1# Fan Monitor Configuration File 2 3## Table of Contents 4* [Overview](#overview) 5* [Data Format](#data-format) 6* [Example](#example) 7* [System Config Location](#system-config-location) 8* [Contents](#contents) 9* [Validation](#validation) 10* [Firmware Updates](#firmware-updates) 11* [Loading and Reloading](#loading-and-reloading) 12 13 14## Overview 15 16The `phosphor-fan-monitor` application is controlled by a configuration 17file (config file) to manage the `Functional` property's state on the 18`xyz.openbmc_project.State.Decorator.OperationalStatus` interface for fan 19inventory objects. The config file defines the method to use in determining the 20functional state and the logging of errors for each fan within a machine. It 21also provides the ability to adjust the determination of a fan being 22non-functional due to fan hardware limitations. 23 24 25## Data Format 26 27The config file is written using the [JSON (JavaScript Object 28Notation)](https://www.json.org/) data format and can be created using a text 29editor. 30 31 32## Example 33 34See [config.json](../../monitor/example/config.json). 35 36 37## System Config Location 38 39The config file name is `config.json`. 40 41### Supported Directory 42 43`/usr/share/phosphor-fan-presence/monitor/` 44 45The supported version of the config file is installed under this read-only 46directory location as part of the firmware image install. This is where the 47config file will be loaded from when no overriding config file exists. 48 49#### Default Location 50 51Where a single config file for 1-or-more system types can be used, 52the config file can be located at the base of the supported directory. 53 54i.e.) `/usr/share/phosphor-fan-presence/monitor/config.json` 55 56#### Compatible System Type Location 57 58The config file location can also be based on a system type. This is necessary 59where more than one type of machine is supported in a single BMC firmware image 60and those system types can not share a common config file. 61 62A system type sub-directory can be obtained from the `IBMCompatibleSystem` 63D-Bus interface's `Names` property. The `Names` property contains a list of one 64or more compatible system types, ordered from most specific to the most general. 65 66Example: 67* `ibm,rainier-2u` 68* `ibm,rainier` 69 70The `phosphor-fan-monitor` application then traverses the supported 71directory, appending each compatible system type entry as a sub-directory from 72most specific to most general until the config file is found. 73 74Example: 751. `/usr/share/phosphor-fan-presence/monitor/ibm,rainier-2u/` 76 * (directory/config file does not exist) 772. `/usr/share/phosphor-fan-presence/monitor/ibm,rainier/config.json` 78 * (config file found) 79 80If a config file is not found and the machine is powered on, an error is logged 81and `phosphor-fan-monitor` application terminates preventing the machine 82from successfully powering on. 83 84### Override Directory 85 86`/etc/phosphor-fan-presence/monitor/` 87 88A different version of the config file can be loaded by placing it into this 89writable directory location. This avoids the need to build and install a new 90firmware image on the BMC when changing the configuration, such as for testing 91purposes. 92 93The override directory may not exist on the BMC, therefore to be able to use 94an overriding config file it must be created using the following command: 95 96`mkdir -p /etc/phosphor-fan-presence/monitor` 97 98### Search Order 99 100The `phosphor-fan-monitor` application will search for the config file at 101the directory locations in the following order: 1021. Override directory 1032. Supported directory 104 * Default location 105 * Compatible System Type location 106 107 108## Contents 109 110### Structure 111 112TBD 113 114### Syntax 115 116TBD 117 118### Comments 119 120TBD 121 122 123## Validation 124 125TBD 126 127 128## Firmware Updates 129 130When a new firmware image is installed on the BMC, it will update the config 131file in the standard directory. 132 133The override directory will **not** be modified by a firmware update. If a 134config file exists in the override directory, it will continue to be used as 135the fan presence configuration instead of the config file located under the 136appropriate location within the supported directory. 137 138 139## Loading and Reloading 140 141The config file is loaded when the `phosphor-fan-monitor` application 142starts. 143 144To force the application to reload the config file, use the following command 145on the BMC: 146 147`systemctl kill -s HUP phosphor-fan-monitor@0.service` 148 149To confirm which config file was loaded, use the following command on the BMC: 150 151`journalctl -u phosphor-fan-monitor@0.service | grep Loading` 152