During the very first installation you will be prompted:

Unique dashboard secret is not defined in .env file. Do you want to generate it? [Y/n]:
DASHBOARD_SECRET=hOYSFI7oOYaRjapPvOXPK7IazH1osZk0
generated and added to .env file.
Please store this secret in a safe place.
You will need it for future upgrades of the Dashboard.

As a message says, store the DASHBOARD_SECRET string somewhere safe.

Data (especially passwords) in persistent volumes in a docker-compose type of installation are encrypted using this DASHBOARD_SECRET. Losing DASHBOARD_SECRET when doing updates or upgrades will lead to losing your encrypted data.

During updates (from an already configured directory), you won't be prompted for this secret string.

During upgrades (from a new release directory), the install script will prompt you to provide the DASHBOARD_SECRET.

11.4.1.  Lost DASHBOARD_SECRET

If you can find this secret string on the already configured installation directory:

shell> cat .env | grep DASHBOARD_SECRET

Alternatively, you can connect to a running docker container (See Section 11.5, “ Connecting to Docker ”), and issue:

shell> echo $DASHBOARD_SECRET

Kubernetes does not use a user defined (or user generated) secret, instead it uses kubernetes secret objects managed by the Kubernetes API itself. To check the secret string inside a kubernetes deployment:

shell> kubectl -n tungsten-dashboard get secret tungsten-dashboard-secret --template={{.data.key}} | base64 --decode