stratisd
A daemon that manages a pool of block devices to create flexible filesystems.
Background
Stratis (which includes stratisd
as well as stratis-cli),
provides ZFS/Btrfs-style features by integrating layers of existing technology:
Linux's devicemapper subsystem, and the XFS filesystem. stratisd
manages
collections of block devices, and exports a D-Bus API. Stratis-cli's stratis
provides a command-line tool which itself uses the D-Bus API to communicate
with stratisd
.
Website
See https://stratis-storage.github.io/.
Getting involved
Communication channels
If you have questions, please don't hesitate to ask them, either on the mailing list or IRC.
Mailing list
Development mailing list: [email protected], -- subscribe here.
IRC
irc.freenode.net #stratis-storage.
For Developers
Stratisd is written in Rust, which helps the implementation be small, correct, and avoid requiring shipping with a large language runtime.
Issue tracking and Development
Stratisd development uses GitHub issue tracking, and new development occurs via GitHub pull requests (PRs). Patches or bug reports may also be sent to the mailing list, if preferred.
Setting up for development
Development Toolchain
stratisd can be built using a range of Rust toolchain versions. The recommended development toolchain usually tracks the Rust stable version, although it may lag it slightly. stratisd is guaranteed to be able to be built on its lowest supported toolchain, which may lag the recommended development toolchain by a few minor versions.
Contributors should use the recommended development toolchain if possible, since the CI makes use of the Rust linter and formatter for that version. The recommended development toolchain version can be determined by inspecting the CI configuration files for the project.
Building
Stratisd requires Rust and Cargo to build. These may be available via
your distribution's package manager. If not, Rustup
is available to install and update the Rust toolchain.
Once toolchain and other dependencies are in place, run make build
to build, and then run the
stratisd
executable as root.
Building tests
The Makefile provides a target, build-tests
which allows compiling the
tests without running any of them, as a convenience to developers.
Secondary dependencies
The Stratis ci repo includes a
script, dependencies_fedora.sh
, which installs all the development
dependencies for stratisd and its CLI on Fedora.
Formatting
Stratisd makes use of rustfmt
to enforce consistent formatting in Rust
files. PRs must pass the fmt
task in the CI in order to be merged.
Run make fmt
to ensure your changes conform to the expected formatting
before submitting a pull request. Formatting changes a bit with different
versions of the compiler; make sure to use the current development version.
Linting
Stratisd makes use of clippy
to detect Rust lints. PRs must pass the
clippy
task in the CI in order to be merged. To check for lints, run
make clippy
. The lints change a bit with different versions of the compiler;
make sure to use the current development version.
Configuring
Stratisd runs as root, and requires access to the D-Bus system bus. Thus in
order to work properly, a D-Bus conf file must exist to grant access, either
installed by distribution packaging; or manually, by copying stratisd.conf
to /etc/dbus-1/system.d/
.
Setting Log Levels
The command-line option, --log-level
, may be used to set the stratisd log
level. This option sets the level for the stratisd components only.
For finer-grained control over the log level of any stratisd component or
dependency use the RUST_LOG
environment variable. Please consult the
documentation for the env_logger
crate for additional information on the use
of RUST_LOG
.
Testing
Stratisd is tested in two ways. The first way makes use of the Rust test infrastructure and has more access to stratisd internals. The second way makes use of the stratisd D-Bus interface.
Tests that make use of the Rust test infrastructure
Stratisd incorporates two testing modalities:
- safe unit tests, which can be run without affecting your storage configuration
- unsafe unit tests, which may create and destroy devices during execution
To run the safe unit tests:
$ make test
For a description of the unsafe unit tests, necessary setup steps, and how to
run them, see tests/README.md
.
Test that interact with stratisd via the D-Bus
For a description of the D-Bus-based tests see
tests/client-dbus/README.rst
.
Allowed Bugs
stratisd
has some bugs; most of these we intend to address in due course.
There is one bug that we have chosen not to fix. This is a bug in our D-Bus
layer that will allow incorrect un-marshalling of certain D-Bus values if
a D-Bus method is invoked with arguments that do not conform to the expected
signature of the method. See
the GitHub issue for
additional details about this bug. Behavior of stratisd
is undefined if a
method is called under the particular circumstances that allow the bug to
manifest.
Licensing
MPL 2.0. All contributions retain ownership by their original author, but must also be licensed under the MPL 2.0 to be merged.