1. Modify the local/etc/hosts file
# Add (*) to / etc/hosts file
cat <<EOF >> /etc/hosts 172.26.48.4 k8s-master 172.26.48.5 k8s-node1 172.26.135.94 k8s-node2 EOF
2. CentOS 7 Configuration of Domestic Ali Cloud Mirror Source
# Replace (>) with / etc/yum.repos.d/kubernetes.repo file
cat <<EOF > /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/ enabled=1 gpgcheck=1 repo_gpgcheck=1 gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg EOF
3. Close SELinux to allow the container to interact with the native file system.
setenforce 0
setenforce: SELinux is disabled
systemctl daemon-reload
4. Modify Network Open Bridge Network Support for (RHEL/CentOS 7) Systems only
cat <<EOF > /etc/sysctl.d/k8s.conf net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 EOF
sysctl -p /etc/sysctl.d/k8s.conf
sysctl --system
5. Shut down swap - there are problems with not closing the configuration node or configuring the master
swapoff -a
6. Install ebtables ethtool, otherwise an error will occur when kubeadm init is executed later
yum install ebtables ethtool -y
# Then modify the current kernel status. This file appears only after the Docker installation is successful.
echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
7. Install kubelet, kubeadm, kubectl
yum install -y kubelet kubeadm kubectl yum install -y kubelet-1.14.2 kubeadm-1.14.2 kubectl-1.14.2
systemctl enable kubelet && systemctl start kubelet
8. Mirror preparation
kubernetes service startup relies on many mirrors, but these mirrors can't be downloaded if they don't turn over the wall in China. Here we can go to Docker Hub to download the image substitution of the specified version. After downloading, we can use docker tag. The command can be changed to a mirror of the specified name.
kubeadm config images list
I0524 22:03:10.774681 19610 version.go:96] could not fetch a
Kubernetes version from the internet: unable to get URL
"https://dl.k8s.io/release/stable-1.txt": Get
https://dl.k8s.io/release/stable-1.txt: net/http: request canceled
while waiting for connection (Client.Timeout exceeded while awaiting
headers) I0524 22:03:10.774766 19610 version.go:97] falling back to
the local client version: v1.14.2 k8s.gcr.io/kube-apiserver:v1.14.2
k8s.gcr.io/kube-controller-manager:v1.14.2
k8s.gcr.io/kube-scheduler:v1.14.2 k8s.gcr.io/kube-proxy:v1.14.2
k8s.gcr.io/pause:3.1 k8s.gcr.io/etcd:3.3.10 k8s.gcr.io/coredns:1.3.1
9. Create the file setup_image.sh, write scripts to download the image in batches, and modify the image tag to match google's k8s image name.
#!/bin/bash
# Define an array of mirror sets
images=(
kube-apiserver:v1.14.2
kube-controller-manager:v1.14.2
kube-scheduler:v1.14.2
kube-proxy:v1.14.2
pause:3.1
etcd:3.3.10
)
# Loop download images from domestic Docker image library https://hub.docker.com
for img in ${images[@]};
do
# Download Mirrors from Domestic Sources
docker pull mirrorgooglecontainers/$img
# Change the image name
docker tag mirrorgooglecontainers/$img k8s.gcr.io/$img
# Delete the source image
docker rmi mirrorgooglecontainers/$img
#
echo '================'
done
# One can't be found in Docker Hub. Change to a download warehouse.
docker pull coredns/coredns:1.3.1
docker tag coredns/coredns:1.3.1 k8s.gcr.io/coredns:1.3.1
docker rmi coredns/coredns:1.3.1
10. Common commands of kubeadm
# Start a Kubernetes master node [root@k8s-master deploy]# kubeadm init # Start a Kubernetes worknode and add it to the cluster [root@k8s-master deploy]# kubeadm join # Update a Kubernetes cluster to a new version [root@k8s-master deploy]# kubeadm upgrade # If you initialize the cluster with v1.7.x or lower versions of kubeadm, you need to configure the cluster to use the kubeadm upgrade command [root@k8s-master deploy]# kubeadm config # Managing tokens used by kubeadm join [root@k8s-master deploy]# kubeadm token # Rebuild link Token [root@k8s-master deploy]# kubeadm token create --print-join-command # View the list of Token s that have not expired [root@k8s-master deploy]# kubeadm token list # Restore any changes made to the host by kubeadm init or kubeadm join [root@k8s-master deploy]# kubeadm reset # Query all pod s [root@k8s-master deploy]# kubectl get pod -A -o wide # Query all nodes [root@k8s-master deploy]# kubectl get nodes -o wide # View the k8s Problem Node Log [root@k8s-master deploy]# journalctl -f -u kubelet # View namespaces [root@k8s-master deploy]# kubectl get namespace
11. Initialize master (normal)
Kubeadm init -- pod-network-cidr= <pod network IP address/subnet mask> -- kubernetes-version= <k8s version>
kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.14.2
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 172.26.48.4:6443 --token yx9yza.rcb08m1giup70y63 \
--discovery-token-ca-cert-hash sha256:f6548aa3508014ac5dab129231b54f5085f37fe8e6fc5d362f787be70a1a8a6e
[root@k8s-master deploy]#
11.1. Errors in initializing master
[root@alimaster k8s]# kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.14.2
[init] Using Kubernetes version: v1.14.2
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 19.03.0-beta5. Latest validated version: 18.09
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR NumCPU]: the number of available CPUs 1 is less than the required 2
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
This is because the cup core is not enough, if the test can be ignored
kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.14.2 --ignore-preflight-errors=NumCPU
12. After the initialization Master is completed, we use the command kubectl get node to view the cluster node information, but you will find that there is no Node information, but the error is as follows:
[root@k8s-master deploy]# kubectl get pods The connection to the server localhost:8080 was refused - did you specify the right host or port?
13. The reason for this is that the log prompt step in init was not executed.
mkdir -p $HOME/.kube cp -i /etc/kubernetes/admin.conf $HOME/.kube/config chown $(id -u):$(id -g) $HOME/.kube/config
[root@k8s-master deploy]# kubectl get node NAME STATUS ROLES AGE VERSION k8s-master NotReady master 9m8s v1.14.2 [root@k8s-master deploy]# [root@k8s-master deploy]# kubectl get pod -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-fb8b8dccf-8xbcf 0/1 Pending 0 10s kube-system coredns-fb8b8dccf-ztxxg 0/1 Pending 0 10s kube-system kube-proxy-kcvph 1/1 Running 0 9s [root@k8s-master deploy]#
14. Installing pod network add-ons
kubernetes provides a variety of network component options, including Calia, Canal, Flannel, Kube-router, Romana, Weave Net can be used, specific use can refer to (3/4) installation of pod network to operate, here we choose Flannel as the network component.
Note: In order for Flannel to work properly, you need to add the pod-network-cidr=10.244.0.0/16 parameter to execute the kubeadm init command. Flannel works on amd64, arm, arm64 and ppc64le, but you have to manually download and replace AMD64 with other platforms except amd64.
# View the distribution information of the current system [root@k8s-master deploy]# lsb_release -a LSB Version: :core-4.1-amd64:core-4.1-noarch Distributor ID: CentOS Description: CentOS Linux release 7.5.1804 (Core) Release: 7.5.1804 Codename: Core [root@k8s-master deploy]# [root@k8s-master deploy]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml [root@k8s-master deploy]# [root@k8s-master deploy]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml [root@k8s-master deploy]# # You need to wait a little while. Running is the only way to check the status. [root@k8s-master deploy]# kubectl get pod -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-fb8b8dccf-8xbcf 1/1 Running 0 2m8s kube-system coredns-fb8b8dccf-ztxxg 1/1 Running 0 2m8s kube-system etcd-k8s-master 1/1 Running 0 81s kube-system kube-apiserver-k8s-master 1/1 Running 0 81s kube-system kube-controller-manager-k8s-master 1/1 Running 0 74s kube-system kube-flannel-ds-amd64-hk4wt 1/1 Running 0 51s kube-system kube-proxy-kcvph 1/1 Running 0 2m7s kube-system kube-scheduler-k8s-master 1/1 Running 0 69s [root@k8s-master deploy]#