kubernetes-v1.20.8二进制安装(六)-kube-scheduler

kube-scheduler 是 kubernetes 的核心组件之一，主要负责整个集群资源的调度功能，根据特定的调度算法和策略，将 Pod 调度到最优的工作节点上面去，从而更加合理、更加充分的利用集群的资源

1. 部署

1.1. 创建证书配置文件

cfssl支持SAN（Subject Alternative Name），它是X.509中定义的一个扩展，使用了SAN字段的SSL证书，可以扩展此证书支持的域名，即一个证书可以支持多个不同域名的解析，即下面的 *.k8s-host.com，有利于节点的扩展，不用和以前的部署中提前将需要的IP写入到证书hosts中。

cat > /opt/software/kubernetes/certs/kube-scheduler-csr.json<<EOF
{
    "CN": "system:kube-scheduler",
    "hosts": [
      "127.0.0.1",
      "*.k8s-host.com"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "ST": "GuangZhou",
            "L": "TianHe",
            "O": "system:kube-scheduler",
            "OU": "system"
        }
    ]
}
EOF

1.2. 签发证书

cd /opt/software/kubernetes/certs/

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-scheduler-csr.json | cfssl-json -bare kube-scheduler

cp kube-scheduler.pem kube-scheduler-key.pem /opt/software/kubernetes/master/certs/

1.3. 生成kubeconfig文件

设置集群参数

cd /opt/software/kubernetes/certs/

kubectl config set-cluster kubernetes --certificate-authority=ca.pem --embed-certs=true --server=https://islb.k8s-host.com:6443 --kubeconfig=/opt/software/kubernetes/master/kubeconfig/kube-scheduler.kubeconfig

• master与node节点的islb.k8s-host.com不同, 是因为master的controller-manager和scheduler服务都与apiserver为同一台服务器,所以直接指向127.0.0.1即可

设置客户端认证参数

kubectl config set-credentials system:kube-scheduler --client-certificate=kube-scheduler.pem --client-key=kube-scheduler-key.pem --embed-certs=true --kubeconfig=/opt/software/kubernetes/master/kubeconfig/kube-scheduler.kubeconfig

设置上下文参数

kubectl config set-context system:kube-scheduler --cluster=kubernetes --user=system:kube-scheduler --kubeconfig=/opt/software/kubernetes/master/kubeconfig/kube-scheduler.kubeconfig

设置默认上下文

kubectl config use-context system:kube-scheduler --kubeconfig=/opt/software/kubernetes/master/kubeconfig/kube-scheduler.kubeconfig

1.4. 生成配置文件

注意各个节点bind-address的修改

cat > /opt/software/kubernetes/master/config/kube-scheduler.conf<<EOF
KUBE_SCHEDULER_OPTS="--address=127.0.0.1 \\
--bind-address=10.0.0.10 \\
--secure-port=10259 \\
--port=10251 \\
--kubeconfig=/opt/software/kubernetes/kubeconfig/kube-scheduler.kubeconfig \\
--tls-cert-file=/opt/software/kubernetes/certs/kube-scheduler.pem \\
--tls-private-key-file=/opt/software/kubernetes/certs/kube-scheduler-key.pem \\
--leader-elect=true \\
--alsologtostderr=true \\
--logtostderr=false \\
--log-dir=/opt/software/kubernetes/logs \\
--v=2"
EOF

• --leader-elect-resource-lock="leases" 用于在leader选举期间锁定资源的类型, 1.20版本默认值为"leases", 1.19版本为"endpointsleases", 查看基础组件信息可使用命令kubectl get leases查看

1.5. 生成service启动文件

cat > /opt/software/kubernetes/master/service/kube-scheduler.service<<EOF 
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes

[Service]
Type=simple
EnvironmentFile=-/opt/software/kubernetes/config/kube-scheduler.conf
ExecStart=/opt/software/kubernetes/bin/kube-scheduler \$KUBE_SCHEDULER_OPTS
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

1.6. 分发

hosts=(master01 master02 master03)
domain='k8s-host.com'
config_files=('config/kube-scheduler.conf')
cd /opt/software/kubernetes
for host in ${hosts[*]}
do
    scp -r master/{bin,certs,kubeconfig,service} ${host}.${domain}:/opt/software/kubernetes/
done

# 不可重复执行,否则覆盖修改的配置
for host in ${hosts[*]}
do
	for file in ${config_files[*]}
	do
    	scp -r master/${file} ${host}.${domain}:/opt/software/kubernetes/${file}
    done
done

1.8. 服务启动

请修改各个节点配置文件的差异地方, 设置service文件软链接且启动

hosts=(master01 master02 master03)
domain='k8s-host.com'
for host in ${hosts[*]}
do
    ssh root@${host}.${domain} "ln -s /opt/software/kubernetes/service/kube-scheduler.service /usr/lib/systemd/system/kube-scheduler.service"
    # 开机启动并启动服务
    ssh root@${host}.${domain} "systemctl daemon-reload && systemctl enable kube-scheduler.service --now "
done

1.9. 验证服务

前提客户端已配置kubectl命令

1.20版本之前可使用命令kubectl get endpoints查看集群信息

# 当前schedulerr的leader为 master01
$ kubectl get leases -n kube-system
NAME                      HOLDER                        AGE
kube-scheduler            master01.k8s-host.com_xxxxx   3d17h

2. 问题

(有待补充)

3. 参考链接