1、環(huán)境準(zhǔn)備
先準(zhǔn)備一臺centos7虛擬機(jī)
2、安裝docker-ce
# 卸載原來的docker
sudo yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-engine
# 安裝依賴
sudo yum update -y && sudo yum install -y yum-utils \
device-mapper-persistent-data \
lvm2
# 添加官方y(tǒng)um庫
sudo yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
# 安裝docker
sudo yum install docker-ce docker-ce-cli containerd.io
# 安裝指定版本docker
yum list docker-ce --showduplicates | sort -r
sudo yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io
# 查看docker版本
docker --version
# 開機(jī)啟動
systemctl enable --now docker
或者使用腳本一鍵安裝
curl -fsSL "https://get.docker.com/" | sh
systemctl enable --now docker
修改docker cgroup驅(qū)動，與k8s一致，使用systemd
# 修改docker cgroup驅(qū)動：native.cgroupdriver=systemd
cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2",
"storage-opts": [
"overlay2.override_kernel_check=true"
]
}
EOF
systemctl restart docker # 重啟使配置生效
3、安裝 kubelet kubeadm kubectl
安裝kubernetes的時(shí)候，需要安裝kubelet, kubeadm等包，但k8s官網(wǎng)給的yum源是packages.cloud.google.com，國內(nèi)訪問不了，此時(shí)我們可以使用阿里云的yum倉庫鏡像。
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
# 關(guān)閉SElinux
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config
# 安裝kubelet kubeadm kubectl
yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
systemctl enable --now kubelet # 開機(jī)啟動kubelet
# centos7用戶還需要設(shè)置路由：
yum install -y bridge-utils.x86_64
modprobe br_netfilter # 加載br_netfilter模塊，使用lsmod查看開啟的模塊
cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system # 重新加載所有配置文件
systemctl disable --now firewalld # 關(guān)閉防火墻
# k8s要求關(guān)閉swap (qxl)
swapoff -a && sysctl -w vm.swappiness=0 # 關(guān)閉swap
sed -ri '/^[^#]*swap/s@^@#@' /etc/fstab # 取消開機(jī)掛載swap
4、準(zhǔn)備所需鏡像
kubeadm config images pull # 拉取集群所需鏡像，這個需要翻墻
# --- 不能翻墻可以嘗試以下辦法 ---
kubeadm config images list # 列出所需鏡像
k8s.gcr.io/kube-apiserver:v1.15.3
k8s.gcr.io/kube-controller-manager:v1.15.3
k8s.gcr.io/kube-scheduler:v1.15.3
k8s.gcr.io/kube-proxy:v1.15.3
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.3.10
k8s.gcr.io/coredns:1.3.1
# 根據(jù)所需鏡像名字先拉取國內(nèi)資源
docker pull mirrorgooglecontainers/kube-apiserver:v1.14.1
docker pull mirrorgooglecontainers/kube-controller-manager:v1.14.1
docker pull mirrorgooglecontainers/kube-scheduler:v1.14.1
docker pull mirrorgooglecontainers/kube-proxy:v1.14.1
docker pull mirrorgooglecontainers/pause:3.1
docker pull mirrorgooglecontainers/etcd:3.3.10
docker pull coredns/coredns:1.3.1 # 這個在mirrorgooglecontainers中沒有
# 修改鏡像tag
docker tag mirrorgooglecontainers/kube-apiserver:v1.14.1 k8s.gcr.io/kube-apiserver:v1.15.3
docker tag mirrorgooglecontainers/kube-controller-manager:v1.14.1 k8s.gcr.io/kube-controller-manager:v1.15.3
docker tag mirrorgooglecontainers/kube-scheduler:v1.14.1 k8s.gcr.io/kube-scheduler:v1.15.3
docker tag mirrorgooglecontainers/kube-proxy:v1.14.1 k8s.gcr.io/kube-proxy:v1.15.3
docker tag mirrorgooglecontainers/pause:3.1 k8s.gcr.io/pause:3.1
docker tag mirrorgooglecontainers/etcd:3.3.10 k8s.gcr.io/etcd:3.3.10
docker tag coredns/coredns:1.3.1 k8s.gcr.io/coredns:1.3.1
# 刪除原來的鏡像
docker rmi mirrorgooglecontainers/kube-apiserver:v1.14.1
docker rmi mirrorgooglecontainers/kube-controller-manager:v1.14.1
docker rmi mirrorgooglecontainers/kube-scheduler:v1.14.1
docker rmi mirrorgooglecontainers/kube-proxy:v1.14.1
docker rmi mirrorgooglecontainers/pause:3.1
docker rmi mirrorgooglecontainers/etcd:3.3.10
docker rmi coredns/coredns:1.3.1
使用虛擬機(jī)的可以做完以上步驟后，使用Vbox進(jìn)行克隆。，一臺做Master，另一臺做Node
修改hostname
vim /etc/hostname
systemctl restart systemd-hostnamed
5、使用kubeadm創(chuàng)建集群
# 初始化Master（Master需要至少2核）此處會各種報(bào)錯,異常...成功與否就在此
kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.15.3 --apiserver-advertise-address=192.168.83.881.14.1
# --apiserver-advertise-address Master節(jié)點(diǎn)IP
# --pod-network-cidr 指定pod網(wǎng)絡(luò)子網(wǎng)，使用fannel網(wǎng)絡(luò)必須使用這個CIDR
# 初始化結(jié)果：
[init] Using Kubernetes version: v1.14.1
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Using existing etcd/ca certificate authority
[certs] Using existing etcd/server certificate and key on disk
[certs] Using existing etcd/peer certificate and key on disk
[certs] Using existing etcd/healthcheck-client certificate and key on disk
[certs] Using existing apiserver-etcd-client certificate and key on disk
[certs] Using existing ca certificate authority
[certs] Using existing apiserver certificate and key on disk
[certs] Using existing apiserver-kubelet-client certificate and key on disk
[certs] Using existing front-proxy-ca certificate authority
[certs] Using existing front-proxy-client certificate and key on disk
[certs] Using the existing "sa" key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 21.503375 seconds
[upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.14" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --experimental-upload-certs
[mark-control-plane] Marking the node master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: w2i0mh.5fxxz8vk5k8db0wq
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
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
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:
#每個機(jī)器創(chuàng)建的master以下部分都不同,需要自己保存好-qxl
kubeadm join 192.168.200.25:6443 --token our9a0.zl490imi6t81tn5u \
--discovery-token-ca-cert-hash sha256:b93f710eb9b389a69f0cd0d6dcf7c82e389a68f009eb6b2028f69d54b099de16
普通用戶設(shè)置權(quán)限
# Master端：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
# Node端：
mkdir -p $HOME/.kube
# 復(fù)制Master端配置文件$HOME/.kube/config到同級目錄，否則后面kubectl get nodes會出現(xiàn)如下錯誤
# The connection to the server localhost:8080 was refused - did you specify the right host or port?
sudo chown $(id -u):$(id -g) $HOME/.kube/config
應(yīng)用flannel網(wǎng)絡(luò)
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
node加入機(jī)器
# node1:
kubeadm join 192.168.200.25:6443 --token w2i0mh.5fxxz8vk5k8db0wq \
--discovery-token-ca-cert-hash sha256:65e82e987f50908f3640df7e05c7a91f390a02726c9142808faa739d4dc24252
# node2:
kubeadm join 192.168.200.25:6443 --token w2i0mh.5fxxz8vk5k8db0wq \
--discovery-token-ca-cert-hash sha256:65e82e987f50908f3640df7e05c7a91f390a02726c9142808faa739d4dc24252
輸出日志：
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
# master：
kubectl get pods --all-namespaces
# ---輸出信息---
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-fb8b8dccf-rn8kd 1/1 Running 0 170m
kube-system coredns-fb8b8dccf-slwr4 1/1 Running 0 170m
kube-system etcd-master 1/1 Running 0 169m
kube-system kube-apiserver-master 1/1 Running 0 169m
kube-system kube-controller-manager-master 1/1 Running 0 169m
kube-system kube-flannel-ds-amd64-l8c7c 1/1 Running 0 130m
kube-system kube-flannel-ds-amd64-lcmxw 1/1 Running 1 117m
kube-system kube-flannel-ds-amd64-pqnln 1/1 Running 1 72m
kube-system kube-proxy-4kcqb 1/1 Running 0 170m
kube-system kube-proxy-jcqjd 1/1 Running 0 72m
kube-system kube-proxy-vm9sj 1/1 Running 0 117m
kube-system kube-scheduler-master 1/1 Running 0 169m
# ---輸出信息---
kubectl get nodes
# ---輸出信息---
NAME STATUS ROLES AGE VERSION
master Ready master 171m v1.14.1
node1 Ready <none> 118m v1.14.1
node2 Ready <none> 74m v1.14.1
# ---輸出信息---
排錯
journalctl -f # 當(dāng)前輸出日志
journalctl -f -u kubelet # 只看當(dāng)前的kubelet進(jìn)程日志
出于安全考慮，默認(rèn)配置下Kubernetes不會將Pod調(diào)度到Master節(jié)點(diǎn)。如果希望將k8s-master也當(dāng)作Node使用，可以執(zhí)行如下命令：
kubectl describe node localhost
#輸出:Taints: node-role.kubernetes.io/master:NoSchedule(這個污點(diǎn)表示默認(rèn)情況下master節(jié)點(diǎn)將不會調(diào)度運(yùn)行Pod，即不運(yùn)行工作負(fù)載。)
#可以部署到master
kubectl taint node k8s-master node-role.kubernetes.io/master=:NoSchedule-
其中k8s-master是主機(jī)節(jié)點(diǎn)hostname如果要恢復(fù)Master Only狀態(tài)，執(zhí)行如下命令：
#不會部署到master
kubectl taint node k8s-master node-role.kubernetes.io/master:NoSchedule
注意：kubeadm初始化的Kubernetes集群，master節(jié)點(diǎn)也被打上了一個node-role.kubernetes.io/master=的label，標(biāo)識這個節(jié)點(diǎn)的角色為master。
給Node設(shè)置Label和設(shè)置污點(diǎn)是兩個不同的操作。
實(shí)踐：Kubernetes master節(jié)點(diǎn)不運(yùn)行工作負(fù)載
Kubernetes集群的Master節(jié)點(diǎn)是十分重要的，一個高可用的Kubernetes集群一般會存在3個以上的master節(jié)點(diǎn)，為了保證master節(jié)點(diǎn)的穩(wěn)定性，一般不推薦將業(yè)務(wù)的Pod調(diào)度到master節(jié)點(diǎn)上。 下面將介紹一下我們使用Kubernetes調(diào)度的Taints和和Tolerations特性確保Kubernetes的Master節(jié)點(diǎn)不執(zhí)行工作負(fù)載的實(shí)踐。
我們的Kubernetes集群中總共有3個master節(jié)點(diǎn)，節(jié)點(diǎn)的名稱分別為k8s-01、k8s-02、k8s-03。 為了保證集群的穩(wěn)定性，同時(shí)提高master節(jié)點(diǎn)的利用率，我們將其中一個節(jié)點(diǎn)設(shè)置為node-role.kubernetes.io/master:NoSchedule，另外兩個節(jié)點(diǎn)設(shè)置為node-role.kubernetes.io/master:PreferNoSchedule，這樣保證3個節(jié)點(diǎn)中的1個無論在任何情況下都將不運(yùn)行業(yè)務(wù)Pod，而另外2個載集群資源充足的情況下盡量不運(yùn)行業(yè)務(wù)Pod。
kubectl taint nodes k8s-01 node-role.kubernetes.io/master=:NoSchedule
kubectl taint nodes k8s-02 node-role.kubernetes.io/master=:PreferNoSchedule
kubectl taint nodes k8s-03 node-role.kubernetes.io/master=:PreferNoSchedule
