ubuntu v21.04安裝k8s(kubernetes) v1.21.2

終於略過前一篇說明的防火牆的阻擋，今天來記錄ubuntu v21.04安裝k8s(kubernetes) v1.21.2安裝成功的步驟

ubuntu v21.04安裝k8s(kubernetes) v1.21.2遇到的問題及處理方式

1.安裝套件apt-transport-https、ca-certificates、curl

sudo apt-get update
遇到網站憑證問題，故加上--allow....設定
sudo apt-get update --allow-unauthenticated --allow-insecure-repositories
sudo apt-get install -y apt-transport-https ca-certificates curl

2.安裝kubelet kubeadm kubectl
1) 設定https://packages.cloud.google.com網站憑證

curl -fsSL https://packages.cloud.google.com/apt/doc/apt-key.gpg | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/kubernetes-archive-keyring.gpg > /dev/null

2) 設定kubernetes安裝apt

echo "deb [arch=amd64 trusted=yes allow-insecure=yes allow-weak=yes allow-downgrade-to-insecure=yes check-valid-until=no] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
或
echo "deb [arch=amd64 trusted=yes allow-insecure=yes allow-weak=yes allow-downgrade-to-insecure=yes check-valid-until=no] https://packages.cloud.google.com/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

註:出現如下訊息

E: 無法取得 https://apt.kubernetes.io/dists/kubernetes-xenial/main/binary-amd64/Packages，Certificate verification failed: The certificate is NOT trusted. The certificate chain uses insecure algorithm. Could not handshake: Error in the certificate verification. [IP: 34.107.204.206 443]
E: Some index files failed to download. They have been ignored, or old ones used instead.

解法: vi etc/apt/apt.conf.d/99verify-peer.conf，若為true，改為false

Acquire { https::Verify-Peer false }

3.swap改由k8s控管，故要關閉swap

swapoff -a
sed -e '/swap/ s/^#*/#/' -i /etc/fstab
free -m

4.初始master，以建立k8s cluster
1) 建置指令
sudo kubeadm init –-pod-network-cidr 10.5.0.0/16 -–v=5

終於看到成功的畫面
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 10.0.2.15:6443 –token xyovgm.p0z428rgi7flwi6a \
–discovery-token-ca-cert-hash sha256:8893a38d20d191ad63714b030926cb904bc468290710237d49d6d11f14a92b48

2)此段需執行

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

3)加node使用此token請記錄下來

kubeadm join 10.0.2.15:6443 –token xyovgm.p0z428rgi7flwi6a \
–discovery-token-ca-cert-hash sha256:8893a38d20d191ad63714b030926cb904bc468290710237d49d6d11f14a92b48

5.設定自動補齊功能

sudo apt-get install -y bash-completion
echo “source /etc/bash_completion" >> ~/.bashrc
echo “source <(kubectl completion bash)" >> ~/.bashrc
source <(kubectl completion bash)

6.若無足夠主機建置

kubectl taint nodes --all node-role.kubernetes.io/master-

收到結果: node/ubuntu-virtualbox untainted

7.列出node數
kubectl get nodes
kubectl get nodes -o wide
收到結果: (STATUS為NOT Ready)

8.列出node內容
kubectl describe node ubuntu-virtualbox

9.設定overlay網路: 用flannel
1)wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

2)vi kube-flannel.yml

修改
net-conf.json: |
{
“Network": “10.5.0.0/16″,
“Backend": {
“Type": “vxlan"
}
}

其中Network值需同kubeadm init時設定的pod-network-cidr一致

3)建立overlay網路
kubectl apply -f kube-flannel.yml
如下圖結果:

4)查看pod狀況
kubectl get pods –all-namespaces
如下圖結果:

註: flannel image因公司擋quay.io這個網址無法下載，故此步驟一直停在image Err的STATUS，後來先在外部將image拉下來，再上傳到內部server，步驟如下
外部電腦:

docker pull quay.io/coreos/flannel:v0.14.0-amd64
docker image save flannel -o flannel.tar

-- 若已run在container內可以用此方式
docker export --output="flannel.jar" flannel

內部Server:

docker load -i flannel.tar

5) 列出node數
kubectl get nodes -o wide
收到結果: (STATUS為Ready)

10.建立nginx pod

kubectl run nginx --image=nginx

註: kubernets 1.18以後請用以下指令

kubectl create deployment nginx-web --image=nginx

這樣才會連deployment及replicaset一同建立，以kubectl get all查看

kubectl get pods -o wide
如下圖結果:

11.改nodeport

kubectl get deployment -o yaml nginx > nginx.yaml
kubectl expose -f nginx.yaml --port=80 --type NodePort
或
kubectl edit svc nginx

12.查看對應的服務port
kubectl get svc
如下圖結果:

13.佈署一個nginx deployment
參考網址: https://kubernetes.io/zh/docs/tasks/run-application/run-stateless-application-deployment/

1) vi nginx_deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
spec:
selector:
matchLabels:
app: nginx
replicas: 2 # tells deployment to run 2 pods matching the template
template:
metadata:
labels:
app: nginx
spec:
containers:
– name: nginx
image: nginx:latest
ports:
– containerPort: 80