Shutown and startup fails when I try creating a Backup

[britianoates]

After I have started the docker instance and ssh in I try to follow these commands:

shutdown immediate; startup mount;

I get a RMAN-03002: failure of startup command at 09/27/2016 19:14:14 RMAN-06171: not connected to target database

examples such as this one seem to do this fine. http://stackoverflow.com/questions/6946586/database-not-open

The goal is to create a backup of our oracledb for testing purposes, but we need to close the database, backup, and remount the database in order to do this. Currently all we've been able to do is shutdown the database, and restart the docker instance to get it back up.

Please help us with creating a backup file.