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Kops on Aws

这也许是最简单直接的Kubernetes安装大法

kops这种方式是我找到的最佳的，最适合于培训课堂需要的安装方式，当然对有类似需求的人有帮助。

Route53 DNS配置

kops需要使用DNS服务，用主机名提供k8s的相关服务访问。配置的注意点：

  • 域名还是有必要有一个的，没有的话注册一个也不贵，以后用着也方便
  • 建议在aws的Route53里做一个二级域名，例如：k8s.devopscoach.org
  • 这个二级域名最好是能被正常公网解析的，为了便于直接访问集群里的服务
  • 用 dig NS k8s.devopscoach.org 可以能正常解析（Mac上是这个命令）

由于全球的域名同步会需要一些时间，因此可以先做这一步，用到的时候，可能就已经同步好了。

kops会将所有主机的域名解析都自动化的添加A记录到这里。

kops On aws

安装工具准备

需要安装的工具包括 kubectl, kops 和 AWS CLI 工具。kops需要调用 AWS CLI来创建所需要的资源。我觉得简单的方法是：在目标的Region里创建一台Amazon AMI的虚拟机，这样AWS CLI就不用装了，而且在云里的话，执行kops的时候，由于有一大堆资源创建更新的api调用，感觉速度比在本机快很多，而且还用担心断网。

可以启动一台t2.micro规格的Amazon AMI即可，另外需要给这个实例配置如下IAM用户权限，在启动的时候选择合适的IAM Role。

  • AmazonEC2FullAccess
  • AmazonRoute53FullAccess
  • AmazonS3FullAccess
  • IAMFullAccess
  • AmazonVPCFullAccess

这台虚拟机启动之后，安装kubectl和kops。

curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl
sudo chmod +x kubectl
sudo mv kubectl /usr/local/bin/kubectl


wget https://github.com/kubernetes/kops/releases/download/1.8.0/kops-linux-amd64
sudo chmod +x kops-linux-amd64
sudo mv kops-linux-amd64 /usr/local/bin/kops

准备ssh登陆秘钥，用户ssh登录各个ec2实例

[ec2-user@ip-172-31-27-182 ~]$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/ec2-user/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/ec2-user/.ssh/id_rsa.
Your public key has been saved in /home/ec2-user/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:oSPZf85vNsC7l9z24umLJs4tQ6qDMCrWfqAVXGYoA34 ec2-user@ip-172-31-27-182
The key's randomart image is:
+---[RSA 2048]----+
|o   .            |
|.o . +           |
| .+E+   .        |
|  .o o . .       |
|    + + S.       |
|  oo . o  +      |
| .+o..  .o.+ o   |
|oo .... .==.O.+. |
|o ... .o .*@+==+.|
+----[SHA256]-----+
[ec2-user@ip-172-31-27-182 ~]$

创建S3 bucket

这是用来存储Kubernetes群集的配置信息的，kops在创建、运行、更新和管理它创建的群集过程中，没个Cluster的信息可以保存在bucket的一个目录中。

[ec2-user@ip-172-31-27-182 ~]$ aws s3 mb s3://clusters.k8s.devopscoach.org
make_bucket: clusters.k8s.devopscoach.org
[ec2-user@ip-172-31-27-182 ~]$ export KOPS_STATE_STORE=s3://clusters.k8s.devopscoach.org

创建完成后，将其放入环境变量中待用。

在集群安装完成之后，bucket里面的文件如下：

kops On aws

创建Kubernetes Cluster

命令行参数如下：

  • kops create cluster //创建集群
  • –cloud=aws //使用aws
  • –zones=ap-northeast-1a //使用这个指定的zone
  • –name=dev.k8s.devopscoach.org //集群的名字
  • –dns-zone=k8s.devopscoach.org //集群所使用的DNS解析区
  • –dns public //对公可访问

命令的执行结果如下。

[ec2-user@ip-172-31-27-182 ~]$ kops create cluster --cloud=aws --zones=ap-northeast-1a --name=dev.k8s.devopscoach.org --dns-zone=k8s.devopscoach.org --dns public
I0401 17:05:06.003257   30031 create_cluster.go:971] Using SSH public key: /home/ec2-user/.ssh/id_rsa.pub
I0401 17:05:07.132058   30031 subnets.go:184] Assigned CIDR 172.20.32.0/19 to subnet ap-northeast-1a
Previewing changes that will be made:


*********************************************************************************

A new kops version is available: 1.8.1

Upgrading is recommended
More information: https://github.com/kubernetes/kops/blob/master/permalinks/upgrade_kops.md#1.8.1

*********************************************************************************

I0401 17:05:12.605297   30031 executor.go:91] Tasks: 0 done / 73 total; 31 can run
I0401 17:05:13.546597   30031 executor.go:91] Tasks: 31 done / 73 total; 24 can run

-----此处删除了n个字符------

  VPC/dev.k8s.devopscoach.org
        CIDR                    172.20.0.0/16
        EnableDNSHostnames      true
        EnableDNSSupport        true
        Shared                  false
        Tags                    {Name: dev.k8s.devopscoach.org, KubernetesCluster: dev.k8s.devopscoach.org, kubernetes.io/cluster/dev.k8s.devopscoach.org: owned}

  VPCDHCPOptionsAssociation/dev.k8s.devopscoach.org
        VPC                     name:dev.k8s.devopscoach.org
        DHCPOptions             name:dev.k8s.devopscoach.org

Must specify --yes to apply changes

Cluster configuration has been created.

Suggestions:
 * list clusters with: kops get cluster
 * edit this cluster with: kops edit cluster dev.k8s.devopscoach.org
 * edit your node instance group: kops edit ig --name=dev.k8s.devopscoach.org nodes
 * edit your master instance group: kops edit ig --name=dev.k8s.devopscoach.org master-ap-northeast-1a

Finally configure your cluster with: kops update cluster dev.k8s.devopscoach.org --yes

[ec2-user@ip-172-31-27-182 ~]$

kops命令列出了所有需要建立的资源清单。而真实的开始资源创建，并搭建和配置Kubernetes集群还需要执行，以上输出中提示的最后一条命令: kops update cluster dev.k8s.devopscoach.org --yes

执行结果如下：

[ec2-user@ip-172-31-27-182 ~]$ kops update cluster dev.k8s.devopscoach.org --yes

*********************************************************************************

A new kops version is available: 1.8.1

Upgrading is recommended
More information: https://github.com/kubernetes/kops/blob/master/permalinks/upgrade_kops.md#1.8.1

*********************************************************************************

I0401 17:13:02.482203   30077 executor.go:91] Tasks: 0 done / 73 total; 31 can run
I0401 17:13:04.389402   30077 vfs_castore.go:430] Issuing new certificate: "apiserver-aggregator-ca"
I0401 17:13:04.628667   30077 vfs_castore.go:430] Issuing new certificate: "ca"
I0401 17:13:07.291294   30077 executor.go:91] Tasks: 31 done / 73 total; 24 can run
I0401 17:13:09.273293   30077 vfs_castore.go:430] Issuing new certificate: "kubelet-api"
I0401 17:13:09.803612   30077 vfs_castore.go:430] Issuing new certificate: "kubelet"
I0401 17:13:09.809131   30077 vfs_castore.go:430] Issuing new certificate: "kube-scheduler"
I0401 17:13:09.973826   30077 vfs_castore.go:430] Issuing new certificate: "apiserver-proxy-client"
I0401 17:13:10.317412   30077 vfs_castore.go:430] Issuing new certificate: "kops"
I0401 17:13:10.321177   30077 vfs_castore.go:430] Issuing new certificate: "apiserver-aggregator"
I0401 17:13:10.440919   30077 vfs_castore.go:430] Issuing new certificate: "kube-controller-manager"
I0401 17:13:10.630182   30077 vfs_castore.go:430] Issuing new certificate: "kubecfg"
I0401 17:13:11.020560   30077 vfs_castore.go:430] Issuing new certificate: "master"
I0401 17:13:11.040010   30077 vfs_castore.go:430] Issuing new certificate: "kube-proxy"
I0401 17:13:12.698208   30077 executor.go:91] Tasks: 55 done / 73 total; 16 can run
I0401 17:13:13.609559   30077 launchconfiguration.go:333] waiting for IAM instance profile "nodes.dev.k8s.devopscoach.org" to be ready
I0401 17:13:13.656221   30077 launchconfiguration.go:333] waiting for IAM instance profile "masters.dev.k8s.devopscoach.org" to be ready
I0401 17:13:24.156701   30077 executor.go:91] Tasks: 71 done / 73 total; 2 can run
I0401 17:13:24.864262   30077 executor.go:91] Tasks: 73 done / 73 total; 0 can run
I0401 17:13:24.864379   30077 dns.go:153] Pre-creating DNS records
I0401 17:13:26.454177   30077 update_cluster.go:248] Exporting kubecfg for cluster
kops has set your kubectl context to dev.k8s.devopscoach.org

Cluster is starting.  It should be ready in a few minutes.

Suggestions:
 * validate cluster: kops validate cluster
 * list nodes: kubectl get nodes --show-labels
 * ssh to the master: ssh -i ~/.ssh/id_rsa admin@api.dev.k8s.devopscoach.org
The admin user is specific to Debian. If not using Debian please use the appropriate user based on your OS.
 * read about installing addons: https://github.com/kubernetes/kops/blob/master/docs/addons.md

以上这套组合拳打出去之后，需要等几分钟才能完成Kubernetes集群的部署。

在以上实例中创建的Ec2实例如下：

  • master-ap-northeast-1a.masters.dev.k8s.devopscoach.org //m3.medium
  • nodes.dev.k8s.devopscoach.org //t2.medium
  • nodes.dev.k8s.devopscoach.org //t2.medium

kops On aws

也创建了两个ASG：

  • 一个是针对master的扩容规则
  • 另外一个是针对worker node的扩容规则

从扩容规则为空可以看出，它主要是用于定义集群规格的，而非自动化扩容的。

kops On aws

在安装完成之后，用一下命令确认集群状态如下：

[ec2-user@ip-172-31-27-182 ~]$ kops validate cluster
Using cluster from kubectl context: dev.k8s.devopscoach.org

Validating cluster dev.k8s.devopscoach.org

INSTANCE GROUPS
NAME                    ROLE    MACHINETYPE     MIN     MAX     SUBNETS
master-ap-northeast-1a  Master  m3.medium       1       1       ap-northeast-1a
nodes                   Node    t2.medium       2       2       ap-northeast-1a

NODE STATUS
NAME                                                    ROLE    READY
ip-172-20-38-48.ap-northeast-1.compute.internal         master  True
ip-172-20-45-235.ap-northeast-1.compute.internal        node    True
ip-172-20-63-157.ap-northeast-1.compute.internal        node    True

Your cluster dev.k8s.devopscoach.org is ready
[ec2-user@ip-172-31-27-182 ~]$ kubectl get nodes --show-labels
NAME                                               STATUS    ROLES     AGE       VERSION   LABELS
ip-172-20-38-48.ap-northeast-1.compute.internal    Ready     master    5m        v1.8.7    beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=m3.medium,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=ap-northeast-1,failure-domain.beta.kubernetes.io/zone=ap-northeast-1a,kops.k8s.io/instancegroup=master-ap-northeast-1a,kubernetes.io/hostname=ip-172-20-38-48.ap-northeast-1.compute.internal,kubernetes.io/role=master,node-role.kubernetes.io/master=
ip-172-20-45-235.ap-northeast-1.compute.internal   Ready     node      4m        v1.8.7    beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=t2.medium,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=ap-northeast-1,failure-domain.beta.kubernetes.io/zone=ap-northeast-1a,kops.k8s.io/instancegroup=nodes,kubernetes.io/hostname=ip-172-20-45-235.ap-northeast-1.compute.internal,kubernetes.io/role=node,node-role.kubernetes.io/node=
ip-172-20-63-157.ap-northeast-1.compute.internal   Ready     node      4m        v1.8.7    beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=t2.medium,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=ap-northeast-1,failure-domain.beta.kubernetes.io/zone=ap-northeast-1a,kops.k8s.io/instancegroup=nodes,kubernetes.io/hostname=ip-172-20-63-157.ap-northeast-1.compute.internal,kubernetes.io/role=node,node-role.kubernetes.io/node=
[ec2-user@ip-172-31-27-182 ~]$

创建并访问服务

如下所示的创建两副本的nginx部署，部署的命令 sample-nginx。

[ec2-user@ip-172-31-27-182 ~]$ kubectl run sample-nginx --image=nginx --replicas=2 --port=80
deployment.apps "sample-nginx" created
[ec2-user@ip-172-31-27-182 ~]$ kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
sample-nginx-7588757c8f-jvkjt   1/1       Running   0          5s
sample-nginx-7588757c8f-zq8tj   1/1       Running   0          5s
[ec2-user@ip-172-31-27-182 ~]$ kubectl get deployments
NAME           DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
sample-nginx   2         2         2            2           13s

然后将这个部署暴露为服务，使用到Kubernetes的命令如下：

[ec2-user@ip-172-31-27-182 ~]$ kubectl expose deployment sample-nginx --port=80 --type=LoadBalancer
service "sample-nginx" exposed
[ec2-user@ip-172-31-27-182 ~]$ kubectl get services -o wide
NAME           TYPE           CLUSTER-IP      EXTERNAL-IP                                                                   PORT(S)        AGE      SELECTOR
kubernetes     ClusterIP      100.64.0.1      <none>                                                                        443/TCP        10m      <none>
sample-nginx   LoadBalancer   100.64.127.19   ae3a1ca9235d111e890d706038dd676b-392190656.ap-northeast-1.elb.amazonaws.com   80:30363/TCP   25s      run=sample-nginx

这条命令 ubectl expose deployment sample-nginx --port=80 --type=LoadBalancer 会创建一个ELB并将，集群里容正在运行的 sample—nginx 服务注册到这个ELB，然后就可以访问浏览到Nginx的默认页面了。

kops On aws

删除集群

用一条命令就能删除以上所建立的Kubernetes集群。

kops delete cluster --name=dev.k8s.devopscoach.org --yes
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