T6406: add container cpu limit option

(cherry picked from commit 81dea05)

Author: nvollmar

interface-definitions/container.xml.in

@@ -192,6 +192,24 @@
               </leafNode>
             </children>
           </tagNode>
+          <leafNode name="cpus">
+            <properties>
+              <help>This limits the number of CPU resources the container can use</help>
+              <valueHelp>
+                <format>u32:0</format>
+                <description>Unlimited</description>
+              </valueHelp>
+              <valueHelp>
+                <format>txt</format>
+                <description>Amount of CPU time the container can use in amount of cores (up to three decimals)</description>
+              </valueHelp>
+              <constraint>
+                <regex>(0|[1-9]\d*)(\.\d{1,3})?</regex>
+              </constraint>
+              <constraintErrorMessage>Container CPU limit must be a (decimal) number in range 0 to number of threads</constraintErrorMessage>
+            </properties>
+            <defaultValue>0</defaultValue>
+          </leafNode>
           <leafNode name="memory">
             <properties>
               <help>Memory (RAM) available to this container</help>

smoketest/scripts/cli/test_container.py

@@ -91,6 +91,22 @@ def test_basic(self):
         # Check for running process
         self.assertEqual(process_named_running(PROCESS_NAME), pid)
 
+    def test_cpu_limit(self):
+        cont_name = 'c2'
+
+        self.cli_set(base_path + ['name', cont_name, 'allow-host-networks'])
+        self.cli_set(base_path + ['name', cont_name, 'image', cont_image])
+        self.cli_set(base_path + ['name', cont_name, 'cpus', '1.25'])
+
+        self.cli_commit()
+
+        pid = 0
+        with open(PROCESS_PIDFILE.format(cont_name), 'r') as f:
+            pid = int(f.read())
+
+        # Check for running process
+        self.assertEqual(process_named_running(PROCESS_NAME), pid)
+
     def test_ipv4_network(self):
         prefix = '192.0.2.0/24'
         base_name = 'ipv4'

src/conf_mode/container.py

@@ -16,6 +16,7 @@
 
 import os
 
+from decimal import Decimal
 from hashlib import sha256
 from ipaddress import ip_address
 from ipaddress import ip_network
@@ -127,6 +128,11 @@ def verify(container):
                         f'locally. Please use "add container image {image}" to add it '\
                         f'to the system! Container "{name}" will not be started!')
 
+            if 'cpus' in container_config:
+                cores = os.cpu_count()
+                if Decimal(container_config['cpus']) > cores:
+                    raise ConfigError(f'Cannot set limit to more cores than available "{name}"!')
+
             if 'network' in container_config:
                 if len(container_config['network']) > 1:
                     raise ConfigError(f'Only one network can be specified for container "{name}"!')
@@ -257,6 +263,7 @@ def verify(container):
 
 def generate_run_arguments(name, container_config):
     image = container_config['image']
+    cpus = container_config['cpus']
     memory = container_config['memory']
     shared_memory = container_config['shared_memory']
     restart = container_config['restart']
@@ -333,7 +340,7 @@ def generate_run_arguments(name, container_config):
     if 'allow_host_pid' in container_config:
       host_pid = '--pid host'
 
-    container_base_cmd = f'--detach --interactive --tty --replace {capabilities} ' \
+    container_base_cmd = f'--detach --interactive --tty --replace {capabilities} --cpus {cpus} ' \
                          f'--memory {memory}m --shm-size {shared_memory}m --memory-swap 0 --restart {restart} ' \
                          f'--name {name} {hostname} {device} {port} {volume} {env_opt} {label} {uid} {host_pid}'