默认情况下,Kubernetes集群上的容器对计算资源维度没有任何限制,可能会导致个别容器资源过大导致影响其他容器正常工作,这时可以使用LimitRange定义容器默认CPU和内存请求值或者最大限制。
LimitRange维度限制:
LimitRange功能是一个准入控制插件,默认已经启用。检查是否开启LimitRange功能的方法如下:
[root@master ~]# kubectl -n kube-system get pod|grep apiserver
kube-apiserver-master.host.com 1/1 Running 28 (95m ago) 62d
[root@master ~]# kubectl -n kube-system exec kube-apiserver-master.host.com -- kube-apiserver -h|grep enable-admission-plugins
--admission-control strings Admission is divided into two phases. In the first phase, only mutating admission plugins run. In the second phase, only validating admission plugins run. The names in the below list may represent a validating plugin, a mutating plugin, or both. The order of plugins in which they are passed to this flag does not matter. Comma-delimited list of: AlwaysAdmit, AlwaysDeny, AlwaysPullImages, CertificateApproval, CertificateSigning, CertificateSubjectRestriction, DefaultIngressClass, DefaultStorageClass, DefaultTolerationSeconds, DenyServiceExternalIPs, EventRateLimit, ExtendedResourceToleration, ImagePolicyWebhook, LimitPodHardAntiAffinityTopology, LimitRanger, MutatingAdmissionWebhook, NamespaceAutoProvision, NamespaceExists, NamespaceLifecycle, NodeRestriction, OwnerReferencesPermissionEnforcement, PersistentVolumeClaimResize, PersistentVolumeLabel, PodNodeSelector, PodSecurity, PodTolerationRestriction, Priority, ResourceQuota, RuntimeClass, SecurityContextDeny, ServiceAccount, StorageObjectInUseProtection, TaintNodesByCondition, ValidatingAdmissionWebhook. (DEPRECATED: Use --enable-admission-plugins or --disable-admission-plugins instead. Will be removed in a future version.)
--enable-admission-plugins strings admission plugins that should be enabled in addition to default enabled ones (NamespaceLifecycle, LimitRanger, ServiceAccount, TaintNodesByCondition, PodSecurity, Priority, DefaultTolerationSeconds, DefaultStorageClass, StorageObjectInUseProtection, PersistentVolumeClaimResize, RuntimeClass, CertificateApproval, CertificateSigning, CertificateSubjectRestriction, DefaultIngressClass, MutatingAdmissionWebhook, ValidatingAdmissionWebhook, ResourceQuota). Comma-delimited list of admission plugins: AlwaysAdmit, AlwaysDeny, AlwaysPullImages, CertificateApproval, CertificateSigning, CertificateSubjectRestriction, DefaultIngressClass, DefaultStorageClass, DefaultTolerationSeconds, DenyServiceExternalIPs, EventRateLimit, ExtendedResourceToleration, ImagePolicyWebhook, LimitPodHardAntiAffinityTopology, LimitRanger, MutatingAdmissionWebhook, NamespaceAutoProvision, NamespaceExists, NamespaceLifecycle, NodeRestriction, OwnerReferencesPermissionEnforcement, PersistentVolumeClaimResize, PersistentVolumeLabel, PodNodeSelector, PodSecurity, PodTolerationRestriction, Priority, ResourceQuota, RuntimeClass, SecurityContextDeny, ServiceAccount, StorageObjectInUseProtection, TaintNodesByCondition, ValidatingAdmissionWebhook. The order of plugins in this flag does not matter.
在"--enable-admission-plugins"中寻找"LimitRanger"发现已经开启。
apiVersion: v1
kind: LimitRange
metadata:
name: cpu-memory-max-min
namespace: test
spec:
limits:
- max:
cpu: 1
memory: 1Gi
min:
cpu: 100m
memory: 100Mi
type: Container
max里面是容器能设置limit的最大值,min里面是容器能设置request的最小值
apiVersion: v1
kind: LimitRange
metadata:
name: cpu-memory-max-min
namespace: test
spec:
limits:
- max:
cpu: 1
memory: 1Gi
min:
cpu: 100m
memory: 100Mi
default:
cpu: 500m
memory: 500Mi
defaultRequest:
cpu: 100m
memory: 100Mi
type: Container
"default"是设置limit的默认值,"defaultRequest"是设置request的默认值
apiVersion: v1
kind: LimitRange
metadata:
name: storage-max-min
namespace: test
spec:
limits:
- max:
storage: 10Gi
min:
storage: 1Gi
type: PersistentVolumeClaim
pvc的使用
[root@master cks]# kubectl get limits -n test
NAME CREATED AT
cpu-memory-max-min 2022-12-17T11:01:11Z
storage-max-min 2022-12-17T10:59:56Z
[root@master cks]# kubectl describe limits -n test
Name: cpu-memory-max-min
Namespace: test
Type Resource Min Max Default Request Default Limit Max Limit/Request Ratio
---- -------- --- --- --------------- ------------- -----------------------
Container memory 100Mi 1Gi 100Mi 500Mi -
Container cpu 100m 1 100m 500m -
Name: storage-max-min
Namespace: test
Type Resource Min Max Default Request Default Limit Max Limit/Request Ratio
---- -------- --- --- --------------- ------------- -----------------------
PersistentVolumeClaim storage 1Gi 10Gi - - -
]]>当多个团队去共享使用一个Kubernetes集群时,会出现不均匀的资源使用,默认情况下资源先到先得,这个时候可以通过ResourceQuota来对命名空间资源使用总量做限制,从而解决这个问题。
ResourceQuota功能是一个准入控制插件,默认已经启用。检查是否开启ResourceQuota功能的方法如下:
[root@master ~]# kubectl -n kube-system get pod|grep apiserver
kube-apiserver-master.host.com 1/1 Running 27 (17h ago) 61d
[root@master ~]# kubectl -n kube-system exec kube-apiserver-master.host.com -- kube-apiserver -h|grep enable-admission-plugins
--admission-control strings Admission is divided into two phases. In the first phase, only mutating admission plugins run. In the second phase, only validating admission plugins run. The names in the below list may represent a validating plugin, a mutating plugin, or both. The order of plugins in which they are passed to this flag does not matter. Comma-delimited list of: AlwaysAdmit, AlwaysDeny, AlwaysPullImages, CertificateApproval, CertificateSigning, CertificateSubjectRestriction, DefaultIngressClass, DefaultStorageClass, DefaultTolerationSeconds, DenyServiceExternalIPs, EventRateLimit, ExtendedResourceToleration, ImagePolicyWebhook, LimitPodHardAntiAffinityTopology, LimitRanger, MutatingAdmissionWebhook, NamespaceAutoProvision, NamespaceExists, NamespaceLifecycle, NodeRestriction, OwnerReferencesPermissionEnforcement, PersistentVolumeClaimResize, PersistentVolumeLabel, PodNodeSelector, PodSecurity, PodTolerationRestriction, Priority, ResourceQuota, RuntimeClass, SecurityContextDeny, ServiceAccount, StorageObjectInUseProtection, TaintNodesByCondition, ValidatingAdmissionWebhook. (DEPRECATED: Use --enable-admission-plugins or --disable-admission-plugins instead. Will be removed in a future version.)
--enable-admission-plugins strings admission plugins that should be enabled in addition to default enabled ones (NamespaceLifecycle, LimitRanger, ServiceAccount, TaintNodesByCondition, PodSecurity, Priority, DefaultTolerationSeconds, DefaultStorageClass, StorageObjectInUseProtection, PersistentVolumeClaimResize, RuntimeClass, CertificateApproval, CertificateSigning, CertificateSubjectRestriction, DefaultIngressClass, MutatingAdmissionWebhook, ValidatingAdmissionWebhook, ResourceQuota). Comma-delimited list of admission plugins: AlwaysAdmit, AlwaysDeny, AlwaysPullImages, CertificateApproval, CertificateSigning, CertificateSubjectRestriction, DefaultIngressClass, DefaultStorageClass, DefaultTolerationSeconds, DenyServiceExternalIPs, EventRateLimit, ExtendedResourceToleration, ImagePolicyWebhook, LimitPodHardAntiAffinityTopology, LimitRanger, MutatingAdmissionWebhook, NamespaceAutoProvision, NamespaceExists, NamespaceLifecycle, NodeRestriction, OwnerReferencesPermissionEnforcement, PersistentVolumeClaimResize, PersistentVolumeLabel, PodNodeSelector, PodSecurity, PodTolerationRestriction, Priority, ResourceQuota, RuntimeClass, SecurityContextDeny, ServiceAccount, StorageObjectInUseProtection, TaintNodesByCondition, ValidatingAdmissionWebhook. The order of plugins in this flag does not matter.
在"--enable-admission-plugins"中寻找"ResourceQuota"发现已经开启。
支持的资源 | 描述 |
---|---|
limits.cpu/memory | 所有Pod上限资源配置总量不超过该值 (所有非终止状态的Pod) |
requests.cpu/memory | 所有Pod请求资源配置总量不超过该值 (所有非终止状态的Pod) |
cpu/memory | 等同于requests.cpu/requests.memory |
requests.storage | 所有PVC请求容量总和不超过该值 |
persistentvolumeclaims | 所有PVC数量总和不超过该值 |
\<storage-class-name\>.storageclass.storage.k8s.io/requests.storage | 所有与\<storage-class-name\>相关的PVC请求容量总和不超过该值 |
\<storage-class-name\>.storageclass.storage.k8s.io/persistentvolumeclaims | 所有与\<storage-class-name\>相关的PVC数量总和不超过该值 |
pods、 count/deployments.apps、count/statfulsets.apps、count/services(services.loadbalancers、 services.nodeports)count/secrets、 count/configmaps、count/job.batch、count/cronjobs.batch | 创建资源数量不超过该值 |
apiVersion: v1
kind: ResourceQuota
metadata:
name: compute-resources
namespace: test
spec:
hard:
requests.cpu: "1"
requests.memory: 10Gi
limits.cpu: "4"
limits.memory: 20Gi
apiVersion: v1
kind: ResourceQuota
metadata:
name: storage-resources
namespace: test
spec:
hard:
requests.storage: 10Gi
managed-nfs-storage.storageclass.storage.k8s.io/requests.storage: 10Gi
"managed-nfs-storage"是动态存储类的名称。
apiVersion: v1
kind: ResourceQuota
metadata:
name: object-counts
namespace: test
spec:
hard:
pods: "10"
count/deployments.apps: "3"
count/services: "3"
限制的是个数,命名空间的总数量不能超过该值。
[root@master ~]# kubectl get quota -n test
NAME AGE REQUEST LIMIT
compute-resources 41m requests.cpu: 0/4, requests.memory: 0/10Gi limits.cpu: 0/6, limits.memory: 0/12Gi
object-counts 4m6s count/deployments.apps: 0/3, count/services: 0/3, pods: 0/10
storage-resources 6m16s managed-nfs-storage.storageclass.storage.k8s.io/requests.storage: 0/10Gi, requests.storage: 0/10Gi
通过上面的命令可以查看额配资源使用的情况。
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