文章目录
1.9、部署kubelet
-
kubelet运行在每个node节点上,接收kube-apiserver发送的请求,管理Pod容器,执行交互命令
-
kubelet启动时自动向kube-apiserver注册节点信息,内置的cAdivsor统计和监控节点的资源使用资源情况
-
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
1.9.0、创建kubelet bootstrap kubeconfig文件
#!/usr/bin/env bash
source /opt/k8s/bin/k8s-env.sh
for node_name in ${NODE_NAMES[@]}
do
printf "\e[1;34m${node_name}\e[0m\n"
# 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=${KUBE_APISERVER} \
--kubeconfig=/opt/k8s/ssl/kubelet-bootstrap-${node_name}.kubeconfig
# 设置客户端认证参数
kubectl config set-credentials kubelet-bootstrap \
--token=${BOOTSTRAP_TOKEN} \
--kubeconfig=/opt/k8s/ssl/kubelet-bootstrap-${node_name}.kubeconfig
# 设置上下文参数
kubectl config set-context default \
--cluster=kubernetes \
--user=kubelet-bootstrap \
--kubeconfig=/opt/k8s/ssl/kubelet-bootstrap-${node_name}.kubeconfig
# 设置默认上下文
kubectl config use-context default --kubeconfig=/opt/k8s/ssl/kubelet-bootstrap-${node_name}.kubeconfig
done
- 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为各个节点创建的token"
k8s-01:~ # kubeadm token list --kubeconfig ~/.kube/config
TOKEN TTL EXPIRES USAGES DESCRIPTION EXTRA GROUPS
5750z9.ycsk3jxiahgz1gkn 23h 2021-02-14T00:55:41+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-05
f4scbn.lev5uqmokwai5k0e 23h 2021-02-14T00:55:40+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-02
kjfsng.qmjesofryg97c80q 23h 2021-02-14T00:55:41+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-04
nseipt.09jaep1j8qnoqn1a 23h 2021-02-14T00:55:40+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-01
zlal1h.856gawjgom560fys 23h 2021-02-14T00:55:40+08:00 authentication,signing kubelet-bootstrap-token system:bootstrappers:k8s-03
- token有效期为1天,超期后将不能被用来bootstrap kubelet,且会被kube-controller-manager的token cleaner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
1.9.1、创建kubelet配置文件
k8s-01:~ # cd /opt/k8s/conf/
k8s-01:/opt/k8s/conf # source /opt/k8s/bin/k8s-env.sh
k8s-01:/opt/k8s/conf # 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: systemd
runtimeRequestTimeout: 10m
hairpinMode: promiscuous-bridge
maxPods: 220
podCIDR: "${CLUSTER_CIDR}"
podPidsLimit: -1
resolvConf: /etc/resolv.conf
maxOpenFiles: 1000000
kubeAPIQPS: 1000
kubeAPIBurst: 2000
serializeImagePulls: false
evictionHard:
memory.available: "100Mi"
nodefs.available: "10%"
nodefs.inodesFree: "5%"
imagefs.available: "15%"
evictionSoft: {
}
enableControllerAttachDetach: true
failSwapOn: true
containerLogMaxSize: 20Mi
containerLogMaxFiles: 10
systemReserved: {
}
kubeReserved: {
}
systemReservedCgroup: ""
kubeReservedCgroup: ""
enforceNodeAllocatable: ["pods"]
EOF
1.9.2、配置kubelet为systemctl启动
k8s-01:~ # cd /opt/k8s/conf/
k8s-01:/opt/k8s/conf # source /opt/k8s/bin/k8s-env.sh
k8s-01:/opt/k8s/conf # cat > kubelet.service.template <<EOF
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=docker.service
Requires=docker.service
[Service]
WorkingDirectory=${K8S_DIR}/kubelet
ExecStart=/opt/k8s/bin/kubelet \\
--v=2 \\
--hostname-override=##NODE_IP## \\
--bootstrap-kubeconfig=/etc/kubernetes/cert/kubelet-bootstrap.kubeconfig \\
--cert-dir=/etc/kubernetes/cert \\
--kubeconfig=/etc/kubernetes/kubelet.kubeconfig \\
--config=/etc/kubernetes/kubelet-config.yaml \\
--logtostderr=true \\
--pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.2 \\
--image-pull-progress-deadline=15m \\
--cni-conf-dir=/etc/cni/net.d \\
--root-dir=${K8S_DIR}/kubelet
Restart=always
RestartSec=5
StartLimitInterval=0
[Install]
WantedBy=multi-user.target
EOF
- –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
1.9.3、拉取kubelet依赖的pause镜像
k8s-01:~ # docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.2
k8s-01:~ # cd /opt/k8s/packages/
k8s-01:/opt/k8s/packages # docker save $(docker images | grep -v REPOSITORY | awk 'BEGIN{OFS=":";ORS=" "}{print $1,$2}') -o pause.tar
"将镜像保存到本地,分发到其他节点"
1.9.4、分发kubelet证书和文件到其他节点
#!/usr/bin/env bash
source /opt/k8s/bin/k8s-env.sh
for (( i=0; i < 5; i++ ))
do
sed -e "s/##NODE_IP##/${NODE_IPS[i]}/" /opt/k8s/conf/kubelet.service.template > \
/opt/k8s/conf/kubelet-${NODE_IPS[i]}.service
sed -e "s/##NODE_IP##/${NODE_IPS[i]}/" /opt/k8s/conf/kubelet-config.yaml.template > \
/opt/k8s/conf/kubelet-config-${NODE_IPS[i]}.yaml.template
done
for node_name in ${NODE_NAMES[@]}
do
printf "\e[1;34m${node_name}\e[0m\n"
scp /opt/k8s/ssl/kubelet-bootstrap-${node_name}.kubeconfig \
${node_name}:/etc/kubernetes/cert/kubelet-bootstrap.kubeconfig
done
for host in ${NODE_IPS[@]}
do
printf "\e[1;34m${host}\e[0m\n"
scp /opt/k8s/conf/kubelet-${host}.service ${host}:/etc/systemd/system/kubelet.service
scp /opt/k8s/conf/kubelet-config-${host}.yaml.template ${host}:/etc/kubernetes/kubelet-config.yaml
scp /opt/k8s/packages/pause.tar ${host}:/opt/k8s/
ssh root@${host} "docker load -i /opt/k8s/pause.tar"
done
1.9.5、授权kubelet-bootstrap用户组允许请求证书
k8s-01:~ # kubectl create clusterrolebinding kubelet-bootstrap --clusterrole=system:node-bootstrapper --group=system:bootstrappers
- 不创建的话,kubelet会启动失败
1.9.6、启动kubelet服务
#!/usr/bin/env bash
source /opt/k8s/bin/k8s-env.sh
for host in ${NODE_IPS[@]}
do
printf "\e[1;34m${host}\e[0m\n"
ssh root@${host} "mkdir -p ${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/"
ssh root@${host} "systemctl daemon-reload && \
systemctl enable kubelet --now && \
systemctl status kubelet | grep Active"
done
- 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
1.9.7、自动approve CSR请求
- 创建三个
ClusterRoleBinding
,分别用于自动approve client
、renew client
、renew server
证书
k8s-01:~ # cd /opt/k8s/conf/
k8s-01:/opt/k8s/conf # 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
k8s-01:/opt/k8s/conf # 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:bootstrappersnode-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:nodesnode-server-cert-renewal
自动approve node后续过期的server证书,自动生成的证书Group
1.9.8、查看节点是否都为ready
k8s-01:~ # kubectl get node
NAME STATUS ROLES AGE VERSION
192.168.72.39 Ready <none> 20s v1.19.7
192.168.72.40 Ready <none> 19s v1.19.7
192.168.72.41 Ready <none> 18s v1.19.7
192.168.72.42 Ready <none> 18s v1.19.7
192.168.72.43 Ready <none> 17s v1.19.7
1.9.9、手动approve server cert csr
- 基于安全考虑,CSR approving controllers不会自动approve kubelet server证书签名请求,需要手动approve
k8s-01:~ # kubectl get csr | grep Pending | awk '{print $1}' | xargs kubectl certificate approve
1.9.10、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
k8s-01:~ # kubectl create sa kubelet-api-test
k8s-01:~ # kubectl create clusterrolebinding kubelet-api-test --clusterrole=system:kubelet-api-admin --serviceaccount=default:kubelet-api-test