Preparing for Encryption Using Cloudera Navigator Encrypt
Before you can encrypt data, you must prepare a storage repository to hold the encrypted data and a mount point through which to access the encrypted data. The storage repository and mount point must exist before encrypting data using the navencrypt-move command.
Data stored and retrieved from the repository is encrypted and decrypted transparently.
- Encrypting a directory that contains or is contained within a mount point for another service (including Navigator Encrypt and NFS). See Encrypting Data for more information.
- Encrypting immutable files or directories containing immutable files.
- Installation or use in chroot environments, including creating chroot environments within an encrypted directory.
- Encrypting HDFS data files.
Navigator Encrypt Commands
|navencrypt||Manage, update, and verify your data.|
|navencrypt-prepare||Prepare your system for encryption by creating mount-points and specifying storage.|
|navencrypt-prepare --undo||Remove a mountpoint that is no longer in use.|
|navencrypt-move||Encrypt/decrypt your data to/from the encrypted filesystem.|
|navencrypt-profile||Generate process profile information in JSON format.|
|navencrypt-module-setup||Build or rebuild the Navigator Encrypt kernel module.|
Preparing for Encryption
- Creating internal encryption keys
- Registering internal keys in Navigator Key Trustee
- Registering mount point in /etc/navencrypt/ztab
- Mounting current mount point
- Establishing encryption method (dm-crypt for devices)
Using the console, you can choose how you want your data stored and accessed. Navigator Encrypt offers block-level encryption with dm-crypt, which protects your data by encrypting the entire device. This enables full disk encryption and is optimized for some system configurations. You can use block-level encryption with logical devices such as a loop device.
See Block-Level Encryption with dm-crypt for more information.
Block-Level Encryption with dm-crypt
- The first parameter is the block device that you want to store the encrypted file system in. Because this device stores all of the encrypted data, it must be as large as or larger than the target data. The device must exist and be empty. Supported storage devices are:
- The second parameter is the mount point for the encrypted file system. This is the location where you can access the encrypted data stored in the first parameter. The mount point must already exist. It is not created by the navencrypt-prepare command.
The entire device in the first parameter is used for encrypted data.
After specifying these two parameters and following the interactive console (discussed further in Preparing for Encryption), you are ready to encrypt your data.
$ sudo navencrypt-prepare <device_name> <mount_point>When specifying the mount point path, do not use a trailing / in the path names. The mount point directory must exist prior to running the navencrypt-prepare command.
$ sudo systemctl start navencrypt-mount
$ sudo /usr/sbin/navencrypt-prepare urandom /mnt/dm_encrypted Type MASTER passphrase: Encryption Type: dmCrypt (LUKS) Cipher: aes Key Size: 256 Random Interface: /dev/urandom Filesystem: ext4 Verifying MASTER key against Navigator Key Trustee (wait a moment) ... OK Generation Encryption Keys with /dev/urandom ... OK Preparing dmCrypt device (--use-urandom) ... OK Creating ext4 filesystem ... OK Registering Encryption Keys (wait a moment) ... OK Mounting /dev/sda1 ... OKAfter you have successfully prepared a client for encryption, you can encrypt and decrypt data using the commands described in Encrypting and Decrypting Data Using Cloudera Navigator Encrypt.
Block-Level Encryption with a Loop Device
A block-level encrypted device can be a physical device or a storage space treated as a device.
$ sudo dd if=/dev/zero of=/dmcrypt/storage bs=1G count=500
The dd command above creates a 500 GB file. Modify the bs and count values to generate the required file size.
After generating the file, run losetup -f to view unused loop devices. Use the available loop device with the navencrypt-prepare -d command, demonstrated below.
$ sudo bash -c 'echo "loop" > /etc/modules-load.d/loop.conf' $ sudo bash -c 'echo "options loop max_loop=8" > /etc/modprobe.d/loop_options.conf'
The data storage directory name (/dmcrypt/storage in the previous example) must contain only alphanumeric characters, spaces, hyphens (-), or underscores (_). Other special characters are not supported.
$ losetup -f /dev/loop0 $ sudo navencrypt-prepare -d /dmcrypt/storage /dev/loop0 /dmcrypt/mountpoint Type MASTER passphrase: Encryption Type: dmCrypt (LUKS) Cipher: aes Key Size: 256 Random Interface: OpenSSL Filesystem: ext4 Options: Verifying MASTER key against KeyTrustee (wait a moment) ... OK Generation Encryption Keys with OpenSSL ... OK Assigning '/dev/loop0'->'/dmcrypt/storage' ... OK Preparing dmCrypt device ... OK Creating ext4 filesystem ... OK Registering Encryption Keys (wait a moment) ... OK Mounting /dev/loop0 ... OK
# <target mount-dir> <source device> <type> <options> /dmcrypt/mountpoint /dev/loop0 luks key=keytrustee,nav_datastore='/dmcrypt/storage'
After you have created the loop device, continue with the instructions in Block-Level Encryption with dm-crypt.
Navigator Encrypt and Device UUIDs
Navigator Encrypt has always prepared and identified devices simply using a device name, such as /dev/sdb1 or /dev/loop0. However, we know that using a device name or label could lead to a conflict and impact system operations.
Navigator Encrypt also supports preparing devices using a UUID, in addition to device name. This UUID is simply a symbolic link to the actual device, and is created when preparing a device with Navigator Encrypt during a navencrypt-prepare operation.
The advantage of using a device UUID is that if a device’s name changes, the UUID associated with that device does not change. To ensure that Navigator Encrypt recognizes devices even when the device name changes, enter the command:
navencrypt-prepare --use-uuid /dev/sda1 /mountpoint
navencrypt-prepare --undo-force /dev/disk/by-uuid/3a602a15-11f7-46ac-ae98-0a51e1b25cf9 navencrypt-prepare --undo /dev/disk/by-uuid/3a602a15-11f7-46ac-ae98-0a51e1b25cf9
Pass-through Mount Options for navencrypt-prepare
Navigator Encrypt 3.5 and higher provides the ability to specify options to pass to the mount command that is executed during /etc/init.d/navencrypt-mount start (systemctl start navencrypt-mount on RHEL 7). These options are specified with the -o option when preparing a mountpoint with the navencrypt-prepare command.
$ sudo navencrypt-prepare -o discard,resize /mnt/t2 /mnt/t2 Type MASTER passphrase: Encryption Type: dmCrypt (LUKS) Cipher: aes Key Size: 256 Random Interface: OpenSSL Filesystem: ext4 Options: discard,resize Verifying MASTER key against Navigator Key Trustee(wait a moment) ... OK Generation Encryption Keys with OpenSSL ... OK Registering Encryption Keys (wait a moment) ... OK Mounting /mnt/t2 ... OK
$ cat /etc/navencrypt/ztab /mnt/t2 /mnt/t2 dmcrypt key=keytrustee,cipher=aes,keysize=256,discard,resize
Options can be added or removed to existing mount points prepared with versions of Navigator Encrypt prior to 3.5 by editing the /etc/navencrypt/ztab file and adding the comma-separated options (no spaces) to the end of each line as seen in the previous example above.
$ mount /mnt/t2 on /mnt/t2 type dmcrypt (rw,dmcrypt_sig=6de3db1e87077adb,ecryptfs_unlink_sigs,noauto,\ dmcrypt_cipher=aes,dmcrypt_key_bytes=32,discard,resize)
For a list of available mount options, see the man pages for cryptsetup and dmCrypt respectively.