Kubernetes: Using Kubeadm to build a node

This is the sixth day of my participation in the August More text Challenge. For details, see: August More Text Challenge

1. Preparation

1. Check the environment

Swapoff -a // Disable swap setenforce 0 // Temporarily disable selinuxCopy the code

The following contents cannot be the same for each machine

Sudo cat/sys/class/dmi/id/product_uuid / / each machine at the same uuid cannot ifconfig - a / / IP cannot be the sameCopy the code

2. Open the port

3. Allow iptables to check bridge traffic

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF
 
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sudo sysctl --system
Copy the code

2. Install

1. Install kubeadm, Kubectl, kubelet

Add mirror cat < < EOF | sudo tee/etc/yum repos. D/kubernetes. '[kubernetes] name = kubernetes baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=0 repo_gpgcheck=0 EOF # Sudo setenforce 0 sudo sed -i 's/^ SELinux =enforcing$/ SELinux =permissive/' sudo setenforce 0 sudo sed -i 's/^ SELinux =enforcing$/ SELinux =permissive/' /etc/selinux/config sudo yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes sudo systemctl enable Kubeadm version kubectl version --client kubelet --versionCopy the code

If the following information is displayed, the installation is successful and the installed version is visible.

2. Install the plug-in

yum -y install socat conntrack-tools
Copy the code

3. Change the docker group to systemd

Docker needs to be installed in advance

sudo mkdir /etc/docker
cat <<EOF | sudo tee /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF
 
sudo systemctl enable docker
sudo systemctl daemon-reload
sudo systemctl restart docker
Copy the code

The above steps can not be modified, but there will be a warning.

4. K8s pull the required mirror

The kubeadm config images pull command can be used to download the image, but there is a high probability that the connection will fail, so use the Ali image command!

If v1.21.0 is used, the statement can be the same as the owner, otherwise, please pull it according to the above command.

Docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.21.1 docker pull Registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.21.1 docker pull Registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.21.1 docker pull Registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.21.1 docker pull Registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.4.1 docker pull Registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.13-0 docker pull coredns/coredns: 1.8.0 comes withCopy the code

When installing k8S, the image with the prefix k8s.gcr. IO will be obtained by default, so change the name of the image downloaded above.

Docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.21.1 k8s. GCR. IO/kube - apiserver: v1.21.1 Docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.21.1 k8s. GCR. IO/kube - proxy: v1.21.1 docker The tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.21.1 K8s. GCR. IO/kube - controller - manager: v1.21.1 docker tag Registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.21.1 k8s. GCR. IO/kube - the scheduler: v1.21.1 docker tag Registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.4.1 k8s. GCR. IO/pause: 3.4.1 track docker tag coredns/coredns: 1.8.0 comes with K8s. GCR. IO/coredns/coredns: v1.8.0 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.4.13-0 K8s. GCR. IO/etcd: 3.4.13-0Copy the code

The above steps are the same as the master installation.

5. Join the master

Modifying a Host Mapping

vi /etc/hosts
Copy the code

Executing the following command is provided for master init

Kubeadm join 192.168.18.15:6443 --token ry0rwa.oly8kisb7ruceenx --discovery-token-ca-cert-hash sha256:16928607989901f182d2f835fb12f450de6bd9e7571b84bf7a93408af917d5e3Copy the code

Change the kubelet startup group to systemd. If the kubelet startup group is already systemd, do not change the value

vi /var/lib/kubelet/config.yaml
Copy the code

If the login fails, the token may be invalid. You can run kubeadm token create to obtain a new token.

6. Specify the configuration file

export KUBECONFIG=/etc/kubernetes/kubelet.conf
Copy the code

Remember that flannel does not need to be installed for Nodes

7. Verify

kubectl get nodes
Copy the code

If the following words appear, it will be successful.

Attention!! In master and Node installations, file downloads fail and errors are reported. The most typical is the master /opt/cni/bin file download often failed if encountered this error. So need many times next time, or directly redo the system, many times to download, until the file download success!!