resolverstats

resolverstats

Name

resolverstats - collect statistics about upstream DNS servers in Redis.

Description

The resolverstats plugin measures the response times of upstream DNS servers in Redis. It works only in combination with the forward and metadata plugins.

A logged event is a comma separated list of:

• Unix timestamp in floating point format,
• IP address of the upstream server,
• State of the transaction (see below),
• Duration of the transaction in seconds as a floating point number.

The state can be one of:

• valid
• timeout
• error

The state invalid is currently not supported.

Note that errors and timeouts are hidden if at least one of the configured upstream DNS servers is working. The forward plugin detects and avoids non-responsive servers automatically.

The last 25000 events are stored under the Redis key:

dns_stats:NAME

Where NAME is configured per server block.

Syntax

resolverstats NAME

The NAME is part of the key that is used to store the events in Redis.

Examples

Collect stats from the configured upstream servers under Redis key dns_stats:custom:

. {
    resolverstats custom
    forward . 1.1.1.1:53 9.9.9.9:53
    metadata
}

Metadata

The metadata and forward plugins must also be enabled.

The plugin will read the following metadata:

• forward/upstream: IP and port of the upstream server

See also

The relevant classes in the ICAP server are:

• JediDnsDataSource
• DnsStatisticsService