Hi,
I just installed a cluster with 6 nodes (3x nodes, 3x workers), and by enabling metrics server:
microk8s kubectl get all -A | grep metrics
kube-system pod/metrics-server-848968bdcd-9ssrz 0/1 CrashLoopBackOff 7 (3m5s ago) 12m
kube-system service/metrics-server ClusterIP 10.152.183.187 <none> 443/TCP 12m
kube-system deployment.apps/metrics-server 0/1 1 0 12m
kube-system replicaset.apps/metrics-server-848968bdcd 1 1 0 12m
microk8s kubectl describe -n kube-system pod metrics-server-848968bdcd-9ssrz
Name: metrics-server-848968bdcd-9ssrz
Namespace: kube-system
Priority: 2000000000
Priority Class Name: system-cluster-critical
Service Account: metrics-server
Node: k8w2/10.0.50.55
Start Time: Wed, 20 Sep 2023 15:24:29 +0200
Labels: k8s-app=metrics-server
pod-template-hash=848968bdcd
Annotations: cni.projectcalico.org/containerID: b54bf1a5b8786d07bf8972cfb105b167f43fccc5daabaed8ebe9401c161c4636
cni.projectcalico.org/podIP: 10.1.155.2/32
cni.projectcalico.org/podIPs: 10.1.155.2/32
Status: Running
IP: 10.1.155.2
IPs:
IP: 10.1.155.2
Controlled By: ReplicaSet/metrics-server-848968bdcd
Containers:
metrics-server:
Container ID: containerd://c3557f71332401b073e104eeb329c1e6a590cdea34ccb9d95adbc91ab69081b2
Image: registry.k8s.io/metrics-server/metrics-server:v0.6.3
Image ID: registry.k8s.io/metrics-server/metrics-server@sha256:c60778fa1c44d0c5a0c4530ebe83f9243ee6fc02f4c3dc59226c201931350b10
Port: 4443/TCP
Host Port: 0/TCP
Args:
--cert-dir=/tmp
--secure-port=4443
--kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
--kubelet-use-node-status-port
--metric-resolution=15s
--kubelet-insecure-tls
State: Waiting
Reason: CrashLoopBackOff
Last State: Terminated
Reason: Error
Exit Code: 2
Started: Wed, 20 Sep 2023 15:32:58 +0200
Finished: Wed, 20 Sep 2023 15:33:29 +0200
Ready: False
Restart Count: 7
Requests:
cpu: 100m
memory: 200Mi
Liveness: http-get https://:https/livez delay=0s timeout=1s period=10s #success=1 #failure=3
Readiness: http-get https://:https/readyz delay=20s timeout=1s period=10s #success=1 #failure=3
Environment: <none>
Mounts:
/tmp from tmp-dir (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-qlkvz (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
tmp-dir:
Type: EmptyDir (a temporary directory that shares a pod's lifetime)
Medium:
SizeLimit: <unset>
kube-api-access-qlkvz:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: Burstable
Node-Selectors: kubernetes.io/arch=amd64
kubernetes.io/os=linux
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning BackOff 2m22s (x31 over 9m47s) kubelet Back-off restarting failed container metrics-server in pod metrics-server-848968bdcd-9ssrz_kube-system(0e104532-48e8-4610-a12b-423711e19a6b)
microk8s kubectl logs -n kube-system metrics-server-848968bdcd-9ssrz
Error: unable to load configmap based request-header-client-ca-file: Get "https://10.152.183.1:443/api/v1/namespaces/kube-system/configmaps/extension-apiserver-authentication": dial tcp 10.152.183.1:443: i/o timeout
Usage:
[flags]
Metrics server flags:
--kubeconfig string The path to the kubeconfig used to connect to the Kubernetes API server and the Kubelets (defaults to in-cluster config)
--metric-resolution duration The resolution at which metrics-server will retain metrics, must set value at least 10s. (default 1m0s)
--version Show version
Kubelet client flags:
--deprecated-kubelet-completely-insecure DEPRECATED: Do not use any encryption, authorization, or authentication when communicating with the Kubelet. This is rarely the right option, since it leaves kubelet communication completely insecure. If you encounter auth errors, make sure you've enabled token webhook auth on the Kubelet, and if you're in a test cluster with self-signed Kubelet certificates, consider using kubelet-insecure-tls instead.
--kubelet-certificate-authority string Path to the CA to use to validate the Kubelet's serving certificates.
--kubelet-client-certificate string Path to a client cert file for TLS.
--kubelet-client-key string Path to a client key file for TLS.
--kubelet-insecure-tls Do not verify CA of serving certificates presented by Kubelets. For testing purposes only.
--kubelet-port int The port to use to connect to Kubelets. (default 10250)
--kubelet-preferred-address-types strings The priority of node address types to use when determining which address to use to connect to a particular node (default [Hostname,InternalDNS,InternalIP,ExternalDNS,ExternalIP])
--kubelet-use-node-status-port Use the port in the node status. Takes precedence over --kubelet-port flag.
Apiserver secure serving flags:
--bind-address ip The IP address on which to listen for the --secure-port port. The associated interface(s) must be reachable by the rest of the cluster, and by CLI/web clients. If blank or an unspecified address (0.0.0.0 or ::), all interfaces will be used. (default 0.0.0.0)
--cert-dir string The directory where the TLS certs are located. If --tls-cert-file and --tls-private-key-file are provided, this flag will be ignored. (default "apiserver.local.config/certificates")
--http2-max-streams-per-connection int The limit that the server gives to clients for the maximum number of streams in an HTTP/2 connection. Zero means to use golang's default.
--permit-address-sharing If true, SO_REUSEADDR will be used when binding the port. This allows binding to wildcard IPs like 0.0.0.0 and specific IPs in parallel, and it avoids waiting for the kernel to release sockets in TIME_WAIT state. [default=false]
--permit-port-sharing If true, SO_REUSEPORT will be used when binding the port, which allows more than one instance to bind on the same address and port. [default=false]
--secure-port int The port on which to serve HTTPS with authentication and authorization. If 0, don't serve HTTPS at all. (default 443)
--tls-cert-file string File containing the default x509 Certificate for HTTPS. (CA cert, if any, concatenated after server cert). If HTTPS serving is enabled, and --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 specified by --cert-dir.
--tls-cipher-suites strings Comma-separated list of cipher suites for the server. If omitted, the default Go cipher suites will be used.
Preferred values: TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384, TLS_CHACHA20_POLY1305_SHA256, TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_RSA_WITH_AES_128_GCM_SHA256, TLS_RSA_WITH_AES_256_CBC_SHA, TLS_RSA_WITH_AES_256_GCM_SHA384.
Insecure values: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_3DES_EDE_CBC_SHA, TLS_RSA_WITH_AES_128_CBC_SHA256, TLS_RSA_WITH_RC4_128_SHA.
--tls-min-version string Minimum TLS version supported. Possible values: VersionTLS10, VersionTLS11, VersionTLS12, VersionTLS13
--tls-private-key-file string File containing the default x509 private key matching --tls-cert-file.
--tls-sni-cert-key namedCertKey A pair of x509 certificate and private key file paths, optionally suffixed with a list of domain patterns which are fully qualified domain names, possibly with prefixed wildcard segments. The domain patterns also allow IP addresses, but IPs should only be used if the apiserver has visibility to the IP address requested by a client. If no domain patterns are provided, the names of the certificate are extracted. Non-wildcard matches trump over wildcard matches, explicit domain patterns trump over extracted names. For multiple key/certificate pairs, use the --tls-sni-cert-key multiple times. Examples: "example.crt,example.key" or "foo.crt,foo.key:*.foo.com,foo.com". (default [])
Apiserver authentication flags:
--authentication-kubeconfig string kubeconfig file pointing at the 'core' kubernetes server with enough rights to create tokenreviews.authentication.k8s.io.
--authentication-skip-lookup If false, the authentication-kubeconfig will be used to lookup missing authentication configuration from the cluster.
--authentication-token-webhook-cache-ttl duration The duration to cache responses from the webhook token authenticator. (default 10s)
--authentication-tolerate-lookup-failure If true, failures to look up missing authentication configuration from the cluster are not considered fatal. Note that this can result in authentication that treats all requests as anonymous.
--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.
--requestheader-allowed-names strings List of client certificate common names to allow to provide usernames in headers specified by --requestheader-username-headers. If empty, any client certificate validated by the authorities in --requestheader-client-ca-file is allowed.
--requestheader-client-ca-file string Root certificate bundle to use to verify client certificates on incoming requests before trusting usernames in headers specified by --requestheader-username-headers. WARNING: generally do not depend on authorization being already done for incoming requests.
--requestheader-extra-headers-prefix strings List of request header prefixes to inspect. X-Remote-Extra- is suggested. (default [x-remote-extra-])
--requestheader-group-headers strings List of request headers to inspect for groups. X-Remote-Group is suggested. (default [x-remote-group])
--requestheader-username-headers strings List of request headers to inspect for usernames. X-Remote-User is common. (default [x-remote-user])
Apiserver authorization flags:
--authorization-always-allow-paths strings A list of HTTP paths to skip during authorization, i.e. these are authorized without contacting the 'core' kubernetes server. (default [/healthz,/readyz,/livez])
--authorization-kubeconfig string kubeconfig file pointing at the 'core' kubernetes server with enough rights to create subjectaccessreviews.authorization.k8s.io.
--authorization-webhook-cache-authorized-ttl duration The duration to cache 'authorized' responses from the webhook authorizer. (default 10s)
--authorization-webhook-cache-unauthorized-ttl duration The duration to cache 'unauthorized' responses from the webhook authorizer. (default 10s)
Apiserver audit log flags:
--audit-log-batch-buffer-size int The size of the buffer to store events before batching and writing. Only used in batch mode. (default 10000)
--audit-log-batch-max-size int The maximum size of a batch. Only used in batch mode. (default 1)
--audit-log-batch-max-wait duration The amount of time to wait before force writing the batch that hadn't reached the max size. Only used in batch mode.
--audit-log-batch-throttle-burst int Maximum number of requests sent at the same moment if ThrottleQPS was not utilized before. Only used in batch mode.
--audit-log-batch-throttle-enable Whether batching throttling is enabled. Only used in batch mode.
--audit-log-batch-throttle-qps float32 Maximum average number of batches per second. Only used in batch mode.
--audit-log-compress If set, the rotated log files will be compressed using gzip.
--audit-log-format string Format of saved audits. "legacy" indicates 1-line text format for each event. "json" indicates structured json format. Known formats are legacy,json. (default "json")
--audit-log-maxage int The maximum number of days to retain old audit log files based on the timestamp encoded in their filename.
--audit-log-maxbackup int The maximum number of old audit log files to retain. Setting a value of 0 will mean there's no restriction on the number of files.
--audit-log-maxsize int The maximum size in megabytes of the audit log file before it gets rotated.
--audit-log-mode string Strategy for sending audit events. Blocking indicates sending events should block server responses. Batch causes the backend to buffer and write events asynchronously. Known modes are batch,blocking,blocking-strict. (default "blocking")
--audit-log-path string If set, all requests coming to the apiserver will be logged to this file. '-' means standard out.
--audit-log-truncate-enabled Whether event and batch truncating is enabled.
--audit-log-truncate-max-batch-size int Maximum size of the batch sent to the underlying backend. Actual serialized size can be several hundreds of bytes greater. If a batch exceeds this limit, it is split into several batches of smaller size. (default 10485760)
--audit-log-truncate-max-event-size int Maximum size of the audit event sent to the underlying backend. If the size of an event is greater than this number, first request and response are removed, and if this doesn't reduce the size enough, event is discarded. (default 102400)
--audit-log-version string API group and version used for serializing audit events written to log. (default "audit.k8s.io/v1")
--audit-policy-file string Path to the file that defines the audit policy configuration.
--audit-webhook-batch-buffer-size int The size of the buffer to store events before batching and writing. Only used in batch mode. (default 10000)
--audit-webhook-batch-max-size int The maximum size of a batch. Only used in batch mode. (default 400)
--audit-webhook-batch-max-wait duration The amount of time to wait before force writing the batch that hadn't reached the max size. Only used in batch mode. (default 30s)
--audit-webhook-batch-throttle-burst int Maximum number of requests sent at the same moment if ThrottleQPS was not utilized before. Only used in batch mode. (default 15)
--audit-webhook-batch-throttle-enable Whether batching throttling is enabled. Only used in batch mode. (default true)
--audit-webhook-batch-throttle-qps float32 Maximum average number of batches per second. Only used in batch mode. (default 10)
--audit-webhook-config-file string Path to a kubeconfig formatted file that defines the audit webhook configuration.
--audit-webhook-initial-backoff duration The amount of time to wait before retrying the first failed request. (default 10s)
--audit-webhook-mode string Strategy for sending audit events. Blocking indicates sending events should block server responses. Batch causes the backend to buffer and write events asynchronously. Known modes are batch,blocking,blocking-strict. (default "batch")
--audit-webhook-truncate-enabled Whether event and batch truncating is enabled.
--audit-webhook-truncate-max-batch-size int Maximum size of the batch sent to the underlying backend. Actual serialized size can be several hundreds of bytes greater. If a batch exceeds this limit, it is split into several batches of smaller size. (default 10485760)
--audit-webhook-truncate-max-event-size int Maximum size of the audit event sent to the underlying backend. If the size of an event is greater than this number, first request and response are removed, and if this doesn't reduce the size enough, event is discarded. (default 102400)
--audit-webhook-version string API group and version used for serializing audit events written to webhook. (default "audit.k8s.io/v1")
Features flags:
--contention-profiling Enable lock contention profiling, if profiling is enabled
--profiling Enable profiling via web interface host:port/debug/pprof/ (default true)
Logging flags:
--add_dir_header If true, adds the file directory to the header of the log messages (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--alsologtostderr log to standard error as well as files (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--log-flush-frequency duration Maximum number of seconds between log flushes (default 5s)
--log_backtrace_at traceLocation when logging hits line file:N, emit a stack trace (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components) (default :0)
--log_dir string If non-empty, write log files in this directory (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--log_file string If non-empty, use this log file (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--log_file_max_size uint Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components) (default 1800)
--logtostderr log to standard error instead of files (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components) (default true)
--one_output If true, only write logs to their native severity level (vs also writing to each lower severity level) (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--skip_headers If true, avoid header prefixes in the log messages (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--skip_log_headers If true, avoid headers when opening log files (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components)
--stderrthreshold severity logs at or above this threshold go to stderr (DEPRECATED: will be removed in a future release, see https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/2845-deprecate-klog-specific-flags-in-k8s-components) (default 2)
-v, --v Level number for the log level verbosity
--vmodule moduleSpec comma-separated list of pattern=N settings for file-filtered logging
panic: unable to load configmap based request-header-client-ca-file: Get "https://10.152.183.1:443/api/v1/namespaces/kube-system/configmaps/extension-apiserver-authentication": dial tcp 10.152.183.1:443: i/o timeout
goroutine 1 [running]:
main.main()
/go/src/sigs.k8s.io/metrics-server/cmd/metrics-server/metrics-server.go:37 +0xa5