Kubernetesお勉強その1【準備】Shellスクリプトで(kubeadm+CRI-O)を構築

- 10月 31, 2021

Dockerは一通り遊んだので、今はやりのコンテナの本命kubernetesに挑戦してみようと考えた。まぁクラウドのGKEとかEKSとかAKSとかクラウドのやつを使えばかなり楽に立てられるんだけどVMで動かすことになるので課金が発生し、そのままクラウド破産につながると怖いので課金が発生しないローカルのVM環境で構築することにした。もともとHyper-VでDocker入のUbuntu20.04LTSイメージを作っているのでそいつを使用する前提です。DockerがKubernetesの推奨CRIから外れるらしいので今回はCRI-Oを利用することにしました。後、なんか複数回使う可能性があるかもしれんので簡易Shellスクリプトにしています。相変わらずヨワヨワなので参考サイトのコピペばかりです。コマンド一発でできるので何回か試行錯誤できそうです。

◆Version等

20.04.3 LTS (Focal Fossa)
Docker version 20.10.10, build b485636
docker-compose version 1.29.1, build c34c88b2
Version:  0.1.0
RuntimeName:  cri-o
RuntimeVersion:  1.22.0
RuntimeApiVersion:  v1alpha2
Client Version: version.Info{Major:"1", Minor:"22", GitVersion:"v1.22.3", GitCommit:"c92036820499fedefec0f847e2054d824aea6cd1", GitTreeState:"clean", BuildDate:"2021-10-27T18:41:28Z", GoVersion:"go1.16.9", Compiler:"gc", Platform:"linux/amd64"}
kubeadm version: &version.Info{Major:"1", Minor:"22", GitVersion:"v1.22.3", GitCommit:"c92036820499fedefec0f847e2054d824aea6cd1", GitTreeState:"clean", BuildDate:"2021-10-27T18:40:11Z", GoVersion:"go1.16.9", Compiler:"gc", Platform:"linux/amd64"}

◆構築手順

1.初期設定用Shellスクリプト

Shellスクリプトを実行すると設定完了後に再起動するのでターミナルを閉じて再接続が必要

$ sudo vi previous_setting.sh
------------------------
#/bin/bash

CMDNAME=`basename $0`

if [ $# -ne 4 ]; then
  echo "Usage: ${CMDNAME} hostipadress gatewayip hostname domain" 1>&2
  exit 1
fi

HOSTIP=$1     
GATEWAYIP=$2  
HOSTNAME=$3   
DOMAIN=$4     
NETWORK=$(echo ${GATEWAYIP} | sed -e "s/\.\([^.]*\)$/.0\/24/")

## Firewall port open
sudo ufw allow from ${NETWORK} to any port 6443
sudo ufw allow from ${NETWORK} to any port 10250
sudo ufw allow from ${NETWORK} to any port 10251
sudo ufw allow from ${NETWORK} to any port 10252
sudo ufw allow from ${NETWORK} to any port 8080
sudo ufw allow from ${NETWORK} to any proto tcp port 2379:2380
sudo ufw allow from ${NETWORK} to any proto tcp port 30000:32767

## Replace ip addr
sudo cp /dev/null /etc/netplan/00-installer-config.yaml

sudo tee /etc/netplan/00-installer-config.yaml <<EOF
# This is the network config written by 'subiquity'
network:
  ethernets:
    eth0:
      addresses:
      - ${HOSTIP}/24
      gateway4: ${GATEWAYIP}
      nameservers:
        addresses:
        - 8.8.8.8
        - 8.8.4.4
  version: 2
EOF

## Set hostname
sudo hostnamectl set-hostname ${HOSTNAME}.${DOMAIN}
sudo cp /dev/null /etc/hosts
sudo tee /etc/hosts <<EOF
127.0.0.1 localhost
127.0.0.1 ${HOSTNAME} ${HOSTNAME}.${DOMAIN}
127.0.1.1 ${HOSTNAME}

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
EOF

## Update install package
sudo apt update
sudo DEBIAN_FRONTEND=noninteractive apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" dist-upgrade

## swap off
sudo swapoff -a
sudo sed -i -e 's!/swap.img!#/swap.img!g' /etc/fstab

## Reflect setting
echo " Close your terminal please "
sudo netplan apply
sudo shutdown -r now
------------------------
$ sudo chmod 755 previous_setting.sh
$ sudo ./previous_setting.sh 192.168.0.100 192.168.0.1 kube-srv yourdomain.local

2.kubernetes準備用Shellスクリプト

OS再起動完了後に実行する。最後に出力されるTokenは忘れずにメモしておくこと

$ sudo vi kurbenetes_setting.sh
------------------------
#/bin/bash

USER=$(echo ${SUDO_USER:-$USER})
UID=$(echo ${SUDO_UID:-$SUDO_UID})
GID=$(echo ${SUDO_GID:-$SUDO_GID})
HOME=/home/${USER}
CMDNAME=`basename $0`

if [ $# -ne 4 ]; then
  echo "Usage: ${CMDNAME} nodetype(master or sub) mainnodeip mainnodehostname domain " 1<&2
  exit 1
fi

NODETYPE=$1
MASTERIP=$2
MASTERNAME=$3
DOMAIN=$4

# Check the following site to find out the latest version of Kubernetes.
# https://kubernetes.io/releases/notes/
OS=xUbuntu_20.04
VERSION=1.22
NETWORK=10.1.0.0/16

# Setting CRI-O
echo "deb https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/${OS}/ /" | sudo tee -a /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list
echo "deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/${VERSION}/${OS}/ /"  | sudo tee -a /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:${VERSION}.list
curl -L https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable:cri-o:${VERSION}/${OS}/Release.key | sudo apt-key add -
curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/${OS}/Release.key | sudo apt-key add -

sudo apt-get -y update
sudo apt-get install -y cri-o cri-o-runc

sudo systemctl daemon-reload
sudo systemctl start crio
sudo systemctl enable crio

# Install kubeadm
echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee -a /etc/apt/sources.list.d/kubernetes.list
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

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

# Setting kubeadm
echo 'KUBELET_EXTRA_ARGS=--cgroup-driver=systemd --container-runtime=remote --container-runtime-endpoint="unix:///var/run/crio/crio.sock"' | sudo tee /etc/default/kubelet
sudo systemctl daemon-reload
sudo systemctl restart kubelet

# Setting Node
mkdir -p ${HOME}/.kube
if [ "$NODETYPE" = "master" ]; then
  # Main node
  sudo kubectl taint nodes --all node-role.kubernetes.io/master-
  curl https://docs.projectcalico.org/manifests/calico.yaml -O
  cp -ap calico.yaml calico.yaml.org
  sed -i -e "s?192.168.0.0/16?${NETWORK}?g" calico.yaml
  sudo kubeadm init --cri-socket /var/run/crio/crio.sock --node-name ${MASTERNAME} --pod-network-cidr=${NETWORK}
  sudo cp -i /etc/kubernetes/admin.conf ${HOME}/.kube/config
  sudo chown ${UID}:${GID} ${HOME}/.kube/config
  kubectl apply -f calico.yaml
  kubectl get nodes
else
  # Sub node
  echo "\n${MASTERIP} ${MASTERNAME} ${MASTERNAME}.${DOMAIN}" | sudo tee -a /etc/hosts
fi

------------------------
$ sudo chmod 755 kurbenetes_setting.sh
$ sudo ./kurbenetes_setting.sh master 192.168.0.100 kube-srv yourdomain.local

◆参考サイト

これでまぁKubernetesのお勉強できる準備が整ったので、本格的にお勉強を開始していこうかなと企てています。次回はとりあえずネットワーク周りとかやっていこうと思ったりなんかしている。

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