admin - The user with the "admin" role is the initial user who sets up security. Thereafter, the "admin" user can perform system functions such as shutting down servers, clearing or deleting caches and cache managers, and reloading configurations.

terracotta - This is the operator role. The default username for the operator role is "terracotta". The "terracotta" user can connect to the TMC and access the read-only areas. In addition, the "terracotta" user can start a secure server. But a user must have the "admin" role in order to run the stop-tc-server script.