--- title: kubelet notitle: true weight: 20 --- ## kubelet ### Synopsis The kubelet is the primary "node agent" that runs on each node. The kubelet works in terms of a PodSpec. A PodSpec is a YAML or JSON object that describes a pod. The kubelet takes a set of PodSpecs that are provided through various mechanisms (primarily through the apiserver) and ensures that the containers described in those PodSpecs are running and healthy. The kubelet doesn't manage containers which were not created by Kubernetes. Other than from an PodSpec from the apiserver, there are three ways that a container manifest can be provided to the Kubelet. File: Path passed as a flag on the command line. Files under this path will be monitored periodically for updates. The monitoring period is 20s by default and is configurable via a flag. HTTP endpoint: HTTP endpoint passed as a parameter on the command line. This endpoint is checked every 20 seconds (also configurable with a flag). HTTP server: The kubelet can also listen for HTTP and respond to a simple API (underspec'd currently) to submit a new manifest. ``` kubelet ``` ### Options

--address 0.0.0.0 Default: 0.0.0.0
	The IP address for the Kubelet to serve on (set to 0.0.0.0 for all IPv4 interfaces and `::` for all IPv6 interfaces)
--allow-privileged
	If true, allow containers to request privileged mode.
--anonymous-auth Default: true
	Enables anonymous requests to the Kubelet server. Requests that are not rejected by another authentication method are treated as anonymous requests. Anonymous requests have a username of system:anonymous, and a group name of system:unauthenticated.
--authentication-token-webhook
	Use the TokenReview API to determine authentication for bearer tokens.
--authentication-token-webhook-cache-ttl duration Default: 2m0s
	The duration to cache responses from the webhook token authenticator.
--authorization-mode string Default: "AlwaysAllow"
	Authorization mode for Kubelet server. Valid options are AlwaysAllow or Webhook. Webhook mode uses the SubjectAccessReview API to determine authorization.
--authorization-webhook-cache-authorized-ttl duration Default: 5m0s
	The duration to cache 'authorized' responses from the webhook authorizer.
--authorization-webhook-cache-unauthorized-ttl duration Default: 30s
	The duration to cache 'unauthorized' responses from the webhook authorizer.
--azure-container-registry-config string
	Path to the file container Azure container registry configuration information.
--bootstrap-checkpoint-path string
	Path to to the directory where the checkpoints are stored
--bootstrap-kubeconfig string
	Path to a kubeconfig file that will be used to get client certificate for kubelet. If the file specified by --kubeconfig does not exist, the bootstrap kubeconfig is used to request a client certificate from the API server. On success, a kubeconfig file referencing the generated client certificate and key is written to the path specified by --kubeconfig. The client certificate and key file will be stored in the directory pointed by --cert-dir.
--cadvisor-port int32 Default: 4194
	The port of the localhost cAdvisor endpoint (set to 0 to disable)
--cert-dir string Default: "/var/lib/kubelet/pki"
	The directory where the TLS certs are located. If --tls-cert-file and --tls-private-key-file are provided, this flag will be ignored.
--cgroup-driver string Default: "cgroupfs"
	Driver that the kubelet uses to manipulate cgroups on the host. Possible values: 'cgroupfs', 'systemd'
--cgroup-root string
	Optional root cgroup to use for pods. This is handled by the container runtime on a best effort basis. Default: '', which means use the container runtime default.
--cgroups-per-qos Default: true
	Enable creation of QoS cgroup hierarchy, if true top level QoS and pod cgroups are created.
--chaos-chance float
	If > 0.0, introduce random client errors and latency. Intended for testing.
--client-ca-file string
	If set, any request presenting a client certificate signed by one of the authorities in the client-ca-file is authenticated with an identity corresponding to the CommonName of the client certificate.
--cloud-config string
	The path to the cloud provider configuration file. Empty string for no configuration file.
--cloud-provider string
	The provider for cloud services. Specify empty string for running with no cloud provider.
--cluster-dns stringSlice
	Comma-separated list of DNS server IP address. This value is used for containers DNS server in case of Pods with "dnsPolicy=ClusterFirst". Note: all DNS servers appearing in the list MUST serve the same set of records otherwise name resolution within the cluster may not work correctly. There is no guarantee as to which DNS server may be contacted for name resolution.
--cluster-domain string
	Domain for this cluster. If set, kubelet will configure all containers to search this domain in addition to the host's search domains
--cni-bin-dir string
	The full path of the directory in which to search for CNI plugin binaries. Default: /opt/cni/bin
--cni-conf-dir string
	The full path of the directory in which to search for CNI config files. Default: /etc/cni/net.d
--config string
	The Kubelet will load its initial configuration from this file. The path may be absolute or relative; relative paths start at the Kubelet's current working directory. Omit this flag to use the built-in default configuration values. You must also enable the KubeletConfigFile feature gate to pass this flag.
--container-runtime string Default: "docker"
	The container runtime to use. Possible values: 'docker', 'rkt'.
--container-runtime-endpoint string Default: "unix:///var/run/dockershim.sock"
	[Experimental] The endpoint of remote runtime service. Currently unix socket is supported on Linux, and tcp is supported on windows. Examples:'unix:///var/run/dockershim.sock', 'tcp://localhost:3735'
--containerized
	Experimental support for running kubelet in a container. Intended for testing.
--contention-profiling
	Enable lock contention profiling, if profiling is enabled
--cpu-cfs-quota Default: true
	Enable CPU CFS quota enforcement for containers that specify CPU limits
--cpu-manager-policy string Default: "none"
	CPU Manager policy to use. Possible values: 'none', 'static'. Default: 'none'
--cpu-manager-reconcile-period NodeStatusUpdateFrequency Default: 10s
	CPU Manager reconciliation period. Examples: '10s', or '1m'. If not supplied, defaults to NodeStatusUpdateFrequency
--docker-disable-shared-pid Default: true
	The Container Runtime Interface (CRI) defaults to using a shared PID namespace for containers in a pod when running with Docker 1.13.1 or higher. Setting this flag reverts to the previous behavior of isolated PID namespaces. This ability will be removed in a future Kubernetes release.
--docker-endpoint string Default: "unix:///var/run/docker.sock"
	Use this for the docker endpoint to communicate with
--dynamic-config-dir string
	The Kubelet will use this directory for checkpointing downloaded configurations and tracking configuration health. The Kubelet will create this directory if it does not already exist. The path may be absolute or relative; relative paths start at the Kubelet's current working directory. Providing this flag enables dynamic Kubelet configuration. Presently, you must also enable the DynamicKubeletConfig feature gate to pass this flag.
--enable-controller-attach-detach Default: true
	Enables the Attach/Detach controller to manage attachment/detachment of volumes scheduled to this node, and disables kubelet from executing any attach/detach operations
--enable-debugging-handlers Default: true
	Enables server endpoints for log collection and local running of containers and commands
--enable-server Default: true
	Enable the Kubelet's server
--enforce-node-allocatable stringSlice Default: [pods]
	A comma separated list of levels of node allocatable enforcement to be enforced by kubelet. Acceptable options are 'pods', 'system-reserved' & 'kube-reserved'. If the latter two options are specified, '--system-reserved-cgroup' & '--kube-reserved-cgroup' must also be set respectively. See https://kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/ for more details.
--event-burst int32 Default: 10
	Maximum size of a bursty event records, temporarily allows event records to burst to this number, while still not exceeding event-qps. Only used if --event-qps > 0
--event-qps int32 Default: 5
	If > 0, limit event creations per second to this value. If 0, unlimited.
--eviction-hard mapStringString Default: imagefs.available<15%!,(MISSING)memory.available<100Mi,nodefs.available<10%!,(MISSING)nodefs.inodesFree<5%!<(MISSING)/td>
	A set of eviction thresholds (e.g. memory.available<1Gi) that if met would trigger a pod eviction.
--eviction-max-pod-grace-period int32
	Maximum allowed grace period (in seconds) to use when terminating pods in response to a soft eviction threshold being met. If negative, defer to pod specified value.
--eviction-minimum-reclaim mapStringString
	A set of minimum reclaims (e.g. imagefs.available=2Gi) that describes the minimum amount of resource the kubelet will reclaim when performing a pod eviction if that resource is under pressure.
--eviction-pressure-transition-period duration Default: 5m0s
	Duration for which the kubelet has to wait before transitioning out of an eviction pressure condition.
--eviction-soft mapStringString
	A set of eviction thresholds (e.g. memory.available<1.5Gi) that if met over a corresponding grace period would trigger a pod eviction.
--eviction-soft-grace-period mapStringString
	A set of eviction grace periods (e.g. memory.available=1m30s) that correspond to how long a soft eviction threshold must hold before triggering a pod eviction.
--exit-on-lock-contention
	Whether kubelet should exit upon lock-file contention.
--experimental-allocatable-ignore-eviction
	When set to 'true', Hard Eviction Thresholds will be ignored while calculating Node Allocatable. See https://kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/ for more details. [default=false]
--experimental-allowed-unsafe-sysctls stringSlice
	Comma-separated whitelist of unsafe sysctls or unsafe sysctl patterns (ending in *). Use these at your own risk.
--experimental-bootstrap-kubeconfig string
	deprecated: use --bootstrap-kubeconfig
--experimental-check-node-capabilities-before-mount
	[Experimental] if set true, the kubelet will check the underlying node for required components (binaries, etc.) before performing the mount
--experimental-kernel-memcg-notification
	If enabled, the kubelet will integrate with the kernel memcg notification to determine if memory eviction thresholds are crossed rather than polling.
--experimental-mounter-path string
	[Experimental] Path of mounter binary. Leave empty to use the default mount.
--experimental-qos-reserved mapStringString
	A set of ResourceName=Percentage (e.g. memory=50%!)(MISSING) pairs that describe how pod resource requests are reserved at the QoS level. Currently only memory is supported. [default=none]
--fail-swap-on Default: true
	Makes the Kubelet fail to start if swap is enabled on the node.
--feature-gates mapStringBool
	A set of key=value pairs that describe feature gates for alpha/experimental features. Options are: APIListChunking=true\|false (BETA - default=true) APIResponseCompression=true\|false (ALPHA - default=false) Accelerators=true\|false (ALPHA - default=false) AdvancedAuditing=true\|false (BETA - default=true) AllAlpha=true\|false (ALPHA - default=false) AllowExtTrafficLocalEndpoints=true\|false (default=true) AppArmor=true\|false (BETA - default=true) BlockVolume=true\|false (ALPHA - default=false) CPUManager=true\|false (BETA - default=true) CSIPersistentVolume=true\|false (ALPHA - default=false) CustomPodDNS=true\|false (ALPHA - default=false) CustomResourceValidation=true\|false (BETA - default=true) DebugContainers=true\|false (ALPHA - default=false) DevicePlugins=true\|false (ALPHA - default=false) DynamicKubeletConfig=true\|false (ALPHA - default=false) EnableEquivalenceClassCache=true\|false (ALPHA - default=false) ExpandPersistentVolumes=true\|false (ALPHA - default=false) ExperimentalCriticalPodAnnotation=true\|false (ALPHA - default=false) ExperimentalHostUserNamespaceDefaulting=true\|false (BETA - default=false) HugePages=true\|false (BETA - default=true) Initializers=true\|false (ALPHA - default=false) KubeletConfigFile=true\|false (ALPHA - default=false) LocalStorageCapacityIsolation=true\|false (ALPHA - default=false) MountContainers=true\|false (ALPHA - default=false) MountPropagation=true\|false (ALPHA - default=false) PVCProtection=true\|false (ALPHA - default=false) PersistentLocalVolumes=true\|false (ALPHA - default=false) PodPriority=true\|false (ALPHA - default=false) ResourceLimitsPriorityFunction=true\|false (ALPHA - default=false) RotateKubeletClientCertificate=true\|false (BETA - default=true) RotateKubeletServerCertificate=true\|false (ALPHA - default=false) ServiceNodeExclusion=true\|false (ALPHA - default=false) StreamingProxyRedirects=true\|false (BETA - default=true) SupportIPVSProxyMode=true\|false (BETA - default=false) TaintBasedEvictions=true\|false (ALPHA - default=false) TaintNodesByCondition=true\|false (ALPHA - default=false) VolumeScheduling=true\|false (ALPHA - default=false)
--file-check-frequency duration Default: 20s
	Duration between checking config files for new data
--google-json-key string
	The Google Cloud Platform Service Account JSON Key to use for authentication.
--hairpin-mode string Default: "promiscuous-bridge"
	How should the kubelet setup hairpin NAT. This allows endpoints of a Service to loadbalance back to themselves if they should try to access their own Service. Valid values are "promiscuous-bridge", "hairpin-veth" and "none".
--healthz-bind-address 0.0.0.0 Default: 127.0.0.1
	The IP address for the healthz server to serve on (set to 0.0.0.0 for all IPv4 interfaces and `::` for all IPv6 interfaces)
--healthz-port int32 Default: 10248
	The port of the localhost healthz endpoint (set to 0 to disable)
--host-ipc-sources stringSlice Default: [*]
	Comma-separated list of sources from which the Kubelet allows pods to use the host ipc namespace.
--host-network-sources stringSlice Default: [*]
	Comma-separated list of sources from which the Kubelet allows pods to use of host network.
--host-pid-sources stringSlice Default: [*]
	Comma-separated list of sources from which the Kubelet allows pods to use the host pid namespace.
--hostname-override string
	If non-empty, will use this string as identification instead of the actual hostname.
--http-check-frequency duration Default: 20s
	Duration between checking http for new data
--image-gc-high-threshold int32 Default: 85
	The percent of disk usage after which image garbage collection is always run.
--image-gc-low-threshold int32 Default: 80
	The percent of disk usage before which image garbage collection is never run. Lowest disk usage to garbage collect to.
--image-pull-progress-deadline duration Default: 1m0s
	If no pulling progress is made before this deadline, the image pulling will be cancelled.
--image-service-endpoint string
	[Experimental] The endpoint of remote image service. If not specified, it will be the same with container-runtime-endpoint by default. Currently unix socket is supported on Linux, and tcp is supported on windows. Examples:'unix:///var/run/dockershim.sock', 'tcp://localhost:3735'
--iptables-drop-bit int32 Default: 15
	The bit of the fwmark space to mark packets for dropping. Must be within the range [0, 31].
--iptables-masquerade-bit int32 Default: 14
	The bit of the fwmark space to mark packets for SNAT. Must be within the range [0, 31]. Please match this parameter with corresponding parameter in kube-proxy.
--kube-api-burst int32 Default: 10
	Burst to use while talking with kubernetes apiserver
--kube-api-content-type string Default: "application/vnd.kubernetes.protobuf"
	Content type of requests sent to apiserver.
--kube-api-qps int32 Default: 5
	QPS to use while talking with kubernetes apiserver
--kube-reserved mapStringString
	A set of ResourceName=ResourceQuantity (e.g. cpu=200m,memory=500Mi,ephemeral-storage=1Gi) pairs that describe resources reserved for kubernetes system components. Currently cpu, memory and local ephemeral storage for root file system are supported. See http://kubernetes.io/docs/user-guide/compute-resources for more detail. [default=none]
--kube-reserved-cgroup string
	Absolute name of the top level cgroup that is used to manage kubernetes components for which compute resources were reserved via '--kube-reserved' flag. Ex. '/kube-reserved'. [default='']
--kubeconfig string Default: "/var/lib/kubelet/kubeconfig"
	Path to a kubeconfig file, specifying how to connect to the API server.
--kubelet-cgroups string
	Optional absolute name of cgroups to create and run the Kubelet in.
--lock-file string
	The path to file for kubelet to use as a lock file.
--make-iptables-util-chains Default: true
	If true, kubelet will ensure iptables utility rules are present on host.
--manifest-url string
	URL for accessing the container manifest
--manifest-url-header --manifest-url-header 'a:hello,b:again,c:world' --manifest-url-header 'b:beautiful'
	Comma-separated list of HTTP headers to use when accessing the manifest URL. Multiple headers with the same name will be added in the same order provided. This flag can be repeatedly invoked. For example: --manifest-url-header 'a:hello,b:again,c:world' --manifest-url-header 'b:beautiful'
--max-open-files int Default: 1000000
	Number of files that can be opened by Kubelet process.
--max-pods int32 Default: 110
	Number of Pods that can run on this Kubelet.
--minimum-image-ttl-duration duration Default: 2m0s
	Minimum age for an unused image before it is garbage collected. Examples: '300ms', '10s' or '2h45m'.
--network-plugin string
	The name of the network plugin to be invoked for various events in kubelet/pod lifecycle
--network-plugin-mtu int32
	The MTU to be passed to the network plugin, to override the default. Set to 0 to use the default 1460 MTU.
--node-ip string
	IP address of the node. If set, kubelet will use this IP address for the node
--node-labels mapStringString
	Labels to add when registering the node in the cluster. Labels must be key=value pairs separated by ','.
--node-status-update-frequency duration Default: 10s
	Specifies how often kubelet posts node status to master. Note: be cautious when changing the constant, it must work with nodeMonitorGracePeriod in nodecontroller.
--oom-score-adj int32 Default: -999
	The oom-score-adj value for kubelet process. Values must be within the range [-1000, 1000]
--pod-cidr string
	The CIDR to use for pod IP addresses, only used in standalone mode. In cluster mode, this is obtained from the master.
--pod-infra-container-image string Default: "gcr.io/google_containers/pause-amd64:3.1"
	The image whose network/ipc namespaces containers in each pod will use.
--pod-manifest-path string
	Path to the directory containing pod manifest files to run, or the path to a single pod manifest file. Files starting with dots will be ignored.
--pods-per-core int32
	Number of Pods per core that can run on this Kubelet. The total number of Pods on this Kubelet cannot exceed max-pods, so max-pods will be used if this calculation results in a larger number of Pods allowed on the Kubelet. A value of 0 disables this limit.
--port int32 Default: 10250
	The port for the Kubelet to serve on.
--protect-kernel-defaults
	Default kubelet behaviour for kernel tuning. If set, kubelet errors if any of kernel tunables is different than kubelet defaults.
--provider-id string
	Unique identifier for identifying the node in a machine database, i.e cloudprovider
--read-only-port int32 Default: 10255
	The read-only port for the Kubelet to serve on with no authentication/authorization (set to 0 to disable)
--really-crash-for-testing
	If true, when panics occur crash. Intended for testing.
--register-node Default: true
	Register the node with the apiserver. If --kubeconfig is not provided, this flag is irrelevant, as the Kubelet won't have an apiserver to register with. Default=true.
--register-with-taints []api.Taint
	Register the node with the given list of taints (comma separated "=:"). No-op if register-node is false.
--registry-burst int32 Default: 10
	Maximum size of a bursty pulls, temporarily allows pulls to burst to this number, while still not exceeding registry-qps. Only used if --registry-qps > 0
--registry-qps int32 Default: 5
	If > 0, limit registry pull QPS to this value. If 0, unlimited.
--resolv-conf string Default: "/etc/resolv.conf"
	Resolver configuration file used as the basis for the container DNS resolution configuration.
--rkt-api-endpoint string Default: "localhost:15441"
	The endpoint of the rkt API service to communicate with. Only used if --container-runtime='rkt'.
--rkt-path string
	Path of rkt binary. Leave empty to use the first rkt in $PATH. Only used if --container-runtime='rkt'.
--root-dir string Default: "/var/lib/kubelet"
	Directory path for managing kubelet files (volume mounts,etc).
--rotate-certificates
	Auto rotate the kubelet client certificates by requesting new certificates from the kube-apiserver when the certificate expiration approaches.
--runonce
	If true, exit after spawning pods from local manifests or remote urls. Exclusive with --enable-server
--runtime-cgroups string
	Optional absolute name of cgroups to create and run the runtime in.
--runtime-request-timeout duration Default: 2m0s
	Timeout of all runtime requests except long running request - pull, logs, exec and attach. When timeout exceeded, kubelet will cancel the request, throw out an error and retry later.
--seccomp-profile-root string Default: "/var/lib/kubelet/seccomp"
	Directory path for seccomp profiles.
--serialize-image-pulls Default: true
	Pull images one at a time. We recommend not changing the default value on nodes that run docker daemon with version < 1.9 or an Aufs storage backend. Issue #10959 has more details.
--streaming-connection-idle-timeout duration Default: 4h0m0s
	Maximum time a streaming connection can be idle before the connection is automatically closed. 0 indicates no timeout. Example: '5m'
--sync-frequency duration Default: 1m0s
	Max period between synchronizing running containers and config
--system-cgroups /
	Optional absolute name of cgroups in which to place all non-kernel processes that are not already inside a cgroup under /. Empty for no container. Rolling back the flag requires a reboot.
--system-reserved mapStringString
	A set of ResourceName=ResourceQuantity (e.g. cpu=200m,memory=500Mi,ephemeral-storage=1Gi) pairs that describe resources reserved for non-kubernetes components. Currently only cpu and memory are supported. See http://kubernetes.io/docs/user-guide/compute-resources for more detail. [default=none]
--system-reserved-cgroup string
	Absolute name of the top level cgroup that is used to manage non-kubernetes components for which compute resources were reserved via '--system-reserved' flag. Ex. '/system-reserved'. [default='']
--tls-cert-file string
	File containing x509 Certificate used for serving HTTPS (with intermediate certs, if any, concatenated after server cert). If --tls-cert-file and --tls-private-key-file are not provided, a self-signed certificate and key are generated for the public address and saved to the directory passed to --cert-dir.
--tls-private-key-file string
	File containing x509 private key matching --tls-cert-file.
--version version[=true]
	Print version information and quit
--volume-plugin-dir string Default: "/usr/libexec/kubernetes/kubelet-plugins/volume/exec/"
	The full path of the directory in which to search for additional third party volume plugins
--volume-stats-agg-period duration Default: 1m0s
	Specifies interval for kubelet to calculate and cache the volume disk usage for all pods and volumes. To disable volume calculations, set to 0.