CPU requests and limits for build pod

Author: noroutine

binderhub/app.py

@@ -57,7 +57,7 @@
                             DataverseProvider)
 from .metrics import MetricsHandler
 
-from .utils import ByteSpecification, url_path_join
+from .utils import CPUSpecification, ByteSpecification, url_path_join
 from .events import EventLog
 
 
@@ -335,6 +335,26 @@ def _valid_badge_base_url(self, proposal):
         config=True
     )
 
+    build_cpu_request = CPUSpecification(
+        0,
+        help="""
+        Amount of cpu to request when scheduling a build
+
+        0 reserves no cpu.
+
+        """,
+        config=True,
+    )
+    build_cpu_limit = CPUSpecification(
+        0,
+        help="""
+        Max amount of cpu allocated for each image build process.
+
+        0 sets no limit.
+        """,
+        config=True,
+    )
+
     build_memory_request = ByteSpecification(
         0,
         help="""
@@ -773,6 +793,8 @@ def initialize(self, *args, **kwargs):
                 "jinja2_env": jinja_env,
                 "build_memory_limit": self.build_memory_limit,
                 "build_memory_request": self.build_memory_request,
+                "build_cpu_limit": self.build_cpu_limit,
+                "build_cpu_request": self.build_cpu_request,
                 "build_docker_host": self.build_docker_host,
                 "build_docker_config": self.build_docker_config,
                 "base_url": self.base_url,

binderhub/build.py

@@ -51,6 +51,8 @@ def __init__(
         image_name,
         git_credentials=None,
         push_secret=None,
+        cpu_limit=0,
+        cpu_request=0,
         memory_limit=0,
         memory_request=0,
         node_selector=None,
@@ -95,6 +97,18 @@ def __init__(
             https://git-scm.com/docs/gitcredentials for more information.
         push_secret : str
             Kubernetes secret containing credentials to push docker image to registry.
+        cpu_limit
+            CPU limit for the docker build process. Can be an integer (1), fraction (0.5) or
+            millicore specification (100m). Value should adhere to K8s specification
+            for CPU meaning. See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#meaning-of-cpu
+            for more information
+        cpu_request
+            CPU request of the build pod. The actual building happens in the
+            docker daemon, but setting request in the build pod makes sure that
+            cpu is reserved for the docker build in the node by the kubernetes
+            scheduler. Value should adhere to K8s specification for CPU meaning.
+            See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#meaning-of-cpu
+            for more information
         memory_limit
             Memory limit for the docker build process. Can be an integer in
             bytes, or a byte specification (like 6M).
@@ -129,6 +143,8 @@ def __init__(
         self.push_secret = push_secret
         self.build_image = build_image
         self.main_loop = IOLoop.current()
+        self.cpu_limit = cpu_limit
+        self.cpu_request = cpu_request
         self.memory_limit = memory_limit
         self.memory_request = memory_request
         self.docker_host = docker_host
@@ -343,8 +359,8 @@ def submit(self):
                         args=self.get_cmd(),
                         volume_mounts=volume_mounts,
                         resources=client.V1ResourceRequirements(
-                            limits={'memory': self.memory_limit},
-                            requests={'memory': self.memory_request},
+                            limits={'memory': self.memory_limit, 'cpu': self.cpu_limit},
+                            requests={'memory': self.memory_request, 'cpu': self.cpu_request},
                         ),
                         env=env
                     )

binderhub/builder.py

@@ -411,6 +411,8 @@ async def get(self, provider_prefix, _unescaped_spec):
             image_name=image_name,
             push_secret=push_secret,
             build_image=self.settings['build_image'],
+            cpu_limit=self.settings['build_cpu_limit'],
+            cpu_request=self.settings['build_cpu_request'],
             memory_limit=self.settings['build_memory_limit'],
             memory_request=self.settings['build_memory_request'],
             docker_host=self.settings['build_docker_host'],

binderhub/tests/test_utils.py

@@ -2,6 +2,7 @@
 from unittest import mock
 
 import pytest
+from traitlets.traitlets import TraitError
 
 from binderhub import utils
 
@@ -137,3 +138,45 @@ def test_ip_in_networks(ip, cidrs, found):
 def test_ip_in_networks_invalid():
     with pytest.raises(ValueError):
         utils.ip_in_networks("1.2.3.4", {}, 0)
+
+@pytest.mark.parametrize(
+    "value, coerced",
+    [
+        ("2", 2),
+        (2, 2),
+        ("0.2", 0.2),
+        (0.2, 0.2),
+        ("200m", "200m"),
+        (None, 0),
+        (0, 0),
+        ("0", 0),
+    ]
+)
+def test_cpu_specification_valid(value, coerced):
+    cpu_spec = utils.CPUSpecification()
+    assert cpu_spec.validate(None, value) == coerced
+
+@pytest.mark.parametrize(
+    "value",
+    [
+        ("0.2m"),
+        ("deadbeef"),
+        ("m"),
+        (""),
+        ("200M"),
+        ("200k"),
+        ("-1"),
+        ("-1m"),
+        ("-0.1m"),
+        (-0.1),
+        (-1),
+        (False),
+        (True),
+        ([]),
+        ({}),
+    ]
+)
+def test_cpu_specification_invalid(value):
+    cpu_spec = utils.CPUSpecification()
+    with pytest.raises(TraitError):
+        _ = cpu_spec.validate(None, value)

binderhub/utils.py

@@ -4,7 +4,7 @@
 import ipaddress
 import time
 
-from traitlets import Integer, TraitError
+from traitlets import Unicode, Integer, TraitError
 
 
 # default _request_timeout for kubernetes api requests
@@ -42,6 +42,86 @@ def rendezvous_rank(buckets, key):
     return [b for (s, b) in sorted(ranking, reverse=True)]
 
 
+class CPUSpecification(Unicode):
+    """
+    Allows specifying CPU limits
+
+    Suffixes allowed are:
+      - m -> millicore
+
+    """
+
+    # Default to allowing None as a value
+    allow_none = True
+
+    def validate(self, obj, value):
+        """
+        Validate that the passed in value is a valid cpu specification
+        in the K8s CPU meaning.
+        
+        See https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/#meaning-of-cpu
+
+        It could either be a pure int or float, when it is taken as a value.
+        In case of integer it can optionally have 'm' suffix to designate millicores.
+        """
+
+        def raise_error(value):
+            raise TraitError(
+                "{val} is not a valid cpu specification".format(
+                    val=value
+                )
+            )
+
+        # Positive filter for numberic values
+        only_positive = lambda v : v if v >= 0 else raise_error(v)
+
+        if value is None:
+            return 0
+
+        if isinstance(value, bool):
+            raise_error(value)
+
+        if isinstance(value, int):
+            return only_positive(int(value))
+
+        if isinstance(value, float):
+            return only_positive(float(value))
+
+        # Must be string
+        if not isinstance(value, str):
+            raise_error(value)
+
+        # Try treat it as integer
+        _int_value = None
+        try:
+            _int_value = int(value)
+        except ValueError:
+            pass
+
+        if isinstance(_int_value, int):
+            return only_positive(_int_value)
+
+        # Try treat it as float
+        _float_value = None
+        try:
+            _float_value = float(value)
+        except ValueError:
+            pass
+
+        if isinstance(_float_value, float):
+            return only_positive(_float_value)
+
+        # Try treat it as millicore spec
+        try:
+            _unused = only_positive(int(value[:-1]))
+        except ValueError:
+            raise_error(value)
+
+        if value[-1] not in ['m']:
+            raise_error(value)
+
+        return value
+
 class ByteSpecification(Integer):
     """
     Allow easily specifying bytes in units of 1024 with suffixes