--- /dev/null
+#!/usr/bin/env python3
+# SPDX-License-Identifier: LGPL-2.1-only
+#
+# Sample program that shows how to use libcgroup to create a systemd scope
+#
+# This program is designed to meet the requirements outlined in the systemd
+# cmdline example [1] via the libcgroup C APIs.
+#
+# [1] https://github.com/libcgroup/libcgroup/blob/main/samples/cmdline/systemd-with-idle-process.md
+#
+#
+# Copyright (c) 2023 Oracle and/or its affiliates.
+# Author: Tom Hromatka <tom.hromatka@oracle.com>
+#
+
+#
+# To run this program:
+# 1. Compile the libcgroup library
+# $ ./bootstrap.sh
+# $ make
+# 2. Note the path to your libcgroup python library
+# $ pushd src/python/build/lib*
+# $ export TMPPATH=$(pwd)
+# $ popd
+# 2. Run the program
+# $ # Note that there are more options. Run `create_systemd_scope.py -h`
+# $ # for more info
+# $ sudo PYTHONPATH=$TMPPATH \
+# ./samples/python/create_systemd_scope.py \
+# --slice <yourslicename> --scope <yourscopename>
+#
+
+from libcgroup import Cgroup, Version, LogLevel
+import multiprocessing
+import argparse
+import signal
+import time
+import sys
+import os
+
+TMP_CGNAME = "tmp"
+HIGH_CGNAME = "high-priority"
+MED_CGNAME = "medium-priority"
+LOW_CGNAME = "low-priority"
+
+
+def parse_args():
+ parser = argparse.ArgumentParser('libcgroup sample program to create a systemd scope')
+
+ delegated_parser = parser.add_mutually_exclusive_group(required=False)
+ delegated_parser.add_argument('-d', '--delegated', help='Create a delegated scope',
+ action='store_true', dest='delegated')
+ delegated_parser.add_argument('-n', '--notdelegated',
+ help='Create a scope that is not delegated',
+ action='store_false', dest='delegated')
+ parser.set_defaults(delegated=True)
+
+ parser.add_argument('-p', '--pid', help='PID to place within the scope. If not provided,'
+ 'libcgroup will place a temporary process in the scope',
+ required=False, type=int, default=None)
+ parser.add_argument('-s', '--scope', help='Name of the scope to be created',
+ required=True, type=str, default=None)
+ parser.add_argument('-t', '--slice', help='Name of the slice where the scope will reside',
+ required=True, type=str, default=None)
+ parser.add_argument('-v', '--verbose', help='Enable verbose logging within libcgroup',
+ required=False, action='store_true')
+
+ args = parser.parse_args()
+
+ return args
+
+
+def create_scope(args):
+ print('\n----------------------------------------------------------------')
+ print('Creating systemd scope, {}/{},'.format(args.slice, args.scope))
+ if args.pid:
+ print('and placing PID, {}, in the scope'.format(args.pid))
+ else:
+ print('and libcgroup will place an idle process in the scope')
+ print('----------------------------------------------------------------\n')
+
+ Cgroup.create_scope(args.scope, args.slice, args.delegated, pid=args.pid)
+ Cgroup.write_default_systemd_scope(args.slice, args.scope, True)
+
+
+def create_tmp_cgroup():
+ cg = Cgroup(TMP_CGNAME, Version.CGROUP_V2)
+ cg.create()
+
+
+def move_pids_to_tmp_cgroup():
+ cg = Cgroup('/', Version.CGROUP_V2)
+ pids = cg.get_processes()
+ for pid in pids:
+ Cgroup.move_process(pid, TMP_CGNAME)
+
+
+def create_high_priority_cgroup():
+ cg = Cgroup(HIGH_CGNAME, Version.CGROUP_V2)
+ cg.add_setting('cpu.weight', '600')
+ cg.add_setting('memory.low', '1G')
+ cg.create()
+
+
+def create_medium_priority_cgroup():
+ cg = Cgroup(MED_CGNAME, Version.CGROUP_V2)
+ cg.add_setting('cpu.weight', '300')
+ cg.add_setting('memory.high', '3G')
+ cg.create()
+
+
+def create_low_priority_cgroup():
+ cg = Cgroup(LOW_CGNAME, Version.CGROUP_V2)
+ cg.add_setting('cpu.weight', '100')
+ cg.add_setting('memory.max', '2G')
+ cg.create()
+
+
+def __infinite_loop():
+ while True:
+ time.sleep(10)
+
+
+def create_process_in_cgroup(cgname):
+ p = multiprocessing.Process(target=__infinite_loop, )
+ p.start()
+
+ Cgroup.move_process(p.pid, cgname)
+
+ return p.pid
+
+
+def delete_tmp_cgroup():
+ cg = Cgroup(TMP_CGNAME, Version.CGROUP_V2)
+ pids = cg.get_processes()
+
+ for pid in pids:
+ os.kill(pid, signal.SIGKILL)
+
+ # I have observed "Device or resource busy" errors when deleting the
+ # cgroup immediately after the os.kill() instruction. Give the kill
+ # command a little time to succeed
+ time.sleep(1)
+
+ cg.delete()
+
+
+def main(args):
+ if args.verbose:
+ Cgroup.log_level(LogLevel.CGROUP_LOG_DEBUG)
+
+ create_scope(args)
+ create_tmp_cgroup()
+ move_pids_to_tmp_cgroup()
+
+ create_high_priority_cgroup()
+ create_medium_priority_cgroup()
+ create_low_priority_cgroup()
+
+ high_pid = create_process_in_cgroup(HIGH_CGNAME)
+ med_pid = create_process_in_cgroup(MED_CGNAME)
+ low_pid = create_process_in_cgroup(LOW_CGNAME)
+
+ delete_tmp_cgroup()
+
+ print('\n----------------------------------------------------------------')
+ print('Cgroup setup completed successfully')
+ print('\t* The scope {} was placed under slice {}'.format(args.scope, args.slice))
+ print('\t* Libcgroup initially placed an idle process in the scope,\n'
+ '\t but it has been removed by this program')
+ print('\t* PID {} has been placed in the {} cgroup'.format(high_pid, HIGH_CGNAME))
+ print('\t* PID {} has been placed in the {} cgroup'.format(med_pid, MED_CGNAME))
+ print('\t* PID {} has been placed in the {} cgroup'.format(low_pid, LOW_CGNAME))
+ print('\nThis program will wait for the aforementioned child processes to\n'
+ 'exit before exiting itself. Systemd will automatically delete the\n'
+ 'scope when there are no longer any processes running within the\n'
+ 'scope. Systemd will not automatically delete the slice.')
+ print('----------------------------------------------------------------\n')
+
+
+if __name__ == '__main__':
+ args = parse_args()
+ sys.exit(main(args))
+
+# vim: set et ts=4 sw=4:
projects / thirdparty / libcgroup.git / commitdiff
