前言
KIND环境介绍及启动(禁用默认的网络插件)请跳转到《KIND网络插件实验:使用bridge作为cni插件》
上文介绍了使用bridge作为KIND网络插件的方法,本文将使用flannel
KIND启动后由于没有网络插件,coredns无法被分配地址,所以没起来。禁用默认网络插件启动后的POD状况如下:
部署flannel
kubectl apply -f flannel-v0.14.0.yaml
YAML文件可以从flannel官网获得
# flannel-v0.14.0.yaml
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:v0.14.0
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:v0.14.0
command:
- /opt/bin/flanneld
args:
- --ip-masq=false
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: true
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
部署完成后会在节点的/etc/cni/net.d目录下生成flannel的配置文件
/etc/cni/net.d# cat 10-flannel.conflist
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
节点subset信息生成在节点的 /run/flannel/subnet.env 文件中
root@cluster1-control-plane:/run/flannel# cat subnet.env
FLANNEL_NETWORK=10.244.0.0/16
FLANNEL_SUBNET=10.244.0.1/24
FLANNEL_MTU=1450
FLANNEL_IPMASQ=false
部署完成后,kube-flannel以DaemonSet方式运行在master和worker节点上,但是coredns等仍旧有问题
通过kubectl describe查看:
… failed to find plugin “flannel” in path [/opt/cni/bin]
Warning FailedCreatePodSandBox 10s kubelet, cluster1-worker Failed to create pod sandbox: rpc error: code = Unknown desc = failed to setup network for sandbox “d9d1f4c592c10514313dec335bc24c6eb9c89903e59fa3db3a7f49696e1dd757”: failed to find plugin “flannel” in path [/opt/cni/bin]
需要下载CNI插件: CNI Plugins v0.8.7 (在1.0.0版本后CNI Plugins中没有flannel了,这是为什么?)
将压缩包放到master和worker的/opt/cni/bin目录下,并且解压
#将插件放到master,worker节点类似
sudo docker cp '/home/cni-plugins-linux-arm64-v0.8.7.tgz' aa7c807c9c4a:/opt/cni/bin/
sudo docker exec -it aa7c807c9c4a /bin/bash
root@cluster1-worker:/# cd /opt/cni/bin/
root@cluster1-worker:/opt/cni/bin# ls
cni-plugins-linux-arm64-v0.8.7.tgz host-local loopback portmap ptp
root@cluster1-worker:/opt/cni/bin# tar -xzvf cni-plugins-linux-arm64-v0.8.7.tgz
./
./macvlan
./flannel
./static
./vlan
./portmap
./host-local
./bridge
./tuning
./firewall
./host-device
./sbr
./loopback
./dhcp
./ptp
./ipvlan
./bandwidth
完成后,集群上的pod都正常运行
进入worker节点可以看到:
cni0网桥和vtep设备flannel.1 (flannel.[VNI],默认为flannel.1) ,mtu 1450表示使用vxlan进行节点间通信
2022-06-01补充:经评论区技术大佬提醒,新版在flannel的yaml部署文件中增加了将二进制文件复制到宿主机/opt/cni/bin的操作,具体yaml文件见官网。yaml文件对应片段如下:
验证
通过上述部署操作,KIND (k8s)环境网络如下
主机 | 主机地址 | POD子网 |
---|---|---|
master node | 172.18.0.3 | 10.244.0.0/24 |
worker node | 172.18.0.2 | 10.244.1.0/24 |
部署测试的deployment,通过测试ip分配正常
进入master上的pod(10.244.0.2),ping worker上的pod(10.244.1.10)
/ # ping 10.244.1.10
PING 10.244.1.10 (10.244.1.10): 56 data bytes
64 bytes from 10.244.1.10: seq=0 ttl=62 time=0.516 ms
64 bytes from 10.244.1.10: seq=1 ttl=62 time=0.480 ms
^C
--- 10.244.1.10 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.480/0.498/0.516 ms
/ # traceroute 10.244.1.10
traceroute to 10.244.1.10 (10.244.1.10), 30 hops max, 46 byte packets
1 10.244.0.1 (10.244.0.1) 0.057 ms 0.029 ms 0.024 ms
2 10.244.1.0 (10.244.1.0) 0.025 ms 0.021 ms 0.017 ms
3 10.244.1.10 (10.244.1.10) 0.015 ms 0.013 ms 0.008 ms
进入worker上的pod,查看路由表:
目的地址是10.244.0.0/16(k8s网络)的包,发往网关10.244.1.1。10.244.1.1是worker节点上的网关cni0的地址。
查看worker节点上的路由表:
目的地址是10.244.0.0/24 网段(master上pod的子网)的包,发往master的vtep设备flannel.1(10.244.0.0)
master节点的flannel.1(10.244.0.0)的MAC地址已经维护在worker节点flannel.1的fdb中
上图中56:a7:fb:b4:49:b2就是master节点flannel.1的MAC地址
总结
k8s网络之Flannel网络中结尾部分讲的很好,直接拿过来引用了
总的来说,flannel更像是经典的桥接模式的扩展。我们知道,在桥接模式中,每台主机的容器都将使用一个默认的网段,容器与容器之间,主机与容器之间都能互相通信。要是,我们能手动配置每台主机的网段,使它们互不冲突。接着再想点办法,将目的地址为非本机容器的流量送到相应主机:如果集群的主机都在一个子网内,就搞一条路由转发过去;若是不在一个子网内,就搞一条隧道转发过去。这样以来,容器的跨网络通信问题就解决了。而flannel做的,其实就是将这些工作自动化了而已。
后续
查看flannel的日志
client_config.go:608] Neither --kubeconfig nor --master was specified. Using the inClusterConfig. This might not work.
貌似使用也没有什么影响
如果要增加–kubeconfig启动参数,需要如下:
# 进到master节点
# 注意:我这个集群的apiserver地址是172.18.0.3,集群name是cluster1
# 切换到需要生成配置文件的目录,比如我这里是/usr/local/flannel-wf/
kubectl config set-cluster cluster1 --kubeconfig=flannel.conf --embed-certs --server=https://172.18.0.3:6443 --certificate-authority=/etc/kubernetes/pki/ca.crt
kubectl config set-credentials flannel --kubeconfig=flannel.conf --token=$(kubectl get sa -n kube-system flannel -o jsonpath={
.secrets[0].name} | xargs kubectl get secret -n kube-system -o jsonpath={
.data.token} | base64 -d)
kubectl config set-context cluster1 --kubeconfig=flannel.conf --user=flannel --cluster=cluster1
# 将生成的flannel.conf复制到其他节点
# cat flannel.conf
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: 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
server: https://172.18.0.3:6443
name: cluster1
contexts:
- context:
cluster: cluster1
user: flannel
name: cluster1
current-context: ""
kind: Config
preferences: {
}
users:
- name: flannel
user:
token: eyJhbGciOiJSUzI1NiIsImtpZCI6ImNPbkpfSkFlVTBWa2RfVjVqZ1d6LXNPUDk1VldSY2NVb1M0empJS3hQQ1EifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJmbGFubmVsLXRva2VuLXM0ajI5Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImZsYW5uZWwiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiI2NzFmNDNiZS0zZjYzLTQwMjktOTQ4Ny1lYWZjZDhmMmQ5ZmIiLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06Zmxhbm5lbCJ9.kHo7v-sKNDiRtOceIcngXzpY83Tp1Fnnyo6ueaDoSffAe3dBqW_W2ExU6F99DpujM6mnmlIUXXAq0Nbv6eANagK4fwGVD20so-mM9bVsOVJP74UufQh9oYhT77BHMMfryW7n3Q-ujerSswSvq5XFCax1WAOhQXYitIETIkD3ePKf5_HteRLLjvCTC2yuFNuYK3ZwpcOdypfvm28p_K6Ly0YW1EjOcN7UJ0FGMTAqJ71jeAT2OlVNxstuhNuMNOIfgyhYZ8lppxPuqh073EjTi0Ss59fRpFJCzbaEsEiIAwiel_hVw8xkNR7zCRvKQMlL5lmF-juMCXeoHeBKPcXwLQ
修改flannel部署yaml文件,仅修改DaemonSet,增加启动参数–kubeconfig,配置文件通过宿主机目录挂载到Pod目录。
其他ClusterRole、SA、ConfigMap等都不改动
---
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:v0.14.0
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:v0.14.0
command:
- /opt/bin/flanneld
args:
- --ip-masq=false
- --kube-subnet-mgr
- --kubeconfig-file=/usr/local/flannel-wf/flannel.conf # 增加启动参数!
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: true
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/
- name: kube-cfg ##
mountPath: /usr/local/flannel-wf # 从宿主机挂载
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
###
- name: kube-cfg
hostPath:
path: /usr/local/flannel-wf # 宿主机目录
重新部署后,查看启动日志就没有这行提示了
$ sudo kubectl logs -f kube-flannel-ds-dn59l -n kube-system
I0426 07:06:52.970794 1 main.go:520] Determining IP address of default interface
I0426 07:06:52.971228 1 main.go:533] Using interface with name eth0 and address 172.18.0.3
I0426 07:06:52.971252 1 main.go:550] Defaulting external address to interface address (172.18.0.3)
I0426 07:06:53.676497 1 kube.go:116] Waiting 10m0s for node controller to sync
I0426 07:06:53.676660 1 kube.go:299] Starting kube subnet manager
I0426 07:06:54.676663 1 kube.go:123] Node controller sync successful
I0426 07:06:54.676715 1 main.go:254] Created subnet manager: Kubernetes Subnet Manager - cluster1-control-plane
I0426 07:06:54.676724 1 main.go:257] Installing signal handlers
I0426 07:06:54.676988 1 main.go:392] Found network config - Backend type: vxlan
I0426 07:06:54.677234 1 vxlan.go:123] VXLAN config: VNI=1 Port=0 GBP=false Learning=false DirectRouting=false
I0426 07:06:54.873344 1 main.go:315] Changing default FORWARD chain policy to ACCEPT
I0426 07:06:54.873695 1 main.go:323] Wrote subnet file to /run/flannel/subnet.env
I0426 07:06:54.873720 1 main.go:327] Running backend.
I0426 07:06:54.873758 1 main.go:345] Waiting for all goroutines to exit
I0426 07:06:54.873809 1 vxlan_network.go:59] watching for new subnet leases