EC2 インスタンス上の httpd の server-status を CloudWatch に追加する

cw-server-status.rb

apache_dir = '/etc/httpd'

cookbook_file "#{apache_dir}/conf.d/server-status.conf" do
  source 'server-status.conf'
  owner 'root'
  group 'root'
  mode '0644'
  action :create
end

cookbook_file '/usr/local/bin/cw-server-status.sh' do
  source 'cw-server-status.sh'
  owner 'root'
  group 'root'
  mode '0755'
  action :create
end

execute "ExtendedStatus On" do
  not_if "grep -e '^ExtendedStatus On' #{apache_dir}/conf/httpd.conf"
  command "echo 'ExtendedStatus On' >> #{apache_dir}/conf/httpd.conf"
  user "root"
  action :run
end

execute "Install crontab" do
  not_if "grep cw-server-status.sh /etc/crontab"
  command "echo '* * * * * root /usr/local/bin/cw-server-status.sh' >> /etc/crontab"
  user 'root'
  action :run
end

service 'httpd' do
  restart_command '/sbin/service httpd restart && sleep 1'
  supports [:restart]
  action :restart
end

cw-server-status.sh

#!/bin/bash

# IAM user:cloudwatch
AWS_DEFAULT_REGION="ap-northeast-1"
AWS_ACCESS_KEY_ID="YOUR ACCESS KEY"
AWS_SECRET_ACCESS_KEY="YOUR SECRET ACCESS KEY"

INSTANCE_ID_URL="http://169.254.169.254/latest/meta-data/instance-id"
INSTANCE_ID=$(curl -s ${INSTANCE_ID_URL})

SERVER_STATUS_URL="http://localhost/server-status?auto"
SERVER_STATUS_HOSTNAME="server-status.localhost"

NAMESPACE="httpd"
TIMESTAMP=$(date -u '+%Y-%m-%dT%H:%M:%SZ')

PUT_METRIC_CMD="/bin/env \
  AWS_DEFAULT_REGION=${AWS_DEFAULT_REGION} \
  AWS_ACCESS_KEY_ID=${AWS_ACCESS_KEY_ID} \
  AWS_SECRET_ACCESS_KEY=${AWS_SECRET_ACCESS_KEY} \
  /usr/bin/aws cloudwatch put-metric-data \
  --region ${AWS_DEFAULT_REGION} \
  --dimensions InstanceId=${INSTANCE_ID} \
  --namespace ${NAMESPACE} \
  --timestamp ${TIMESTAMP}"

TMP_FILE="/tmp/server-status"

# GET /server-status
curl -H"Host: ${SERVER_STATUS_HOSTNAME}" \
  -s -L ${SERVER_STATUS_URL} > ${TMP_FILE}

# put-metric-data
${PUT_METRIC_CMD} --metric-name ReqPerSec --unit Count \
  --value $(grep ReqPerSec ${TMP_FILE} | awk '{print $2}')

${PUT_METRIC_CMD} --metric-name BusyWorkers --unit Count \
  --value $(grep BusyWorkers ${TMP_FILE} | awk '{print $2}')

${PUT_METRIC_CMD} --metric-name IdleWorkers --unit Count \
  --value $(grep IdleWorkers ${TMP_FILE} | awk '{print $2}')

server-status.conf

<VirtualHost *:80>
    ServerName   server-status.localhost
    DocumentRoot /var/www/html
    ErrorLog     /var/log/httpd/server-status.localhost-error_log
    CustomLog    /var/log/httpd/server-status.localhost-access_log combined

    DirectoryIndex index.html

    <Location "/server-status">
        SetHandler server-status
        Order deny,allow
        Deny from all
        Allow from 127.0.0.1
    </Location>
</VirtualHost>

# vim:set ts=4 sw=4 expandtab ft=apache: