Kubernetes Study Guide (2)- Using Kubeadm to build a cluster

Now that Kubernetes has been installed on each machine, let’s first build the Master machine

The cluster structures,

in`Master`Create a configuration file on the machine`kubeadm-init.yaml`

cat <<EOF > kubeadm-init.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.66wcf1rc5wk6637f            ## token is recommended not to use the default
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: "IPADDRESS"     # Intranet IP address
  bindPort: 6443            Port # API
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: master001
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  extraArgs: 
    advertise-address: "IPADDRESS"    ## Machine interconnection required
  certSANs:
  - "IPADDRESS"
  timeoutForControlPlane: 10m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: gcr.azk8s.cn/google_containers       # image repository source, here using Azure imageKind: ClusterConfiguration kubernetesVersion: v1.17.0The version number must be correct. As of the author, the latest version is 1.17.0Networking: dnsDomain: cluster.local serviceSubnet: 10.96.0.0/12 podSubnet: 192.168.0.0/24## Deploy Calico's Pod network segment
scheduler: {}
EOF
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The IPADDRESS in the above configuration file serves as a placeholder. You can run the following command to replace the IPADDRESS with the Intranet IP address (eth0 is read by default. If you specify it manually, please change it.)

ip=$(ifconfig eth0 | grep "inet" | awk '{print $2}')
sed -i "s/IPADDRESS/$ip/g" kubeadm-init.yaml
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Start the deployment

## Ignore swap, insufficient CPU
If you close swap, CPU >=2 can cancel ignore error
kubeadm init --config kubeadm-init.yaml --ignore-preflight-errors=NumCPU 
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If kubeadm init is repeated, kubeadm reset should be used to re-initialize it

The output

# kubeadm init --config kubeadm-init.yaml --ignore-preflight-errors=NumCPUW0109 08:51:56.532812 validation. Go :28] Cannot validate kube-proxy config-no validator is available for W0109 Validation. Go :28] Cannot validate kubelet config - no validator is available [init] Using Kubernetes version: v1.17.0# # # have slightly

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

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 172.17.50.23:6443 --token abcdef.66wcf1rc5wk6637f \
    --discovery-token-ca-cert-hash sha256:201961c9ccd44987f265b1a3d84de663332b50d0ecd2677a5b2be025416d1cea
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Continue to complete commands

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
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Note down the kubeadm join command and use it later on the Node machine

The installation`Calico`The network plugin

kubectl apply -f https://raw.githubusercontent.com/charSLee013/Kubernetes-learn/master/chapter02/calico.yaml
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The original address on the https://docs.projectcalico.org/v3.11/manifests/calico.yaml source file podSubnet is amended as 192.168.0.0/24 192.168.0.0/16 here

Make sure all pods are in the Running state

kubectl get pod --all-namespaces -o wide
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The output

NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES kube-system Calico-kube-controllers -648F4868b8-wmdlz 1/1 Running 0 69s 192.168.0.1 master001 <none> <none> kube-system Calico-node-lmkhv 1/1 Running 0 70s 172.17.50.23 master001 <none> <none> kube-system coreDNS-6cd559f5d5-2h4pb                   1/1     Running   0          2m38s   192.168.0.3    master001   <none>           <none>
kube-system   coredns-6cd559f5d5-6zl68 1/1 Running 0 2m38s 192.168.0.2 master001 <none> <none> kube-system etcd-master001 1/1 Running 0 2m51s 172.17.50.23 master001 < None > < None > kube-system kube-apiserver-master001 1/1 Running 0 2m51s 172.17.50.23 master001 <none> <none> kube-system kube-controller-manager-master001 1/1 Running 0 2m51s 172.17.50.23 master001 <none> <none> Kube-system kube-proxy-5kfjh 1/1 Running 0 2m38s 172.17.50.23 master001 <none> <none> kube-system Kube-scheduler-master001 1/1 Running 0 2m51s 172.17.50.23 master001 <none> <none>Copy the code

If you want`master`Also participate in the workload (optional)

For clusters initialized with kubeadm, pods are not scheduled to Master nodes for security reasons, meaning that Master nodes are not recommended to participate in workloads

# kubectl taint nodes master001 node-role.kubernetes.io/master-
node/master001 untainted
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Add nodes to the Kubernetes cluster

Install Docker, Kubelet kubeadm kubectl, etc

Add a command

kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash> \
## Define the node name, otherwise use hostname
--node-name=xxxxx
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To view`The node node`

# # the master machine
# kubectl get nodesNAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME master001 Ready master 11m v1.17.0 172.17.50.23 < None > CentOS Linux 7 (Core) 3.10.0-514.26.2.el7.x86_64 DOCker ://18.6.3 node1 Ready < None > 56s V1.17.0 172.17.50.24 < None > CentOS Linux 7 (Core) 3.10.0-514.26.2.el7.x86_64 docker://18.6.3 node2 NotReady <none> 22s V1.17.0 172.17.50.25 < None > CentOS Linux 7 (Core) 3.10.0-514.26.2.el7.x86_64 docker://18.6.3Copy the code

To check the token value, run the following command on the master node

If no token exists, run the kubeadm token create command to create one

# kubeadm token list

TOKEN                     TTL         EXPIRES                     USAGES                   DESCRIPTION                                                EXTRA GROUPS
<YOUR_TOKEN>  23h         2020-01-10T09:10:05+08:00   authentication,signing   <none>                                                     system:bootstrappers:kubeadm:default-node-token
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To check the hash value, run the following command on the master node

openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | \
   openssl dgst -sha256 -hex | sed 's/^.* //'
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other

Remove node

Execute on master

kubectl drain node1 --delete-local-data --force --ignore-daemonsets
kubectl delete node <node name>
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Execute on Node

kubeadm reset
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Test the DNS

Execute on master

# kubectl run curl --image=radial/busyboxplus:curl -it

kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.
If you don't see a command prompt, try pressing enter.
[ root@curl-69c656fd45-pg4pn:/ ]$
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And then execute

[root@curl-69c656fd45-pg4pn:/]$nslookup kubearntes.default Server: 10.96.0.10 Address 1: 10.96.0.10 kube - DNS. Kube - system. SVC. Cluster. The local nslookup: can't resolve 'kubearntes.default'## exitCopy the code

One-click deployment command

Execute on Master machine

If it is not installed, run the following command to install it
curl -sSL https://raw.githubusercontent.com/charSLee013/Kubernetes-learn/master/chapter01/kubernetes-centos-install.sh | bash

# # deployment
curl -sSL https://raw.githubusercontent.com/charSLee013/Kubernetes-learn/master/chapter02/kubeam-init-master.sh | bash
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Node machine

If it is not installed, run the following command to install it
curl -sSL https://raw.githubusercontent.com/charSLee013/Kubernetes-learn/master/chapter01/kubernetes-centos-install.sh | bash

Copy the join command from master
kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash> \
## Define the node name, otherwise use hostname
--node-name=xxxxx
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Kubernetes Study Guide (2)- Using Kubeadm to build a cluster