Instance identification

Reference | Administration

If you are running multiple instances of the same application, either on a single VM/server/container, or across multiple hosts, it is often useful to assign each instance a unique ID.

You can provide an instance ID, to each instance of your application via a command line argument which is then made available to your application components if they need it.

Providing an ID via the command line

Start your application with the -i argument. E.g.:

myapp -i myid

You will see a message similar to:

29/Oct/2019:11:01:08 Z INFO  [grncInit] Instance ID: myid

Generating an instance ID

If you set the flag -u when starting your application, Granitic will generate a V4 UUID and use that as an instance ID.

Accessing the ID from your components

If your component implements instance.Receiver (e.g. implements the method RegisterInstanceID(*instance.Identifier)), the instance ID will be passed in to that method before the container starts your components.

The instance ID will also be injected into your application’s merged configuration and can be found at the config path System.InstanceID

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