手动搭建k8s-1.16.6高可用集群之部署worker节点-部署kubelet组件
kubelet 运行在每个 worker 节点上，接收 kube-apiserver 发送的请求，管理 Pod 容器，执行交互式命令，如 exec、run、logs 等。
kubelet 启动时自动向 kube-apiserver 注册节点信息，内置的 cadvisor 统计和监控节点的资源使用情况。
为确保安全，部署时关闭了 kubelet 的非安全 http 端口，对请求进行认证和授权，拒绝未授权的访问(如 apiserver、heapster 的请求)。
注意：如果没有特殊指明，本文档的所有操作均在 k8s-01 节点上执行。
下载和分发在部署master节点时已经做过，依赖包也在work节点中安装了，可以直接进入配置步骤。
一、创建 kubelet bootstrap kubeconfig 文件
cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
do
echo ">>> ${node_name}"
# 创建 token
export BOOTSTRAP_TOKEN=$(kubeadm token create \
--description kubelet-bootstrap-token \
--groups system:bootstrappers:${node_name} \
--kubeconfig ~/.kube/config)
# 设置集群参数
kubectl config set-cluster kubernetes \
--certificate-authority=/etc/kubernetes/cert/ca.pem \
--embed-certs=true \
--server=${KUBE_APISERVER} \
--kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig
# 设置客户端认证参数
kubectl config set-credentials kubelet-bootstrap \
--token=${BOOTSTRAP_TOKEN} \
--kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig
# 设置上下文参数
kubectl config set-context default \
--cluster=kubernetes \
--user=kubelet-bootstrap \
--kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig
# 设置默认上下文
kubectl config use-context default --kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig
done
EOF
- 向 kubeconfig 写入的是 token，bootstrap 结束后 kube-controller-manager 为 kubelet 创建 client 和 server 证书；
查看 kubeadm 为各节点创建的 token：
$ kubeadm token list --kubeconfig ~/.kube/config
TOKEN TTL EXPIRES USAGES DESCRIPTION EXTRA GROUPS
0boq46.air2700q4l4daby7 23h 2020-04-28T10:40:17+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-02
l93gf9.n45ukklp406m8cvu 23h 2020-04-28T10:40:18+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-03
lcuvuj.zl6gfsgpkw55cmxw 23h 2020-04-28T10:40:16+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-01
- token 有效期为 1 天，超期后将不能再被用来 boostrap kubelet，且会被 kube-controller-manager 的 tokencleaner 清理；
- kube-apiserver 接收 kubelet 的 bootstrap token 后，将请求的 user 设置为
system:bootstrap:，group 设置为system:bootstrappers，后续将为这个 group 设置 ClusterRoleBinding；
二、分发 bootstrap kubeconfig 文件到所有 worker 节点
cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
do
echo ">>> ${node_name}"
scp kubelet-bootstrap-${node_name}.kubeconfig root@${node_name}:/etc/kubernetes/kubelet-bootstrap.kubeconfig
done
EOF
三、创建和分发 kubelet 参数配置文件
从 v1.10 开始，部分 kubelet 参数需在配置文件中配置，kubelet --help 会提示：
DEPRECATED: This parameter should be set via the config file specified by the Kubelet's --config flag
创建 kubelet 参数配置文件模板
$ cd /opt/k8s/work
$ source /opt/k8s/bin/environment.sh
$ cat > kubelet-config.yaml.template <<EOF
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address: "##NODE_IP##"
staticPodPath: ""
syncFrequency: 1m
fileCheckFrequency: 20s
httpCheckFrequency: 20s
staticPodURL: ""
port: 10250
readOnlyPort: 0
rotateCertificates: true
serverTLSBootstrap: true
authentication:
anonymous:
enabled: false
webhook:
enabled: true
x509:
clientCAFile: "/etc/kubernetes/cert/ca.pem"
authorization:
mode: Webhook
registryPullQPS: 0
registryBurst: 20
eventRecordQPS: 0
eventBurst: 20
enableDebuggingHandlers: true
enableContentionProfiling: true
healthzPort: 10248
healthzBindAddress: "##NODE_IP##"
clusterDomain: "${CLUSTER_DNS_DOMAIN}"
clusterDNS:
- "${CLUSTER_DNS_SVC_IP}"
nodeStatusUpdateFrequency: 10s
nodeStatusReportFrequency: 1m
imageMinimumGCAge: 2m
imageGCHighThresholdPercent: 85
imageGCLowThresholdPercent: 80
volumeStatsAggPeriod: 1m
kubeletCgroups: ""
systemCgroups: ""
cgroupRoot: ""
cgroupsPerQOS: true
cgroupDriver: cgroupfs
runtimeRequestTimeout: 10m
hairpinMode: promiscuous-bridge
maxPods: 220
podCIDR: "${CLUSTER_CIDR}"
podPidsLimit: -1
resolvConf: /etc/resolv.conf
maxOpenFiles: 1000000
kubeAPIQPS: 1000
kubeAPIBurst: 2000
serializeImagePulls: false
evictionHard:
memory.available: "100Mi"
nodefs.available: "10%"
nodefs.inodesFree: "5%"
imagefs.available: "15%"
evictionSoft: {}
enableControllerAttachDetach: true
failSwapOn: true
containerLogMaxSize: 20Mi
containerLogMaxFiles: 10
systemReserved: {}
kubeReserved: {}
systemReservedCgroup: ""
kubeReservedCgroup: ""
enforceNodeAllocatable: ["pods"]
EOF
- address：kubelet 安全端口（https，10250）监听的地址，不能为 127.0.0.1，否则 kube-apiserver、heapster 等不能调用 kubelet 的 API；
- readOnlyPort=0：关闭只读端口(默认 10255)，等效为未指定；
- authentication.anonymous.enabled：设置为 false，不允许匿名访问 10250 端口；
- authentication.x509.clientCAFile：指定签名客户端证书的 CA 证书，开启 HTTP 证书认证；
- authentication.webhook.enabled=true：开启 HTTPs bearer token 认证；
- 对于未通过 x509 证书和 webhook 认证的请求(kube-apiserver 或其他客户端)，将被拒绝，提示 Unauthorized；
- authroization.mode=Webhook：kubelet 使用 SubjectAccessReview API 查询 kube-apiserver 某 user、group 是否具有操作资源的权限(RBAC)；
- featureGates.RotateKubeletClientCertificate、featureGates.RotateKubeletServerCertificate：自动 rotate 证书，证书的有效期取决于 kube-controller-manager 的 --experimental-cluster-signing-duration 参数；
- 需要 root 账户运行；
为各节点创建和分发 kubelet 配置文件：
cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
do
echo ">>> ${node_ip}"
sed -e "s/##NODE_IP##/${node_ip}/" kubelet-config.yaml.template > kubelet-config-${node_ip}.yaml.template
scp kubelet-config-${node_ip}.yaml.template root@${node_ip}:/etc/kubernetes/kubelet-config.yaml
done
EOF
四、创建和分发 kubelet systemd unit 文件
创建 kubelet systemd unit 文件模板：
$ cd /opt/k8s/work
$ source /opt/k8s/bin/environment.sh
$ cat > kubelet.service.template <<EOF
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=docker.service
Requires=docker.service
[Service]
WorkingDirectory=${K8S_DIR}/kubelet
ExecStart=/opt/k8s/bin/kubelet \\
--bootstrap-kubeconfig=/etc/kubernetes/kubelet-bootstrap.kubeconfig \\
--cert-dir=/etc/kubernetes/cert \\
--root-dir=${K8S_DIR}/kubelet \\
--kubeconfig=/etc/kubernetes/kubelet.kubeconfig \\
--config=/etc/kubernetes/kubelet-config.yaml \\
--hostname-override=##NODE_NAME## \\
--image-pull-progress-deadline=15m \\
--volume-plugin-dir=${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/ \\
--logtostderr=true \\
--v=2
Restart=always
RestartSec=5
StartLimitInterval=0
[Install]
WantedBy=multi-user.target
EOF
- 如果设置了
--hostname-override选项，则kube-proxy也需要设置该选项，否则会出现找不到 Node 的情况； --bootstrap-kubeconfig：指向 bootstrap kubeconfig 文件，kubelet 使用该文件中的用户名和 token 向 kube-apiserver 发送 TLS Bootstrapping 请求；- K8S approve kubelet 的 csr 请求后，在
--cert-dir目录创建证书和私钥文件，然后写入--kubeconfig文件； --pod-infra-container-image不使用 redhat 的pod-infrastructure:latest镜像，它不能回收容器的僵尸；
为各节点创建和分发 kubelet systemd unit 文件：
cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
do
echo ">>> ${node_name}"
sed -e "s/##NODE_NAME##/${node_name}/" kubelet.service.template > kubelet-${node_name}.service
scp kubelet-${node_name}.service root@${node_name}:/etc/systemd/system/kubelet.service
done
EOF
五、 授予 kube-apiserver 访问 kubelet API 的权限
在执行 kubectl exec、run、logs 等命令时，apiserver 会将请求转发到 kubelet 的 https 端口。这里定义 RBAC 规则，授权 apiserver 使用的证书（kubernetes.pem）用户名（CN：kuberntes-master）访问 kubelet API 的权限：
$ kubectl create clusterrolebinding kube-apiserver:kubelet-apis --clusterrole=system:kubelet-api-admin --user kubernetes-master
六、 Bootstrap Token Auth 和授予权限
kubelet 启动时查找 --kubeletconfig 参数对应的文件是否存在，如果不存在则使用 --bootstrap-kubeconfig 指定的 kubeconfig 文件向 kube-apiserver 发送证书签名请求 (CSR)。
kube-apiserver 收到 CSR 请求后，对其中的 Token 进行认证，认证通过后将请求的 user 设置为 system:bootstrap:，group 设置为 system:bootstrappers，这一过程称为 Bootstrap Token Auth。
默认情况下，这个 user 和 group 没有创建 CSR 的权限，kubelet 启动失败，错误日志如下：
$ sudo journalctl -u kubelet -a |grep -A 2 'certificatesigningrequests'
May 26 12:13:41 zhangjun-k8s-01 kubelet[128468]: I0526 12:13:41.798230 128468 certificate_manager.go:366] Rotating certificates
May 26 12:13:41 zhangjun-k8s-01 kubelet[128468]: E0526 12:13:41.801997 128468 certificate_manager.go:385] Failed while requesting a signed certificate from the master: cannot create certificate signing request: certificatesigningrequests.certificates.k8s.io is forbidden: User "system:bootstrap:82jfrm" cannot create resource "certificatesigningrequests" in API group "certificates.k8s.io" at the cluster scope
解决办法是：创建一个 clusterrolebinding，将 group system:bootstrappers 和 clusterrole system:node-bootstrapper 绑定：
$ kubectl create clusterrolebinding kubelet-bootstrap --clusterrole=system:node-bootstrapper --group=system:bootstrappers
七、自动 approve CSR 请求，生成 kubelet client 证书
kubelet 创建 CSR 请求后，下一步需要创建被 approve，有两种方式：
- kube-controller-manager 自动 aprrove；
- 手动使用命令
kubectl certificate approve；
CSR 被 approve 后，kubelet 向 kube-controller-manager 请求创建 client 证书，kube-controller-manager 中的 csrapproving controller 使用 SubjectAccessReview API 来检查 kubelet 请求（对应的 group 是 system:bootstrappers）是否具有相应的权限。
创建三个 ClusterRoleBinding，分别授予 group system:bootstrappers 和 group system:nodes 进行 approve client、renew client、renew server 证书的权限（server csr 是手动 approve 的，见后文）：
$ cd /opt/k8s/work
$ cat > csr-crb.yaml <<EOF
# Approve all CSRs for the group "system:bootstrappers"
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: auto-approve-csrs-for-group
subjects:
- kind: Group
name: system:bootstrappers
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: system:certificates.k8s.io:certificatesigningrequests:nodeclient
apiGroup: rbac.authorization.k8s.io
---
# To let a node of the group "system:nodes" renew its own credentials
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: node-client-cert-renewal
subjects:
- kind: Group
name: system:nodes
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: system:certificates.k8s.io:certificatesigningrequests:selfnodeclient
apiGroup: rbac.authorization.k8s.io
---
# A ClusterRole which instructs the CSR approver to approve a node requesting a
# serving cert matching its client cert.
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: approve-node-server-renewal-csr
rules:
- apiGroups: ["certificates.k8s.io"]
resources: ["certificatesigningrequests/selfnodeserver"]
verbs: ["create"]
---
# To let a node of the group "system:nodes" renew its own server credentials
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: node-server-cert-renewal
subjects:
- kind: Group
name: system:nodes
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: approve-node-server-renewal-csr
apiGroup: rbac.authorization.k8s.io
EOF
$ kubectl apply -f csr-crb.yaml
- auto-approve-csrs-for-group：自动 approve node 的第一次 CSR； 注意第一次 CSR 时，请求的 Group 为 system:bootstrappers；
- node-client-cert-renewal：自动 approve node 后续过期的 client 证书，自动生成的证书 Group 为 system:nodes;
- node-server-cert-renewal：自动 approve node 后续过期的 server 证书，自动生成的证书 Group 为 system:nodes;
八、 启动 kubelet 服务
cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
do
echo ">>> ${node_ip}"
ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/"
ssh root@${node_ip} "/usr/sbin/swapoff -a"
ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kubelet && systemctl restart kubelet"
done
EOF
- 启动服务前必须先创建工作目录；
- 关闭 swap 分区，否则 kubelet 会启动失败；
kubelet 启动后使用 --bootstrap-kubeconfig 向 kube-apiserver 发送 CSR 请求，当这个 CSR 被 approve 后，kube-controller-manager 为 kubelet 创建 TLS 客户端证书、私钥和 --kubeletconfig 文件。
注意：kube-controller-manager 需要配置 --cluster-signing-cert-file 和 --cluster-signing-key-file 参数，才会为 TLS Bootstrap 创建证书和私钥。
九、 查看 kubelet 情况
稍等一会，三个节点的 CSR 都被自动 approved：
$ kubectl get csr
NAME AGE REQUESTOR CONDITION
csr-2fx9g 88m system:node:k8s-03 Pending
csr-2njv6 27m system:node:k8s-02 Pending
csr-4jrhg 12m system:node:k8s-02 Pending
csr-6hd29 73m system:node:k8s-01 Pending
csr-8clpb 103m system:node:k8s-03 Pending
csr-8ksf7 12m system:node:k8s-03 Pending
csr-bvk7t 103m system:bootstrap:l93gf9 Approved,Issued
csr-c87bf 43m system:node:k8s-01 Pending
csr-clt98 88m system:node:k8s-02 Pending
csr-d69cn 103m system:node:k8s-01 Pending
csr-fl545 103m system:bootstrap:lcuvuj Approved,Issued
csr-j6bvl 58m system:node:k8s-02 Pending
csr-mds2m 73m system:node:k8s-03 Pending
csr-nxndm 73m system:node:k8s-02 Pending
csr-pncm2 12m system:node:k8s-01 Pending
csr-pqf4l 43m system:node:k8s-03 Pending
csr-s477f 103m system:bootstrap:0boq46 Approved,Issued
csr-sm474 88m system:node:k8s-01 Pending
csr-t9pv9 58m system:node:k8s-01 Pending
csr-tj974 27m system:node:k8s-03 Pending
csr-v9k5d 58m system:node:k8s-03 Pending
csr-vgw7m 103m system:node:k8s-02 Pending
csr-z9txp 43m system:node:k8s-02 Pending
csr-zn6h5 27m system:node:k8s-01 Pending
- Pending 的 CSR 用于创建 kubelet server 证书，需要手动 approve，参考后文。
所有节点均 ready：
$ kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-01 Ready <none> 104m v1.16.6
k8s-02 Ready <none> 104m v1.16.6
k8s-03 Ready <none> 104m v1.16.6
kube-controller-manager 为各 node 生成了 kubeconfig 文件和公私钥：
$ ls -l /etc/kubernetes/kubelet.kubeconfig
-rw------- 1 root root 2246 Apr 27 11:29 /etc/kubernetes/kubelet.kubeconfig
$ ls -l /etc/kubernetes/cert/kubelet-client-*
-rw------- 1 root root 1273 Apr 27 11:30 /etc/kubernetes/cert/kubelet-client-2020-04-27-11-30-01.pem
lrwxrwxrwx 1 root root 59 Apr 27 11:30 /etc/kubernetes/cert/kubelet-client-current.pem -> /etc/kubernetes/cert/kubelet-client-2020-04-27-11-30-01.pem
- 没有自动生成 kubelet server 证书；
十、 手动 approve server cert csr
基于安全性考虑，CSR approving controllers 不会自动 approve kubelet server 证书签名请求，需要手动 approve：
$ kubectl get csr
NAME AGE REQUESTOR CONDITION
csr-2fx9g 92m system:node:k8s-03 Pending
csr-2njv6 31m system:node:k8s-02 Pending
csr-4jrhg 15m system:node:k8s-02 Pending
csr-6hd29 77m system:node:k8s-01 Pending
csr-8clpb 107m system:node:k8s-03 Pending
csr-8ksf7 15m system:node:k8s-03 Pending
csr-bvk7t 107m system:bootstrap:l93gf9 Approved,Issued
csr-c87bf 46m system:node:k8s-01 Pending
csr-clt98 92m system:node:k8s-02 Pending
csr-d69cn 107m system:node:k8s-01 Pending
csr-fl545 107m system:bootstrap:lcuvuj Approved,Issued
csr-fp5t2 11s system:node:k8s-02 Pending
csr-j6bvl 61m system:node:k8s-02 Pending
csr-mds2m 76m system:node:k8s-03 Pending
csr-mq8qq 7s system:node:k8s-01 Pending
csr-nxndm 77m system:node:k8s-02 Pending
csr-pg5dt 4s system:node:k8s-03 Pending
csr-pncm2 15m system:node:k8s-01 Pending
csr-pqf4l 46m system:node:k8s-03 Pending
csr-s477f 107m system:bootstrap:0boq46 Approved,Issued
csr-sm474 92m system:node:k8s-01 Pending
csr-t9pv9 61m system:node:k8s-01 Pending
csr-tj974 31m system:node:k8s-03 Pending
csr-v9k5d 61m system:node:k8s-03 Pending
csr-vgw7m 107m system:node:k8s-02 Pending
csr-z9txp 46m system:node:k8s-02 Pending
csr-zn6h5 31m system:node:k8s-01 Pending
# 手动 approve
$ kubectl get csr | grep Pending | awk '{print $1}' | xargs kubectl certificate approve
# 自动生成了 server 证书
$ ls -l /etc/kubernetes/cert/kubelet-*
-rw------- 1 root root 1273 Apr 27 11:30 /etc/kubernetes/cert/kubelet-client-2020-04-27-11-30-01.pem
lrwxrwxrwx 1 root root 59 Apr 27 11:30 /etc/kubernetes/cert/kubelet-client-current.pem -> /etc/kubernetes/cert/kubelet-client-2020-04-27-11-30-01.pem
-rw------- 1 root root 1309 Apr 27 13:17 /etc/kubernetes/cert/kubelet-server-2020-04-27-13-17-46.pem
lrwxrwxrwx 1 root root 59 Apr 27 13:17 /etc/kubernetes/cert/kubelet-server-current.pem -> /etc/kubernetes/cert/kubelet-server-2020-04-27-13-17-46.pem
十一、 kubelet api 认证和授权
kubelet 配置了如下认证参数：
- authentication.anonymous.enabled：设置为 false，不允许匿名访问 10250 端口；
- authentication.x509.clientCAFile：指定签名客户端证书的 CA 证书，开启 HTTPs 证书认证；
- authentication.webhook.enabled=true：开启 HTTPs bearer token 认证；
同时配置了如下授权参数：
- authroization.mode=Webhook：开启 RBAC 授权；
kubelet 收到请求后，使用 clientCAFile 对证书签名进行认证，或者查询 bearer token 是否有效。如果两者都没通过，则拒绝请求，提示 Unauthorized：
$ curl -s --cacert /etc/kubernetes/cert/ca.pem https://192.168.0.71:10250/metrics
Unauthorized
$ curl -s --cacert /etc/kubernetes/cert/ca.pem -H "Authorization: Bearer 123456" https://192.168.0.71:10250/metrics
Unauthorized
通过认证后，kubelet 使用 SubjectAccessReview API 向 kube-apiserver 发送请求，查询证书或 token 对应的 user、group 是否有操作资源的权限(RBAC)；
1、证书认证和授权
# 权限不足的证书；
$ curl -s --cacert /etc/kubernetes/cert/ca.pem --cert /etc/kubernetes/cert/kube-controller-manager.pem --key /etc/kubernetes/cert/kube-controller-manager-key.pem https://192.168.0.71:10250/metrics
Forbidden (user=system:kube-controller-manager, verb=get, resource=nodes, subresource=metrics)
# 使用部署 kubectl 命令行工具时创建的、具有最高权限的 admin 证书；
$ curl -s --cacert /etc/kubernetes/cert/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://192.168.0.71:10250/metrics|head
# HELP apiserver_audit_event_total [ALPHA] Counter of audit events generated and sent to the audit backend.
# TYPE apiserver_audit_event_total counter
apiserver_audit_event_total 0
# HELP apiserver_audit_requests_rejected_total [ALPHA] Counter of apiserver requests rejected due to an error in audit logging backend.
# TYPE apiserver_audit_requests_rejected_total counter
apiserver_audit_requests_rejected_total 0
# HELP apiserver_client_certificate_expiration_seconds [ALPHA] Distribution of the remaining lifetime on the certificate used to authenticate a request.
# TYPE apiserver_client_certificate_expiration_seconds histogram
apiserver_client_certificate_expiration_seconds_bucket{le="0"} 0
apiserver_client_certificate_expiration_seconds_bucket{le="1800"} 0
--cacert、--cert、--key的参数值必须是文件路径，如上面的./admin.pem不能省略./，否则返回401 Unauthorized；
2、 bear token 认证和授权
创建一个 ServiceAccount，将它和 ClusterRole system:kubelet-api-admin 绑定，从而具有调用 kubelet API 的权限：
$ kubectl create sa kubelet-api-test
$ kubectl create clusterrolebinding kubelet-api-test --clusterrole=system:kubelet-api-admin --serviceaccount=default:kubelet-api-test
$ SECRET=$(kubectl get secrets | grep kubelet-api-test | awk '{print $1}')
$ TOKEN=$(kubectl describe secret ${SECRET} | grep -E '^token' | awk '{print $2}')
$ echo ${TOKEN}
$ curl -s --cacert /etc/kubernetes/cert/ca.pem -H "Authorization: Bearer ${TOKEN}" https://192.168.0.71:10250/metrics | head
# HELP apiserver_audit_event_total [ALPHA] Counter of audit events generated and sent to the audit backend.
# TYPE apiserver_audit_event_total counter
apiserver_audit_event_total 0
# HELP apiserver_audit_requests_rejected_total [ALPHA] Counter of apiserver requests rejected due to an error in audit logging backend.
# TYPE apiserver_audit_requests_rejected_total counter
apiserver_audit_requests_rejected_total 0
# HELP apiserver_client_certificate_expiration_seconds [ALPHA] Distribution of the remaining lifetime on the certificate used to authenticate a request.
# TYPE apiserver_client_certificate_expiration_seconds histogram
apiserver_client_certificate_expiration_seconds_bucket{le="0"} 0
apiserver_client_certificate_expiration_seconds_bucket{le="1800"} 0
3、cadvisor 和 metrics
cadvisor 是内嵌在 kubelet 二进制中的，统计所在节点各容器的资源(CPU、内存、磁盘、网卡)使用情况的服务。
浏览器访问 https://192.168.0.71:10250/metrics 和 https://192.168.0.71:10250/metrics/cadvisor 分别返回 kubelet 和 cadvisor 的 metrics。
注意：
- kubelet.config.json 设置 authentication.anonymous.enabled 为 false，不允许匿名证书访问 10250 的 https 服务；
- 参考A.浏览器访问kube-apiserver安全端口.md，创建和导入相关证书，然后访问上面的 10250 端口；
查看到的内容如下：
参考文章：
- kubelet 认证和授权：https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet-authentication-authorization/