On 12/14/2011 08:43 PM, Kevin Constantine wrote: > On Wed, Dec 14, 2011 at 4:30 AM, Jan Safranek <jsafr...@redhat.com > <mailto:jsafr...@redhat.com>> wrote: > > New documentation file is added. It should describe how systemd and > libcgroup should work together and how to configure a system to have > control groups created by libcgroup's cgconfig service. > > I'm going to install this README into /usr/share/doc/libcgroup-*/. > > I know I am not Shakespeare and also English is not my mother > language, feel > free to comment also the style and grammar. Missing/wrong articles is my > speciality :). > > Signed-off-by: Jan Safranek <jsafr...@redhat.com > <mailto:jsafr...@redhat.com>> > --- > > README_systemd | 68 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 68 insertions(+), 0 deletions(-) > create mode 100644 README_systemd > > diff --git a/README_systemd b/README_systemd > new file mode 100644 > index 0000000..3bb2f6b > --- /dev/null > +++ b/README_systemd > @@ -0,0 +1,68 @@ > +Integration with systemd > +======================== > + > +systemd is a system and service manager for Linux, compatible with SysV > +and LSB init scripts. systemd heavily uses control groups to manage > and control > +services. > + > +Most of the libcgroup tools and APIs can be safely used on systems > with systemd > +without any problems. This document tries to describe how to > configure systemd > +and libcgroup so they can safely live together and mutually benefit > from each > +other. > + > +References > +========== > +[1] http://www.freedesktop.org/wiki/Software/systemd > +Systemd home page. > + > +[2] http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups > +This is the most usefult document describing systemd expectations > on applications > +(incl. libcgroup tools). > + > + > +Compilation > +=========== > +As stated in [2], libcgroup should not touch "name=systemd" > hierarchy. Compile > +libcgroup with --enable-opaque-hierarchy configure option to do so: > + > +./configure --enable-opaque-hierarchy=name=systemd > + > +Libcgroup and all its tools won't then see the "name=systemd" > hierarchy at all. > +For example, lsgcroup won't show it's content and cgclear won't > remove it. > + > + > +Startup and services > +==================== > + > +Systemd automatically mounts all available controllers on system > boot ("cpu" > +and "cpuacct" together in one hierarchy by default) and can > automatically put > +service processes into control groups with configured parameters - > by default, > +each service is automatically put into > "cpu,cpuacct:/system/$service_name" > +control group. System admin has full control on parameters of each > group and > > +also which controllers are used. Consult systemd documentation, mainly > > > The System Administrator has full control of parameters in each group > and of which controllers are used > > +systemd.conf(5) and systemd.exec(5), for details. > + > +In vast majority of use cases, this should be enough and libcgroup > does not need > +to be used. > > > In *the* vast majority of use cases > > > + > +For specific use cases, e.g. when different tree of control groups > is needed, > > > when *a* different tree of control > > > +libcgroup provides cgconfig service. This service can create > arbitrary control > +group hierarchies. In this case, follow these steps: > + > +1. Set 'DefaultControllers=' in /etc/systemd/system.conf so systemd > does not > +create control groups for services automatically. > + > +2. Prepare /etc/cgconfig.conf and enable cgconfig service. The > service will > +parse /etc/cgconfig.conf file during machine boot and create all > control > +groups which are defined in it. The service automatically sets '+t' > ("sticky") > +bit on tasks file as recommended in [2]. > + > +3. For each service that should start in specific control group, > add following > +lines into it's unit file: > > > add *the* following lines into *its* unit file > > > + After=cgconfig.service > + ControlGroup=<name of the control group(s)> > + > +This ensures the service is started only after cgconfig creates > necessary > +hierarchy for it and also tells systemd into which control group > should be the > > +service started. > > > creates *the* necessary hierarchy for it. It also tells systemd which > control group it should use to start the service. > > -kevin
Thanks a lot for the review! I'll send updated version shortly. Jan ------------------------------------------------------------------------------ 10 Tips for Better Server Consolidation Server virtualization is being driven by many needs. But none more important than the need to reduce IT complexity while improving strategic productivity. Learn More! http://www.accelacomm.com/jaw/sdnl/114/51507609/ _______________________________________________ Libcg-devel mailing list Libcg-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libcg-devel
