From 099b906fe716e4606bbb405632e0a80503d4a708 Mon Sep 17 00:00:00 2001 From: Chris Friesen Date: Fri, 3 Sep 2021 18:05:15 -0400 Subject: [PATCH] kubeadm: create platform pods with zero CPU resources This specifies zero CPU resources when creating the manifests for the static platform pods, as a workaround for the lack of separate resource tracking for platform resources. This specifies zero CPU and Memory resources for the coredns deployment. manifests.go is the main source file for this, not sure if the coredns.yaml are used but they are updated to be consistent. This specifies CPU limit of 1 for kube-apiserver pod so that it is treated as a burstable QoS. This gives a boost of cgroup CPUShares since the burstable cgroup parent has significantly more CPUShares than best-effort on typical systems. This improves kube-apiserver API responsiveness. This increases kube-apiserver Readiness probe periodSeconds to 10 based on WRS/SS joint recommendation for minimum probe settings. This reduces likelihood of kube-apiserver probe failure and subsequent pod-restart under servere load. This also reduces CPU demand. Signed-off-by: Daniel Safta Signed-off-by: Boovan Rajendran Signed-off-by: Jim Gauld --- cluster/addons/dns/coredns/coredns.yaml.base | 4 ++-- cluster/addons/dns/coredns/coredns.yaml.in | 4 ++-- cluster/addons/dns/coredns/coredns.yaml.sed | 4 ++-- cmd/kubeadm/app/phases/addons/dns/manifests.go | 4 ++-- .../app/phases/controlplane/manifests.go | 8 +++++--- cmd/kubeadm/app/util/staticpod/utils.go | 17 ++++++++++++++++- 6 files changed, 29 insertions(+), 12 deletions(-) diff --git a/cluster/addons/dns/coredns/coredns.yaml.base b/cluster/addons/dns/coredns/coredns.yaml.base index dea3749f217..908fd2b246a 100644 --- a/cluster/addons/dns/coredns/coredns.yaml.base +++ b/cluster/addons/dns/coredns/coredns.yaml.base @@ -145,8 +145,8 @@ spec: limits: memory: __DNS__MEMORY__LIMIT__ requests: - cpu: 100m - memory: 70Mi + cpu: 0 + memory: 0 args: [ "-conf", "/etc/coredns/Corefile" ] volumeMounts: - name: config-volume diff --git a/cluster/addons/dns/coredns/coredns.yaml.in b/cluster/addons/dns/coredns/coredns.yaml.in index 808dd54b545..1bc9c632a3a 100644 --- a/cluster/addons/dns/coredns/coredns.yaml.in +++ b/cluster/addons/dns/coredns/coredns.yaml.in @@ -145,8 +145,8 @@ spec: limits: memory: 'dns_memory_limit' requests: - cpu: 100m - memory: 70Mi + cpu: 0 + memory: 0 args: [ "-conf", "/etc/coredns/Corefile" ] volumeMounts: - name: config-volume diff --git a/cluster/addons/dns/coredns/coredns.yaml.sed b/cluster/addons/dns/coredns/coredns.yaml.sed index 8788f41d31c..5be046ad844 100644 --- a/cluster/addons/dns/coredns/coredns.yaml.sed +++ b/cluster/addons/dns/coredns/coredns.yaml.sed @@ -145,8 +145,8 @@ spec: limits: memory: $DNS_MEMORY_LIMIT requests: - cpu: 100m - memory: 70Mi + cpu: 0 + memory: 0 args: [ "-conf", "/etc/coredns/Corefile" ] volumeMounts: - name: config-volume diff --git a/cmd/kubeadm/app/phases/addons/dns/manifests.go b/cmd/kubeadm/app/phases/addons/dns/manifests.go index 97c7f8b3e60..87df378cfc0 100644 --- a/cmd/kubeadm/app/phases/addons/dns/manifests.go +++ b/cmd/kubeadm/app/phases/addons/dns/manifests.go @@ -95,8 +95,8 @@ spec: limits: memory: 170Mi requests: - cpu: 100m - memory: 70Mi + cpu: 0 + memory: 0 args: [ "-conf", "/etc/coredns/Corefile" ] volumeMounts: - name: config-volume diff --git a/cmd/kubeadm/app/phases/controlplane/manifests.go b/cmd/kubeadm/app/phases/controlplane/manifests.go index 8cd0bf577cd..03e5739f5dc 100644 --- a/cmd/kubeadm/app/phases/controlplane/manifests.go +++ b/cmd/kubeadm/app/phases/controlplane/manifests.go @@ -63,7 +63,9 @@ func GetStaticPodSpecs(cfg *kubeadmapi.ClusterConfiguration, endpoint *kubeadmap LivenessProbe: staticpodutil.LivenessProbe(staticpodutil.GetAPIServerProbeAddress(endpoint), "/livez", int(endpoint.BindPort), v1.URISchemeHTTPS), ReadinessProbe: staticpodutil.ReadinessProbe(staticpodutil.GetAPIServerProbeAddress(endpoint), "/readyz", int(endpoint.BindPort), v1.URISchemeHTTPS), StartupProbe: staticpodutil.StartupProbe(staticpodutil.GetAPIServerProbeAddress(endpoint), "/livez", int(endpoint.BindPort), v1.URISchemeHTTPS, cfg.APIServer.TimeoutForControlPlane), - Resources: staticpodutil.ComponentResources("250m"), + // WRS: Increase kube-apiserver cgroup CPUShares to improve API responsiveness; + // achieved by setting CPU Limits to make it burstable QoS. + Resources: staticpodutil.ComponentLimitResources("0", "1"), Env: kubeadmutil.GetProxyEnvVars(), }, mounts.GetVolumes(kubeadmconstants.KubeAPIServer), map[string]string{kubeadmconstants.KubeAPIServerAdvertiseAddressEndpointAnnotationKey: endpoint.String()}), @@ -75,7 +77,7 @@ func GetStaticPodSpecs(cfg *kubeadmapi.ClusterConfiguration, endpoint *kubeadmap VolumeMounts: staticpodutil.VolumeMountMapToSlice(mounts.GetVolumeMounts(kubeadmconstants.KubeControllerManager)), LivenessProbe: staticpodutil.LivenessProbe(staticpodutil.GetControllerManagerProbeAddress(cfg), "/healthz", kubeadmconstants.KubeControllerManagerPort, v1.URISchemeHTTPS), StartupProbe: staticpodutil.StartupProbe(staticpodutil.GetControllerManagerProbeAddress(cfg), "/healthz", kubeadmconstants.KubeControllerManagerPort, v1.URISchemeHTTPS, cfg.APIServer.TimeoutForControlPlane), - Resources: staticpodutil.ComponentResources("200m"), + Resources: staticpodutil.ComponentResources("0"), Env: kubeadmutil.GetProxyEnvVars(), }, mounts.GetVolumes(kubeadmconstants.KubeControllerManager), nil), kubeadmconstants.KubeScheduler: staticpodutil.ComponentPod(v1.Container{ @@ -86,7 +88,7 @@ func GetStaticPodSpecs(cfg *kubeadmapi.ClusterConfiguration, endpoint *kubeadmap VolumeMounts: staticpodutil.VolumeMountMapToSlice(mounts.GetVolumeMounts(kubeadmconstants.KubeScheduler)), LivenessProbe: staticpodutil.LivenessProbe(staticpodutil.GetSchedulerProbeAddress(cfg), "/healthz", kubeadmconstants.KubeSchedulerPort, v1.URISchemeHTTPS), StartupProbe: staticpodutil.StartupProbe(staticpodutil.GetSchedulerProbeAddress(cfg), "/healthz", kubeadmconstants.KubeSchedulerPort, v1.URISchemeHTTPS, cfg.APIServer.TimeoutForControlPlane), - Resources: staticpodutil.ComponentResources("100m"), + Resources: staticpodutil.ComponentResources("0"), Env: kubeadmutil.GetProxyEnvVars(), }, mounts.GetVolumes(kubeadmconstants.KubeScheduler), nil), } diff --git a/cmd/kubeadm/app/util/staticpod/utils.go b/cmd/kubeadm/app/util/staticpod/utils.go index 75efc4f0f98..46fa7a006ba 100644 --- a/cmd/kubeadm/app/util/staticpod/utils.go +++ b/cmd/kubeadm/app/util/staticpod/utils.go @@ -92,6 +92,18 @@ func ComponentResources(cpu string) v1.ResourceRequirements { } } +// ComponentLimitResources returns the v1.ResourceRequirements object needed for allocating a specified amount of the CPU with Limits +func ComponentLimitResources(cpu string, lcpu string) v1.ResourceRequirements { + return v1.ResourceRequirements{ + Requests: v1.ResourceList{ + v1.ResourceCPU: resource.MustParse(cpu), + }, + Limits: v1.ResourceList{ + v1.ResourceCPU: resource.MustParse(lcpu), + }, + } +} + // NewVolume creates a v1.Volume with a hostPath mount to the specified location func NewVolume(name, path string, pathType *v1.HostPathType) v1.Volume { return v1.Volume{ @@ -252,7 +264,10 @@ func LivenessProbe(host, path string, port int, scheme v1.URIScheme) *v1.Probe { func ReadinessProbe(host, path string, port int, scheme v1.URIScheme) *v1.Probe { // sets initialDelaySeconds as '0' because we don't want to delay user infrastructure checks // looking for "ready" status on kubeadm static Pods - return createHTTPProbe(host, path, port, scheme, 0, 15, 3, 1) + // WRS/SS joint recommendation: All pods probes should have following minimum probe + // settings unless required by the service (initialDelaySecond 0, periodSeconds 10, + // timeoutSeconds 5, successThreshold 1, failureThreshold 3) + return createHTTPProbe(host, path, port, scheme, 0, 15, 3, 10) } // StartupProbe creates a Probe object with a HTTPGet handler -- 2.25.1