CKA [Installation] – Ubuntu 从0架设，架设Scheduler

Kubernetes当中的Scheduler的作用就是安排pod在哪个node部署, 然后就会告知apiserver ，接着apiserver就会让kubelet去部署。

1. 设置Certificate

cd /root/certificates
{
openssl genrsa -out kube-scheduler.key 2048

openssl req -new -key kube-scheduler.key -subj "/CN=system:kube-scheduler" -out kube-scheduler.csr

openssl x509 -req -in kube-scheduler.csr -CA ca.crt -CAkey ca.key -CAcreateserial  -out kube-scheduler.crt -days 1000
}

2. 创建scheduler 连接到apiserver的kubeconfig文件

{
  kubectl config set-cluster kubernetes-from-scratch \
    --certificate-authority=ca.crt \
    --embed-certs=true \
    --server=https://127.0.0.1:6443 \
    --kubeconfig=kube-scheduler.kubeconfig

  kubectl config set-credentials system:kube-scheduler \
    --client-certificate=kube-scheduler.crt \
    --client-key=kube-scheduler.key \
    --embed-certs=true \
    --kubeconfig=kube-scheduler.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-from-scratch \
    --user=system:kube-scheduler \
    --kubeconfig=kube-scheduler.kubeconfig

  kubectl config use-context default --kubeconfig=kube-scheduler.kubeconfig
}

3. 把scheduler的kubeconfig文件copy到kubernetes目录中

cp kube-scheduler.kubeconfig /var/lib/kubernetes/

4. 设置systemd service

cat <<EOF | sudo tee /etc/systemd/system/kube-scheduler.service
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes

[Service]
ExecStart=/usr/local/bin/kube-scheduler \\
  --kubeconfig=/var/lib/kubernetes/kube-scheduler.kubeconfig \\
  --authentication-kubeconfig=/var/lib/kubernetes/kube-scheduler.kubeconfig \\
  --authorization-kubeconfig=/var/lib/kubernetes/kube-scheduler.kubeconfig \\
  --bind-address=127.0.0.1 \\
  --leader-elect=true
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

cp /root/binaries/kubernetes/server/bin/kube-scheduler /usr/local/bin

5. 检查scheduler的status

systemctl start kube-scheduler

systemctl status kube-scheduler

systemctl enable kube-scheduler