---
title: "Application logs"
description: "Select application, check, job, or Guardian logs and understand log-driver retention."
---

> Documentation Index
> Fetch the complete documentation index at: https://cdelivery.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Application logs

New applications default to Insight logging when both the Insight server and collection agent are deployed; otherwise they follow the host. You can choose another driver. Enabling Insight does not change existing applications.

Open an application's logs and select the source that actually produced the output. The business process and its checks run in different containers.

## Sources

| Source | Output |
| --- | --- |
| App | Business application |
| XHealth | Health-check task |
| XJob and task name | Scheduled command |
| GuardianApp | Release candidate |
| GuardianCheck | Candidate validation |

Choose a time range around the failure and verify timestamps and task identity. A check failure may have no corresponding error in the application's own log.

## Logging configuration

FollowHost uses the host's logging behavior. JSON-file logging supports local rotation; the console defaults to five files of 10 MiB. The file count can be 1–100 and each file up to 1 GiB. Insight logging requires its collection component.

Changing the log driver affects new tasks. It does not migrate or backfill output from old tasks, whose availability depends on their original driver and retention.

## Diagnose

For an empty view, confirm the source, range, task lifetime, driver, and whether the process writes to standard output/error. Files written only inside the container do not automatically appear here.

For a query failure, inspect collection and storage connectivity rather than assuming there were no errors. Logs may contain application-provided credentials or personal data; arbitrary text is not automatically redacted.

Use [events](/docs/guides/observability/events/) to correlate changes, and [collection settings](/docs/guides/observability/settings/) to manage retained history.

Source: https://cdelivery.dev/docs/guides/observability/logs/application/index.mdx