Monitoring DNS

This article will help you get the Dns plugin for sd-agent configured and returning metrics

Installing the dns plugin package

Install the dns plugin on Debian/Ubuntu:

sudo apt-get install sd-agent-dns-check

Install the dns plugin on RHEL/CentOS:

sudo yum install sd-agent-dns-check

Read more about agent plugins.

Configuring the agent to monitor DNS

1. Configure /etc/sd-agent/conf.d/dns_check.yaml

init_config:

instances:
  - name: Server Density (com)
    # nameserver: 8.8.8.8   # The nameserver to query, this must be an IP address
    hostname: serverdensity.com # the record to fetch
    # record_type: AAAA   # default is A
  - name: Example (org)
    hostname: example.org

If you do not provide a nameserver the check will use the nameserver configured in the local network settings.

2. Restart the agent

sudo /etc/init.d/sd-agent restart

or

sudo systemctl restart sd-agent

Verifying the configuration
Execute info to verify the configuration with the following:

sudo /etc/init.d/sd-agent info 

or

/usr/share/python/sd-agent/agent.py info

If the agent has been configured correctly you'll see an output such as:

dns
-----
  - instance #0 [OK]
  - Collected * metrics

You can also view the metrics returned with the following command:

sudo -u sd-agent /usr/share/python/sd-agent/agent.py check dns_check

Configuring graphs

Click the name of your server from the Devices list in your Server Density account then go to the Metrics tab. Click the + Graph button on the right then choose the dns metrics to display the graphs. The metrics will also be available to select when building dashboard graphs.

Monitored metrics

Metric	Values
dns.response_time The response time for DNS query for a given record, tagged by hostname, e.g. 'hostname:example.com'.	second / None Type: float