二进制安装k8s

2020-08-19 k8s 评论字数统计: 2543字阅读时长: 6分

requirment

生产环境的部署Kubernetes集群方案

kubeadm

Kubeadm是一个K8s部署工具，提供kubeadm init和kubeadm join，用于快速部署Kubernetes集群。

官方地址：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/

kubeasz

国内大佬开源的使用Ansible脚本安装K8S集群，方便直接，不受国内网络环境影响

github地址：https://github.com/easzlab/kubeasz

二进制包编译安装

从github下载发行版的二进制包，手动部署每个组件，组成Kubernetes集群。

上述两种方式虽然降低部署门槛，但屏蔽了很多细节，遇到问题很难排查。如果想更容易可控，推荐使用二进制包部署Kubernetes集群，虽然手动部署麻烦点，期间可以学习很多工作原理，也利于后期维护。（主要是有利于学习）

安装要求

连通外网
具有内网静态ip
~~4台linux(我用ubuntu20)服务器~~ ，all in one

规划

角色	IP	组件
master1	192.168.1.81	kube-apiserver，kube-controller-manager，kube-scheduler，etcd，kubelet，kube-proxy，docker

主机初始化

# 关闭swap
sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久
# 根据规划设置主机名
hostnamectl set-hostname <hostname>
# 将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

apt install bash-completion conntrack ipvsadm jq libseccomp2 golang-cfssl

# 方便后续操作
cat <<EOF >> ~/.bashrc
export PATH=/opt/etcd/bin:/opt/kubernetes/bin:/opt/cni/bin:$PATH
EOF

部署etcd

颁发证书

# 创建工作目录：
mkdir -p ~/TLS/{etcd,k8s} && cd TLS/etcd
# 自签CA：
cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "www": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF

cat > ca-csr.json << EOF
{
    "CN": "etcd CA",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing"
        }
    ]
}
EOF

# 使用自签CA签发Etcd HTTPS证书
cat > server-csr.json << EOF
{
    "CN": "etcd",
    "hosts": [
    "192.168.1.81"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing"
        }
    ]
}
EOF

下载源码及配置

wget https://github.com/etcd-io/etcd/releases/download/v3.4.11/etcd-v3.4.11-linux-amd64.tar.gz
mkdir /opt/etcd/{bin,cfg,ssl} -p
tar zxvf etcd-v3.4.11-linux-amd64.tar.gz
mv etcd-v3.4.11-linux-amd64/{etcd,etcdctl} /opt/etcd/bin/

cat > /opt/etcd/cfg/etcd.conf << EOF
#[Member]
ETCD_NAME="etcd-1"
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://192.168.1.81:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.1.81:2379"
#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.1.81:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.1.81:2379"
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.1.81:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
EOF

systemd管理etcd

cat > /usr/lib/systemd/system/etcd.service << EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
[Service]
Type=notify
ExecStart=/opt/etcd/bin/etcd \
--name=etcd-1 \
--data-dir=/var/lib/etcd/default.etcd \
--listen-peer-urls=https://192.168.1.81:2380 \
--listen-client-urls=https://192.168.1.81:2379 \
--initial-advertise-peer-urls=https://192.168.1.81:2380 \
--initial-cluster='etcd-1=https://192.168.1.81:2380' \
--initial-cluster-state='new' \
--initial-cluster-token='etcd-cluster' \
--advertise-client-urls='https://192.168.1.81:2379' \
--cert-file=/opt/etcd/ssl/server.pem \
--key-file=/opt/etcd/ssl/server-key.pem \
--peer-cert-file=/opt/etcd/ssl/server.pem \
--peer-key-file=/opt/etcd/ssl/server-key.pem \
--trusted-ca-file=/opt/etcd/ssl/ca.pem \
--peer-trusted-ca-file=/opt/etcd/ssl/ca.pem \
--logger=zap
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF
export PATH=/opt/etcd/bin:$PATH
#验证集群状态
etcdctl --cacert=/opt/etcd/ssl/ca.pem --cert=/opt/etcd/ssl/server.pem --key=/opt/etcd/ssl/server-key.pem --endpoints="https://192.168.1.81:2379" endpoint health

docker

apt install docker.io
cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": [
    "https://30l6yhjq.mirror.aliyuncs.com"
  ],
  "exec-opts": [ "native.cgroupdriver=systemd" ]
}
EOF
systemctl daemon-reload
systemctl restart docker
systemctl enable docker

kube-apiserver

自签证书颁发机构

cd ~/TLS/k8s

cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "kubernetes": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF
cat > ca-csr.json << EOF
{
    "CN": "kubernetes",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF
cfssl gencert -initca ca-csr.json | cfssljson -bare ca -

自签apiserver https证书

cat > server-csr.json << EOF
{
    "CN": "kubernetes",
    "hosts": [
      "10.0.0.1",
      "127.0.0.1",
      "192.168.1.81",
      "kubernetes",
      "kubernetes.default",
      "kubernetes.default.svc",
      "kubernetes.default.svc.cluster",
      "kubernetes.default.svc.cluster.local"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF

启用 TLS Bootstrapping 机制,创建token文件

cat > /opt/kubernetes/cfg/token.csv << EOF
c47ffb939f5ca36231d9e3121a252940,kubelet-bootstrap,10001,"system:node-bootstrapper"
EOF

apiserver

wget https://dl.k8s.io/v1.18.8/kubernetes-server-linux-amd64.tar.gz
mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs}
tar zxvf kubernetes-server-linux-amd64.tar.gz
cd kubernetes/server/bin
# 拷贝二进制文件
cp kube-apiserver kube-scheduler kube-controller-manager kubectl /opt/kubernetes/bin

# 拷贝证书
cp ~/TLS/k8s/ca*pem ~/TLS/k8s/server*pem /opt/kubernetes/ssl/

systemd管理apiserver

cat > /usr/lib/systemd/system/kube-apiserver.service << EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/opt/kubernetes/bin/kube-apiserver \
--logtostderr=false \
--v=2 \
--log-dir=/opt/kubernetes/logs \
--etcd-servers=https://192.168.1.81:2379 \
--bind-address=192.168.1.81 \
--secure-port=6443 \
--advertise-address=192.168.1.81 \
--allow-privileged=true \
--service-cluster-ip-range=10.0.0.0/24 \
--enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,NodeRestriction \
--authorization-mode=RBAC,Node \
--enable-bootstrap-token-auth=true \
--token-auth-file=/opt/kubernetes/cfg/token.csv \
--service-node-port-range=20000-40000 \
--kubelet-client-certificate=/opt/kubernetes/ssl/server.pem \
--kubelet-client-key=/opt/kubernetes/ssl/server-key.pem \
--tls-cert-file=/opt/kubernetes/ssl/server.pem  \
--tls-private-key-file=/opt/kubernetes/ssl/server-key.pem \
--client-ca-file=/opt/kubernetes/ssl/ca.pem \
--service-account-key-file=/opt/kubernetes/ssl/ca-key.pem \
--etcd-cafile=/opt/etcd/ssl/ca.pem \
--etcd-certfile=/opt/etcd/ssl/server.pem \
--etcd-keyfile=/opt/etcd/ssl/server-key.pem \
--audit-log-maxage=30 \
--audit-log-maxbackup=3 \
--audit-log-maxsize=100 \
--audit-log-path=/opt/kubernetes/logs/k8s-audit.log
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl start kube-apiserver
systemctl enable kube-apiserver

kube-controller-manager

systemd管理controller-manager

cat > /usr/lib/systemd/system/kube-controller-manager.service << EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/opt/kubernetes/bin/kube-controller-manager \
--logtostderr=false \
--v=2 \
--log-dir=/opt/kubernetes/logs \
--leader-elect=true \
--master=127.0.0.1:8080 \
--bind-address=127.0.0.1 \
--allocate-node-cidrs=true \
--cluster-cidr=10.244.0.0/16 \
--service-cluster-ip-range=10.0.0.0/24 \
--cluster-signing-cert-file=/opt/kubernetes/ssl/ca.pem \
--cluster-signing-key-file=/opt/kubernetes/ssl/ca-key.pem  \
--root-ca-file=/opt/kubernetes/ssl/ca.pem \
--service-account-private-key-file=/opt/kubernetes/ssl/ca-key.pem \
--experimental-cluster-signing-duration=87600h0m0s
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl start kube-controller-manager
systemctl enable kube-controller-manager

kube-scheduler

cat > /usr/lib/systemd/system/kube-scheduler.service << EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/opt/kubernetes/bin/kube-scheduler \
--logtostderr=false \
--v=2 \
--log-dir=/opt/kubernetes/logs \
--leader-elect \
--master=127.0.0.1:8080 \
--bind-address=127.0.0.1
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl start kube-scheduler
systemctl enable kube-scheduler

至此，master所需组件已经安装完毕

kubelet

拷贝二进制文件

mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs}
cd kubernetes/server/bin
cp kubelet kube-proxy /opt/kubernetes/bin

配置参数文件

cat > /opt/kubernetes/cfg/kubelet-config.yml << EOF
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address: 0.0.0.0
port: 10250
readOnlyPort: 10255
cgroupDriver: cgroupfs
clusterDNS:
- 10.0.0.2
clusterDomain: cluster.local
failSwapOn: false
authentication:
  anonymous:
    enabled: false
  webhook:
    cacheTTL: 2m0s
    enabled: true
  x509:
    clientCAFile: /opt/kubernetes/ssl/ca.pem
authorization:
  mode: Webhook
  webhook:
    cacheAuthorizedTTL: 5m0s
    cacheUnauthorizedTTL: 30s
evictionHard:
  imagefs.available: 15%
  memory.available: 100Mi
  nodefs.available: 10%
  nodefs.inodesFree: 5%
maxOpenFiles: 1000000
maxPods: 110
EOF

生成bootstrap.kubeconfig文件

KUBE_APISERVER="https://192.168.1.81:6443" # apiserver IP:PORT
TOKEN="c47ffb939f5ca36231d9e3121a252940" # 与token.csv里保持一致

# 生成 kubelet bootstrap kubeconfig 配置文件
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=bootstrap.kubeconfig
kubectl config set-credentials "kubelet-bootstrap" \
  --token=${TOKEN} \
  --kubeconfig=bootstrap.kubeconfig
kubectl config set-context default \
  --cluster=kubernetes \
  --user="kubelet-bootstrap" \
  --kubeconfig=bootstrap.kubeconfig
kubectl config use-context default --kubeconfig=bootstrap.kubeconfig

cp bootstrap.kubeconfig /opt/kubernetes/cfg

systemd管理kubelet

cat > /usr/lib/systemd/system/kubelet.service << EOF
[Unit]
Description=Kubernetes Kubelet
After=docker.service
[Service]
ExecStart=/opt/kubernetes/bin/kubelet \
--logtostderr=false \
--v=2 \
--log-dir=/opt/kubernetes/logs \
--hostname-override=km1 \
--network-plugin=cni \
--kubeconfig=/opt/kubernetes/cfg/kubelet.kubeconfig \
--bootstrap-kubeconfig=/opt/kubernetes/cfg/bootstrap.kubeconfig \
--config=/opt/kubernetes/cfg/kubelet-config.yml \
--cert-dir=/opt/kubernetes/ssl \
--pod-infra-container-image=easzlab/pause-amd64:3.2
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl start kubelet
systemctl enable kubelet

批准kubelet证书申请并加入集群

kubectl get csr
kubectl certificate approve node-csr-1hBi056TVssBlAKSC2wQgcqeJNdY9cTJKS8Ytziub24
kubectl get node

由于cni没有部署，所以node is NotReady

kube-proxy

配置proxy参数

cat > /opt/kubernetes/cfg/kube-proxy-config.yml << EOF
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
bindAddress: 0.0.0.0
metricsBindAddress: 0.0.0.0:10249
clientConnection:
  kubeconfig: /opt/kubernetes/cfg/kube-proxy.kubeconfig
hostnameOverride: km1
clusterCIDR: 10.0.0.0/24
EOF

生成kube-proxy.kubeconfig

# 切换工作目录
cd ~/TLS/k8s

# 创建证书请求文件
cat > kube-proxy-csr.json << EOF
{
  "CN": "system:kube-proxy",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "k8s",
      "OU": "System"
    }
  ]
}
EOF

# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-proxy-csr.json | cfssljson -bare kube-proxy

生成kube-proxy.kubeconfig文件

KUBE_APISERVER="https://192.168.1.81:6443"

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=kube-proxy.kubeconfig
kubectl config set-credentials kube-proxy \
  --client-certificate=./kube-proxy.pem \
  --client-key=./kube-proxy-key.pem \
  --embed-certs=true \
  --kubeconfig=kube-proxy.kubeconfig
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-proxy \
  --kubeconfig=kube-proxy.kubeconfig
kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig

cp kube-proxy.kubeconfig /opt/kubernetes/cfg/

systemd管理kube-proxy

cat > /usr/lib/systemd/system/kube-proxy.service << EOF
[Unit]
Description=Kubernetes Proxy
After=network.target
[Service]
ExecStart=/opt/kubernetes/bin/kube-proxy \
--logtostderr=false \
--v=2 \
--log-dir=/opt/kubernetes/logs \
--config=/opt/kubernetes/cfg/kube-proxy-config.yml
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl start kube-proxy
systemctl enable kube-proxy

部署CNI网络

wget https://github.com/containernetworking/plugins/releases/download/v0.8.6/cni-plugins-linux-amd64-v0.8.6.tgz
mkdir -p /opt/cni/bin
tar zxvf cni-plugins-linux-amd64-v0.8.6.tgz -C /opt/cni/bin

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
sed -i -r "s#quay.io/coreos/flannel:.*-amd64#lizhenliang/flannel:v0.12.0-amd64#g" kube-flannel.yml
kubectl apply -f kube-flannel.yml

正常情况下 node 已经Ready

授权apiserver访问kubelet

cat > apiserver-to-kubelet-rbac.yaml << EOF
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:kube-apiserver-to-kubelet
rules:
  - apiGroups:
      - ""
    resources:
      - nodes/proxy
      - nodes/stats
      - nodes/log
      - nodes/spec
      - nodes/metrics
      - pods/log
    verbs:
      - "*"
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: system:kube-apiserver
  namespace: ""
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:kube-apiserver-to-kubelet
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: kubernetes
EOF

kubectl apply -f apiserver-to-kubelet-rbac.yaml

部署core dns

cat > coredns.yaml << EOF
apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:coredns
rules:
- apiGroups:
  - ""
  resources:
  - endpoints
  - services
  - pods
  - namespaces
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:coredns
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:coredns
subjects:
- kind: ServiceAccount
  name: coredns
  namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
data:
  Corefile: |
    .:53 {
        errors
        health {
          lameduck 5s
        }
        ready
        kubernetes cluster.local. in-addr.arpa ip6.arpa {
          pods insecure
          fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        reload
        loadbalance
    }
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/name: "CoreDNS"
spec:
  replicas: 1
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
    spec:
      priorityClassName: system-cluster-critical
      serviceAccountName: coredns
      tolerations:
        - key: "CriticalAddonsOnly"
          operator: "Exists"
      nodeSelector:
        beta.kubernetes.io/os: linux
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: k8s-app
                operator: In
                values: ["kube-dns"]
            topologyKey: kubernetes.io/hostname
      containers:
      - name: coredns
        image: coredns/coredns:1.7.0
        imagePullPolicy: IfNotPresent
        resources:
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        args: [ "-conf", "/etc/coredns/Corefile" ]
        volumeMounts:
        - name: config-volume
          mountPath: /etc/coredns
          readOnly: true
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9153
          name: metrics
          protocol: TCP
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
      dnsPolicy: Default
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile
---
apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  annotations:
    prometheus.io/port: "9153"
    prometheus.io/scrape: "true"
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: "CoreDNS"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 10.0.0.2
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP
  - name: metrics
    port: 9153
    protocol: TCP
EOF

kubectl apply -f coredns.yaml

DNS解析测试

kubectl run -it --rm dns-test --image=busybox:1.28.4 sh
nslookup kubernetes

# 正常情况下会显示
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes
Address 1: 10.0.0.1 kubernetes.default.svc.cluster.local

总结

etcd和api server都是只用https通讯, 所以要注意证书过期时间
etcd只有api server访问
controller-manager，scheduler ，kubelet会访问api server，采用http 长连接方式watch apiserver状态变化，使用短连接报告apiserver自身状态

本文链接: https://blog.yoogo.top/2020/08/%E4%BA%8C%E8%BF%9B%E5%88%B6%E5%AE%89%E8%A3%85k8s/
License: CC BY 4.0 CN