cloudwatch.rb --ec2 --instance=i-7ef62176 --metric=CPUUtilization --window=600 --period=300 -w 80 -c 95
OK - Id: i-7ef62176 Metric: CPUUtilization, Last Value: 0.334000 Unit: Percent (2014-06-16 15:43:00 UTC)
|Average=0.334000 Minimum=0.000000 Maximum=1.670000 Sum=1.670000	

Pre requisites

  • Ruby environment with ruby version > 1.9.1 (see below)
  • Configuration file config.yml, unless you supply the credentials on the command line
  • Ruby

    Ubuntu 12.04 LTS

    If your installation come with ruby 1.8, you might have to start the script with /usr/bin/ruby1.9.1 ./check_cloudwatch.rb, unless you follow the second step on how to make ruby1.9.1 default in your installation.

    sudo apt-get install -y ruby1.9.1 ruby1.9.1-dev \
         rubygems1.9.1 irb1.9.1 ri1.9.1 rdoc1.9.1 \
         build-essential libopenssl-ruby1.9.1 libssl-dev zlib1g-dev
    sudo gem install aws-sdk-core --pre

    Note: to make ruby1.9.1 default on your system, follow the instructions on:

    sudo apt-get update
    sudo apt-get install ruby1.9.1 ruby1.9.1-dev \
       rubygems1.9.1 irb1.9.1 ri1.9.1 rdoc1.9.1 \
       build-essential libopenssl-ruby1.9.1 libssl-dev zlib1g-dev
    sudo update-alternatives --install /usr/bin/ruby ruby /usr/bin/ruby1.9.1 400 \
              --slave   /usr/share/man/man1/ruby.1.gz ruby.1.gz \
                             /usr/share/man/man1/ruby1.9.1.1.gz \
             --slave   /usr/bin/ri ri /usr/bin/ri1.9.1 \
             --slave   /usr/bin/irb irb /usr/bin/irb1.9.1 \
             --slave   /usr/bin/rdoc rdoc /usr/bin/rdoc1.9.1
     # choose your interpreter
     # changes symlinks for /usr/bin/ruby , /usr/bin/gem
     # /usr/bin/irb, /usr/bin/ri and man (1) ruby
     sudo update-alternatives --config ruby
     sudo update-alternatives --config gem
     # now try
     ruby --version


    sudo yum install -y gcc make \
    libxml2 libxml2-devel libxslt libxslt-devel \
    rubygems ruby-devel
    sudo gem install nokogiri -- --with-xml2-lib=/usr/local/lib \
    --with-xml2-include=/usr/local/include/libxml2 \
    --with-xslt-lib=/usr/local/lib \
    sudo gem install aws-sdk --no-ri --no-rdoc

    OP5 Appliance (CentOS)

    Pre-requisites already in place.



    ./check_cloudwatch.rb --instance="<INSTANCE_NAME>" --elb --metric="HealthyHostCount" --window=120 --period=60 --critical=:1+ --warning=:2+
    OK - Metric: HealthyHostCount, Last Average: 2.0 Count (2014-06-14 13:34:00 UTC)
    ./check_cloudwatch.rb -i <INSTANCE_NAME> --window=3600 --metric=HTTPCode_Backend_2XX --window=300 --period=300 --critical=15 --warning=10 --statistics="Sum"


    The threshold parameter can be a single value or a range, and can handle decimal values.

    The thresholds can be "soft" or "hard", meaning that ha hard threshold will include the parameter value (by comparing >= or <=). A soft threshold means that the check will not trigger when the checked value is equal to the threshold value (by comparing > or <).

    A soft threshold is selected by suffixing "+" to the threshold.

    Examples of valid thresholds are:

    1, 1.0, 1:+, :1.5, 0:1000, @1:100

    Listing metrics

    You can list available metrics for your instance, your load balancer, etc, by using the --list-metrics parameter.

    ./check_cloudwatch.rb --ec2 -i INSTANCE_ID  --list-metrics

    Statistics window, and statistics period

    The collection of AWS metrics is not done every minute. For example CPUUtilization is collected every 5 minutes. If you are asking for a window of 60 seconds and a period of 60 seconds, it is very likely that Cloudwatch will return an empty result set since there is no data to be presented for that period. This is a feature of how the AWS Cloudwatch data is collected.

    The workaround for this is to ask for a longer period, say 10 minutes or longer, to make sure you will get at least one metric in your result set.

    ./check_cloudwatch.rb --ec2 -i INSTANCE_ID --metric="CPUUtilization" --window=600 --period=60