雲端虛擬機 Ubuntu 20.04 安裝 Kubernetes

之前都是在VM測試用Ubuntu 18.04 快速用 apt 安裝，但發現 20.04 沒有這麼順利，所以這邊就簡單照網路操作安裝，順便紀錄一下。

安裝 K8S

安裝kubelet, kubeadm and kubectl

sudo apt update
sudo apt -y install curl apt-transport-https
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list


sudo apt update
sudo apt -y install vim git curl wget kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

確認結果

1	kubectl version --client && kubeadm version

關掉swap

1 2	sudo sed -i '/ swap / s/^$.*$$/#\1/g' /etc/fstab sudo swapoff -a

設定 kernel modules

# Enable kernel modules
sudo modprobe overlay
sudo modprobe br_netfilter

# Add some settings to sysctl
sudo tee /etc/sysctl.d/kubernetes.conf<<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

# Reload sysctl
sudo sysctl --system

確認執行結果

1	lsmod \| grep br_netfilter

安裝 Container runtime

docker

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# Add repo and Install packages
sudo apt update
sudo apt install -y curl gnupg2 software-properties-common apt-transport-https ca-certificates

## 上下面這段要分開複製執行
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt update
sudo apt install -y containerd.io docker-ce docker-ce-cli

# Create required directories
sudo mkdir -p /etc/systemd/system/docker.service.d

# Create daemon json config file
sudo tee /etc/docker/daemon.json <<EOF
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF

# Start and enable Services
sudo systemctl daemon-reload 
sudo systemctl restart docker
sudo systemctl enable docker

啟用 kubelet

1	sudo systemctl enable kubelet

pull 相關 kubernetes image 元件

1	sudo kubeadm config images pull

kubernetes-master 初始化 kubernetes 網路

kubernetes-master 需要做，worker跳過
kubernetes-master 需要做，worker跳過
kubernetes-master 需要做，worker跳過

# calic 的網路範圍，但我後來失敗改用flannel
# sudo kubeadm init \
  --pod-network-cidr=192.168.0.0/16
# flannel IP範圍是  10.244.0.0 /16
sudo kubeadm init --pod-network-cidr=10.244.0.0/16

The screenshot below shows that the initialization was successful. We have also added a flag to specify the pod network with the IP 10.244.0.0, It’s the default IP that the kube-flannel uses. We will discuss more on the pod network in the next step.

這邊有失敗的話，可以執行kubeadm reset重設定。再重新執行

參考:初始化 Kubernetes 问题（端口占用）_u013004700的专栏-CSDN博客_k8s端口占用

結果下面會顯示

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 192.168.100.11:6443 --token a3egpo.22u4srzgnrmoaxfe \
        --discovery-token-ca-cert-hash sha256:ca6ab702a4247c0d7dd0daf040e9c53d90b8e5c3085dada496bec7ec4e98ed55

kubectl 連線設定

kubectl 連線設定套用

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mkdir -p $HOME/.kube
sudo cp -f /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

可以看到安裝完某些服務Pendding

查加 worker1 指令

忘記怎麼加可以下

1	kubeadm token create --print-join-command

會顯示加 worker指令

接下來要加 worker 指令

加入 bash auto-completion

1	echo 'source <(kubectl completion bash)' >>~/.bashrc

重新 ssh 進來就可以正常使用。

參考:bash auto-completion on Linux | Kubernetes

怎麼移除 worker

Master

# 停用 node 掉度
kubectl drain k8s-worker1 --delete-local-data --force --ignore-daemonsets
# 刪掉 node(worker)
kubectl delete node k8s-worker1

Worker

1	sudo kubeadm reset

參考:

安裝 K8S 網路套件(calic)

建議使用IP 範圍選172開頭，我最後選擇flannel ，跑網路這一快才成功。因為我IP是10開頭，不確定是不是因為這樣撞到IP，所以我才換flannel。

1 2	kubectl create -f https://docs.projectcalico.org/manifests/tigera-operator.yaml kubectl create -f https://docs.projectcalico.org/manifests/custom-resources.yaml

flannel

參考How to Install and Use Kubernetes on Ubuntu 20.04 • CloudSigma

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kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml

可以查看結果