1 Managing Log Levels in Swarm Cluster Using a Shell Script
- 1.1 Script Features
- 1.2 Requirements
- 1.3 Script Usage
- 1.4 Instruction for Use
  - 1.4.1 Behavior
    - 1.4.1.1 Output Messages
  - 1.4.2 Example Output
  - 1.4.3 Error Handling
- 1.5 Notes
- 1.6 Script Source Code

Managing Log Levels in Swarm Cluster Using a Shell Script

The Swarm Log Level Management Script (castor-change-log-level.sh) is designed to manage and dynamically adjust log levels on a DataCore Swarm cluster, providing options to change the log level temporarily and automatically revert it after a specified duration. It supports background execution via screen or tmux, making it ideal for long-running operations that require detachment from the terminal.

Script Features

Set and Revert Log Levels: Temporarily change the log level and revert after a specified duration.
Flexible JSON Parsing: Uses jq for JSON parsing if available; defaults to jq otherwise.
Background Execution: Optionally runs in the background using screen or tmux.
Log Size Monitoring: Reports the log size generated during the temporary log level change.
Countdown Display: Shows a countdown for the specified duration.

Requirements

jq (optional): Used for parsing JSON responses; falls back to grep if unavailable.
screen or tmux (optional): Required for background execution.
Permissions: Ensure sufficient permissions to execute on the DataCore Swarm server and access required files.

Script Usage

./castor-change-log-level.sh -d <node_ip> -p <admin:password> -i <new_log_level> [-t <duration_in_seconds>] [--background] [-v]

Parameter	Description

Parameter	Description
`-d, --swarm_ip`	IP address of the Swarm API endpoint (or set `SCSP_HOST` environment variable).
`-p, --credentials`	Admin credentials in the format `admin:password`.
`-i, --log.level`	New log level to set (values: `10, 15, 20, 30, 40, 50`).
`-t, --time`	Duration in seconds to keep the new log level (optional).
`--persistent`	Runs the script in a detached session using `screen` or `tmux`, allowing continued operation if terminal session ends.
`-v, --verbose`	Enables verbose mode to display debug information.

Instruction for Use

Example 1: Set log level to 20 and keep it for 10 seconds

./castor-change-log-level.sh -d 192.168.8.84 -p admin:datacore -i 20 -t 10

Example 2: Run in background mode with verbose logging

./castor-change-log-level.sh -d 192.168.8.84 -p admin:datacore -i 20 -t 30 --background -v

Behavior

Log Level Change: Sets the log level to the specified value. If the current log level matches the requested level, the script skips the update.
Countdown: During the specified duration, the script displays a countdown every second.
Revert Log Level: After the countdown, the log level reverts to the initial value.
Log Size Report: Provides approximately log size generated during the temporary log level change.
Debug Mode: When -v is specified, debug messages display the script's internal operations.

Output Messages

Message	Description

Message	Description
`Swarm IP:`	Displays the specified Swarm IP address.
`Credentials:`	Credentials are masked for security.
`Cluster Name:`	Displays the cluster name retrieved from the Swarm API.
`New log level:`	Shows the new log level requested.
`Current log level:`	Displays the current log level.
`Updating log level to X...`	Indicates the beginning of the log level update process.
`Log level changed successfully...`	Confirms that the log level was successfully updated.
`Keeping log level at X for Y...`	Shows the temporary period for which the new log level is retained, with a countdown.
`Time's up! Reverting log level...`	Indicates that the temporary period has ended and the script is reverting the log level.
`Approximate X new logs generated...`	Provides information on the amount of logging activity generated during the temporary log level.

Example Output

Error Handling

Missing Parameters: Missing parameters prompt a usage message.
Invalid Duration: If a non-numeric duration is provided, you’re prompted to enter a valid duration in seconds.
Connection Issues: If unable to connect to the Swarm API, check the IP, credentials, and network access.

Notes

Credentials are masked in the output for security.
Log file sizes are shown in human-readable format (GB, MB, KB, B).

This script provides administrators with an effective way to adjust and monitor Swarm logging, supporting both temporary and permanent log level changes for troubleshooting and performance monitoring.

Script Source Code

Latest version: castor-change-log-level.sh

Swarm Documentation

Setting and Managing Swarm Log Levels with script