dockerW15.md

W15 20191217

Disclaimer: The doc isn't completed.

• W15 20191217
  • Environment
    • Prerequisite
    • My Configuration
  • Install Kubernetes
    • Disable Swap
    • Configure DNS Server
    • Install Docker
    • Install Kubelet, kubeadm and kubectl
  • Create Cluster with Kubeadm
    • Initialize Master Node
    • Configure Kubectl
    • Install Pod Network (flannel)
    • Join slave1, slave2 to cluster
    • Get Node Status
  • Reference
  • 雜記

Environment

Prerequisite

• deb/rpm-compatible OS
  • e.g., Ubuntu 16.04+, CentOS 7, Debian 9+, etc.
• Hardware
  • 2 CPUs or more on the control-plane node
  • 2 GB or more of RAM per machine
• Network
  • Full network connectivity among all machines in the cluster. A public or private network is fine.
  • Certain ports are open on your machines. See here for more details.
• Other
  • Unique hostname, MAC address, and product_uuid for every node. See here for more details.
  • Swap disabled

My Configuration

• All my VM machines are based on Ubuntu 16.04 LTS, running on the Google Cloud Platform.

Node	CPU cores	RAM	IP address
master	4	15G	-
slave1	2	7.5G	-
slave2	2	7.5G	-

Install Kubernetes

This doc is mainly for Ubuntu 16.04, the commands may differ if you're using other distro.

Disable Swap

• In order to run kubelet properly, you must disable swap on all the machines.

sudo swapoff -a // disable swap for all devices

sudo free -m // make sure swap is unused

Configure DNS Server

• Change the nameserver to 8.8.8.8 (Google Public DNS) for all the machines.

vi /etc/resolv.conf

Install Docker

• Install Docker on all the machines.
• This step could take a while...

apt-get update && apt-get install -y docker.io

Install Kubelet, kubeadm and kubectl

apt-get update && apt-get install -y apt-transport-https

curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF

apt-get update

apt-get install -y kubelet kubeadm kubectl

Create Cluster with Kubeadm

Initialize Master Node

• 10.244.0.0/16: flannel network

kubeadm init --apiserver-advertise-address <masterIP> --pod-network-cidr=10.244.0.0/16

• After executing this command, don't forget to save the command under Your Kubernetes master has initialized successfully!

Configure Kubectl

• Copy and paste the command in the previous step.

• Enable kubectl auto-complete feature

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

Install Pod Network (flannel)

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

Join slave1, slave2 to cluster

• After kubeadm init, there're command to join.
• If you miss that, run kubeadm token list.

kubeadm join --token <token> <masterIP:port>

Get Node Status

kubectl get nodes

kubectl get pods --all-namespaces

kubectl describe pods <podName> kube-flannel --namespace=kube-system // show detail

Reference

• Installing kubeadm - Kubernetes
• Creating a single control-plane cluster with kubeadm - Kubernetes
• How do I disable swap? - Ask Ubuntu

---

雜記

kubectl get pods // 先取得 Pod Name
kubectl exec <httpd_pod_name> -it -- /bin/sh

// 上述的例子中 Pod 內只有一個 Container，但如果今天 Pod 內有多個 container，需要在後方加上 -c <container_name>
kubectl exec <httpd_pod_name> -it -c <container_name> -- /bin/sh

• 書中的內容較舊，因此部份檔案可能需要修改
• 但老師有放修正後的檔案在 192.168.60.15/docker/k8s 資料夾中