The userspace solution for control groups Linux Kongress 2010 - - PowerPoint PPT Presentation

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The userspace solution for control groups Linux Kongress 2010 - - PowerPoint PPT Presentation

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The userspace solution for control groups Linux Kongress 2010 Dhaval Giani dhaval.giani@gmail.com RETIS Lab, Scuola Superiore SantAnna September 2010 Dhaval Giani The userspace solution for control groups Control Groups What are cgroups?

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The userspace solution for control groups

Linux Kongress 2010 Dhaval Giani dhaval.giani@gmail.com

RETIS Lab, Scuola Superiore Sant’Anna

September 2010

Dhaval Giani The userspace solution for control groups

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Control Groups

What are cgroups?

Dhaval Giani The userspace solution for control groups

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Control Groups

What are cgroups? Well, the last talk should have covered it

Dhaval Giani The userspace solution for control groups

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Control Groups

cgroups should die.

  • Peter Zijlstra

Dhaval Giani The userspace solution for control groups

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Control Groups

Next time something is added to the kernel please mark it as ”Hey, please don’t use it, this is only here so that you don’t use it. Thanks!” Maybe then dumb-ass folks like me will notice and refrain from using it.

  • Lennart Poettering

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libcgroup

Looks to provide a programming interface without the programmer having to care about how cgroups are setup.

Dhaval Giani The userspace solution for control groups

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libcgroup

Looks to provide a programming interface without the programmer having to care about how cgroups are setup. Tools

Dhaval Giani The userspace solution for control groups

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libcgroup

Looks to provide a programming interface without the programmer having to care about how cgroups are setup. Tools Library

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots.

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup cgred - Automatic classification daemon originally based on user classfication.

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup cgred - Automatic classification daemon originally based on user classfication. Now enhanced for process based classification as well.

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup cgred - Automatic classification daemon originally based on user classfication. Now enhanced for process based classification as well. cgset/cgget - List cgroup values

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup cgred - Automatic classification daemon originally based on user classfication. Now enhanced for process based classification as well. cgset/cgget - List cgroup values lscgroup - List all cgroups

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup cgred - Automatic classification daemon originally based on user classfication. Now enhanced for process based classification as well. cgset/cgget - List cgroup values lscgroup - List all cgroups Some more

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

cgconfigparser - Used for parsing a configuration file and maintaining persistence across reboots. cgclear - Used to destroy all control group hierarchies unless you use Fedora where it does not touch systemd hierarchies cgexec - Used to start a process in a cgroup cgred - Automatic classification daemon originally based on user classfication. Now enhanced for process based classification as well. cgset/cgget - List cgroup values lscgroup - List all cgroups Some more cgsnapshot - Under review right now, to generate configurations from current setup.

Dhaval Giani The userspace solution for control groups

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libcgroup - tools

Basically trying to cover a good set of requirements from the administrator’s point of view.

Dhaval Giani The userspace solution for control groups

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libcgroup - library

Three main types of API

Dhaval Giani The userspace solution for control groups

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libcgroup - library

Three main types of API cgroup manipulation API

Dhaval Giani The userspace solution for control groups

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libcgroup - library

Three main types of API cgroup manipulation API data structure manipulation API

Dhaval Giani The userspace solution for control groups

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libcgroup - library

Three main types of API cgroup manipulation API data structure manipulation API configuration API

Dhaval Giani The userspace solution for control groups

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libcgroup API

The manipulation API

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libcgroup API

The manipulation API cgroup init

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libcgroup API

The manipulation API cgroup init cgroup create cgroup

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libcgroup API

The manipulation API cgroup init cgroup create cgroup cgroup modify cgroup

Dhaval Giani The userspace solution for control groups

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libcgroup API

The manipulation API cgroup init cgroup create cgroup cgroup modify cgroup cgroup delete cgroup

Dhaval Giani The userspace solution for control groups

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libcgroup API

The manipulation API cgroup init cgroup create cgroup cgroup modify cgroup cgroup delete cgroup cgroup get cgroup

Dhaval Giani The userspace solution for control groups

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libcgroup API

The manipulation API cgroup init cgroup create cgroup cgroup modify cgroup cgroup delete cgroup cgroup get cgroup some more

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used to modify the cgroup data structure

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used to modify the cgroup data structure which is the main data structure describing the cgroup

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libcgroup API

Used to modify the cgroup data structure which is the main data structure describing the cgroup cgroup new cgroup

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used to modify the cgroup data structure which is the main data structure describing the cgroup cgroup new cgroup cgroup add controller

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used to modify the cgroup data structure which is the main data structure describing the cgroup cgroup new cgroup cgroup add controller cgroup add value family

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used to modify the cgroup data structure which is the main data structure describing the cgroup cgroup new cgroup cgroup add controller cgroup add value family cgroup [sg]et uid gid

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used by cgconfigparser and cgclear.

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used by cgconfigparser and cgclear. Used to load the configuration file, both for the superuser and the regular user (the so called cascaded configurations).

Dhaval Giani The userspace solution for control groups

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libcgroup API

Used by cgconfigparser and cgclear. Used to load the configuration file, both for the superuser and the regular user (the so called cascaded configurations). Not yet implemented for cgclear, but its on its way.

Dhaval Giani The userspace solution for control groups

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Issues

Written by kernel developers!

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Issues

Written by kernel developers! So thread safe

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Issues

Written by kernel developers! So thread safe as opposed to thread aware!

Dhaval Giani The userspace solution for control groups

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Issues

Written by kernel developers! So thread safe as opposed to thread aware! The locking model is being modified at git://libcg.git.sf.net/gitroot/libcg/ libcgroup-context.git

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Issues

Key Goal - Subsystem Independent Programming.

Dhaval Giani The userspace solution for control groups

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Issues

Key Goal - Subsystem Independent Programming. Or Programmer should not care how subsystems are mounted.

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Programmer does not need to bother where cgroups are mounted

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Programmer does not need to bother where cgroups are mounted But the how still has to be bothered about

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Programmer does not need to bother where cgroups are mounted But the how still has to be bothered about Blame the cgroup developers for that

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Subsystem Independent Programming

Consider the following two scenarios

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Subsystem Independent Programming

Consider the following two scenarios mount -t cgroup -o memory,cpuset cgroup /cgroup

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Consider the following two scenarios mount -t cgroup -o memory,cpuset cgroup /cgroup and

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Consider the following two scenarios mount -t cgroup -o memory,cpuset cgroup /cgroup and mount -t cgroup -o cpuset cpuset /cgroup/cpuset mount -t cgroup -o memory memory /cgroup/memory

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Consider the following two scenarios mount -t cgroup -o memory,cpuset cgroup /cgroup and mount -t cgroup -o cpuset cpuset /cgroup/cpuset mount -t cgroup -o memory memory /cgroup/memory What is the main difference between the two from a programmer’s point of view?

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Simple solution

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Simple solution Copy the values from the parent

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Subsystem Independent Programming

Consider another scenario

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Consider another scenario mount -t cgroup -o cpu,cpuset cgroup /cgroup

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

Consider another scenario mount -t cgroup -o cpu,cpuset cgroup /cgroup Well, the simple solution does fail quite spectacularly

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Subsystem Independent Programming

We do have another problem

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Subsystem Independent Programming

We do have another problem Programmer still needs to know the internals of the subsystem he wants to manipulate

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Subsystem Independent Programming

Layer 2

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Subsystem Independent Programming

Layer 2 Subsystem specific programming

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Subsystem Independent Programming

Layer 2 Subsystem specific programming Possibility of callbacks

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Subsystem Independent Programming

Layer 2 Subsystem specific programming Possibility of callbacks Hiding some of the subsystem complexity

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Subsystem Independent Programming

But is that the complete solution?

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Subsystem Independent Programming

But is that the complete solution? Not really

Dhaval Giani The userspace solution for control groups

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Subsystem Independent Programming

But is that the complete solution? Not really We need to modify both the kernel and the userspace!

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libcgroup

Not a bad start, but still a long way to go!

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Questions?

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Thank you!

Dhaval Giani The userspace solution for control groups