# ceph-authtool

`ceph-authtool` is a utility used to manage Ceph authentication keys and credentials. This tool helps create, view, and modify Ceph authentication keys, which are essential for managing access control in a Ceph cluster. Ceph uses a Public Key Infrastructure (PKI)-like system to authenticate various entities such as monitors, OSDs, and clients.

## Common `ceph-authtool` Commands and Subcommands

### 1. **Create a New Keyring**

Creates a new Ceph keyring file.

```bash
ceph-authtool --create-keyring <keyring-file>
```

* Example:

  ```bash
  ceph-authtool --create-keyring /etc/ceph/ceph.client.admin.keyring
  ```

This command creates a new keyring file called `ceph.client.admin.keyring` that will be used for storing the admin key for Ceph.

### 2. **Generate a New Key**

Generates a new key and adds it to a keyring.

```bash
ceph-authtool <keyring-file> --gen-key --name <entity>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --gen-key --name client.admin
  ```

This command generates a new authentication key for the entity `client.admin` and stores it in the specified keyring file.

### 3. **Import Keys**

Imports a key from one keyring to another keyring.

```bash
ceph-authtool <keyring-file> --import-keyring <source-keyring>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --import-keyring /tmp/temp-keyring
  ```

This command imports the keys from `temp-keyring` into the admin keyring.

### 4. **View a Keyring**

Prints the details of a keyring, including the entities and their keys.

```bash
ceph-authtool <keyring-file> --print-key
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --print-key
  ```

This command prints out the content of the keyring, including the key for the `client.admin`.

### 5. **Add a New Key to Keyring**

Adds an existing key for a specific entity to the keyring.

```bash
ceph-authtool <keyring-file> --add-key <key> --name <entity>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --add-key AQABCF....== --name client.admin
  ```

This adds the provided authentication key (`AQABCF...==`) for `client.admin` into the specified keyring.

### 6. **Remove a Key from a Keyring**

Removes a specific entity's key from a keyring.

```bash
ceph-authtool <keyring-file> --delete <entity>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --delete client.admin
  ```

This removes the `client.admin` entity from the specified keyring.

### 7. **Change the Permissions of a Key**

Sets or modifies the capabilities of an entity in the keyring.

```bash
ceph-authtool <keyring-file> --cap <entity> <caps>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --cap client.admin mon 'allow *' osd 'allow *'
  ```

This command sets the capabilities of `client.admin` to have full access to both monitors and OSDs.

### 8. **Extract a Key to a File**

Extracts the key for a specific entity and saves it to a file.

```bash
ceph-authtool <keyring-file> --print-key --name <entity> --out-file <output-file>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --print-key --name client.admin --out-file /tmp/client.admin.key
  ```

This extracts the key for `client.admin` and saves it to the file `/tmp/client.admin.key`.

### 9. **Convert Keyring Format**

Converts a keyring from one format to another.

```bash
ceph-authtool <keyring-file> --convert-keyring <new-format>
```

* Example:

  ```bash
  ceph-authtool /etc/ceph/ceph.client.admin.keyring --convert-keyring base64
  ```

This converts the keyring to a base64-encoded format.

### Typical Use Cases:

* **Creating and Managing Client Authentication:** To manage client authentication in a Ceph cluster, `ceph-authtool` is used to create, add, and modify the keys stored in keyrings, ensuring secure access to cluster resources.
* **Cluster Authentication:** Ceph components (e.g., monitors, OSDs) require keyrings to authenticate with each other. Using `ceph-authtool`, you can generate and manage these keys effectively.
* **Backup of Keyrings:** Administrators can use `ceph-authtool` to print keys and store them in separate files for backup or migration purposes.

## Conclusion

`ceph-authtool` is an essential command-line tool for managing Ceph authentication keys. It allows administrators to create, modify, and manage keyrings for various entities like clients, OSDs, and monitors, ensuring secure and proper access control within the Ceph cluster.
