Viewing Trident's Background Log

Trident records trace level logging information while it is performing an install or update. This can be useful for debugging and troubleshooting issues.

Location of the Log File

By default, Trident saves these logs to the following location:

/var/log/trident-full.log

Contents

This log file has similar contents to the output of Trident itself, with the exception that this log is NOT filtered, meaning all log messages, regardless of their level will be present in this file.

NOTE: The file is truncated every time Trident is restarted!

Format

The file is a JSON stream, with each line being a JSON object. The JSON object represents a full log line, with the following fields:

Field	Type	Description
level	String	one of trace, debug, info, warn, error.
message	String	the log message itself.
target	String	Rust log target (generally the module path).
module	String	Rust module path.
file	String	Source file where the log was generated.
line	u32	Line number where the log was generated.

Logs from Past Servicing

In addition to the full Trident log file from the current servicing, the user can also view the logs from any past servicing executed by Trident. These logs are persisted from the MOS or old target OS to the directory adjacent to the datastore in the updated target OS.

After each servicing, the full Trident log is persisted to a file named trident-<servicing_state>-<timestamp>.log, where the timestamp corresponds to the time when the log was persisted to the updated target OS. Servicing state is the state that Trident was in when the logs were copied over: e.g. the logs for the staging of an A/B update would be named trident-ab-update-staged-<timestamp>.log.

Similarly, Trident also persists the metrics logs to the updated target OS, i.e. trident-metrics-<servicing_state>-<timestamp>.log.