Run a Kubernets cluster on Ubunt

2021-05-31 本文已影响0人 Yoke_336e

The preparatory work

Close the swap partion
We can use sudo vim /etc/fstab to modify.Comment out the line swap.Then reboot server.We can use free -h to verify success.
Configure keyless login
1. Use ssh-keygen to initialize the local public and private keys on the master and worker nodes
2. Use ssh-copy-id to send the master local public key to the worker.I use ssh-copy-id -i .ssh/id_rsa.pub yoke@192.168.139.140 to send.
3. We can use ssh yoke@192.168.139.140 to try connecting to see if you need a password.

Install the docker

Just a command.sudo apt install docker.io.We need to do some configuration for Docker.

sudo vim /etc/docker/daemon.json.copy the following content into the json file.
{
  "registry-mirrors": [
    "https://dockerhub.azk8s.cn",
    "https://reg-mirror.qiniu.com",
    "https://quay-mirror.qiniu.com"
  ],
  "exec-opts": [ "native.cgroupdriver=systemd" ]
}

Then we must reboot docker.sudo systemctl daemon-reload && sudo systemctl restart docker

Install kubernets

First,we use the following commands to install kubernets tools.

apt-get update && apt-get install -y apt-transport-https
curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add - 
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y kubelet kubeadm kubectl

The master and worker need to do all of the above operations.

Config master node

Bootstrap master node

We must as root before we execute the following commands.First,we can use kubeadm init to bootstrap master node.But domestic cannot pull some mirror image, so using --image-repository to configure the domestic source.The --apiserver-advertise-address points to the master node ip address.--pod-network-cidr is used to config flannel network.At the same time,we can use kubeadm config images list to list all required images.

kubeadm init --apiserver-advertise-address=192.168.139.140 --image-repository registry.aliyuncs.com/google_containers --pod-network-cidr=10.244.0.0/16

However,the above command may report the following error.This is because there is no the coredns image on Aliyun.We had to manually change the source for the download.But the downloaded version must be correspond to the Kubernets version.

error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR ImagePull]: failed to pull image registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0: output: Error response from daemon: pull access denied for registry.aliyuncs.com/google_containers/coredns/coredns, repository does not exist or may require 'docker login': denied: requested access to the resource is denied

We can use kubeadm config images list to list all required images.

k8s.gcr.io/kube-apiserver:v1.21.1
k8s.gcr.io/kube-controller-manager:v1.21.1
k8s.gcr.io/kube-scheduler:v1.21.1
k8s.gcr.io/kube-proxy:v1.21.1
k8s.gcr.io/pause:3.4.1
k8s.gcr.io/etcd:3.4.13-0
k8s.gcr.io/coredns/coredns:v1.8.0

Then docker pull registry.cn-beijing.aliyuncs.com/dotbalo/coredns:1.8.0 is used to download the coredns.,docker tag registry.cn-beijing.aliyuncs.com/dotbalo/coredns:1.8.0 registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0 is used to unify.
Finaly run kubeadm init --apiserver-advertise-address=192.168.139.141 --image-repository registry.aliyuncs.com/google_containers --pod-network-cidr=10.244.0.0/16.If all is well, the following should appear.

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 192.168.139.141:6443 --token 1t19hg.gtdbd7exc6lue4e2 \
    --discovery-token-ca-cert-hash sha256:801877496bf306b16f9af651907f1b739918b87f1cffb13cedb58092873e168e

As indicated above, we need to execute：export KUBECONFIG=/etc/kubernetes/admin.conf.

Deploy the Flannel network

It also just a command.kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
At this point, the configuration of the master node is complete.

Config worker node

Executes an instruction that was just displayed after the master node was started.

kubeadm join 192.168.139.141:6443 --token 1t19hg.gtdbd7exc6lue4e2 \
    --discovery-token-ca-cert-hash sha256:801877496bf306b16f9af651907f1b739918b87f1cffb13cedb58092873e168e

If the log is as follows, the configuration of the worker node is successful.

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

Finally, on the master node, we can verify the success by executing kubectl get nodes.

NAME      STATUS   ROLES                  AGE   VERSION
master    Ready    control-plane,master   12m   v1.21.1
worker1   Ready    <none>                 89s   v1.21.1