A vIDM appliance will sometimes not start some services like sshd if there is a configuration error, consequently no ssh access will be available.
This also prevents the console from providing a shell from which the configuration file can be reviewed and corrected, and the sshd service restarted.
VMware Identity Manager 3.3.7
To gain access to a recovery shell:
1. Reset/reboot the appliance in vCenter, and during the PhotonOS splash screen press 'e' to edit the GRUB options
2. Edit the command to include:
init=/usr/bin/bash
This will present the GRUB menu, which can be edited to provide a bash environment.
Keep in mind the / filesystem will be mounted in read-only mode, so to make changes to files, remount the / filesystem in read/write mode:
#mount -o rw,remount /