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Understanding the LocalConfiguration.json file - C agent

  • Article
  • 03/28/2022

The Defender for IoT security agent uses configurations from a local configuration file. The security agent reads the configuration once, at agent start-up. The configuration found in the local configuration file contains authentication configuration and other agent related configurations. The file contains configurations in "Key-Value" pairs in JSON notation and the configurations get populated when the agent is installed.

By default, the file is located at: /var/ASCIoTAgent/LocalConfiguration.json

Changes to the configuration file take place when the agent is restarted.

Security agent configurations for C

Configuration Name Possible values Details
AgentId GUID The agent Unique identifier
TriggerdEventsInterval ISO8601 string Scheduler interval for triggered events collection
ConnectionTimeout ISO8601 string Time period before the connection to IoThub gets timed out
Authentication JsonObject Authentication configuration. This object contains all the information needed for authentication against IoTHub
Identity "DPS", "SecurityModule", "Device" Authentication identity - DPS if authentication is made through DPS, SecurityModule if authentication is made via Defender-IoT-micro-agentcredentials or device if authentication is made with Device credentials
AuthenticationMethod "SasToken", "SelfSignedCertificate" the user secret for authentication - Choose SasToken if the use secret is a Symmetric key, choose self-signed certificate if the secret is a self-signed certificate
FilePath Path to file (string) Path to the file that contains the authentication secret
HostName string The host name of the Azure IoT hub. usually <my-hub>.azure-devices.net
DeviceId string The ID of the device (as registered in Azure IoT Hub)
DPS JsonObject DPS related configurations
IDScope string ID scope of DPS
RegistrationId string DPS device registration ID
Logging JsonObject Agent logger related configurations
SystemLoggerMinimumSeverity 0 <= number <= 4 log messages equal and above this severity will be logged to /var/log/syslog (0 is the lowest severity)
DiagnosticEventMinimumSeverity 0 <= number <= 4 log messages equal and above this severity will be sent as diagnostic events (0 is the lowest severity)

Security agent configurations code example

{
    "Configuration" : {
        "AgentId" : "b97faf0a-0f57-471f-9dab-46a8e1764946",
        "TriggerdEventsInterval" : "PT2M",
        "ConnectionTimeout" : "PT30S",
        "Authentication" : {
            "Identity" : "Device",
            "AuthenticationMethod" : "SasToken",
            "FilePath" : "/path/to/my/SymmetricKey",
            "DeviceId" : "my-device",
            "HostName" : "my-iothub.azure-devices.net",
            "DPS" : {
                "IDScope" : "",
                "RegistrationId" : ""
            }
        },
        "Logging": {
            "SystemLoggerMinimumSeverity": 0,
            "DiagnoticEventMinimumSeverity": 2
        }
    }
}

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