Deployment logs and limitations

Last updated on Dec 4, 2025

Harness deployment logging has the following limitations:

Log size limits

The following table shows the log size limits for different Harness modules:

Limit Type	CI Module	Other Modules (CD, CCM, etc.)
Total log size per step	5MB	25MB
Maximum size per log line	70KB	25KB

When logs exceed the size limit, Harness truncates the oldest log lines and retains the newest ones.
You can export full CI logs to an external cache. For information about CI log limits and exporting CI logs, go to Truncated execution logs.

Line limit: The Harness log service has a limit of 5000 lines. Logs rendered in the Harness UI are truncated from the top if the logs exceed the 5000 line limit.

note

If you need logs more than 5000 lines, contact Harness Support

Step runtime limit: Steps exceeding a 5-hour runtime may experience log visibility issues. We are working to address this limitation.

When running pipelines, you may notice differences between real-time log display and the complete logs available after step completion:

During step execution, the initial log display shows approximately 10,000 lines in real-time
The complete log becomes visible after refreshing the page once the step is complete
This behavior is by design and does not affect the execution of your steps

The log system uses batching to optimize log storage and display:

The 5,000 line limit applies at the step level per request
Log batching allows multiple log lines within each message, effectively increasing the total number of lines stored
Logs are flushed every second from the delegate to the log service
The batch size depends on how many logs the step produces within that flush interval
If a task produces more log lines than the configured limit within 100ms, older logs from that batch may be truncated

Real-time monitoring: During execution, you might see fewer lines than actually generated, or notice a mismatch between log line numbers and displayed content
Post-execution: The full log output becomes available after step completion and page refresh
Log line count: The total number of visible log lines can vary depending on the log generation rate and batching behavior

To work effectively with log display behavior:

For critical log analysis, wait for step completion and refresh the page to view complete logs
Consider breaking down steps that generate excessive logs into smaller tasks
Add identifiers or markers to log lines to make them easily searchable
If you notice missing logs during real-time monitoring, refresh the page after step completion to view the full output