Bind Queries Statistics Test

To be able to understand the workload of BIND DNS, you should track the flow of queries into the server and out of it (to other DNS servers). This is what the Bind Query Statistics test does. This test reports the count of incoming and outgoing queries for each Resource Record (RR) type of the target BIND DNS. Resource Records define data types in the Domain Name System (DNS). Typically, they are stored in binary format internally for use by the BIND DNS. When zone transfers are performed, Resource Records are sent across the network in text format. Some of the common RR types are as follows: A, AAAA, A6, AFSDB, CNAME, DNAME, DNSKEY, SRV, etc.

Using this test, administrators can easily assess the current load on the server and rapidly detect a potential overload condition. Moreover, in times of abnormal load, you can use this test to identify the RR that is seeing maximum traffic and is thus contributing to the load.

Target of the test : A BIND DNS server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every Resource Record type in BIND DNS

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the host for which this test is to be configured.

Port

Refers to the port at which the specified host listens to. By default, this is 53.

Path of RNDC

To monitor BIND DNS, this test uses a name server control utility in bind called Remote Name Daemon Control (RNDC). RNDC is a command line utility that allows command line control of the administration and operations of a name server, both locally and remotely. Periodically, this test runs the rndc stats command of this utility to pull metrics of interest. To enable the test to run this command, configure the full path to the folder where RNDC is located, against Path of RNDC. The default location of RNDC is /usr/sbin. If it is installed in a different location in your environment, then specify the same here.

Path of RNDC Output File

This test runs the rndc stats command of to pull metrics of interest from the target BIND DNS server. This command instructs BIND to dump the statistics to a statistics-file configured in the configuration file for the named server - /etc/named.conf. To enable this test to read from this statistics-file, specify the full path to the statistics-file against Path of RNDC Output File. By default, metrics are written to the named_stats.txt file in the /var/named/data/ folder. If chroot is enabled, then this file will typically be available in the /var/named/chroot/var/named/data folder.

Use SUDO

To run this test and report metrics, the eG agent install user should have permissions to run the rndc stats command and read from the statistics-file. If the eG agent install user possesses these privileges, then set the Use SUDO flag to No. If the eG agent install user does not have the required permissions, then do the following:

  • Edit the sudoers file on the target host and append an entry of the following format to it:

    <eG_agent_install_user>; ALL=(ALL) NOPASSWD:<Command>;

    For instance, if the eG agent install user is eguser, then the entry in the sudoers file should be:

    eguser ALL=(ALL) NOPASSWD: rndc stats

  • Then, save the file.
  • Finally, set the Use SUDO parameter to Yes.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Incoming queries

Indicates the number of incoming queries for this Resource Record type.

Number

These are good measures of the current workload of BIND DNS. In the event of an overload, you can compare these metrics across RRs to know which RR is contributing to the load.

Outgoing queries

Indicates the number of outgoing queries for this Resource Record type.

Number