寫在前面
本章是kubernetes系列教程第二=篇，主要介紹通過kubeadm安裝工具部署kubernetes集羣，考慮到國內網絡限制，已將鏡像下載到網盤，方便大家可離線部署。
1. 環境概述
1.1 安裝概述
kubernetes常規的安裝方式包含兩種：二進制手動安裝和kubeadm自動化安裝，新版kubeadm目前已將kubernetes管理組件以pod的形式部署在集羣中，社區目前推薦使用kubeadm的方式一件自動化部署，有興趣的也可以通過二進制的方式一步一步部署kubernetes集羣。不管用哪種方式，受限於GFW，大部分鏡像需要***才能下載，大家自行補腦和解決，本文以離線的方式安裝部署，將下載的鏡像倒入到各個安裝即可。
1.2 環境介紹
軟件版本
| 軟件名 | 軟件版本 |
|---|---|
| OS | CentOS Linux release 7.6.1810 (Core) |
| Docker | docker-ce-18.03.1.ce-1.el7 |
| Kubernetes | 1.14.1 |
| Kubeadm | kubeadm-1.14.1-0.x86_64 |
| etcd | 3.3.10 |
| flannel | v0.11.0 |
環境說明,三臺機器均爲騰訊雲上購買的CVM（Cloud Virtual Machine），機器配置是2vcpu+4G memory+50G disk
| 主機名 | 角色 | IP地址 | 軟件 |
|---|---|---|---|
| node-1 | master | 10.254.100.101 | docker,kubelet,etcd,kube-apiserver,kube-controller-manager,kube-scheduler |
| node-2 | worker | 10.254.100.102 | docker,kubelet,kube-proxy,flannel |
| node-3 | worker | 10.254.100.103 | docker,kubelet,kube-proxy,flannel |
1.3 環境準備
1. 設置主機名，其他兩個節點類似設置
root@VM_100_101_centos ~# hostnamectl set-hostname node-1
root@VM_100_101_centos ~# hostname
node-12. 設置hosts文件，其他兩個節點設置相同內容
root@node-1 ~# vim /etc/hosts
127.0.0.1 localhost localhost.localdomain
10.254.100.101 node-1
10.254.100.102 node-2
10.254.100.103 node-33.設置無密碼登陸
生成密鑰對
root@node-1 .ssh# ssh-keygen -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:zultDMEL8bZmpbUjQahVjthVAcEkN929w5EkUmPkOrU root@node-1
The key's randomart image is:
+---RSA 2048----+
| .=O=+=o.. |
| o+o..+.o+ |
| .oo=. o. o |
| . . * oo .+ |
| oSOo.E . |
| oO.o. |
| o++ . |
| . .o |
| ... |
+----SHA256-----+拷貝公鑰到node-2和node-3節點
root@node-1 .ssh# ssh-copy-id -i /root/.ssh/id_rsa.pub node-2:
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
The authenticity of host 'node-1 (10.254.100.101)' can't be established.
ECDSA key fingerprint is SHA256:jLUH0exgyJdsy0frw9R+FiWy+0o54LgB6dgVdfc6SEE.
ECDSA key fingerprint is MD5:f4:86:a8:0e:a6:03:fc:a6:04:df:91:d8:7a:a7:0d:9e.
Are you sure you want to continue connecting (yes/no)? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@node-1's password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh 'node-2'"
and check to make sure that only the key(s) you wanted were added.拷貝公鑰到node-3節點
root@node-1 .ssh# ssh-copy-id -i /root/.ssh/id_rsa.pub node-3:
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@node-3's password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh 'node-3'"
and check to make sure that only the key(s) you wanted were added.4.測試無密碼登陸
root@node-1 ~# ssh node-2 hostname
node-2
root@node-1 ~# ssh node-3 hostname
node-35. 關閉防火牆和SElinux
[root@node-1 ~]# systemctl stop firewalld
[root@node-1 ~]# systemctl disable firewalld
[root@node-1 ~]# sed -i '/^SELINUX=/ s/enforcing/disabled/g' /etc/selinux/config
[root@node-1 ~]# setenforce 01.4 安裝Docker
1. 下載docker源
[root@node-1 ~]# wget -O /etc/yum.repos.d/docker-ce.repo https://download.docker.com/linux/centos/docker-ce.repo2.安裝docker-ce
[root@node-1 ~]# yum install docker-ce-18.03.1.ce-1.el7.centos3. 設置cgroup driver類型爲systemd
[root@node-1 ~]# 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"
> ]
> }
> EOF4. 啓動docker服務並驗證
[root@node-1 ~]# systemctl restart docker
[root@node-1 ~]# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@node-1 ~]# docker version
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 8
Server Version: 18.03.1-ce
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: systemd
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 773c489c9c1b21a6d78b5c538cd395416ec50f88
runc version: 4fc53a81fb7c994640722ac585fa9ca548971871
init version: 949e6fa
Security Options:
seccomp
Profile: default
Kernel Version: 3.10.0-957.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 3.701GiB
Name: node-1
ID: WCUZ:IJ3M:XGX4:S77A:3UG5:PTL4:MFJE:NNUT:IP4J:4PFU:OYMQ:X4LG
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false5. 驗證安裝
[root@node-1 ~]# docker info
Client:
Debug Mode: false
Server:
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 0
Server Version: 19.03.1
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: systemd. #cgroup驅動類型
Plugins:
Volume: local
Network: bridge host ipvlan macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 894b81a4b802e4eb2a91d1ce216b8817763c29fb
runc version: 425e105d5a03fabd737a126ad93d62a9eeede87f
init version: fec3683
Security Options:
seccomp
Profile: default
Kernel Version: 3.10.0-957.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 3.701GiB
Name: node-1
ID: WCUZ:IJ3M:XGX4:S77A:3UG5:PTL4:MFJE:NNUT:IP4J:4PFU:OYMQ:X4LG
Docker Root Dir: /var/lib/docker
Debug Mode: false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled2. 安裝kubernetes集羣
2.1 安裝kubeadm等組件
1. 安裝kubernetes源，國內可以使用阿里的kubernetes源，速度會快一點
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
2. 安裝kubeadm，kubelet，kubectl
[root@node-1 ~]# yum install kubeadm-1.14.1-0 kubectl-1.14.1-0 kubelet-1.14.1-0 --disableexcludes=kubernetes -y
已加載插件：fastestmirror, langpacks
Loading mirror speeds from cached hostfile
正在解決依賴關係
--> 正在檢查事務
---> 軟件包 kubeadm.x86_64.0.1.14.1-0 將被 安裝
--> 正在處理依賴關係 kubernetes-cni >= 0.7.5，它被軟件包 kubeadm-1.14.1-0.x86_64 需要
--> 正在處理依賴關係 cri-tools >= 1.11.0，它被軟件包 kubeadm-1.14.1-0.x86_64 需要
---> 軟件包 kubectl.x86_64.0.1.14.1-0 將被 安裝
---> 軟件包 kubelet.x86_64.0.1.14.1-0 將被 安裝
--> 正在處理依賴關係 socat，它被軟件包 kubelet-1.14.1-0.x86_64 需要
--> 正在處理依賴關係 conntrack，它被軟件包 kubelet-1.14.1-0.x86_64 需要
--> 正在檢查事務
---> 軟件包 conntrack-tools.x86_64.0.1.4.4-4.el7 將被 安裝
--> 正在處理依賴關係 libnetfilter_cttimeout.so.1(LIBNETFILTER_CTTIMEOUT_1.1)(64bit)，它被軟件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在處理依賴關係 libnetfilter_cttimeout.so.1(LIBNETFILTER_CTTIMEOUT_1.0)(64bit)，它被軟件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在處理依賴關係 libnetfilter_cthelper.so.0(LIBNETFILTER_CTHELPER_1.0)(64bit)，它被軟件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在處理依賴關係 libnetfilter_queue.so.1()(64bit)，它被軟件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在處理依賴關係 libnetfilter_cttimeout.so.1()(64bit)，它被軟件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
--> 正在處理依賴關係 libnetfilter_cthelper.so.0()(64bit)，它被軟件包 conntrack-tools-1.4.4-4.el7.x86_64 需要
---> 軟件包 cri-tools.x86_64.0.1.13.0-0 將被 安裝
---> 軟件包 kubernetes-cni.x86_64.0.0.7.5-0 將被 安裝
---> 軟件包 socat.x86_64.0.1.7.3.2-2.el7 將被 安裝
--> 正在檢查事務
---> 軟件包 libnetfilter_cthelper.x86_64.0.1.0.0-9.el7 將被 安裝
---> 軟件包 libnetfilter_cttimeout.x86_64.0.1.0.0-6.el7 將被 安裝
---> 軟件包 libnetfilter_queue.x86_64.0.1.0.2-2.el7_2 將被 安裝
--> 解決依賴關係完成
依賴關係解決
==========================================================================================================================================================
Package 架構 版本 源 大小
==========================================================================================================================================================
正在安裝:
kubeadm x86_64 1.14.1-0 kubernetes 8.7 M
kubectl x86_64 1.14.1-0 kubernetes 9.5 M
kubelet x86_64 1.14.1-0 kubernetes 23 M
爲依賴而安裝:
conntrack-tools x86_64 1.4.4-4.el7 os 186 k
cri-tools x86_64 1.13.0-0 kubernetes 5.1 M
kubernetes-cni x86_64 0.7.5-0 kubernetes 10 M
libnetfilter_cthelper x86_64 1.0.0-9.el7 os 18 k
libnetfilter_cttimeout x86_64 1.0.0-6.el7 os 18 k
libnetfilter_queue x86_64 1.0.2-2.el7_2 os 23 k
socat x86_64 1.7.3.2-2.el7 os 290 k
事務概要
==========================================================================================================================================================
需要安裝幾個重要依賴包：socat，cri-tools，cni等。
3. 設置iptables網橋參數
[root@node-1 ~]# cat <<EOF > /etc/sysctl.d/k8s.conf
> net.bridge.bridge-nf-call-ip6tables = 1
> net.bridge.bridge-nf-call-iptables = 1
> EOF
[root@node-1 ~]# sysctl --system,然後使用sysctl -a|grep 參數的方式驗證是否生效
4. 啓動kubelet服務
[root@node-1 ~]# systemctl restart kubelet
[root@node-1 ~]# systemctl enable kubelet2.2 倒入安裝鏡像
從網盤中（地址：https://pan.baidu.com/s/1hw8Q0Vf3xvhKoEiVtMi6SA）將kubernetes所需的鏡像下載到本地並解壓，進入到kubernetes/v.14.1目錄下，執行如下操作步驟：1.從雲盤中下載鏡像並上傳到各個節點，進入到鏡像所在節點，倒入到環境。
[root@node-1 v1.14.1]# docker image load -i etcd:3.3.10.tar
[root@node-1 v1.14.1]# docker image load -i pause:3.1.tar
[root@node-1 v1.14.1]# docker image load -i coredns:1.3.1.tar
[root@node-1 v1.14.1]# docker image load -i flannel:v0.11.0-amd64.tar
[root@node-1 v1.14.1]# docker image load -i kube-apiserver:v1.14.1.tar
[root@node-1 v1.14.1]# docker image load -i kube-controller-manager:v1.14.1.tar
[root@node-1 v1.14.1]# docker image load -i kube-scheduler:v1.14.1.tar
[root@node-1 v1.14.1]# docker image load -i kube-proxy:v1.14.1.tar
2. 檢查鏡像列表
[root@node-1 v1.14.1]# docker image list
REPOSITORY TAG IMAGE ID CREATED SIZE
k8s.gcr.io/kube-proxy v1.14.1 20a2d7035165 3 months ago 82.1MB
k8s.gcr.io/kube-apiserver v1.14.1 cfaa4ad74c37 3 months ago 210MB
k8s.gcr.io/kube-scheduler v1.14.1 8931473d5bdb 3 months ago 81.6MB
k8s.gcr.io/kube-controller-manager v1.14.1 efb3887b411d 3 months ago 158MB
quay.io/coreos/flannel v0.11.0-amd64 ff281650a721 6 months ago 52.6MB
k8s.gcr.io/coredns 1.3.1 eb516548c180 6 months ago 40.3MB
k8s.gcr.io/etcd 3.3.10 2c4adeb21b4f 8 months ago 258MB
k8s.gcr.io/pause 3.1 da86e6ba6ca1 19 months ago 742kB2.3 kubeadm初始化集羣
1. kubeadm初始化集羣，使用kubeadm初始化的時候需要使用--pod-network-cidr指定pod使用的網段，設置值根據不同的網絡plugin選擇，本文以flannel爲例設置值爲10.244.0.0/16（如果設置不一樣，需要在後續初始化網絡插件時候和對應插件的yaml文件保持一致），此外如果安裝有多個不同的container runtime可以通過--cri-socket指定socket文件所屬路徑，如果有多個網卡可以通過--apiserver-advertise-address指定master地址，缺省會選擇雲主機默認網關所屬的地址。
[root@node-1 ~]# kubeadm init --apiserver-advertise-address 10.254.100.101 --apiserver-bind-port 6443 --kubernetes-version 1.14.1 --pod-network-cidr 10.244.0.0/16
[init] Using Kubernetes version: v1.14.1
[preflight] Running pre-flight checks
[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.03.1-ce. Latest validated version: 18.09
[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'#下載鏡像
[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"#生成CA等證書
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [node-1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.254.100.101]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [node-1 localhost] and IPs [10.254.100.101 127.0.0.1 ::1]
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [node-1 localhost] and IPs [10.254.100.101 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "sa" key and public 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"#生成master節點靜態pod配置文件
[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 18.012370 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 node-1 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node node-1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: r8n5f2.9mic7opmrwjakled
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles#配置RBAC授權
[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 #配置環境變量配置文件
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: #安裝網絡插件
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:
kubeadm join 10.254.100.101:6443 --token r8n5f2.9mic7opmrwjakled \ #添加節點命令，優先記錄下來
--discovery-token-ca-cert-hash sha256:16e383c8abff6233021331944080087f0514ddd15d96c65d19443b0af02d64ab 通過kubeadm init --apiserver-advertise-address 10.254.100.101 --apiserver-bind-port 6443 --kubernetes-version 1.14.1 --pod-network-cidr 10.244.0.0/16安裝命令，顯示了kubeadm安裝過程中的一些重要步驟：下載鏡像，生成證書，生成配置文件，配置RBAC授權認證，配置環境變量，安裝網絡插件指引，添加node指引配置文件。
2.生成kubectl環境配置文件
[root@node-1 ~]# mkdir /root/.kube
[root@node-1 ~]# cp -i /etc/kubernetes/admin.conf /root/.kube/config
[root@node-1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
node-1 NotReady master 6m29s v1.14.13. 添加node節點，將另外兩個節點加入到集羣中，複製上述的添加節點命令到指定節點添加即可。
[root@node-3 ~]# kubeadm join 10.254.100.101:6443 --token r8n5f2.9mic7opmrwjakled \
> --discovery-token-ca-cert-hash sha256:16e383c8abff6233021331944080087f0514ddd15d96c65d19443b0af02d64ab
[preflight] Running pre-flight checks
[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.03.1-ce. Latest validated version: 18.09
[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.
以此類推到node-2節點添加即可，添加完之後通過kubectl get nodes驗證，此時由於還沒有安裝網絡plugin，
所有的node節點均顯示NotReady狀態：
[root@node-1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
node-1 NotReady master 16m v1.14.1
node-2 NotReady <none> 4m34s v1.14.1
node-3 NotReady <none> 2m10s v1.14.1- 安裝網絡plugin，kubernetes支持多種類型網絡插件，要求網絡支持CNI插件即可，CNI是Container Network Interface，要求kubernetes的中pod網絡訪問方式：node和node之間網絡互通，pod和pod之間網絡互通，node和pod之間網絡互通，不同的CNI plugin支持的特性有所差別。kubernetes支持多種開源的網絡CNI插件，常見的有flannel，calico，canal，weave等。flannel是一種overlay的網絡模型，通過vxlan隧道方式構建tunnel網絡，實現k8s中網絡的互聯，後續在做介紹，如下是安裝過程：
[root@node-1 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml
podsecuritypolicy.extensions/psp.flannel.unprivileged created
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-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created通過上述輸出可知道，部署flannel 需要RBAC授權，配置configmap和daemonset，其中Daemonset能夠適配各種類型的CPU架構，默認安裝了多個，一般是adm64即可，可以將上述的url下載編輯，保留kube-flannel-ds-amd64這個daemonset即可，或者將其刪除
1. 查看flannel安裝的daemonsets
[root@node-1 ~]# kubectl get daemonsets -n kube-system
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
kube-flannel-ds-amd64 3 3 3 3 3 beta.kubernetes.io/arch=amd64 2m34s
kube-flannel-ds-arm 0 0 0 0 0 beta.kubernetes.io/arch=arm 2m34s
kube-flannel-ds-arm64 0 0 0 0 0 beta.kubernetes.io/arch=arm64 2m34s
kube-flannel-ds-ppc64le 0 0 0 0 0 beta.kubernetes.io/arch=ppc64le 2m34s
kube-flannel-ds-s390x 0 0 0 0 0 beta.kubernetes.io/arch=s390x 2m34s
kube-proxy 3 3 3 3 3 <none> 30m
刪除不需要的damonsets
[root@node-1 ~]# kubectl delete daemonsets kube-flannel-ds-arm kube-flannel-ds-arm64 kube-flannel-ds-ppc64le kube-flannel-ds-s390x -n kube-system
daemonset.extensions "kube-flannel-ds-arm" deleted
daemonset.extensions "kube-flannel-ds-arm64" deleted
daemonset.extensions "kube-flannel-ds-ppc64le" deleted
daemonset.extensions "kube-flannel-ds-s390x" deleted此時再驗證node的安裝情況,所有節點均已顯示爲Ready狀態，安裝完畢！
[root@node-1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
node-1 Ready master 29m v1.14.1
node-2 Ready <none> 17m v1.14.1
node-3 Ready <none> 15m v1.14.12.4 配置kubectl命令補全功能
使用kubectl和kubernetes交互時候可以使用縮寫模式也可以使用完整模式，如kubectl get nodes和kubectl get no能實現一樣的效果，爲了提高工作效率，可以使用命令補全的方式加快工作效率。
[root@node-1 ~]# kubectl completion bash >/etc/kubernetes/kubectl.sh
[root@node-1 ~]# echo "source /etc/kubernetes/kubectl.sh" >>/root/.bashrc
[root@node-1 ~]# cat /root/.bashrc
# .bashrc
# User specific aliases and functions
alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'
# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
source /etc/kubernetes/kubectl.
使配置生效
[root@node-1 ~]# source /etc/kubernetes/kubectl.sh
命令行中輸入kubectl get co再按TAB鍵就能自動補全了
[root@node-1 ~]# kubectl get co
componentstatuses configmaps controllerrevisions.apps
[root@node-1 ~]# kubectl get componentstatuses 3. 驗證安裝服務狀態
- 驗證node狀態
獲取node的列表，可以查看到狀態， 角色，啓動市場，版本，
[root@node-1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
node-1 Ready master 46m v1.14.1
node-2 Ready <none> 34m v1.14.1
node-3 Ready <none> 32m v1.14.1
查看node的詳細信息，可以查看到標籤，地址，資源情況，資源分配情況，event日誌信息等
[root@node-1 ~]# kubectl describe node node-1
Name: node-1
Roles: master
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=node-1
kubernetes.io/os=linux
node-role.kubernetes.io/master=
Annotations: flannel.alpha.coreos.com/backend-data: {"VtepMAC":"3a:32:d1:a2:ac:e2"}
flannel.alpha.coreos.com/backend-type: vxlan
flannel.alpha.coreos.com/kube-subnet-manager: true
flannel.alpha.coreos.com/public-ip: 10.254.100.101
kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
node.alpha.kubernetes.io/ttl: 0
volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp: Sat, 10 Aug 2019 17:35:45 +0800
Taints: node-role.kubernetes.io/master:NoSchedule
Unschedulable: false
Conditions:
Type Status LastHeartbeatTime LastTransitionTime Reason Message
---- ------ ----------------- ------------------ ------ -------
MemoryPressure False Sat, 10 Aug 2019 18:22:26 +0800 Sat, 10 Aug 2019 17:35:42 +0800 KubeletHasSufficientMemory kubelet has sufficient memory available
DiskPressure False Sat, 10 Aug 2019 18:22:26 +0800 Sat, 10 Aug 2019 17:35:42 +0800 KubeletHasNoDiskPressure kubelet has no disk pressure
PIDPressure False Sat, 10 Aug 2019 18:22:26 +0800 Sat, 10 Aug 2019 17:35:42 +0800 KubeletHasSufficientPID kubelet has sufficient PID available
Ready True Sat, 10 Aug 2019 18:22:26 +0800 Sat, 10 Aug 2019 18:04:26 +0800 KubeletReady kubelet is posting ready status
Addresses:
InternalIP: 10.254.100.101
Hostname: node-1
Capacity:
cpu: 2
ephemeral-storage: 51473868Ki
hugepages-2Mi: 0
memory: 3880524Ki
pods: 110
Allocatable:
cpu: 2
ephemeral-storage: 47438316671
hugepages-2Mi: 0
memory: 3778124Ki
pods: 110
System Info:
Machine ID: 0ea734564f9a4e2881b866b82d679dfc
System UUID: DA7F90FC-7E95-4570-A0E9-317270B8EE3C
Boot ID: 84b9bebb-598b-48ab-b0c4-bbd19d8d566e
Kernel Version: 3.10.0-957.el7.x86_64
OS Image: CentOS Linux 7 (Core)
Operating System: linux
Architecture: amd64
Container Runtime Version: docker://18.3.1
Kubelet Version: v1.14.1
Kube-Proxy Version: v1.14.1
PodCIDR: 10.244.0.0/24
Non-terminated Pods: (5 in total)
Namespace Name CPU Requests CPU Limits Memory Requests Memory Limits AGE
--------- ---- ------------ ---------- --------------- ------------- ---
kube-system etcd-node-1 0 (0%) 0 (0%) 0 (0%) 0 (0%) 46m
kube-system kube-apiserver-node-1 250m (12%) 0 (0%) 0 (0%) 0 (0%) 46m
kube-system kube-controller-manager-node-1 200m (10%) 0 (0%) 0 (0%) 0 (0%) 46m
kube-system kube-proxy-x5t6r 0 (0%) 0 (0%) 0 (0%) 0 (0%) 47m
kube-system kube-scheduler-node-1 100m (5%) 0 (0%) 0 (0%) 0 (0%) 46m
Allocated resources:
(Total limits may be over 100 percent, i.e., overcommitted.)
Resource Requests Limits
-------- -------- ------
cpu 550m (27%) 0 (0%)
memory 0 (0%) 0 (0%)
ephemeral-storage 0 (0%) 0 (0%)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 47m kubelet, node-1 Starting kubelet.
Normal NodeHasSufficientMemory 47m (x8 over 47m) kubelet, node-1 Node node-1 status is now: NodeHasSufficientMemory
Normal NodeHasNoDiskPressure 47m (x8 over 47m) kubelet, node-1 Node node-1 status is now: NodeHasNoDiskPressure
Normal NodeHasSufficientPID 47m (x7 over 47m) kubelet, node-1 Node node-1 status is now: NodeHasSufficientPID
Normal NodeAllocatableEnforced 47m kubelet, node-1 Updated Node Allocatable limit across pods
Normal Starting 47m kube-proxy, node-1 Starting kube-proxy.
Normal NodeReady 18m kubelet, node-1 Node node-1 status is now: NodeReady
- 查看組建狀態,kubernetes中核心的組建，包括scheduler，controller-manager，etcd
[root@node-1 ~]# kubectl get componentstatuses
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health":"true"} - 查看pod的情況,master中的角色包括kube-apiserver，kube-scheduler，kube-controller-manager，etcd，coredns以pods形式部署在集羣中，worker節點的kube-proxy也以pod的形式部署。實際上pod是以其他控制器如daemonset的形式控制的。
查看當前系統中所有運行的pods狀態。
[root@node-1 ~]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-fb8b8dccf-hrqm8 1/1 Running 0 50m
coredns-fb8b8dccf-qwwks 1/1 Running 0 50m
etcd-node-1 1/1 Running 0 48m
kube-apiserver-node-1 1/1 Running 0 49m
kube-controller-manager-node-1 1/1 Running 0 49m
kube-proxy-lfckv 1/1 Running 0 38m
kube-proxy-x5t6r 1/1 Running 0 50m
kube-proxy-x8zqh 1/1 Running 0 36m
kube-scheduler-node-1 1/1 Running 0 49m
查看daemonsets和deployments列表
[root@node-1 ~]# kubectl get ds -n kube-system
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
kube-flannel-ds-amd64 3 3 3 3 3 beta.kubernetes.io/arch=amd64 3m21s
kube-proxy 3 3 3 3 3 <none> 58m
[root@node-1 ~]# kubectl get deployments -n kube-system
NAME READY UP-TO-DATE AVAILABLE AGE
coredns 2/2 2 2 58m
上述輸出中可以看到flannel和kube-proxy是以Daemonsets的形式部署在集羣中，coredns是以deployments的形式部署，
但並未看到kube-apiserver等控制器，實際上master的組件是一種靜態pod（static pod）的形式部署在集羣中。4. 參考文檔
-
Container Runtime安裝文檔https://kubernetes.io/docs/setup/production-environment/container-runtimes/
-
kubeadm安裝https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
- 初始化kubeadm集羣https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/#pod-network
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