Stratis Description

2021-12-09

Dennis Keefe, Stratis Team

Stratis Description

Stratis is a tool to easily configure pools and filesystems with enhanced storage functionality that works within the existing Linux storage management stack. To achieve this, Stratis prioritizes a straightforward command-line experience, a rich API, and a fully automated approach to storage management. It builds upon elements of the existing storage stack as much as possible. Specifically, Stratis uses device-mapper, LUKS, XFS, and Clevis. Stratis may also incorporate additional technologies in the future.

Stratis can configure an encrypted or unencrypted pool of storage with one or more file systems quickly and without prior knowledge of the many storage layers and commands.

Linux has a number of storage technologies that provide advanced functionality to applications for accessing and storing data. Examples of some of these products that Stratis uses are:

device-mapper - A framework for logical to physical mapping of data blocks
LUKS - An on disk format for encryption that can securely manages multiple passwords
XFS - A scalable, journaling, and performant filesystem
Clevis - A framework for automated decryption

Learning and gaining experience in a number of different storage technologies can take many years. Each of those technologies may have their own unique command-line syntax, APIs, options, and logging. Stratis simplifies volume and filesystem management by providing a single CLI and API for users to set up complex storage stacks without having to spend time learning each independent storage technology.

CLI Example

The simplicity that Stratis provides can be seen when comparing the CLI commands used for creating a filesystem that encrypts data-at-rest, to the method an advanced user would use to configure each layer separately:

Stratis commands to create an encrypted pool and filesystem:

> stratis key set testkey --capture-key
    <enter passphrase>
> stratis pool create p1 --key-desc testkey /dev/sdb
> stratis fs create p1 fs1

Commands an advanced user would use to configure a similar filesystem:

> cryptsetup -y -v luksFormat /dev/sdb
    <enter "YES">
    <enter passphrase>
    <verify passphrase>
> cryptsetup -v luksOpen /dev/sdb luks-device
> pvcreate /dev/mapper/luks-device
> vgcreate vg1 /dev/mapper/luks-device
> lvcreate -L 100M -T vg1/athinpool
> lvcreate -V1G -T vg1/athinpool -n thinvolume
> mkfs.xfs /dev/mapper/vg1-thinvolume

API Example

Stratis has also built a D-Bus API for developers to implement the storage management features directly into their project. The benefits to developers interested in using Stratis and its D-Bus API would be:

It provides a feature rich file system and storage management API
Well designed and tested code ensures the developer can work on the important details of their project
Moves the responsibility of maintaining code for setting up storage to the Stratis project.

Here is an example of how to call Stratis D-Bus API using the busctl utility from a command-line

Create a pool:

> busctl call org.storage.stratis3 /org/storage/stratis3 org.storage.stratis3.Manager.r0 CreatePool "s(bq)as(bs)(b(ss))" poolname 0 0 2 /dev/sda /dev/sdb 0 "" 0 "" ""

Print version:

> busctl get-property org.storage.stratis3 /org/storage/stratis3 org.storage.stratis3.Manager.r0 Version

Print engine state:

> busctl call org.storage.stratis3 /org/storage/stratis3 org.storage.stratis3.Manager.r0 EngineStateReport

Get ManagedObjects:

> busctl call org.storage.stratis3 /org/storage/stratis3 org.freedesktop.DBus.ObjectManager GetManagedObjects

Stratis Description

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