enable support for kubernetes to ignore isolcpus

The normal mechanisms for allocating isolated CPUs do not allow
a mix of isolated and exclusive CPUs in the same container.  In
order to allow this in *very* limited cases where the pod spec
is known in advance we will add the ability to disable the normal
isolcpus behaviour.

If the file "/etc/kubernetes/ignore_isolcpus" exists, then kubelet
will basically forget everything it knows about isolcpus and just
treat them like regular CPUs.

The admin user can then rely on the fact that CPU allocation is
deterministic to ensure that the isolcpus they configure end up being
allocated to the correct pods.

Story: 2008760
Task: 42164
Change-Id: Ie38c81209ee407ac98b4882f2581fc14622b3af1
Signed-off-by: Chris Friesen <chris.friesen@windriver.com>
This commit is contained in:
Chris Friesen 2020-10-26 17:30:00 -04:00
parent 4150b7a6b6
commit 777b7d8863
2 changed files with 81 additions and 0 deletions

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@ -0,0 +1,79 @@
From 8b765213a4e6d5cd4eecf361dadfec2851f1dd59 Mon Sep 17 00:00:00 2001
From: Chris Friesen <chris.friesen@windriver.com>
Date: Fri, 23 Oct 2020 17:46:10 -0600
Subject: [PATCH] enable support for kubernetes to ignore isolcpus
The normal mechanisms for allocating isolated CPUs do not allow
a mix of isolated and exclusive CPUs in the same container. In
order to allow this in *very* limited cases where the pod spec
is known in advance we will add the ability to disable the normal
isolcpus behaviour.
If the file "/etc/kubernetes/ignore_isolcpus" exists, then kubelet
will basically forget everything it knows about isolcpus and just
treat them like regular CPUs.
The admin user can then rely on the fact that CPU allocation is
deterministic to ensure that the isolcpus they configure end up being
allocated to the correct pods.
---
pkg/kubelet/cm/cpumanager/cpu_manager.go | 9 +++++++++
pkg/kubelet/cm/cpumanager/policy_static.go | 8 ++++++++
2 files changed, 17 insertions(+)
diff --git a/pkg/kubelet/cm/cpumanager/cpu_manager.go b/pkg/kubelet/cm/cpumanager/cpu_manager.go
index c682f813..92992991 100644
--- a/pkg/kubelet/cm/cpumanager/cpu_manager.go
+++ b/pkg/kubelet/cm/cpumanager/cpu_manager.go
@@ -19,6 +19,7 @@ package cpumanager
import (
"fmt"
"math"
+ "os"
"sync"
"time"
"strings"
@@ -56,6 +57,14 @@ const cpuManagerStateFileName = "cpu_manager_state"
// get the system-level isolated CPUs
func getIsolcpus() cpuset.CPUSet {
+
+ // This is a gross hack to basically turn off awareness of isolcpus to enable
+ // isolated cpus to be allocated to pods the same way as non-isolated CPUs.
+ if _, err := os.Stat("/etc/kubernetes/ignore_isolcpus"); err == nil {
+ klog.Infof("[cpumanager] turning off isolcpus awareness")
+ return cpuset.NewCPUSet()
+ }
+
dat, err := ioutil.ReadFile("/sys/devices/system/cpu/isolated")
if err != nil {
klog.Errorf("[cpumanager] unable to read sysfs isolcpus subdir")
diff --git a/pkg/kubelet/cm/cpumanager/policy_static.go b/pkg/kubelet/cm/cpumanager/policy_static.go
index 1913065e..4fb3202f 100644
--- a/pkg/kubelet/cm/cpumanager/policy_static.go
+++ b/pkg/kubelet/cm/cpumanager/policy_static.go
@@ -18,6 +18,7 @@ package cpumanager
import (
"fmt"
+ "os"
"strconv"
v1 "k8s.io/api/core/v1"
@@ -510,6 +511,13 @@ func isKubeInfra(pod *v1.Pod) bool {
// get the isolated CPUs (if any) from the devices associated with a specific container
func (p *staticPolicy) podIsolCPUs(pod *v1.Pod, container *v1.Container) cpuset.CPUSet {
+
+ // This is a gross hack to basically turn off awareness of isolcpus to enable
+ // isolated cpus to be allocated to pods the same way as non-isolated CPUs.
+ if _, err := os.Stat("/etc/kubernetes/ignore_isolcpus"); err == nil {
+ return cpuset.NewCPUSet()
+ }
+
// NOTE: This is required for TestStaticPolicyAdd() since makePod() does
// not create UID. We also need a way to properly stub devicemanager.
if len(string(pod.UID)) == 0 {
--
2.16.6

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@ -64,6 +64,7 @@ Patch6: kubelet-cpumanager-infrastructure-pods-use-system-re.patch
Patch7: kubelet-cpumanager-introduce-concept-of-isolated-CPU.patch
Patch8: Fix-exclusive-CPU-allocations-being-deleted-at-conta.patch
Patch9: kubeadm-create-platform-pods-with-zero-CPU-resources.patch
Patch10: add-option-to-disable-isolcpu-awareness.patch
# It obsoletes cadvisor but needs its source code (literally integrated)
Obsoletes: cadvisor
@ -852,6 +853,7 @@ Kubernetes client tools like kubectl
%patch7 -p1
%patch8 -p1
%patch9 -p1
%patch10 -p1
# copy contrib folder
mkdir contrib