Supervisors are one of the core things that make Erlang/OTP what it is. An active OTP application consists of one or more processes that do the work. Those processes are started indirectly by supervisors, which are responsible for supervising them and restarting them if necessary. A running application is essentially a tree of processes, both supervisors and workers, where the root of the tree is the root supervisor.
"Supervisor" is a concept in the Erlang programming language. It refers to a process whose role is to monitor other processes, and restart them if they crash.
The supervisor is responsible for starting, stopping and monitoring its child processes. The basic idea of a supervisor is that it should keep its child processes alive by restarting them when necessary.
The children of a supervisor is defined as a list of child specifications. When the supervisor is started, the child processes are started in order from left to right according to this list. When the supervisor terminates, it first terminates its child processes in reversed start order, from right to left.
