It is recommended to use fixed numbers, such as [ 1, 2, 3, 4 ] if
you have, for example 4 instances of the application running
on the same 'host'.
You can also use names for an instance, however, the identifier should
be unique for this 'host', and should not change for the lifetime of
the application (so using PID as instance is discouraged for example);
Application instance
It is recommended to use fixed numbers, such as [ 1, 2, 3, 4 ] if you have, for example 4 instances of the application running on the same 'host'. You can also use names for an instance, however, the identifier should be unique for this 'host', and should not change for the lifetime of the application (so using PID as instance is discouraged for example);