ceph/README.md

Ceph - a scalable distributed storage system

Please see https://ceph.com/ for current info.

Contributing Code

Most of Ceph is dual licensed under the LGPL version 2.1 or 3.0. Some miscellaneous code is under a BSD-style license or is public domain. The documentation is licensed under Creative Commons Attribution Share Alike 3.0 (CC-BY-SA-3.0). There are a handful of headers included here that are licensed under the GPL. Please see the file COPYING for a full inventory of licenses by file.

Code contributions must include a valid "Signed-off-by" acknowledging the license for the modified or contributed file. Please see the file SubmittingPatches.rst for details on what that means and on how to generate and submit patches.

We do not require assignment of copyright to contribute code; code is contributed under the terms of the applicable license.

Checking out the source

Clone the ceph/ceph repository from github by running the following command on a system that has git installed:

git clone git@github.com:ceph/ceph

Alternatively, if you are not a github user, you should run the following command on a system that has git installed:

git clone https://github.com/ceph/ceph.git

When the ceph/ceph repository has been cloned to your system, run the following command to check out the git submodules associated with the ceph/ceph repository:

git submodule update --init --recursive

Build Prerequisites

section last updated 27 Jul 2023

Make sure that curl is installed. The Debian and Ubuntu apt command is provided here, but if you use a system with a different package manager, then you must use whatever command is the proper counterpart of this one:

apt install curl

Install Debian or RPM package dependencies by running the following command:

./install-deps.sh

Install the python3-routes package:

apt install python3-routes

Building Ceph

These instructions are meant for developers who are compiling the code for development and testing. To build binaries that are suitable for installation we recommend that you build .deb or .rpm packages, or refer to ceph.spec.in or debian/rules to see which configuration options are specified for production builds.

Build instructions:

./do_cmake.sh
cd build
ninja

do_cmake.sh defaults to creating a debug build of Ceph that can be up to 5x slower with some workloads. Pass -DCMAKE_BUILD_TYPE=RelWithDebInfo to do_cmake.sh to create a non-debug release.

The number of jobs used by ninja is derived from the number of CPU cores of the building host if unspecified. Use the -j option to limit the job number if the build jobs are running out of memory. On average, each job takes around 2.5GiB memory.

This assumes that you make your build directory a subdirectory of the ceph.git checkout. If you put it elsewhere, just point CEPH_GIT_DIR to the correct path to the checkout. Additional CMake args can be specified by setting ARGS before invoking do_cmake.sh. See cmake options for more details. For example:

ARGS="-DCMAKE_C_COMPILER=gcc-7" ./do_cmake.sh

To build only certain targets use:

ninja [target name]

To install:

ninja install

CMake Options

If you run the cmake command by hand, there are many options you can set with "-D". For example, the option to build the RADOS Gateway is defaulted to ON. To build without the RADOS Gateway:

cmake -DWITH_RADOSGW=OFF [path to top-level ceph directory]

Another example below is building with debugging and alternate locations for a couple of external dependencies:

cmake -DCMAKE_INSTALL_PREFIX=/opt/ceph -DCMAKE_C_FLAGS="-Og -g3 -gdwarf-4" \
..

Ceph has several bundled dependencies such as Boost, RocksDB and Arrow. By default, cmake will build these bundled dependencies from source instead of using libraries that are already installed on the system. You can opt-in to using these system libraries, provided they meet the minimum version required by Ceph, with cmake options like WITH_SYSTEM_BOOST:

cmake -DWITH_SYSTEM_BOOST=ON [...]

To view an exhaustive list of -D options, you can invoke cmake with:

cmake -LH

If you often pipe ninja to less and would like to maintain the diagnostic colors for errors and warnings (and if your compiler supports it), you can invoke cmake with:

cmake -DDIAGNOSTICS_COLOR=always ...

Then you'll get the diagnostic colors when you execute:

ninja | less -R

Other available values for 'DIAGNOSTICS_COLOR' are 'auto' (default) and 'never'.

Building a source tarball

To build a complete source tarball with everything needed to build from source and/or build a (deb or rpm) package, run

./make-dist

This will create a tarball like ceph-$version.tar.bz2 from git. (Ensure that any changes you want to include in your working directory are committed to git.)

Running a test cluster

To run a functional test cluster,

cd build
ninja vstart        # builds just enough to run vstart
../src/vstart.sh --debug --new -x --localhost --bluestore
./bin/ceph -s

Almost all of the usual commands are available in the bin/ directory. For example,

./bin/rados -p rbd bench 30 write
./bin/rbd create foo --size 1000

To shut down the test cluster,

../src/stop.sh

To start or stop individual daemons, the sysvinit script can be used:

./bin/init-ceph restart osd.0
./bin/init-ceph stop

Running unit tests

To build and run all tests (in parallel using all processors), use ctest:

cd build
ninja
ctest -j$(nproc)

(Note: Many targets built from src/test are not run using ctest. Targets starting with "unittest" are run in ninja check and thus can be run with ctest. Targets starting with "ceph_test" can not, and should be run by hand.)

When failures occur, look in build/Testing/Temporary for logs.

To build and run all tests and their dependencies without other unnecessary targets in Ceph:

cd build
ninja check -j$(nproc)

To run an individual test manually, run ctest with -R (regex matching):

ctest -R [regex matching test name(s)]

(Note: ctest does not build the test it's running or the dependencies needed to run it)

To run an individual test manually and see all the tests output, run ctest with the -V (verbose) flag:

ctest -V -R [regex matching test name(s)]

To run tests manually and run the jobs in parallel, run ctest with the -j flag:

ctest -j [number of jobs]

There are many other flags you can give ctest for better control over manual test execution. To view these options run:

man ctest

Building the Documentation

Prerequisites

The list of package dependencies for building the documentation can be found in doc_deps.deb.txt:

sudo apt-get install `cat doc_deps.deb.txt`

Building the Documentation

To build the documentation, ensure that you are in the top-level /ceph directory, and execute the build script. For example:

admin/build-doc

Reporting Issues

To report an issue and view existing issues, please visit https://tracker.ceph.com/projects/ceph.