From 5c789dcd87cd6db69e53399a581d61c8fb308f7d Mon Sep 17 00:00:00 2001 From: Boovan Rajendran Date: Mon, 4 Sep 2023 08:25:03 -0400 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. Signed-off-by: Daniel Safta Signed-off-by: Ramesh Kumar Sivanandam Signed-off-by: Boovan Rajendran --- pkg/kubelet/cm/cpumanager/cpu_manager.go | 8 ++++++++ pkg/kubelet/cm/cpumanager/policy_static.go | 7 +++++++ 2 files changed, 15 insertions(+) diff --git a/pkg/kubelet/cm/cpumanager/cpu_manager.go b/pkg/kubelet/cm/cpumanager/cpu_manager.go index 6e9d3938aef..0f48d521d6f 100644 --- a/pkg/kubelet/cm/cpumanager/cpu_manager.go +++ b/pkg/kubelet/cm/cpumanager/cpu_manager.go @@ -21,6 +21,7 @@ import ( "fmt" "io/ioutil" "math" + "os" "strings" "sync" "time" @@ -56,6 +57,13 @@ 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.New() + } + 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 ab4164e8736..54bcfdb71a1 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" @@ -752,6 +753,12 @@ 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.New() + } + // 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 { -- 2.25.1