使用kubeadm方式安装kubernetes 1.10.0
- 环境准备
#系统环境
lsb_release -a
Distributor ID: CentOS
Description: CentOS Linux release 7.3.1611 (Core)
Release: 7.3.1611
Codename: Core
说明：如提示：-bash: lsb_release: command not found，请yum install -y redhat-lsb
#查看selinux状态
getenforce
Disabled
#关闭防火墙
systemctl disable firewalld
systemctl stop firewalld
systemctl status firewalld
- docker安装部署 所需docker安装包，请点击17.03自行下载使用。
#docker安装
yum install -y yum-utils device-mapper-persistent-data lvm2
yum install -y docker-ce-selinux-17.03.1.ce-1.el7.centos.noarch.rpm
yum install -y docker-ce-17.03.1.ce-1.el7.centos.x86_64.rpm
#docker启动
systemctl enable docker
systemctl start docker
systemctl status docker
#docker 版本
docker --version
Docker version 17.03.1-ce, build c6d412e
- 基础镜像准备 本次演示 kubernetes 所依赖的各个镜像列表如下：
k8s.gcr.io/kube-apiserver-amd64:v1.10.0
k8s.gcr.io/kube-controller-manager-amd64:v1.10.0
k8s.gcr.io/kube-scheduler-amd64:v1.10.0
k8s.gcr.io/kube-proxy-amd64:v1.10.0
k8s.gcr.io/k8s-dns-dnsmasq-nanny-amd64:1.14.8
k8s.gcr.io/k8s-dns-sidecar-amd64:1.14.8
k8s.gcr.io/k8s-dns-kube-dns-amd64:1.14.8
k8s.gcr.io/pause-amd64:3.1
quay.io/coreos/flannel:v0.9.1
quay.io/calico/node:v2.6.2
quay.io/calico/cni:v1.11.0
k8s.gcr.io/etcd-amd64:3.1.12
k8s.gcr.io/heapster-amd64:v1.5.3
k8s.gcr.io/heapster-influxdb-amd64:v1.3.3
k8s.gcr.io/heapster-grafana-amd64:v4.4.3
k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3
k8s.gcr.io/kubernetes-dashboard-init-amd64:v1.0.1
所需镜像，请点击images自行下载。
- 系统配置 根据官方文档中limitations小节中的内容，对各节点系统做如下设置:
#设置系统参数 – 允许路由转发，不对bridge的数据进行处理
#创建/etc/sysctl.d/k8s.conf文件:
touch /etc/sysctl.d/k8s.conf
#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
sysctl -p /etc/sysctl.d/k8s.conf
使修改生效。
- 安装kubeadm和kubelet 下面在各节点安装kubeadm和kubelet
#配置yum源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
#生成缓存
yum clean all
yum makecache
#查看kubeadm, kubelet, kubectl的最新版本
yum list kubeadm --showduplicates |sort -r
kubeadm.x86_64 1.10.0-0 kubernetes
yum list kubelet --showduplicates |sort -r
kubelet.x86_64 1.10.0-0 kubernetes
yum list kubectl --showduplicates |sort -r
kubectl.x86_64 1.10.0-0 kubernetes
直接安装即可：
yum install -y kubelet kubeadm kubectl kubernetes-cni
#启动kubelet.service
systemctl enable kubelet.service
systemctl start kubelet.service
systemctl status kubelet.service
注意⚠️：阿里云的kubernetes的yum源是不断更新的，所以yum安装之前，请先确定下安装包版本是否是1.10.0的！
- 初始化master准备 #说明： （1）kubeadm 等相关 rpm 安装后会生成 /etc/kubernetes 目录，而 kubeadm init 时候又会检测这些目录是否存在，如果存在则停止初始化，所以要先清理一下。
#清理命令
kubeadm reset
参考官网tear down部分内容。
（2）初始化以前记得一定要启动 kubelet。
#启动命令如下：
systemctl enable kubelet
systemctl start kubelet
（3）安装ebtables包 新版本直接 init 会提示 ebtables not found in system path 错误，所以还得先安装一下这个包在初始化
#安装 ebtables
yum install -y ebtables
（4）修改kubelet配置文件
kubelet和docker 的cgroup driver 有2种方式:cgroupfs和systemd.注意保持 2个应用
的driver保持一致。
#查看kubelet的driver
cat /etc/systemd/system/kubelet.service.d/10-kubeadm.conf其中包含如下内容:
Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=systemd"
#查看docker的driver
docker info
Server Version: 17.03.1-ce
。。。
Cgroup Driver: cgroupfs
。。。
#更改kubelet的driver
Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=cgroupfs"
（5）关闭系统Swap Kubernetes 1.8开始要求关闭系统的Swap，如果不关闭，默认配置下kubelet将无法启动。可以通过kubelet的启动参数--fail-swap-on=false更改这个限制。
#关闭系统的Swap方法
swapoff -a
#修改 /etc/fstab 文件，注释掉 SWAP 的自动挂载，使用free -m确认swap已经关闭。 swappiness参数调整，修改/etc/sysctl.d/k8s.conf添加下面一行：
vm.swappiness=0
#执行
sysctl -p /etc/sysctl.d/k8s.conf
使修改生效。
说明：因为这里本次用于测试的主机上还运行其他服务，关闭swap可能会对其他服务产生影响，所以这里修改kubelet的启动参数--fail-swap-on=false去掉这个限制。 注意⚠️如果碰到一下错误：
[kubelet-check] The HTTP call equal to 'curl -sSL http://localhost:10255/healthz' failed with error: Get http://localhost:10255/healthz: dial tcp [::1]:10255: getsockopt: connection refused.
解决方法：
#修改/etc/systemd/system/kubelet.service.d/10-kubeadm.conf，加入：
Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false"
#使配置修改生效：
systemctl daemon-reload
- 使用kubeadm init初始化集群 #使用kubeadm初始化集群，在Master Node上执行下面的命令：
kubeadm init \
--kubernetes-version=v1.10.0 \
--pod-network-cidr=10.244.0.0/16 \
--apiserver-advertise-address=10.0.0.39 （master这台主机的IP）
#说明 我们选择flannel作为Pod网络插件，所以上面的命令指定–pod-network-cidr=10.244.0.0/16 #执行时的WARNING
[WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
#执行时如有：
[preflight] Some fatal errors occurred:
[ERROR Swap]: running with swap on is not supported. Please disable swap
请添加–ignore-preflight-errors=Swap参数忽略这个错误，重新运行。
即：
kubeadm init \
--kubernetes-version=v1.10.0 \
--pod-network-cidr=10.244.0.0/16 \
--apiserver-advertise-address=10.0.0.39 \
--ignore-preflight-errors=Swap
#整个初始化流程
kubeadm init --kubernetes-version=v1.10.0 --pod-network-cidr=10.244.0.0/16
--apiserver-advertise-address=10.0.0.39
[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 [swarm2 kubernetes
kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] an
d IPs [10.96.0.1 10.0.0.39]
[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 [swarm2] and IPs
[10.0.0.39]
[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.co
nf"
[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 22.002127 seconds
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in
the "kube-system" Namespace
[markmaster] Will mark node swarm2 as master by adding a label and a taint
[markmaster] Master swarm2 tainted and labelled with key/value:
node-role.kubernetes.io/master=""
[bootstraptoken] Using token: 4g0p8w.w5p29ukwvitim2ti
[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 10.0.0.39:6443 --token 4g0p8w.w5p29ukwvitim2ti --discovery-token
-ca-cert-hash sha256:21d0adbfcb409dca97e655641573b2ee51c77a212f194e20a3
07cb459e5f77c8
#关键内容说明
[certificates] 生成相关的各种证书
[kubeconfig] 接下来是生成证书和相关的kubeconfig文件，
这个目前我们在Kubernetes 1.6 高可用集群部署也是这么做的，
目前没看出有什么新东西。
[bootstraptoken] 生成token记录下来，后边使用kubeadm join往集群中添加节点时
会用到。
下面的命令是配置常规用户如何使用kubectl访问集群：
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 10.0.0.39:6443 --token 4g0p8w.w5p29ukwvitim2ti
--discovery-token-ca-cert-hash sha256:21d0adbfcb409dca97e655641573b2ee51c
77a212f194e20a307cb459e5f77c8
这条命令一定保存好！！
如果你需要重新做 kubeadm init ，那么我们最好把上次初始化和容器服务全部清理掉，具体步骤：
（1）kubeadm reset
（2）systemctl stop kubelet
（3）docker stop $(docker ps -qa) && docker rm $(docker ps -qa) ## 如果docker上有其他服务，请不要使用这个命令，这时你需要手动排查出kubernetes相关容器并删除
（4）systemctl start kubelet
（5）kubeadm init
- master节点验证 #查看一下集群状态
kubectl get cs
error: the server doesn't have a resource type "cs"
kubectl get nodes
Unable to connect to the server: x509: certificate signed by unknown authority
(possibly because of "crypto/rsa: verification error" while trying to verify
candidate authority certificate "kubernetes")
#解决方法：
mkdir -p /root/.kube/
cp -i /etc/kubernetes/admin.conf /root/.kube/config
chown root:root /root/.kube/config
#再次查看集群状态
kubectl get cs
NAME STATUS MESSAGE ERROR
controller-manager Healthy ok
scheduler Healthy ok
etcd-0 Healthy {"health": "true"}
#查看集群节点
kubectl get nodes
NAME STATUS ROLES AGE VERSION
swarm2 Ready master 1d v1.10.0
#命令行验证
命令：
curl --cacert /etc/kubernetes/pki/ca.crt --cert /etc/kubernetes/pki/apiserver-kubelet-client.crt --key /etc/kubernetes/pki/apiserver-kubelet-client.key https://10.0.0.39:6443
- 查看当前Network kubeadm init成功之后，此时的master node上k8s的核心组件均正常启动，而且是多以container的形式启动。
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c2eb8ca152a2 k8s.gcr.io/pause-amd64:3.1 "/pause" 20 minutes ago Up 20 minutes k8s_POD_kube-flannel-ds-nhjx5_kube-system_a3016d6d-51dd-11e8-a243-0017fa00e437_0
eb98616f7458 6f7f2dc7fab5 "/sidecar --v=2 --..." 25 minutes ago Up 25 minutes k8s_sidecar_kube-dns-86f4d74b45-ztrbs_kube-system_17bb3bf9-50e1-11e8-921b-0017fa00e437_4
912942318fed c2ce1ffb51ed "/dnsmasq-nanny -v..." 25 minutes ago Up 25 minutes k8s_dnsmasq_kube-dns-86f4d74b45-ztrbs_kube-system_17bb3bf9-50e1-11e8-921b-0017fa00e437_4
d5b193a4d60e 80cc5ea4b547 "/kube-dns --domai..." 25 minutes ago Up 25 minutes k8s_kubedns_kube-dns-86f4d74b45-ztrbs_kube-system_17bb3bf9-50e1-11e8-921b-0017fa00e437_4
c120c761b764 9df3c00f55e6 "kube-apiserver --..." 25 minutes ago Up 25 minutes k8s_kube-apiserver_kube-apiserver-swarm2_kube-system_659a6e4a0a2629e2c62563857da54a7f_3
81533f3ea2a7 k8s.gcr.io/pause-amd64:3.1 "/pause" 25 minutes ago Up 25 minutes k8s_POD_kube-dns-86f4d74b45-ztrbs_kube-system_17bb3bf9-50e1-11e8-921b-0017fa00e437_4
867ce7e1d7f8 ceecd7155649 "kube-scheduler --..." 25 minutes ago Up 25 minutes k8s_kube-scheduler_kube-scheduler-swarm2_kube-system_0ede54c0e24ebcdc8ec84ec2aa830bfc_4
01474f2a8879 6e6237849607 "/usr/local/bin/ku..." 25 minutes ago Up 25 minutes k8s_kube-proxy_kube-proxy-2tghd_kube-system_17c7aa1b-50e1-11e8-921b-0017fa00e437_4
be4c6d21dc4d 52920ad46f5b "etcd --peer-key-f..." 25 minutes ago Up 25 minutes k8s_etcd_etcd-swarm2_kube-system_11d7cb74cd31e890a93f59d783573f27_3
912413c032e1 8401bb3ff261 "kube-controller-m..." 25 minutes ago Up 25 minutes k8s_kube-controller-manager_kube-controller-manager-swarm2_kube-system_c9074b2decba8a970cedd0fa9c4dd366_3
6609d479936e k8s.gcr.io/pause-amd64:3.1 "/pause" 25 minutes ago Up 25 minutes k8s_POD_kube-apiserver-swarm2_kube-system_659a6e4a0a2629e2c62563857da54a7f_3
ddfb3e0b37f5 k8s.gcr.io/pause-amd64:3.1 "/pause" 25 minutes ago Up 25 minutes k8s_POD_kube-scheduler-swarm2_kube-system_0ede54c0e24ebcdc8ec84ec2aa830bfc_4
67c0c0001635 k8s.gcr.io/pause-amd64:3.1 "/pause" 25 minutes ago Up 25 minutes k8s_POD_kube-proxy-2tghd_kube-system_17c7aa1b-50e1-11e8-921b-0017fa00e437_4
5dac6220b6dc k8s.gcr.io/pause-amd64:3.1 "/pause" 25 minutes ago Up 25 minutes k8s_POD_etcd-swarm2_kube-system_11d7cb74cd31e890a93f59d783573f27_5
7c88b16b245d k8s.gcr.io/pause-amd64:3.1 "/pause" 25 minutes ago Up 25 minutes k8s_POD_kube-controller-manager-swarm2_kube-system_c9074b2decba8a970cedd0fa9c4dd366_4
不过这些核心组件并不是跑在pod network中的（没错，此时的pod network还没有创建），而是采用了host network。以kube-apiserver的pod信息为例：
kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
kube-apiserver-swarm2 1/1 Running 3 1d
#查看kube-apiserver的容器id
docker ps |grep apiserver
c120c761b764 9df3c00f55e6 "kube-apiserver --..." 33 minutes ago Up 33 minutes k8s_kube-apiserver_kube-apiserver-swarm2_kube-system_659a6e4a0a2629e2c62563857da54a7f_3
#查看对应的pause容器的network属性
docker inspect c120c761b764
"NetworkMode": "host",
- 安装flannel pod网络
#创建kube-flannel.yml
mkdir /etc/kubernetes/manifests/my.conf
#下载kube-flannel.yml文件
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
#修改文件
image:quay.io/coreos/flannel:v0.10.0-amd64
更改为：
image: quay.io/coreos/flannel:v0.9.1
#启动flannel
cd /etc/kubernetes/manifests/my.conf
kubectl create -f kube-flannel.yml
- 查看master中所有pod的状态
kubectl get pod --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE
kube-system etcd-swarm2 1/1 Running 3 1d 10.0.0.39 swarm2
kube-system kube-apiserver-swarm2 1/1 Running 3 1d 10.0.0.39 swarm2
kube-system kube-controller-manager-swarm2 1/1 Running 3 1d 10.0.0.39 swarm2
kube-system kube-dns-86f4d74b45-ztrbs 3/3 Running 12 1d 10.244.0.6 swarm2
kube-system kube-flannel-ds-nhjx5 1/1 Running 0 36m 10.0.0.39 swarm2
kube-system kube-proxy-2tghd 1/1 Running 4 1d 10.0.0.39 swarm2
kube-system kube-scheduler-swarm2 1/1 Running 4 1d 10.0.0.39 swarm2
或使用：
kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
etcd-swarm2 1/1 Running 3 1d
kube-apiserver-swarm2 1/1 Running 3 1d
kube-controller-manager-swarm2 1/1 Running 3 1d
kube-dns-86f4d74b45-ztrbs 3/3 Running 12 1d
kube-flannel-ds-nhjx5 1/1 Running 0 37m
kube-proxy-2tghd 1/1 Running 4 1d
kube-scheduler-swarm2 1/1 Running 4 1d
-
向Kubernetes集群添加／删除Node 关于这部分操作，请点击参考Node操作
-
参考文档
