使用 kubeadm 搭建 kubernetes1.10 集群
PS:所有节点安装之前记得先把镜像准备好,否者将无法启动,也不报错。
$ cat /etc/hosts
192.168.11.1 master
192.168.11.2 node
禁用防火墙:
$ systemctl stop firewalld
$ systemctl disable firewalld
禁用SELINUX:
$ setenforce 0
$ cat /etc/selinux/config
SELINUX=disabled
创建/etc/sysctl.d/k8s.conf
文件,添加如下内容:
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
执行如下命令使修改生效:
$ modprobe br_netfilter
$ sysctl -p /etc/sysctl.d/k8s.conf
镜像
如果你的节点上面有科学上网的工具,可以忽略这一步,我们需要提前将所需的gcr.io
上面的镜像下载到节点上面,当然前提条件是你已经成功安装了docker
。
master
节点,执行下面的命令:
docker pull registry-vpc.cn-shenzhen.aliyuncs.com/cp_m/kube-apiserver-amd64:v1.10.0
docker pull registry-vpc.cn-shenzhen.aliyuncs.com/cp_m/kube-scheduler-amd64:v1.10.0
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/kube-controller-manager-amd64:v1.10.0
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/kube-proxy-amd64:v1.10.0
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/k8s-dns-kube-dns-amd64:1.14.8
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/k8s-dns-dnsmasq-nanny-amd64:1.14.8
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/k8s-dns-sidecar-amd64:1.14.8
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/etcd-amd64:3.1.12
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/pause-amd64:3.1
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/kube-apiserver-amd64:v1.10.0 k8s.gcr.io/kube-apiserver-amd64:v1.10.0
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/kube-scheduler-amd64:v1.10.0 k8s.gcr.io/kube-scheduler-amd64:v1.10.0
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/kube-controller-manager-amd64:v1.10.0 k8s.gcr.io/kube-controller-manager-amd64:v1.10.0
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/kube-proxy-amd64:v1.10.0 k8s.gcr.io/kube-proxy-amd64:v1.10.0
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/k8s-dns-kube-dns-amd64:1.14.8 k8s.gcr.io/k8s-dns-kube-dns-amd64:1.14.8
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/k8s-dns-dnsmasq-nanny-amd64:1.14.8 k8s.gcr.io/k8s-dns-dnsmasq-nanny-amd64:1.14.8
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/k8s-dns-sidecar-amd64:1.14.8 k8s.gcr.io/k8s-dns-sidecar-amd64:1.14.8
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/etcd-amd64:3.1.12 k8s.gcr.io/etcd-amd64:3.1.12
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64 quay.io/coreos/flannel:v0.10.0-amd64
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/pause-amd64:3.1 k8s.gcr.io/pause-amd64:3.1
可以将上面的命令保存为一个shell
脚本,然后直接执行即可。这些镜像是在master
节点上需要使用到的镜像,一定要提前下载下来。
其他Node
,执行下面的命令:
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/kube-proxy-amd64:v1.10.0
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/pause-amd64:3.1
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/kubernetes-dashboard-amd64:v1.8.3
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/heapster-influxdb-amd64:v1.3.3
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/heapster-grafana-amd64:v4.4.3
docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/heapster-amd64:v1.4.2
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64 quay.io/coreos/flannel:v0.10.0-amd64
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/pause-amd64:3.1 k8s.gcr.io/pause-amd64:3.1
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/kube-proxy-amd64:v1.10.0 k8s.gcr.io/kube-proxy-amd64:v1.10.0
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/kubernetes-dashboard-amd64:v1.8.3 k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/heapster-influxdb-amd64:v1.3.3 k8s.gcr.io/heapster-influxdb-amd64:v1.3.3
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/heapster-grafana-amd64:v4.4.3 k8s.gcr.io/heapster-grafana-amd64:v4.4.3
docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/heapster-amd64:v1.4.2 k8s.gcr.io/heapster-amd64:v1.4.2
上面的这些镜像是在Node
节点中需要用到的镜像,在join
节点之前也需要先下载到节点上面。
安装 kubeadm、kubelet、kubectl
在确保docker
安装完成后,上面的相关环境配置也完成了,对应所需要的镜像(如果可以科学上网可以跳过这一步)也下载完成了,现在我们就可以来安装kubeadm
了,我们这里是通过指定yum
源的方式来进行安装的:
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
当然了,上面的yum
源也是需要科学上网的,如果不能科学上网的话,我们可以使用阿里云的源进行安装:
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
目前阿里云的源最新版本已经是1.10版本,所以可以直接安装。yum
源配置完成后,执行安装命令即可:
$ yum makecache fast && yum install -y kubelet kubeadm kubectl
正常情况我们可以都能顺利安装完成上面的文件。
配置 kubelet
安装完成后,我们还需要对kubelet
进行配置,因为用yum
源的方式安装的kubelet
生成的配置文件将参数--cgroup-driver
改成了systemd
,而docker
的cgroup-driver
是cgroupfs
,这二者必须一致才行,我们可以通过docker info
命令查看:
$ docker info |grep Cgroup
Cgroup Driver: cgroupfs
修改文件kubelet
的配置文件/etc/systemd/system/kubelet.service.d/10-kubeadm.conf
,将其中的KUBELET_CGROUP_ARGS
参数更改成cgroupfs
:
Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=cgroupfs"
另外还有一个问题是关于交换分区的,之前我们在手动搭建高可用的kubernetes 集群一文中已经提到过,Kubernetes
从1.8开始要求关闭系统的 Swap ,如果不关闭,默认配置的kubelet
将无法启动,我们可以通过 kubelet 的启动参数--fail-swap-on=false
更改这个限制,所以我们需要在上面的配置文件中增加一项配置(在ExecStart
之前):
Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false"
当然最好的还是将swap
给关掉,这样能提高kubelet
的性能。修改完成后,重新加载我们的配置文件即可:
$ systemctl daemon-reload
集群安装
初始化
到这里我们的准备工作就完成了,接下来我们就可以在master
节点上用kubeadm
命令来初始化我们的集群了:
$ kubeadm init --kubernetes-version=v1.10.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=192.168.11.1
命令非常简单,就是kubeadm init
,后面的参数是需要安装的集群版本,因为我们这里选择flannel
作为 Pod 的网络插件,所以需要指定–pod-network-cidr=10.244.0.0/16
,然后是apiserver
的通信地址,这里就是我们master
节点的IP 地址。执行上面的命令,如果出现running with swap on is not supported. Please disable swap
之类的错误,则我们还需要增加一个参数–ignore-preflight-errors=Swap
来忽略swap
的错误提示信息:
$ kubeadm init \
--kubernetes-version=v1.10.0 \
--pod-network-cidr=10.244.0.0/16 \
--apiserver-advertise-address=192.168.11.1 \
--ignore-preflight-errors=Swap
[init] Using Kubernetes version: v1.10.0
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks.
[WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
[preflight] Starting the kubelet service
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [ydzs-master1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.151.30.57]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated etcd/server certificate and key.
[certificates] etcd/server serving cert is signed for DNS names [localhost] and IPs [127.0.0.1]
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [ydzs-master1] and IPs [10.151.30.57]
[certificates] Generated etcd/healthcheck-client certificate and key.
[certificates] Generated apiserver-etcd-client certificate and key.
[certificates] Generated sa key and public key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] Waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests".
[init] This might take a minute or longer if the control plane images have to be pulled.
[apiclient] All control plane components are healthy after 22.007661 seconds
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[markmaster] Will mark node ydzs-master1 as master by adding a label and a taint
[markmaster] Master ydzs-master1 tainted and labelled with key/value: node-role.kubernetes.io/master=""
[bootstraptoken] Using token: 8xomlq.0cdf2pbvjs2gjho3
[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: kube-dns
[addons] Applied essential addon: kube-proxy
Your Kubernetes master 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/
You can now join any number of machines by running the following on each node
as root:
kubeadm join 192.168.11.1:6443 --token 8xomlq.0cdf2pbvjs2gjho3 --discovery-token-ca-cert-hash sha256:92802317cb393682c1d1356c15e8b4ec8af2b8e5143ffd04d8be4eafb5fae368
上面的信息记录了kubeadm
初始化整个集群的过程,生成相关的各种证书、kubeconfig
文件、bootstraptoken
等等,后边是使用kubeadm join
往集群中添加节点时用到的命令,下面的命令是配置如何使用kubectl
访问集群的方式:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
最后给出了将节点加入集群的命令:
kubeadm join 192.168.11.1:6443 --token 8xomlq.0cdf2pbvjs2gjho3 --discovery-token-ca-cert-hash sha256:92802317cb393682c1d1356c15e8b4ec8af2b8e5143ffd04d8be4eafb5fae368
我们根据上面的提示配置好kubectl
后,就可以使用kubectl
来查看集群的信息了:
$ kubectl get cs
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health": "true"}
$ kubectl get csr
NAME AGE REQUESTOR CONDITION
node-csr-8qygb8Hjxj-byhbRHawropk81LHNPqZCTePeWoZs3-g 1h system:bootstrap:8xomlq Approved,Issued
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
ydzs-master1 Ready master 3h v1.10.0
如果你的集群安装过程中遇到了其他问题,我们可以使用下面的命令来进行重置:
$ kubeadm reset
$ ifconfig cni0 down && ip link delete cni0
$ ifconfig flannel.1 down && ip link delete flannel.1
$ rm -rf /var/lib/cni/
安装 Pod Network
接下来我们来安装flannel
网络插件,很简单,和安装普通的POD
没什么两样:
$ wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
$ kubectl apply -f kube-flannel.yml
clusterrole.rbac.authorization.k8s.io "flannel" created
clusterrolebinding.rbac.authorization.k8s.io "flannel" created
serviceaccount "flannel" created
configmap "kube-flannel-cfg" created
daemonset.extensions "kube-flannel-ds" created
另外需要注意的是如果你的节点有多个网卡的话,需要在kube-flannel.yml
中使用--iface
参数指定集群主机内网网卡的名称,否则可能会出现dns无法解析。flanneld
启动参数加上--iface=<iface-name>
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth0
安装完成后使用kubectl get pods
命令可以查看到我们集群中的组件运行状态,如果都是Running
状态的话,那么恭喜你,你的master
节点安装成功了。
$ kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-ydzs-master1 1/1 Running 0 10m
kube-system kube-apiserver-ydzs-master1 1/1 Running 0 10m
kube-system kube-controller-manager-ydzs-master1 1/1 Running 0 10m
kube-system kube-dns-86f4d74b45-f5595 3/3 Running 0 10m
kube-system kube-flannel-ds-qxjs2 1/1 Running 0 1m
kube-system kube-proxy-vf5fg 1/1 Running 0 10m
kube-system kube-scheduler-ydzs-master1 1/1 Running 0 10m
kubeadm
初始化完成后,默认情况下Pod
是不会被调度到master
节点上的,所以现在还不能直接测试普通的Pod
,需要添加一个工作节点后才可以。
添加节点
同样的上面的环境配置、docker 安装、kubeadmin、kubelet、kubectl 这些都在Node(192.168.11.2)节点安装配置好过后,我们就可以直接在 Node 节点上执行kubeadm join
命令了(上面初始化的时候有),同样加上参数--ignore-preflight-errors=Swap
:
$ kubeadm join 192.168.11.1:6443 --token 8xomlq.0cdf2pbvjs2gjho3 --discovery-token-ca-cert-hash sha256:92802317cb393682c1d1356c15e8b4ec8af2b8e5143ffd04d8be4eafb5fae368 --ignore-preflight-errors=Swap
[preflight] Running pre-flight checks.
[WARNING Swap]: running with swap on is not supported. Please disable swap
[WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
[discovery] Trying to connect to API Server "10.151.30.57:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://192.168.11.1:6443"
[discovery] Requesting info from "https://10.151.30.57:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "10.151.30.57:6443"
[discovery] Successfully established connection with API Server "10.151.30.57:6443"
This node has joined the cluster:
* Certificate signing request was sent to master and a response
was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the master to see this node join the cluster.
我们可以看到该节点已经加入到集群中去了,然后我们把master
节点的~/.kube/config
文件拷贝到当前节点对应的位置即可使用kubectl
命令行工具了。
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
evjfaxic Ready <none> 1h v1.10.0
ydzs-master1 Ready master 3h v1.10.0
创建个nginx pod测试一下
docker pull
registry.cn-hangzhou.aliyuncs.com/qinyujia-test/nginx
apiVersion: v1
kind: Pod
metadata:
name: nginx
labels:
app: nginx
spec:
containers:
- name: nginx
image: registry.cn-hangzhou.aliyuncs.com/qinyujia-test/nginx
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
restartPolicy: Always
---
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
type: NodePort
sessionAffinity: ClientIP
selector:
app: nginx
ports:
- port: 80
nodePort: 30080
kubectl create -f hello.yaml
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