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Maintained by AxonOps — production-grade documentation from engineers who operate distributed databases at scale Simplify Cassandra Ops Simplify Kafka Ops

Logs and Events

AxonOps provides a powerful logging feature that allows you to search and filter logs based on different parameters such as:

  • DC/Rack/Node
  • Log Level
  • Event Type
  • Source
  • Log Content

The logs and events are visible in two locations allowing quick access to them without having to log in to the individual servers:

  1. Within the Logs & Events tab:

    Logs & Events UI

  2. Within the AxonOps Dashboard by dragging the bottom handle icon up:

    Dashboard UI

Search by Log Level

Filter logs based on their log levels to focus on specific severity levels. The log level indicates the importance or severity of a message from the most critical (ERROR) to less severe (DEBUG).

Selecting Log Levels

Setting up the Debug Level

To search logs by DEBUG level you have to enable DEBUG logs in Cassandra by editing the logback.xml file:

<appender name="SYSTEMLOG" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
        <level>DEBUG</level>

Note: Enabling DEBUG logs within Cassandra is not advised during normal operations and should only be activated for short periods of time on select nodes when debugging issues where INFO logs do not provide enough visibility.

Leaving DEBUG logs on indefinitely can cause immense strain on the Cassandra process due to its high CPU usage.

Search by Logs Source and Event Type

You can filter logs based on the log source (cassandra, axon-server, and axon-agent logs) and event type to narrow down search results.

Event Types Event Types continued

Search by Content

For free text search, enter a keyword in the Message field or use the /<expression>/ syntax to search by regex expressions.

Example Search Terms

Currently the following keyword syntax is supported:

  • hello
    • matches hello
  • hello world
    • matches hello or world
  • "hello world"
    • matches exact hello world
  • +-hello
    • matches excluding hello
  • +-"hello world"
    • matches excluding hello world
  • +-hello +-world
    • matches excluding hello or world
  • /.*repair.*/
    • displays logs that contain a specific word or phrase
  • /(Validated|Compacted)/
    • displays logs that match either what is before or after the |, in this case Validated or Compacted
  • /Segment.*deleted/
    • displays logs that contain both patterns in a line, in this case Segment and deleted