Cleaning up TAS for VMs CredHub

This topic provides the steps for cleaning up Tanzu Application Service (TAS for VMs) CredHub entries that are no longer needed.

To interact with the CredHub service we can use either the HTTP API or the CredHub CLI. These instructions use the CLI that is included on the Tanzu Operations Manager VM.

Tanzu Support recommends capturing a backup of CredHub prior to any modifications.

It is important to remember that when a CredHub entry is deleted, it is permanently gone. It cannot be retrieved.

Delete CredHub entries that are no longer needed

SSH into Tanzu Operations Manager and follow the steps in Accessing Tanzu Application Service CredHub to connect to TAS CredHub.
Create a working directory for the artifacts and proceed to generate a CredHub backup. It is paramount to perform this backup prior to any modifications:
```
$ mkdir ~/credhub-cleanup-working-dir

$ cd ~/credhub-cleanup-working-dir

~/credhub-cleanup-working-dir$ credhub export -f credhub-export-$(date '+%Y-%m-%d-T%H-%M-%S').yml
```
The -f flag points to the file i which to save the export. The date command within the filename will indicate the date and time of the backup.

Exporting a backup can take some time if there are many entries. To see the API calls made by the CredHub CLI command run export CREDHUB_DEBUG=true prior to CredHub CLI command. If exporting the backup fails, contact Tanzu Support.

Generate a list of all CredHub names:

$ credhub find | grep name | cut -d' ' -f3 > credhub-names-$(date '+%Y-%m-%d-T%H-%M-%S').txt

Review the list of CredHub names obtained in an earlier step and issue a credhub delete command on every name that is no longer desired or needed.

Remember, once the credential is deleted, it is unrecoverable. Ensure that you have captured a backup first.

Example of a credhub delete command:
```
credhub delete -n /tanzu-mysql/backups/952615b9-7bb7-4773-b82a-b0d711318992_1657645964302
```

Repeat this step for all undesired CredHub entries.