12 Kubernetes

v1.23.5

swapoff -a

cat <<EOF | tee /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter

cat <<EOF | tee /etc/sysctl.d/99-kubernetes-cri.conf
net.bridge.bridge-nf-call-iptables  = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF

sysctl --system

apt update
apt install -y apt-transport-https ca-certificates curl software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -

add-apt-repository \
    "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
    $(lsb_release -cs) \
    stable"

apt update && apt install containerd.io
systemctl status containerd

mkdir -p /etc/containerd
containerd config default | tee /etc/containerd/config.toml
systemctl restart containerd

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

apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"

apt update
apt install -y kubeadm kubelet kubectl kubernetes-cni

apt policy kubelet
apt install -y kubelet=1.17.11-00 kubeadm=1.17.11-00 kubectl=1.17.11-00

kubeadm init

名前や、CIDRを指定する場合

kubeadm init --node-name master --pod-network-cidr=10.224.0.0/16

こんなのが表示されれば成功です。

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 172.16.0.82:6443 --token qc0yz3.rs9q3122p8s2mko1 \
	--discovery-token-ca-cert-hash sha256:6687ea8b6dc4871f30edc0544b836e6ada87cf540bb4fb126b25b6f90177db88

export KUBECONFIG=/etc/kubernetes/admin.conf

# kubectl get node
NAME     STATUS     ROLES                  AGE   VERSION
master   NotReady   control-plane,master   83s   v1.23.5

kubectl completion bash >/etc/bash_completion.d/kubectl

下記の方法でaliasによりもっと短いコマンドにできます。
2022.05.28 kubectl をaliasで短く

workerノードでも手順1~3を実行

その後下記でjoinする

kubeadm join 172.16.0.82:6443 --token qc0yz3.rs9q3122p8s2mko1 \
--discovery-token-ca-cert-hash sha256:6687ea8b6dc4871f30edc0544b836e6ada87cf540bb4fb126b25b6f90177db88

kubeadm token create --print-join-command

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

# kubectl get node
NAME       STATUS     ROLES                  AGE    VERSION
master     NotReady   control-plane,master   8m3s   v1.23.5
worker01   NotReady   <none>                 3m8s   v1.23.5

↓

# kubectl get node
NAME       STATUS   ROLES                  AGE     VERSION
master     Ready    control-plane,master   13m     v1.23.5
worker01   Ready    <none>                 8m30s   v1.23.5

kubernetes作成したばかりでは、Podネットワークは外部との通信できません。

Podから外部へ通信するには、IPマスカレードの設定を入れてあげる必要があります。