Tableau Server on Linux Help

Tableau Server needs to store a number of secrets that it uses to perform various functions, typically securing internal communication, communicating with other applications or the operating system or providing secure communication with clients. In this context, the term secret may refer to a password, a token, or other string that is used to authenticate one entity to another.

There are two categories of secrets that are required to run Tableau Server. They differ according to how the secrets are generated:

• Secrets that are generated by administrators. These include credentials and associated secrets for the Run As User account and the SMTP credentials used by Tableau Server.
• Secrets that are automatically generated by various processes in the system. For example, a secret is required to protect communication between the Cluster Controller and ZooKeeper processes. And a number of different passwords are required for each service and programmatic user that communicates with Postgres.

Most secrets are encrypted while at rest. When a secret is needed, it is decrypted at run time.

This topic describes how secrets storage works and what you need to do to properly manage storage of secrets on Tableau Server.

Understanding how secrets storage works

During installation Tableau Server generates and stores a master key in a Java keystore. The master key is used to encrypt a configuration encryption key that is used across the system.

Whenever a new secret is created or updated, the secret is encrypted with the configuration encryption key. The encrypted value is then stored with its corresponding configuration parameter in a YAML file on the server. Parameters that hold an encrypted value use the format, ENC(<encrypted string>), where <encrypted string> is a Base64-encoded encrypted string.

At run time, when a given secret needs to be accessed, the encrypted values are read into memory and decrypted with the configuration encryption key.

In the case of pending changes, where secrets are entered during a configuration change, the entire transaction is encrypted. In this scenario, after you enter a secret and save the pending change, the secret is transmitted to the Coordination Service (over encrypted SSL). The Coordination Service encrypts the secret and stores it until the pending changes are applied. When changes are applied, the secret (still encrypted) is promoted to the current configuration version.

Tableau Server encrypts secrets using 256-bit AES in GCM mode. The keys used for secure storage are different than the asset keys that are used to encrypt embedded database credentials before they are stored in the repository.

Who has access to the master key?

Import and export configuration information

Tableau Services Manager introduces the capability to import and export configuration information using tsm settings export.

Note: This version of Tableau Server does not support restoring configuration information from a backup. Instead, we recommend using the export and import configuration commands to backup and restore configuration information.

While configuration secrets are encrypted when stored on disk internally, when the configuration is exported to a file, secrets are written into the file in plain text. It is up to the administrator to take measures to protect this file. There are a variety of options available:

• Write the file to an encrypted file system.
• Write the file to a directory that is restricted to specific users or groups by file system permissions.
• Encrypt the output file.

Securing secrets for import and export operations

Secrets storage event logging

The following events related to secrets storage are logged:

• Generating new encryption keys
• Encryption key is rolled or changed
• Encrypting a new value in the configuration file

For more information about log files and where they are stored, see Work with Log Files.

Managing secrets

As a Tableau Server administrator the most important task related to secrets storage is to periodically update secrets. In some cases (server troubleshooting or auditing), you may need to retrieve a password.

For other operations, such as upgrading versions, backing up and restoring, or adding new nodes to a cluster – as noted above – Tableau Server manages secrets storage and related processes automatically.

Updating secrets

You should update secrets periodically, according to your company's security policy.

To update the master key and automatically generated secrets, run tsm security regenerate-internal-tokens.

Retrieving passwords

In some cases, you may need to retrieve a password for troubleshooting or other operations. For example, you may need the Postgres read only user credentials that are generated and encrypted by Tableau Server. In these cases, you can run a tsm command that will retrieve and decrypt the password for you.

To retrieve a password, open Command Prompt and issue a tsm configuration get command for one of the parameters listed in the table below.

For example, to retrieve a password for the Postgres read only user, type the following command:

tsm configuration get -k pgsql.readonly_password

The command will return the password in clear text:

$ tsm configuration get -k pgsql.readonly_password

password