Kubernetes 1.6 高可用集群部署

Kubernetes 1.6 高可用集群部署

2017-04-25
Kubernetes

我们已经可以很方便的使用kubeadm快速初始化Kubernetes集群,但kubeadm当前还不能用于生产环境,同时kubeadm初始化的集群的Master节点不是高可用的,后端存储etcd也是单点。因此,本文将基于Kubernetes二进制包手动部署一个高可用的Kubernetes 1.6集群,将启用ApiServer的TLS双向认证和RBAC授权等安全机制。 通过这个手动部署的过程,我们还可以更加深入理解Kubernetes各组件的交互和运行原理。

kubernetes-ha

1. 环境准备 #

1.1 系统环境 #

操作系统CentOS 7.3

1192.168.61.11 node1
2192.168.61.12 node2
3192.168.61.13 node3

1.2 安装包下载 #

这里下载kubernetes二进制安装包:

1wget https://dl.k8s.io/v1.6.2/kubernetes-server-linux-amd64.tar.gz
2
3tar -zxvf kubernetes-server-linux-amd64.tar.g

1.3 系统配置 #

在各节点创建/etc/sysctl.d/k8s.conf文件,添加如下内容:

1net.bridge.bridge-nf-call-ip6tables = 1
2net.bridge.bridge-nf-call-iptables = 1

执行sysctl -p /etc/sysctl.d/k8s.conf使修改生效。

禁用selinux:

1setenforce 0
2vi /etc/selinux/config
3SELINUX=disabled

1.3 etcd高可用集群部署 #

Kubernetes使用etcd作为ApiServer的持久化存储,因此需要部署高可用的etcd集群,安全要求我们为etcd集群开启TLS通信和认证。 在node1~node3三个节点上部署etcd集群,这里不再展开,可参考前面写的一篇《etcd 3.1 高可用集群搭建》

最终部署的etcd集群如下:

1node1 https://192.168.61.11:2379
2node2 https://192.168.61.12:2379
3node3 https://192.168.61.13:2379

1.4 在各节点安装Docker #

在集群各个服务器节点上安装Docker。根据最近的文档Kubernetes 1.6还没有针对docker 1.13和最新的docker 17.03上做测试和验证,所以这里安装Kubernetes官方推荐的Docker 1.12版本。Docker的安装比较简单,这里也不展开,可参考《使用kubeadm安装Kubernetes 1.6》中的“安装Docker 1.12”章节。

2. Kubernetes各组件TLS证书和密钥 #

我们将禁用kube-apiserver的HTTP端口,启用Kubernetes集群相关组件的TLS通信和双向认证,下面将使用工具生成各组件TLS的证书和私钥。

我们将使用cfssl生成所需要的私钥和证书。 cfssl在《etcd 3.1 高可用集群搭建》中已经用过,这里直接使用。

2.1 CA证书和私钥 #

复用《etcd 3.1 高可用集群搭建》中使用的ca-config.json:

 1{
 2  "signing": {
 3    "default": {
 4      "expiry": "87600h"
 5    },
 6    "profiles": {
 7      "frognew": {
 8        "usages": [
 9            "signing",
10            "key encipherment",
11            "server auth",
12            "client auth"
13        ],
14        "expiry": "87600h"
15      }
16    }
17  }
18}

创建CA证书签名请求配置ca-csr.json:

 1{
 2  "CN": "kubernetes",
 3  "key": {
 4    "algo": "rsa",
 5    "size": 2048
 6  },
 7  "names": [
 8    {
 9      "C": "CN",
10      "ST": "BeiJing",
11      "L": "BeiJing",
12      "O": "k8s",
13      "OU": "cloudnative"
14    }
15  ]
16}
  • CN即Common Name,kube-apiserver从证书中提取该字段作为请求的用户名
  • O即Organization,kube-apiserver 从证书中提取该字段作为请求用户所属的组

下面使用cfss生成CA证书和私钥:

1cfssl gencert -initca ca-csr.json | cfssljson -bare ca
1ls
2ca-config.json  ca.csr  ca-csr.json  ca-key.pem  ca.pem

ca-key.pem和ca.pem需要保存在一个安全的地方,后边会用到。

2.2 创建kube-apiserver证书和私钥 #

创建kube-apiserver证书签名请求配置apiserver-csr.json:

 1{
 2    "CN": "kubernetes",
 3    "hosts": [
 4      "127.0.0.1",
 5      "192.168.61.10",
 6      "192.168.61.11",
 7      "192.168.61.12",
 8      "192.168.61.13",
 9      "10.96.0.1",
10      "kubernetes",
11      "kubernetes.default",
12      "kubernetes.default.svc",
13      "kubernetes.default.svc.cluster",
14      "kubernetes.default.svc.cluster.local"
15    ],
16    "key": {
17        "algo": "rsa",
18        "size": 2048
19    },
20    "names": [
21        {
22            "C": "CN",
23            "ST": "BeiJing",
24            "L": "BeiJing",
25            "O": "k8s",
26            "OU": "cloudnative"
27        }
28    ]
29}

注意上面配置hosts字段中指定授权使用该证书的IP和域名列表,因为现在要生成的证书需要被Kubernetes Master集群各个节点使用,所以这里指定了各个节点的IP和hostname。 另外,我们为了实现kube-apiserver的高可用,我们将在其前面部署一个高可用的负载均衡器,Kubernetes的一些核心组件,通过这个负载均衡器和apiserver进行通信,因此这里在证书请求配置的hosts字段中还要加上这个负载均衡器的IP地址,这里是192.168.61.10。 同时还要指定集群内部kube-apiserver的多个域名和IP地址10.96.0.1(后边kube-apiserver-service-cluster-ip-range=10.96.0.0/12参数的指定网段的第一个IP)。

下面生成kube-apiserver的证书和私钥:

1cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew apiserver-csr.json | cfssljson -bare apiserver
2ls apiserver*
3apiserver.csr  apiserver-csr.json  apiserver-key.pem  apiserver.pem

2.3 创建kubernetes-admin客户端证书和私钥 #

创建admin证书的签名请求配置admin-csr.json:

 1{
 2  "CN": "kubernetes-admin",
 3  "hosts": [
 4  	  "192.168.61.11",
 5      "192.168.61.12",
 6      "192.168.61.13"
 7  ],
 8  "key": {
 9    "algo": "rsa",
10    "size": 2048
11  },
12  "names": [
13    {
14      "C": "CN",
15      "ST": "BeiJing",
16      "L": "BeiJing",
17      "O": "system:masters",
18      "OU": "cloudnative"
19    }
20  ]
21}

kube-apiserver将提取CN作为客户端的用户名,这里是kubernetes-admin,将提取O作为用户所属的组,这里是system:master。 kube-apiserver预定义了一些 RBAC使用的ClusterRoleBindings,例如 cluster-admin将组system:masters与 ClusterRole cluster-admin绑定,而cluster-admin拥有访问kube-apiserver的所有权限,因此kubernetes-admin这个用户将作为集群的超级管理员。

了解Kubernetes的RBAC和ApiServer的认证的内容可参考之前写过的两篇《Kubernetes 1.6新特性学习:RBAC授权》《Kubernetes集群安全:Api Server认证》

下面生成kubernetes-admin的证书和私钥:

1cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew admin-csr.json | cfssljson -bare admin
2
3ls admin*
4admin.csr  admin-csr.json  admin-key.pem  admin.pem

2.4 创建kube-controller-manager客户端证书和私钥 #

下面创建kube-controller-manager客户端访问ApiServer所需的证书和私钥。 controller-manager证书的签名请求配置controller-manager-csr.json:

 1{
 2  "CN": "system:kube-controller-manager",
 3  "hosts": [
 4  	  "192.168.61.11",
 5      "192.168.61.12",
 6      "192.168.61.13"
 7  ],
 8  "key": {
 9    "algo": "rsa",
10    "size": 2048
11  },
12  "names": [
13    {
14      "C": "CN",
15      "ST": "BeiJing",
16      "L": "BeiJing",
17      "O": "system:kube-controller-manager",
18      "OU": "cloudnative"
19    }
20  ]
21}

kube-apiserver将提取CN作为客户端的用户名,这里是system:kube-controller-manager。 kube-apiserver预定义的 RBAC使用的ClusterRoleBindings system:kube-controller-manager将用户system:kube-controller-manager与ClusterRole system:kube-controller-manager绑定。

下面生成证书和私钥:

1cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew controller-manager-csr.json | cfssljson -bare controller-manager
2
3ls controller-manager*
4controller-manager.csr  controller-manager-csr.json  controller-manager-key.pem  controller-manager.pem

2.5 创建kube-scheduler客户端证书和私钥 #

下面创建kube-scheduler客户端访问ApiServer所需的证书和私钥。 scheduler证书的签名请求配置scheduler-csr.json:

 1{
 2  "CN": "system:kube-scheduler",
 3  "hosts": [
 4  	  "192.168.61.11",
 5      "192.168.61.12",
 6      "192.168.61.13"
 7  ],
 8  "key": {
 9    "algo": "rsa",
10    "size": 2048
11  },
12  "names": [
13    {
14      "C": "CN",
15      "ST": "BeiJing",
16      "L": "BeiJing",
17      "O": "system:kube-scheduler",
18      "OU": "cloudnative"
19    }
20  ]
21}

kube-scheduler将提取CN作为客户端的用户名,这里是system:kube-scheduler。 kube-apiserver预定义的RBAC使用的ClusterRoleBindings system:kube-scheduler将用户system:kube-scheduler与ClusterRole system:kube-scheduler绑定。

下面生成证书和私钥:

1cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew scheduler-csr.json | cfssljson -bare scheduler
2
3ls scheduler*
4scheduler.csr  scheduler-csr.json  scheduler-key.pem  scheduler.pem

3. Kubernetes Master集群部署 #

部署的Master节点集群由Node1, Node2, Node3三个节点组成,每个节点上部署kube-apiserver,kube-controller-manager,kube-scheduler三个核心组件。 kube-apiserver的3个实例同时提供服务,在其前端部署一个高可用的负载均衡器作为kube-apiserver的地址。 kube-controller-manager和kube-scheduler也是各自3个实例,在同一时刻只能有1个实例工作,这个实例通过选举产生。

将前面生成的 ca.pem, apiserver-key.pem, apiserver.pem, admin.pem, admin-key.pem, controller-manager.pem, controller-manager-key.pem, scheduler-key.pem, scheduler.pem拷贝到各个节点的/etc/kubernetes/pki目录下:

1mkdir -p /etc/kubernetes/pki
2cp {ca.pem,apiserver-key.pem,apiserver.pem,admin.pem, admin-key.pem, controller-manager.pem, controller-manager-key.pem,scheduler-key.pem, scheduler.pem} /etc/kubernetes/pki

将Kubernetes二进制包解压后kubernetes/server/bin中的kube-apiserver,kube-controller-manager,kube-scheduler,kubectl,kube-proxy,kubelet拷贝到各节点的/usr/local/bin目录中:

1cp {kube-apiserver,kube-controller-manager,kube-scheduler,kubectl,kube-proxy,kubelet} /usr/local/bin/

3.1 kube-apiserver部署 #

创建kube-apiserver的systemd unit文件/usr/lib/systemd/system/kube-apiserver.service,注意替换INTERNAL_IP变量的值:

 1mkdir -p /var/log/kubernetes
 2export INTERNAL_IP=192.168.61.11
 3cat > /usr/lib/systemd/system/kube-apiserver.service <<EOF
 4[Unit]
 5Description=kube-apiserver
 6After=network.target
 7After=etcd.service
 8
 9[Service]
10EnvironmentFile=-/etc/kubernetes/apiserver
11ExecStart=/usr/local/bin/kube-apiserver \
12	    --logtostderr=true \
13	    --v=0 \
14	    --advertise-address=${INTERNAL_IP} \
15	    --bind-address=${INTERNAL_IP} \
16	    --secure-port=6443 \
17	    --insecure-port=0 \
18	    --allow-privileged=true \
19	    --etcd-servers=https://192.168.61.11:2379,https://192.168.61.12:2379,https://192.168.61.13:2379 \
20	    --etcd-cafile=/etc/etcd/ssl/ca.pem \
21	    --etcd-certfile=/etc/etcd/ssl/etcd.pem \
22	    --etcd-keyfile=/etc/etcd/ssl/etcd-key.pem \
23	    --storage-backend=etcd3 \
24	    --service-cluster-ip-range=10.96.0.0/12 \
25	    --tls-cert-file=/etc/kubernetes/pki/apiserver.pem \
26	    --tls-private-key-file=/etc/kubernetes/pki/apiserver-key.pem \
27	    --client-ca-file=/etc/kubernetes/pki/ca.pem \
28	    --service-account-key-file=/etc/kubernetes/pki/ca-key.pem \
29	    --experimental-bootstrap-token-auth=true \
30	    --apiserver-count=3 \
31	    --enable-swagger-ui=true \
32	    --admission-control=NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,ResourceQuota,DefaultTolerationSeconds \
33	    --authorization-mode=RBAC \
34	    --audit-log-maxage=30 \
35	    --audit-log-maxbackup=3 \
36	    --audit-log-maxsize=100 \
37	    --audit-log-path=/var/log/kubernetes/audit.log
38Restart=on-failure
39Type=notify
40LimitNOFILE=65536
41
42[Install]
43WantedBy=multi-user.target
44EOF
  • --insecure-port禁用了不安全的http端口
  • --secure-port指定https安全端口,kube-scheduler、kube-controller-manager、kubelet、kube-proxy、kubectl等组件都将使用安全端口与ApiServer通信(实际上会由我们在前端部署的负载均衡器代理)。
  • --authorization-mode=RBAC表示在安全端口启用RBAC授权模式,在授权过程会拒绝会授权的请求。kube-scheduler、kube-controller-manager、kubelet、kube-proxy、kubectl等组件都使用各自证书或kubeconfig指定相关的User、Group来通过RBAC授权。
  • --admission-control为准入机制,这里配置了NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,ResourceQuota,DefaultTolerationSeconds
  • --service-cluster-ip-range指定Service Cluster IP的地址段,注意该地址段是Kubernetes Service使用的,是虚拟IP,从外部不能路由可达。

启动kube-apiserver:

1systemctl daemon-reload
2systemctl enable kube-apiserver
3systemctl start kube-apiserver
4systemctl status kube-apiserver

3.2 配置kubectl访问apiserver #

我们已经部署了kube-apiserver,并且前面已经kubernetes-admin的证书和私钥,我们将使用这个用户访问ApiServer。

 1kubectl --server=https://192.168.61.11:6443 \
 2--certificate-authority=/etc/kubernetes/pki/ca.pem  \
 3--client-certificate=/etc/kubernetes/pki/admin.pem \
 4--client-key=/etc/kubernetes/pki/admin-key.pem \
 5get componentstatuses
 6NAME                 STATUS      MESSAGE                                                                                        ERROR
 7scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused
 8controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: getsockopt: connection refused
 9etcd-0               Healthy     {"health": "true"}
10etcd-2               Healthy     {"health": "true"}
11etcd-1               Healthy     {"health": "true"}

上面我们使用kubectl命令打印出了Kubernetes核心组件的状态,因为我们还没有部署kube-scheduler和controller-manager,所以这两个组件当前是不健康的。

前面面使用kubectl时需要指定ApiServer的地址以及客户端的证书,用起来比较繁琐。 接下来我们创建kubernetes-admin的kubeconfig文件 admin.conf。

 1cd /etc/kubernetes
 2export KUBE_APISERVER="https://192.168.61.11:6443"
 3
 4# set-cluster
 5kubectl config set-cluster kubernetes \
 6  --certificate-authority=/etc/kubernetes/pki/ca.pem \
 7  --embed-certs=true \
 8  --server=${KUBE_APISERVER} \
 9  --kubeconfig=admin.conf
10
11# set-credentials
12kubectl config set-credentials kubernetes-admin \
13  --client-certificate=/etc/kubernetes/pki/admin.pem \
14  --embed-certs=true \
15  --client-key=/etc/kubernetes/pki/admin-key.pem \
16  --kubeconfig=admin.conf
17
18# set-context
19kubectl config set-context kubernetes-admin@kubernetes \
20  --cluster=kubernetes \
21  --user=kubernetes-admin \
22  --kubeconfig=admin.conf
23  
24# set default context
25kubectl config use-context kubernetes-admin@kubernetes --kubeconfig=admin.conf

为了使用kubectl访问apiserver使用admin.conf,将其拷贝到$HOME/.kube中并重命名成config:

1cp /etc/kubernetes/admin.conf ~/.kube/config

尝试直接使用kubectl命令访问apiserver:

1kubectl get cs
2NAME                 STATUS      MESSAGE                                                                                        ERROR
3scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused
4controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: getsockopt: connection refused
5etcd-0               Healthy     {"health": "true"}
6etcd-1               Healthy     {"health": "true"}
7etcd-2               Healthy     {"health": "true"}

因为我们已经把kubernetes-admin用户的相关信息和证书保存到了admin.conf中,所以可以删除/etc/kubernetes/pki中的admin.pem和admin-key.pem:

1cd /etc/kubernetes/pki
2rm -f admin.pem admin-key.pem

3.3 kube-apiserver高可用 #

经过前面的步骤,我们已经在node1,node2,node3上部署了Kubernetes Master节点的kube-apiserver,地址如下:

1https://192.168.61.11:6443
2https://192.168.61.12:6443
3https://192.168.61.13:6443

为了实现高可用,可以在前面放一个负载均衡器来代理访问kube-apiserver的请求,再对负载均衡器实现高可用。 例如,HAProxy+Keepavlided,我们在node1~node3这3个Master节点上运行keepalived和HAProxy,3个keepalived争抢同一个VIP地址,3个HAProxy也都尝试去绑定到这个VIP的同一个端口。 例如:192.168.61.10:5000,当某个Haproxy出现异常后,其他节点上的Keepalived会争抢到VIP,同时这个节点上HAProxy会接管流量。

HAProxy+Keepavlided的部署这里不再展开。 最终kube-apiserver高可用的地址为https://192.168.61.10:5000,修改前面$HOME/.kube/config中的clusters:cluster:server的值为这个地址。

1kubectl get cs
2NAME                 STATUS      MESSAGE                                                                                        ERROR
3scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused
4controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: getsockopt: connection refused
5etcd-0               Healthy     {"health": "true"}
6etcd-1               Healthy     {"health": "true"}
7etcd-2               Healthy     {"health": "true"}

3.4 kube-controller-manager部署 #

前面已经创建了controller-manager.pem和controller-manage-key.pem,下面生成controller-manager的kubeconfig文件controller-manager.conf:

 1cd /etc/kubernetes
 2export KUBE_APISERVER="https://192.168.61.10:5000"
 3
 4# set-cluster
 5kubectl config set-cluster kubernetes \
 6  --certificate-authority=/etc/kubernetes/pki/ca.pem \
 7  --embed-certs=true \
 8  --server=${KUBE_APISERVER} \
 9  --kubeconfig=controller-manager.conf
10
11# set-credentials
12kubectl config set-credentials system:kube-controller-manager \
13  --client-certificate=/etc/kubernetes/pki/controller-manager.pem \
14  --embed-certs=true \
15  --client-key=/etc/kubernetes/pki/controller-manager-key.pem \
16  --kubeconfig=controller-manager.conf
17
18# set-context
19kubectl config set-context system:kube-controller-manager@kubernetes \
20  --cluster=kubernetes \
21  --user=system:kube-controller-manager \
22  --kubeconfig=controller-manager.conf
23  
24# set default context
25kubectl config use-context system:kube-controller-manager@kubernetes --kubeconfig=controller-manager.conf

controller-manager.conf文件生成后将这个文件分发到各个Master节点的/etc/kubernetes目录下。

创建kube-controller-manager的systemd unit文件/usr/lib/systemd/system/kube-controller-manager.service:

 1export KUBE_APISERVER="https://192.168.61.10:5000"
 2cat > /usr/lib/systemd/system/kube-controller-manager.service <<EOF
 3[Unit]
 4Description=kube-controller-manager
 5After=network.target
 6After=kube-apiserver.service
 7
 8[Service]
 9EnvironmentFile=-/etc/kubernetes/controller-manager
10ExecStart=/usr/local/bin/kube-controller-manager \
11	    --logtostderr=true \
12	    --v=0 \
13	    --master=${KUBE_APISERVER} \
14	    --kubeconfig=/etc/kubernetes/controller-manager.conf \
15	    --cluster-name=kubernetes \
16	    --cluster-signing-cert-file=/etc/kubernetes/pki/ca.pem \
17	    --cluster-signing-key-file=/etc/kubernetes/pki/ca-key.pem \
18	    --service-account-private-key-file=/etc/kubernetes/pki/ca-key.pem \
19	    --root-ca-file=/etc/kubernetes/pki/ca.pem \
20	    --insecure-experimental-approve-all-kubelet-csrs-for-group=system:bootstrappers \
21	    --use-service-account-credentials=true \
22	    --service-cluster-ip-range=10.96.0.0/12 \
23	    --cluster-cidr=10.244.0.0/16 \
24	    --allocate-node-cidrs=true \
25	    --leader-elect=true \
26	    --controllers=*,bootstrapsigner,tokencleaner
27Restart=on-failure
28Type=simple
29LimitNOFILE=65536
30
31[Install]
32WantedBy=multi-user.target
33EOF
  • --service-cluster-ip-rangekube-api-server中指定的参数值一致

在各节点上启动:

1systemctl daemon-reload
2systemctl enable kube-controller-manager
3systemctl start kube-controller-manager
4systemctl status kube-controller-manager

在node1,node2,node3上完成部署和启动后,查看一下状态:

1kubectl get cs
2NAME                 STATUS      MESSAGE                                                                                        ERROR
3scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused
4controller-manager   Healthy     ok
5etcd-1               Healthy     {"health": "true"}
6etcd-2               Healthy     {"health": "true"}
7etcd-0               Healthy     {"health": "true"}

到这一步三个Master节点上的kube-controller-manager部署完成,通过选举出一个leader工作。 分别在三个节点查看状态:

 1#node1
 2systemctl status -l kube-controller-manager
 3......
 4...... attempting to acquire leader lease...
 5
 6#node2
 7systemctl status -l kube-controller-manager
 8......
 9...... controllermanager.go:437] Started "endpoint"
10...... controllermanager.go:437] Started "replicationcontroller"
11...... replication_controller.go:150] Starting RC Manager
12...... controllermanager.go:437] Started "replicaset"
13...... replica_set.go:155] Starting ReplicaSet controller
14...... controllermanager.go:437] Started "disruption"
15...... disruption.go:269] Starting disruption controller
16...... controllermanager.go:437] Started "statefuleset"
17...... stateful_set.go:144] Starting statefulset controller
18...... controllermanager.go:437] Started "bootstrapsigner"
19
20#node3
21systemctl status -l kube-controller-manager
22......
23...... attempting to acquire leader lease...

从输出的日志可以看出现在第二个节点上的kube-controller-manager。

3.5 kube-scheduler部署 #

前面已经创建了scheduler.pem和scheduler-key.pem,下面生成kube-scheduler的kubeconfig文件scheduler.conf:

 1cd /etc/kubernetes
 2export KUBE_APISERVER="https://192.168.61.10:5000"
 3
 4# set-cluster
 5kubectl config set-cluster kubernetes \
 6  --certificate-authority=/etc/kubernetes/pki/ca.pem \
 7  --embed-certs=true \
 8  --server=${KUBE_APISERVER} \
 9  --kubeconfig=scheduler.conf
10
11# set-credentials
12kubectl config set-credentials system:kube-scheduler \
13  --client-certificate=/etc/kubernetes/pki/scheduler.pem \
14  --embed-certs=true \
15  --client-key=/etc/kubernetes/pki/scheduler-key.pem \
16  --kubeconfig=scheduler.conf
17
18# set-context
19kubectl config set-context system:kube-scheduler@kubernetes \
20  --cluster=kubernetes \
21  --user=system:kube-scheduler \
22  --kubeconfig=scheduler.conf
23  
24# set default context
25kubectl config use-context system:kube-scheduler@kubernetes --kubeconfig=scheduler.conf

scheduler.conf文件生成后将这个文件分发到各个Master节点的/etc/kubernetes目录下。

创建kube-scheduler的systemd unit文件/usr/lib/systemd/system/kube-scheduler.service:

 1export KUBE_APISERVER="https://192.168.61.10:5000"
 2cat > /usr/lib/systemd/system/kube-scheduler.service <<EOF
 3[Unit]
 4Description=kube-scheduler
 5After=network.target
 6After=kube-apiserver.service
 7
 8[Service]
 9EnvironmentFile=-/etc/kubernetes/scheduler
10ExecStart=/usr/local/bin/kube-scheduler \
11	    --logtostderr=true \
12	    --v=0 \
13	    --master=${KUBE_APISERVER} \
14	    --kubeconfig=/etc/kubernetes/scheduler.conf \
15	    --leader-elect=true
16Restart=on-failure
17Type=simple
18LimitNOFILE=65536
19
20[Install]
21WantedBy=multi-user.target
22EOF

在各节点上启动:

1systemctl daemon-reload
2systemctl enable kube-scheduler
3systemctl start kube-scheduler
4systemctl status kube-scheduler

到这一步三个Master节点上的kube-scheduler部署完成,通过选举出一个leader工作。

查看Kubernetes Master集群各个核心组件的状态全部正常。

1kubectl get cs
2NAME                 STATUS    MESSAGE              ERROR
3controller-manager   Healthy   ok
4scheduler            Healthy   ok
5etcd-2               Healthy   {"health": "true"}
6etcd-0               Healthy   {"health": "true"}
7etcd-1               Healthy   {"health": "true"}

4. Kubernetes Node节点部署 #

Kubernetes的一个Node节点上需要运行如下组件:

  • Docker,这个我们前面在做环境准备的时候已经在各节点部署和运行了
  • kubelet
  • kube-proxy

下面我们以在node1上为例部署这些组件:

4.1 CNI安装 #

1wget https://github.com/containernetworking/cni/releases/download/v0.5.2/cni-amd64-v0.5.2.tgz
2mkdir -p /opt/cni/bin
3tar -zxvf cni-amd64-v0.5.2.tgz -C /opt/cni/bin
4ls /opt/cni/bin/
5bridge  cnitool  dhcp  flannel  host-local  ipvlan  loopback  macvlan  noop  ptp  tuning

4.2 kubelet部署 #

首先确认将kubelet的二进制文件拷贝到/usr/local/bin下。 创建kubelet的工作目录:

1mkdir -p /var/lib/kubelet

安装依赖包:

1yum install ebtables socat util-linux conntrack-tools

接下来创建访问ApiServer的证书和私钥,kubelet-csr.json:

 1{
 2  "CN": "system:node:node1",
 3  "hosts": [
 4  ],
 5  "key": {
 6    "algo": "rsa",
 7    "size": 2048
 8  },
 9  "names": [
10    {
11      "C": "CN",
12      "ST": "BeiJing",
13      "L": "BeiJing",
14      "O": "system:nodes",
15      "OU": "cloudnative"
16    }
17  ]
18}
  • 注意CN为用户名,使用system:node:<node-name>
  • O为用户组,Kubernetes RBAC定义了ClusterRoleBinding将Group system:nodes和ClusterRole system:node关联。

生成证书和私钥:

1cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew kubelet-csr.json | cfssljson -bare kubelet
2ls kubelet*
3kubelet.csr  kubelet-csr.json  kubelet-key.pem  kubelet.pem

生成kubeconfig文件kubelet.conf:

 1cd /etc/kubernetes
 2export KUBE_APISERVER="https://192.168.61.10:5000"
 3# set-cluster
 4kubectl config set-cluster kubernetes \
 5  --certificate-authority=/etc/kubernetes/pki/ca.pem \
 6  --embed-certs=true \
 7  --server=${KUBE_APISERVER} \
 8  --kubeconfig=kubelet.conf
 9# set-credentials
10kubectl config set-credentials system:node:node1 \
11  --client-certificate=/etc/kubernetes/pki/kubelet.pem \
12  --embed-certs=true \
13  --client-key=/etc/kubernetes/pki/kubelet-key.pem \
14  --kubeconfig=kubelet.conf
15# set-context
16kubectl config set-context system:node:node1@kubernetes \
17  --cluster=kubernetes \
18  --user=system:node:node1 \
19  --kubeconfig=kubelet.conf
20# set default context
21kubectl config use-context system:node:node1@kubernetes --kubeconfig=kubelet.conf

创建kubelet的systemd unit service文件,注意替换NodeIP变量:

 1export KUBE_APISERVER="https://192.168.61.10:5000"
 2export NodeIP="192.168.61.11"
 3cat > /usr/lib/systemd/system/kubelet.service <<EOF
 4[Unit]
 5Description=kubelet
 6After=docker.service
 7Requires=docker.service
 8
 9[Service]
10WorkingDirectory=/var/lib/kubelet
11EnvironmentFile=-/etc/kubernetes/kubelet
12ExecStart=/usr/local/bin/kubelet \
13        --logtostderr=true \
14        --v=0 \
15        --address=${NodeIP} \
16        --api-servers==${KUBE_APISERVER} \
17        --cluster-dns=10.96.0.10 \
18        --cluster-domain=cluster.local \
19        --kubeconfig=/etc/kubernetes/kubelet.conf \
20        --require-kubeconfig=true \
21        --pod-manifest-path=/etc/kubernetes/manifests \
22        --allow-privileged=true \
23        --authorization-mode=AlwaysAllow \
24#        --authorization-mode=Webhook \
25#        --client-ca-file=/etc/kubernetes/pki/ca.pem \
26        --network-plugin=cni \
27        --cni-conf-dir=/etc/cni/net.d \
28        --cni-bin-dir=/opt/cni/bin
29Restart=on-failure
30
31[Install]
32WantedBy=multi-user.target
33EOF
  • --pod-manifest-path=/etc/kubernetes/manifests指定了静态Pod定义的目录。可以提前创建好这个目录mkdir -p /etc/kubernetes/manifests。关于静态Pod的内容可参考之前写的一篇《Kubernetes资源对象之Pod》中的静态Pod的内容。
  • --authorization-mode=AlwaysAllow 这里并没有启用Kubernetes 1.5的新特性即kubelet API的认证授权功能,先设置AlwaysAllow和我们的线上环境保持一致

启动kubelet:

1systemctl daemon-reload
2systemctl enable kubelet
3systemctl start kubelet
4systemctl status kubelet
1kubectl get nodes
2NAME      STATUS    AGE       VERSION
3node1     NotReady     35s       v1.6.2

4.3 kube-proxy部署 #

首先确认已经将kuber-proxy的二进制文件拷贝到/usr/local/bin下。 创建kubelet的工作目录:

1mkdir -p /var/lib/kube-proxy

接下来创建访问ApiServer的证书和私钥,kube-proxy-csr.json:

 1{
 2  "CN": "system:kube-proxy",
 3  "hosts": [
 4  ],
 5  "key": {
 6    "algo": "rsa",
 7    "size": 2048
 8  },
 9  "names": [
10    {
11      "C": "CN",
12      "ST": "BeiJing",
13      "L": "BeiJing",
14      "O": "system:kube-proxy",
15      "OU": "cloudnative"
16    }
17  ]
18}
  • CN 指定该证书的 User为 system:kube-proxy。Kubernetes RBAC定义了ClusterRoleBinding将system:kube-proxy用户与system:node-proxier 角色绑定。system:node-proxier具有kube-proxy组件访问ApiServer的相关权限。

生成证书和私钥:

1cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=frognew kube-proxy-csr.json | cfssljson -bare kube-proxy
2ls kube-proxy*
3kube-proxy.csr  kube-proxy-csr.json  kube-proxy-key.pem  kube-proxy.pem

生成kubeconfig文件kube-proxy.conf:

 1cd /etc/kubernetes
 2export KUBE_APISERVER="https://192.168.61.10:5000"
 3# set-cluster
 4kubectl config set-cluster kubernetes \
 5  --certificate-authority=/etc/kubernetes/pki/ca.pem \
 6  --embed-certs=true \
 7  --server=${KUBE_APISERVER} \
 8  --kubeconfig=kube-proxy.conf
 9# set-credentials
10kubectl config set-credentials system:kube-proxy \
11  --client-certificate=/etc/kubernetes/pki/kube-proxy.pem \
12  --embed-certs=true \
13  --client-key=/etc/kubernetes/pki/kube-proxy-key.pem \
14  --kubeconfig=kube-proxy.conf
15# set-context
16kubectl config set-context system:kube-proxy@kubernetes \
17  --cluster=kubernetes \
18  --user=system:kube-proxy \
19  --kubeconfig=kube-proxy.conf
20# set default context
21kubectl config use-context system:kube-proxy@kubernetes --kubeconfig=kube-proxy.conf

创建kube-proxy的systemd unit service文件,注意替换NodeIP变量:

 1export KUBE_APISERVER="https://192.168.61.10:5000"
 2export NodeIP="192.168.61.11"
 3cat > /usr/lib/systemd/system/kube-proxy.service <<EOF
 4[Unit]
 5Description=kube-proxy
 6After=network.target
 7
 8[Service]
 9WorkingDirectory=/var/lib/kube-proxy
10EnvironmentFile=-/etc/kubernetes/kube-proxy
11ExecStart=/usr/local/bin/kube-proxy \
12        --logtostderr=true \
13        --v=0 \
14        --bind-address=${NodeIP} \
15        --kubeconfig=/etc/kubernetes/kube-proxy.conf \
16        --cluster-cidr=10.244.0.0/16
17        
18Restart=on-failure
19
20[Install]
21WantedBy=multi-user.target
22EOF

启动kubelet-proxy:

1systemctl daemon-reload
2systemctl enable kube-proxy
3systemctl start kube-proxy
4systemctl status -l kube-proxy

4.4 部署Pod Network插件flannel #

flannel以DaemonSet的形式运行在Kubernetes集群中。 由于我们的etcd集群启用了TLS认证,为了从flannel容器中能访问etcd,我们先把etcd的TLS证书信息保存到Kubernetes的Secret中。

 1kubectl create secret generic etcd-tls-secret  --from-file=/etc/etcd/ssl/etcd.pem --from-file=/etc/etcd/ssl/etcd-key.pem  --from-file=/etc/etcd/ssl/ca.pem -n kube-system
 2
 3
 4kubectl describe secret etcd-tls-secret -n kube-system
 5Name:           etcd-tls-secret
 6Namespace:      kube-system
 7Labels:         <none>
 8Annotations:    <none>
 9
10Type:   Opaque
11
12Data
13====
14etcd-key.pem:   1675 bytes
15etcd.pem:       1489 bytes
16ca.pem:         1330 bytes
1mkdir -p ~/k8s/flannel
2cd ~/k8s/flannel
3wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel-rbac.yml
4wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

对kube-flannel.yml做以下修改:

 1apiVersion: extensions/v1beta1
 2kind: DaemonSet
 3metadata:
 4  ......
 5spec:
 6  template:
 7    metadata:
 8      ......
 9    spec:
10      ......
11      containers:
12      - name: kube-flannel
13        image: quay.io/coreos/flannel:v0.7.1-amd64
14        command: [
15             "/opt/bin/flanneld",
16             "--ip-masq",
17             "--kube-subnet-mgr",
18             "-etcd-endpoints=https://192.168.61.11:2379,https://192.168.61.12:2379,https://192.168.61.13:2379",
19             "-etcd-cafile=/etc/etcd/ssl/ca.pem",
20             "--etcd-certfile=/etc/etcd/ssl/etcd.pem",
21             "-etcd-keyfile=/etcd/etcd/ssl/etcd-key.pem",
22             "--iface=etn0" ]
23        securityContext:
24          privileged: true
25        ......
26        volumeMounts:
27        ......
28        - name: etcd-tls-secret
29          readOnly: true
30          mountPath: /etc/etcd/ssl/
31      ......
32      volumes:
33        ......
34        - name: etcd-tls-secret
35          secret:
36            secretName: etcd-tls-secret
  • flanneld的启动参数中加入以下参数
  • -etcd-endpoints配置etcd集群的访问地址
  • -etcd-cafile配置etcd的CA证书,/etc/etcd/ssl/ca.pem从etcd-tls-secret这个Secret挂载
  • --etcd-certfile配置etcd的公钥证书,/etc/etcd/ssl/etcd.pem从etcd-tls-secret这个Secret挂载
  • --etcd-keyfile配置etcd的私钥,/etc/etcd/ssl/etcd-key.pem从etcd-tls-secret这个Secret挂载
  • --iface当Node节点有多个网卡时用于指明具体的网卡名称

下面部署flannel:

1kubectl create -f kube-flannel-rbac.yml
2kubectl create -f kube-flannel.yml
 1kubectl get pods --all-namespaces
 2NAMESPACE     NAME                    READY     STATUS    RESTARTS   AGE
 3kube-system   kube-flannel-ds-dhz6m   2/2       Running   0          10s
 4
 5ifconfig flannel.1
 6flannel.1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1450
 7        inet 10.244.0.0  netmask 255.255.255.255  broadcast 0.0.0.0
 8        ether c2:e6:ad:26:f5:f6  txqueuelen 0  (Ethernet)
 9        RX packets 0  bytes 0 (0.0 B)
10        RX errors 0  dropped 0  overruns 0  frame 0
11        TX packets 0  bytes 0 (0.0 B)
12        TX errors 0  dropped 1 overruns 0  carrier 0  collisions 0

4.5 部署kube-dns插件 #

Kubernetes支持kube-dns以Cluster Add-On的形式运行。Kubernetes会在集群中调度一个DNS的Pod和Service。

1mkdir -p ~/k8s/kube-dns
2wget https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/kubedns-cm.yaml
3wget https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/kubedns-sa.yaml
4wget https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/kubedns-svc.yaml.base
5wget https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/kubedns-controller.yaml.base
6wget https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/transforms2sed.sed

查看transforms2sed.sed:

1s/__PILLAR__DNS__SERVER__/$DNS_SERVER_IP/g
2s/__PILLAR__DNS__DOMAIN__/$DNS_DOMAIN/g
3s/__MACHINE_GENERATED_WARNING__/Warning: This is a file generated from the base underscore template file: __SOURCE_FILENAME__/g

$DNS_SERVER_IP替换成10.96.0.10,将DNS_DOMAIN替换成cluster.local.。 注意$DNS_SERVER_IP要和kubelet设置的--cluster-dns参数一致

执行:

1cd ~/k8s/kube-dns
2sed -f transforms2sed.sed kubedns-svc.yaml.base > kubedns-svc.yaml
3sed -f transforms2sed.sed kubedns-controller.yaml.base > kubedns-controller.yaml
  • 上面的变量DNS_SERVER要和kubelet设置的--cluster-dns参数一致。
1kubectl create -f kubedns-cm.yaml
2kubectl create -f kubedns-sa.yaml
3kubectl create -f kubedns-svc.yaml
4kubectl create -f kubedns-controller.yaml 

查看kube-dns的Pod,确认所有Pod都处于Running状态:

1 kubectl get pods --all-namespaces
2NAMESPACE     NAME                       READY     STATUS    RESTARTS   AGE
3kube-system   kube-dns-806549836-rv4mm   3/3       Running   0          12s
4kube-system   kube-flannel-ds-jnpg9      2/2       Running   0          5m

测试一下DNS功能是否好用:

1kubectl run curl --image=radial/busyboxplus:curl -i --tty
2
3nslookup kubernetes.default
4Server:    10.96.0.10
5Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
6
7Name:      kubernetes
8Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local

kube-dns是Kubernetes实现服务发现的重要组件之一,默认情况下只会创建一个DNS Pod,在生产环境中我们可能需要对kube-dns进行扩容。 有两种方式:

  • 手动扩容 kubectl --namespace=kube-system scale deployment kube-dns --replicas=<NUM_YOU_WANT>
  • 使用DNS Horizontal Autoscaler

4.6 添加新的Node节点 #

重复4.1~4.3的步骤,添加新的Node节点。 在添加新节点时注意以下事项:

  • 4.2中生成kubelet访问ApiServer的证书和私钥,以及基于证书生成kubeconfig文件时,CN用户名使用system:node:<node-name>。每个Node节点是不同的。
  • 4.3中不需要再生成kube-proxy访问ApiServer的证书和私钥,只需将已有Node节点上的kubeconfig文件kube-proxy.conf分发到新的节点上即可。
1kubectl get nodes
2NAME      STATUS    AGE       VERSION
3node1     Ready     2h        v1.6.2
4node2     Ready     12m       v1.6.2
5node3     Ready     10m       v1.6.2

注意生产环境是需要将Master节点隔离的,不建议在Master节点跑工作负载。因为测试环境机器有限,所以这里的Node节点也是node1~node3。

5. dashboard插件部署 #

1mkdir -p ~/k8s/dashboard
2cd ~/k8s/dashboard
3wget https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml
4kubectl create -f kubernetes-dashboard.yaml
1kubectl get pod,svc -n kube-system -l app=kubernetes-dashboard
2NAME                                       READY     STATUS    RESTARTS   AGE
3po/kubernetes-dashboard-2457468166-5q9xk   1/1       Running   0          6m
4
5NAME                       CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
6svc/kubernetes-dashboard   10.102.242.110   <nodes>       80:31632/TCP   6m

6. heapster插件部署 #

下面安装Heapster为集群添加使用统计和监控功能,为Dashboard添加仪表盘。 使用InfluxDB做为Heapster的后端存储,开始部署:

1mkdir -p ~/k8s/heapster
2cd ~/k8s/heapster
3wget https://raw.githubusercontent.com/kubernetes/heapster/master/deploy/kube-config/influxdb/grafana.yaml
4wget https://raw.githubusercontent.com/kubernetes/heapster/master/deploy/kube-config/rbac/heapster-rbac.yaml
5wget https://raw.githubusercontent.com/kubernetes/heapster/master/deploy/kube-config/influxdb/heapster.yaml
6wget https://raw.githubusercontent.com/kubernetes/heapster/master/deploy/kube-config/influxdb/influxdb.yaml
7
8kubectl create -f ./

最后确认所有的pod都处于running状态,打开Dashboard,集群的使用统计会以仪表盘的形式显示出来。

7. 部署示例应用 #

接下来部署一个基于微服务的应用,做一个测试:

1kubectl create namespace sock-shop
2kubectl apply -n sock-shop -f "https://github.com/microservices-demo/microservices-demo/blob/master/deploy/kubernetes/complete-demo.yaml?raw=true"

这个应用服务的镜像较多,需要耐心等待:

 1kubectl get pod -n sock-shop -o wide
 2NAME                            READY     STATUS    RESTARTS   AGE       IP            NODE
 3carts-153328538-8r4pv           1/1       Running   0          12m       10.244.0.10   node1
 4carts-db-4256839670-cw9pr       1/1       Running   0          12m       10.244.0.9    node1
 5catalogue-114596073-z2079       1/1       Running   0          12m       10.244.2.5    node3
 6catalogue-db-1956862931-ld598   1/1       Running   0          12m       10.244.1.6    node2
 7front-end-3570328172-vfj7r      1/1       Running   0          12m       10.244.0.11   node1
 8orders-2365168879-h3zwr         1/1       Running   0          12m       10.244.1.7    node2
 9orders-db-836712666-954nd       1/1       Running   0          12m       10.244.2.6    node3
10payment-1968871107-9511t        1/1       Running   0          12m       10.244.0.12   node1
11queue-master-2798459664-h99nt   1/1       Running   0          12m       10.244.1.8    node2
12rabbitmq-3429198581-2hvzl       1/1       Running   0          12m       10.244.2.7    node3
13shipping-2899287913-kxt4k       1/1       Running   0          12m       10.244.0.13   node1
14user-468431046-6tf0w            1/1       Running   0          11m       10.244.1.9    node2
15user-db-1166754267-qrqnf        1/1       Running   0          11m       10.244.2.8    node3
1kubectl -n sock-shop get svc front-end
2NAME        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
3front-end   10.103.64.184   <nodes>       80:30001/TCP   13m

大功告成O(∩_∩)O~,在浏览器中打开http://<NodeIP>:30001,浏览一下这个应用吧。

参考文档 #

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