记一次 Kubeadm 部署 k8s + Flannel
以 master 节点的配置为例记录一下在 CentOS 7.0 上使用 kubeadm 部署 kubernetes 集群 + Flannel 插件的过程
一、基础环境配置
安装 wget
yum install -y wget
配置 YUM 软件源
- 配置阿里镜像源
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
- 配置 kubernetes 源
vi /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
yum clean all
yum makecache fast
常用软件安装
yum install -y net-tools
yum install -y vim
安装 Docker
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O/etc/yum.repos.d/docker-ce.repo
yum -y install docker-ce
systemctl start docker
systemctl enable docker
配置时间同步
不然后面 Flannel 安装时会出现证书错误
yum install ntpdate -y
ntpdate cn.pool.ntp.org
安装 kubeadm，kubelet 和 kubectl
yum install -y kubectl-1.18.0 kubeadm-1.18.0 kubelet-1.18.0 --nogpgcheck
关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
禁用 SELinux
setenforce 0
vi /etc/selinux/config
SELINUX=disabled
关闭 swap
vim /etc/fstab # 永久关闭 注释swap那一行
创建 /etc/sysctl.d/k8s.conf 文件，添加如下内容：
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
配置 hosts 文件
根据个人集群规划配置 /etc/hosts
192.168.99.101 node01
192.168.99.102 node02
192.168.99.103 node03
二、Master 节点部署
生成配置文件
kubeadm config print init-defaults ClusterConfiguration > kubeadm.yaml
修改配置文件
vim kubeadm.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: 192.168.99.101 # 配置 master 节点地址
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: node01 # 节点名
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers # 配置阿里云镜像地址
kind: ClusterConfiguration
kubernetesVersion: v1.18.0 # 配置 kubernetes 版本
networking:
dnsDomain: cluster.local
podSubnet: 10.244.0.0/16 # 配置 Pod 子网
serviceSubnet: 10.96.0.0/12
scheduler: {}
执行 kubeadm 初始化
kubeadm init --config kubeadm.yaml --ignore-preflight-errors=Swap
初始化后保存好最后一行和 join token 相关的日志，后面 Worker 节点加入集群会用到
kubeadm join 192.168.204.101:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:c8fc8a67017...5b09d8aa1104
根据日志中的要求执行如下命令：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
检查 Pod 的运行情况：
kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-7ff77c879f-5zv6l 1/1 Pending 0 43m
kube-system coredns-7ff77c879f-p94cx 1/1 Pending 0 43m
kube-system etcd-practice 1/1 Running 0 43m
kube-system kube-apiserver-practice 1/1 Running 0 43m
kube-system kube-controller-manager-practice 1/1 Running 0 43m
kube-system kube-flannel-ds-amd64-6vffj 1/1 Running 0 33m
kube-system kube-proxy-dnp4l 1/1 Running 0 43m
kube-system kube-scheduler-practice 1/1 Running 0 43m
发现 coredns 处于 Pending 状态，无法成功运行，这是因为集群还没有安装网络插件，接下来我们安装 Flannel
Flannel 网络插件安装
准备 kube-flannel-rbac.yml kube-flannel.yml 两个文件，国内被墙可能无法 wget 下来，这里直接手动准备文件，我是从本机用 SS 翻墙下载好 scp -r 到 Linux 服务器上的
kubectl apply -f kube-fannel-rbac.yml
kubectl apply -f kube-flannel.yml
(文末附 kube-flannel-rbac.yml kube-flannel.yml 两个文件)
Flannel 安装好后，检查 Pod 运行情况
kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-7ff77c879f-5zv6l 1/1 Running 0 43m
kube-system coredns-7ff77c879f-p94cx 1/1 Running 0 43m
kube-system etcd-practice 1/1 Running 0 43m
kube-system kube-apiserver-practice 1/1 Running 0 43m
kube-system kube-controller-manager-practice 1/1 Running 0 43m
kube-system kube-flannel-ds-amd64-6vffj 1/1 Running 0 33m
kube-system kube-proxy-dnp4l 1/1 Running 0 43m
kube-system kube-scheduler-practice 1/1 Running 0 43m
注意：coredns 一直 pending 的话，子节点加入就好了，因为主节点有 taints，无法调度
三、Worker 节点加入
worker 节点的环境配置参考 master 即可，只不过最后的 kubeadm 通过 join 而不是 Init 加入集群，加入集群的命令在上面 master 节点初始化集群后已经回显给出，在 worker 节点运行即可：
kubeadm join 192.168.204.101:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:c8fc8a67017...5b09d8aa1104 --ignore-preflight-errors=Swap
注意加上 --ignore-preflight-errors=Swap，否则可能会报错
可以加入 --v=2 命令查看 join 过程详情，便于排查故障
给 Node 打上 Worker 标签
kubectl label node node02 node-role.kubernetes.io/worker=worker
kubectl label node node03 node-role.kubernetes.io/worker=worker
NAME STATUS ROLES AGE VERSION
node01 NotReady master 8m22s v1.18.0
node02 NotReady worker 3m56s v1.18.0
node03 NotReady worker 3m54s v1.18.0
故障排除
1. 提示 [ERROR FileContent–proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1
解决方式：
echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
echo 1 > /proc/sys/net/bridge/bridge-nf-call-ip6tables
2. master 初始化时报 [kubelet-check] Initial timeout of 40s passed
解决方式：
swapoff -a # will turn off the swap
kubeadm reset
systemctl daemon-reload
systemctl restart kubelet
iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X # will reset iptables
这是在 Stack Overflow 上找到的解决方案：
3. worker 节点 join 时 [preflight] Running pre-flight checks 之后卡住，–v=2 输出过程日志发现：connect: no route to host
问题说明：iptables 防火墙问题
解决方式：
systemctl stop kubelet
systemctl stop docker
iptables --flush
iptables -tnat --flush
systemctl start kubelet
systemctl start docker
4. coredns 一直 pending
子节点加入就好了，因为主节点有 taints，无法调度
附
kube-flannel-rbac.yml
# Create the clusterrole and clusterrolebinding:
# $ kubectl create -f kube-flannel-rbac.yml
# Create the pod using the same namespace used by the flannel serviceaccount:
# $ kubectl create --namespace kube-system -f kube-flannel.yml
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
rules:
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
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']
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/v1beta1
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/v1beta1
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-amd64
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
- key: kubernetes.io/arch
operator: In
values:
- amd64
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.12.0-amd64
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:v0.12.0-amd64
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"]
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
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-arm64
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
- key: kubernetes.io/arch
operator: In
values:
- arm64
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.12.0-arm64
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:v0.12.0-arm64
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"]
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
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-arm
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
- key: kubernetes.io/arch
operator: In
values:
- arm
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.12.0-arm
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:v0.12.0-arm
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"]
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
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-ppc64le
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
- key: kubernetes.io/arch
operator: In
values:
- ppc64le
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.12.0-ppc64le
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:v0.12.0-ppc64le
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"]
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
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-s390x
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
- key: kubernetes.io/arch
operator: In
values:
- s390x
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.12.0-s390x
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:v0.12.0-s390x
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"]
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
参考
- K8S安装部署在centos7下 https://www.cnblogs.com/niewx5201314/p/11663137.html
- kubeadm join 超时 uploading crisocket: timed out waiting for the condition https://blog.csdn.net/gs80140/article/details/92798027
- kubeadm 安装kubetnetes(flannel) https://blog.csdn.net/qq_21816375/article/details/73691684