kubeadm部署单节点k8s集群
环境说明
- k8s版本：1.20.0
- docker版本： 19.03.9
- kubeadm版本：1.20.0
| 主机名 | IP 地址 | 角色 | 系统 |
|---|---|---|---|
| k8s-master | 192.168.200.175 | k8s-master | Centos7.6 |
| k8s-node-1 | 192.168.200.176 | k8s-node1 | Centos7.6 |
| k8s-node-2 | 192.168.200.177 | k8s-node2 | Centos7.6 |
环境初始化
关闭selinux、firewalld、swap，清空iptables规则，配置主机名、hosts文件以及配置kubernetes的转发规则，每台服务器上执行：
[root@master ~]# hostnamectl set-hostname master
[root@master ~]# vim /etc/hosts
192.168.200.175 master
192.168.200.176 node1
192.168.200.177 node2
配置转发相关
[root@master ~]# vim /etc/sysctl.conf
...
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
vm.swappiness=0
[root@master ~]# sysctl -p
安装docker
每台机器执行
[root@master ~]# wget -O /etc/yum.repos.d/docker-ce.repo http://download.docker.com/linux/centos/docker-ce.repo
# 列出所有Docker的版本
[root@master ~]# yum list docker-ce --showduplicates | sort -r
...
docker-ce.x86_64 3:19.03.15-3.el7 docker-ce-stable
...
# 安装19.03版本Docker
[root@master ~]# yum install -y docker-ce-19.03.9-3.el7
[root@master ~]# systemctl start docker
[root@master ~]# systemctl enable docker
[root@master ~]# vim /etc/docker/daemon.json
{
"exec-opts": ["native.cgroupdriver=systemd"],
"registry-mirrors": ["https://mirrors.ccs.tencentyun.com"]
}
[root@master ~]# systemctl daemon-reload
[root@master ~]# systemctl restart docker
升级系统以及内核
配置kubernetes
每台机器执行
[root@master ~]# cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.cloud.tencent.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enable=1
gpgcheck=0
repo_gpgcheck=0
EOF
安装集群所需要的三个软件kubeadm、kubectl、kubelet，这里都选择1.20.0版本的，安装命令如下：
[root@master ~]# yum install -y kubeadm-1.20.0 kubectl-1.20.0 kubelet-1.20.0
[root@master ~]# systemctl enable kubelet
#设置kubelet
[root@master ~]# DOCKER_CGROUPS=$(docker info | grep 'Cgroup' | cut -d' ' -f4)
[root@master ~]# cat >/etc/sysconfig/kubelet<<EOF
KUBELET_EXTRA_ARGS="--cgroup-driver=$DOCKER_CGROUPS"
EOF
下载kubernetes所有组件的Docker镜像，1.20版本对应的8个组件版本如下
kube-apiserver:v1.20.0
kube-scheduler:v1.20.0
kube-controller-manager:v1.20.0
kube-proxy:v1.20.0
etcd:3.4.13-0
coredns:1.7.0
pause:3.2
flannel:v0.13.1-rc1 # 网络组件
dashboard:v2.0.0-rc7 # 仪表盘相关组件，可以忽略
metrics-scraper:v1.0.4 # 仪表盘相关组件，可以忽略
由于kubeadm初始化文件中使用的是 k8s.gcr.io这个仓库地址，需要科学上网才能拉取镜像，，Docker Hub下载只需要在前面加前缀tangxu/就行，如下：
[root@master ~]# docker pull tangxu/kube-controller-manager:v1.20.0
[root@master ~]# docker pull tangxu/kube-apiserver:v1.20.0
[root@master ~]# docker pull tangxu/kube-scheduler:v1.20.0
[root@master ~]# docker pull tangxu/kube-proxy:v1.20.0
[root@master ~]# docker pull tangxu/flannel:v0.13.1-rc1
[root@master ~]# docker pull tangxu/etcd:3.4.13-0
[root@master ~]# docker pull tangxu/coredns:1.7.0
[root@master ~]# docker pull tangxu/pause:3.2
[root@master ~]# docker pull tangxu/dashboard:v2.0.0-rc7
[root@master ~]# docker pull tangxu/metrics-scraper:v1.0.4
重新改下镜像的名字，因为初始化yaml文件中仓库地址与离线的镜像不匹配，如果不修改名字的话，不能使用已经离线的镜像，需要重新拉取，而拉取需要科学上网，Docker Hub下载的镜像修改名字如下：
[root@master ~]# docker tag tangxu/kube-controller-manager:v1.20.0 k8s.gcr.io/kube-controller-manager:v1.20.0
[root@master ~]# docker tag tangxu/kube-apiserver:v1.20.0 k8s.gcr.io/kube-apiserver:v1.20.0
[root@master ~]# docker tag tangxu/kube-scheduler:v1.20.0 k8s.gcr.io/kube-scheduler:v1.20.0
[root@master ~]# docker tag tangxu/etcd:3.4.13-0 k8s.gcr.io/etcd:3.4.13-0
[root@master ~]# docker tag tangxu/coredns:1.7.0 k8s.gcr.io/coredns:1.7.0
[root@master ~]# docker tag tangxu/pause:3.2 k8s.gcr.io/pause:3.2
[root@master ~]# docker tag tangxu/kube-proxy:v1.20.0 k8s.gcr.io/kube-proxy:v1.20.0
[root@master ~]# docker tag tangxu/flannel:v0.13.1-rc1 quay.io/coreos/flannel:v0.13.1-rc1
[root@master ~]# docker tag tangxu/dashboard:v2.0.0-rc7 kubernetesui/dashboard:v2.0.0-rc7
[root@master ~]# docker tag tangxu/metrics-scraper:v1.0.4 kubernetesui/metrics-scraper:v1.0.4
初始化集群
master节点执行，生成集群的初始化配置文件：
[root@master ~]# kubeadm config print init-defaults > kubeadm-config.yaml
[root@master ~]# vim ./kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 192.168.0.175 # master节点内网ip
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: master
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
ControlPlaneEndpoint: "mycluster:6443"
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.20.0
networking:
dnsDomain: cluster.local
podSubnet: "10.244.0.0/16" # 使用flannel网络插件这样写网段
serviceSubnet: 10.96.0.0/12
scheduler: {}
主要修改下advertiseAddress的ip地址为master节点的地址，然后在dnsDomain: cluster.local下面增加 podSubnet: “10.244.0.0/16”
开始初始化
[root@master ~]# kubeadm init --config=kubeadm-config.yaml
[init] Using Kubernetes version: v1.20.0
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local master] and IPs [10.96.0.1 10.0.1.7]
[certs] Generating "apiserver-kubelet-client" certificate and key
...
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.0.175:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:59a7d6f60dd67d0be0af8022b1b21cadc77797e89cb6a9d0b7587c1ead4906ee
执行下提示中的命令
[root@master ~]# mkdir -p $HOME/.kube
[root@master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
查看组件准备状态
[root@master ~]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME STATUS MESSAGE ERROR
scheduler Unhealthy Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused
controller-manager Unhealthy Get "http://127.0.0.1:10252/healthz": dial tcp 127.0.0.1:10252: connect: connection refused
etcd-0 Healthy {"health":"true"}
这里scheduler和 controller-manager显示不健康，需要修改2个配置文件 kube-controller-manager.yaml和 kube-scheduler.yaml，将配置文件中 --prot = 0这项注释掉：
[root@master ~]# vim /etc/kubernetes/manifests/kube-controller-manager.yaml
spec:
containers:
- command:
...
- --leader-elect=true
# - --port=0
...
[root@master ~]# vim /etc/kubernetes/manifests/kube-scheduler.yaml
spec:
containers:
- command:
- kube-scheduler
- --authentication-kubeconfig=/etc/kubernetes/scheduler.conf
- --authorization-kubeconfig=/etc/kubernetes/scheduler.conf
- --bind-address=127.0.0.1
- --kubeconfig=/etc/kubernetes/scheduler.conf
- --leader-elect=true
# - --port=0
修改保存完成后，等待一会儿状态就正常了：
[root@master ~]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME STATUS MESSAGE ERROR
controller-manager Healthy ok
scheduler Healthy ok
etcd-0 Healthy {"health":"true"}
加入工作节点
node节点执行如下操作
[root@node1 ~]# kubeadm join 192.168.200.175:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:59a7d6f60dd67d0be0af8022b1b21cadc77797e89cb6a9d0b7587c1ead4906ee
执行后看到以下提示说明节点成功加入集群：
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
查看集群所有节点
[root@node1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 18m v1.20.0
node1 Ready <none> 14m v1.20.0
node2 Ready <none> 14m v1.20.0
安装网络组件
未安装网络组件flannel之前这里的 STATUS状态会是未准备状态，安装网络组件之后就可以了，安装网络组件flannel，kube-flannel.yml文件如下：
[root@master ~]# vim kube-flannel.yml
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
defaultAddCapabilities: []
requiredDropCapabilities: []
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
rules:
- apiGroups: ['extensions']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
hostNetwork: true
priorityClassName: system-node-critical
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.13.1-rc1
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.13.1-rc1
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN", "NET_RAW"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
部署flannel
[root@master ~]# kubectl apply -f kube-flannel.yml
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
查看所有组件运行状态：
[root@master ~]# kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-79495b5589-4k7vg 1/1 Running 0 15m
kube-system coredns-79495b5589-hzrkk 1/1 Running 0 15m
kube-system etcd-master 1/1 Running 2 15m
kube-system kube-apiserver-master 1/1 Running 7 15m
kube-system kube-controller-manager-master 1/1 Running 3 15m
kube-system kube-flannel-ds-2h478 1/1 Running 0 15m
kube-system kube-flannel-ds-9fzq2 1/1 Running 0 15m
kube-system kube-flannel-ds-fxhpv 1/1 Running 1 15m
kube-system kube-proxy-9thzf 1/1 Running 0 15m
kube-system kube-proxy-kqmhp 1/1 Running 0 15m
kube-system kube-proxy-r5zvb 1/1 Running 1 15m
kube-system kube-scheduler-master 1/1 Running 3 15m
kube-system metrics-server-7dcbcf9794-hgdm2 1/1 Running 0 15m
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