之前的博文中已经介绍过使用kubeadm自动化安装Kubernetes ,但是由于各个组件都是以容器的方式运行,对于具体的配置细节没有太多涉及,为了更好的理解Kubernetes中各个组件的作用,本篇博文将使用二进制的方式安装Kubernetes集群,对于各个组件的配置做进一步的详细说明。
在1.10版本中,已经逐步废弃掉了非安全端口(默认8080)的连接方式,这里会介绍使用ca证书双向认证的方式来建立集群,配置过程稍复杂。
环境说明
1、两台CentOS7 主机,解析主机名,关闭防火墙,Selinux,同步系统时间:
10.0.0.1 node-1 Master
10.0.0.2 node-2 Node
Master上部署:
- etcd
- kube-apiserver
- kube-controller-manager
- kube-scheduler
Node上部署:
- Docker
- kubelet
- kube-proxy
2、下载官方的软件包https://github.com/kubernetes/kubernetes/ ,这里我们下载二进制文件,这里我们选择了1.10.2的版本:
- kubernetes-server-linux-amd64.tar.gz
- kubernetes-node-linux-amd64.tar
Master部署
由于使用的是二进制包,解压后直接将对应的文件拷贝到执行目录即可:
# tar xf kubernetes-server-linux-amd64.tar.gz
# cd kubernetes/server/bin
# cp `ls|egrep -v "*.tar|*_tag"` /usr/bin/
下面对具体的服务配置进行说明。
1、etcd
etcd服务是Kubernetes集群的核心数据库,在安装各个服务之前需要先安装启动。这里演示的是部署etcd单节点,当然也可以配置3节点的集群。如果想配置更加简单,推荐直接使用yum方式安装。
# wget https://github.com/coreos/etcd/releases/download/v3.2.20/etcd-v3.2.20-linux-amd64.tar.gz
# tar xf etcd-v3.2.20-linux-amd64.tar.gz
# cd etcd-v3.2.20-linux-amd64
# cp etcd etcdctl /usr/bin/
# mkdir /var/lib/etcd
# mkdir /etc/etcd
编辑systemd管理文件:
vim /usr/lib/systemd/system/etcd.service
[Unit]
Description=Etcd Server
After=network.target
[Service]
Type=simple
WorkingDirectory=/var/lib/etcd/
EnvironmentFile=-/etc/etcd/etcd.conf
ExecStart=/usr/bin/etcd
[Install]
WantedBy=multi-user.target
启动服务:
systemctl daemon-reload
systemctl start etcd
systemctl status etcd.service
查看服务状态:
[[email protected] ~]# netstat -lntp|grep etcd
tcp 0 0 127.0.0.1:2379 0.0.0.0:* LISTEN 18794/etcd
tcp 0 0 127.0.0.1:2380 0.0.0.0:* LISTEN 18794/etcd
[[email protected] ~]# etcdctl cluster-health
member 8e9e05c52164694d is healthy: got healthy result from http://localhost:2379
cluster is healthy
说明: etcd 会启用两个端口,其中2379 是集群的通信端口,2380是服务端口。如果是配置etcd集群,则要修改配置文件,设置监听IP和端口。
2、kube-apiserver
1、编辑systemd的启动文件:
vim /usr/lib/systemd/system/kube-apiserver.service
[Unit]
Description=Kubernetes API Server
Documentation=https://kubernetes.io/docs/concepts/overview
After=network.target
After=etcd.service
[Service]
EnvironmentFile=/etc/kubernetes/apiserver
ExecStart=/usr/bin/kube-apiserver $KUBE_API_ARGS
Restart=on-failure
Type=notify
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
2、配置参数文件(需要先创建配置目录):
# cat /etc/kubernetes/apiserver
KUBE_API_ARGS="--storage-backend=etcd3 --etcd-servers=http://127.0.0.1:2379 --bind-address=0.0.0.0 --secure-port=6443 --service-cluster-ip-range=10.222.0.0/16 --service-node-port-range=1-65535 --client-ca-file=/etc/kubernetes/ssl/ca.crt --tls-private-key-file=/etc/kubernetes/ssl/server.key --tls-cert-file=/etc/kubernetes/ssl/server.crt --enable-admission-plugins=NamespaceLifecycle,LimitRanger,SecurityContextDeny,ServiceAccount,DefaultStorageClass,ResourceQuota --logtostderr=false --log-dir=/var/log/kubernetes --v=2"
- service-cluster-ip-range是servcies的虚拟IP的IP范围,这里可以自己定义,不能当前的宿主机网段重叠。
- bind-addres 指定的apiserver监听地址,对应的监听端口是6443,使用的https的方式。
- client-ca-file 这是认证的相关文件,这预先定义,后面会创建证书文件,并放置到对应的路径。
3、创建日志目录和证书目录,如果没有配文件目录也需要创建:
mkdir /var/log/kubernetes
mkdir /etc/kubernetes
mkdir /etc/kubernetes/ssl
3、kube-controller-manager
1、配置systemd的启动文件:
# cat /usr/lib/systemd/system/kube-controller-manager.service
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://kubernetes.io/docs/setup
After=kube-apiserver.service
Requires=kube-apiserver.service
[Service]
EnvironmentFile=/etc/kubernetes/controller-manager
ExecStart=/usr/bin/kube-controller-manager $KUBE_CONTROLLER_MANAGER_ARGS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
2、配置启动参数文件:
# cat /etc/kubernetes/controller-manager
KUBE_CONTROLLER_MANAGER_ARGS="--master=https://10.0.0.1:6443 --service-account-private-key-file=/etc/kubernetes/ssl/server.key --root-ca-file=/etc/kubernetes/ssl/ca.crt --kubeconfig=/etc/kubernetes/kubeconfig"
4、kube-scheduler
1、配置systemd启动文件:
# cat /usr/lib/systemd/system/kube-scheduler.service
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://kubernetes.io/docs/setup
After=kube-apiserver.service
Requires=kube-apiserver.service
[Service]
EnvironmentFile=/etc/kubernetes/scheduler
ExecStart=/usr/bin/kube-scheduler $KUBE_SCHEDULER_ARGS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
2、配置参数文件:
# cat /etc/kubernetes/scheduler
KUBE_SCHEDULER_ARGS="--master=https://10.0.0.1:6443 --kubeconfig=/etc/kubernetes/kubeconfig"
5、创建kubeconfig文件
# cat /etc/kubernetes/kubeconfig
apiVersion: v1
kind: Config
users:
- name: controllermanager
user:
client-certificate: /etc/kubernetes/ssl/cs_client.crt
client-key: /etc/kubernetes/ssl/cs_client.key
clusters:
- name: local
cluster:
certificate-authority: /etc/kubernetes/ssl/ca.crt
contexts:
- context:
cluster: local
user: controllermanager
name: my-context
current-context: my-context
6、创建CA证书
1、配置kube-apiserver的CA证书和私钥文件,:
# cd /etc/kubernetes/ssl/
# openssl genrsa -out ca.key 2048
# openssl req -x509 -new -nodes -key ca.key -subj "/CN=10.0.0.1" -days 5000 -out ca.crt # CN指定Master的IP地址
# openssl genrsa -out server.key 2048
2、创建master_ssl.cnf文件:
# cat master_ssl.cnf
[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
[req_distinguished_name]
[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = @alt_names
[alt_names]
DNS.1 = kubernetes
DNS.2 = kubernetes.default
DNS.3 = kubernetes.default.svc
DNS.4 = kubernetes.default.svc.cluster.local
DNS.5 = k8s_master
IP.1 = 10.222.0.1 # ClusterIP 地址
IP.2 = 10.0.0.1 # master IP地址
3、基于上述文件,创建server.csr和 server.crt文件,执行如下命令:
# openssl req -new -key server.key -subj "/CN=node-1" -config master_ssl.cnf -out server.csr # CN指定主机名
# openssl x509 -req -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -days 5000 -extensions v3_req -extfile master_ssl.cnf -out server.crt
提示: 执行以上命令后会生成6个文件,ca.crt ca.key ca.srl server.crt server.csr server.key。
4、设置kube-controller-manager相关证书:
# cd /etc/kubernetes/ssl/
# openssl genrsa -out cs_client.key 2048
# openssl req -new -key cs_client.key -subj "/CN=node-1" -out cs_client.csr # CN指定主机名
# openssl x509 -req -in cs_client.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out cs_client.crt -days 5000
5、确保/etc/kubernetes/ssl/ 目录下有如下文件:
[[email protected] ssl]# ll
total 36
-rw-r--r-- 1 root root 1090 May 25 15:34 ca.crt
-rw-r--r-- 1 root root 1675 May 25 15:33 ca.key
-rw-r--r-- 1 root root 17 May 25 15:41 ca.srl
-rw-r--r-- 1 root root 973 May 25 15:41 cs_client.crt
-rw-r--r-- 1 root root 887 May 25 15:41 cs_client.csr
-rw-r--r-- 1 root root 1675 May 25 15:40 cs_client.key
-rw-r--r-- 1 root root 1192 May 25 15:37 server.crt
-rw-r--r-- 1 root root 1123 May 25 15:36 server.csr
-rw-r--r-- 1 root root 1675 May 25 15:34 server.key
7、启动服务:
1、启动kube-apiserver:
# systemctl daemon-reload
# systemctl enable kube-apiserver
# systemctl start kube-apiserver
说明:kube-apiserver 默认会启动两个端口(8080和6443),其中,8080是各个组件之间通信的端口,在新的版本中已经很少使用,kube-apiserver所在的主机一般称为Master, 另一个端口6443是为HTTPS提供身份验证和授权的端口。
2、启动kube-controller-manager:
# systemctl daemon-reload
# systemctl enable kube-controller-manager
# systemctl start kube-controller-manager
说明:此服务会启动一个10252的端口
3、启动kube-scheduler
# systemctl daemon-reload
# systemctl enable kube-scheduler
# systemctl start kube-scheduler
说明: 此服务会启动一个10251的端口
5、启动各项服务时,分别查看对应的日志和启动状态信息,确认服务没有报错
# systemctl status KUBE-SERVEICE-NAME
Node 部署
Node节点上部署的服务非常简单,只需要部署 docker、kubelet和kube-proxy服务即可。
先配置如下文件:
# cat /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
上传Kubernetes的Node节点二进制包,解压后执行如下命令:
tar xf kubernetes-node-linux-amd64.tar.gz
cd /kubernetes/node/bin
cp kubectl kubelet kube-proxy /usr/bin/
mkdir /var/lib/kubelet
mkdir /var/log/kubernetes
mkdir /etc/kubernetes
1、Docker
1、安装Docker17.03版本:
yum install docker-ce-selinux-17.03.2.ce-1.el7.centos.noarch.rpm -y
yum install docker-ce-17.03.2.ce-1.el7.centos.x86_64.rpm -y
2、配置启动参数:
vim /usr/lib/systemd/system/docker.service
...
ExecStart=/usr/bin/dockerd --registry-mirror https://qxx96o44.mirror.aliyuncs.com
...
3、启动:
systemctl daemon-reload
systemctl enable docker
systemctl start docker
2、 创建kubelet证书
每台Node节点上都需要配置kubelet的客户端证书。
复制Master上的ca.crt,ca.key到Node节点上的ssl目录,执行如下命令生成kubelet_client.crt和kubelet_client.csr文件:
# cd /etc/kubernetes/ssl/
# openssl genrsa -out kubelet_client.key 2048
# openssl req -new -key kubelet_client.key -subj "/CN=10.0.0.2" -out kubelet_client.csr # CN指定Node节点的IP
# openssl x509 -req -in kubelet_client.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out kubelet_client.crt -days 5000
3、kubelet
1、配置启动文件:
# cat /usr/lib/systemd/system/kubelet.service
[Unit]
Description=Kubernetes API Server
Documentation=https://kubernetes.io/doc
After=docker.service
Requires=docker.service
[Service]
WorkingDirectory=/var/lib/kubelet
ExecStart=/usr/bin/kubelet --kubeconfig=/etc/kubernetes/kubeconfig.yaml --logtostderr=false --log-dir=/var/log/kubernetes --v=2
Restart=on-failure
[Install]
WantedBy=multi-user.target
2、配置文件:
# cat /etc/kubernetes/kubeconfig.yaml
apiVersion: v1
kind: Config
users:
- name: kubelet
user:
client-certificate: /etc/kubernetes/ssl/kubelet_client.crt
client-key: /etc/kubernetes/ssl/kubelet_client.key
clusters:
- name: local
cluster:
certificate-authority: /etc/kubernetes/ssl/ca.crt
server: https://10.0.0.1:6443
contexts:
- context:
cluster: local
user: kubelet
name: my-context
current-context: my-context
3、启动服务:
# systemctl daemon-reload
# systemctl start kubelet
# systemctl enable kubelet
4、在master上验证:
[[email protected] ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
node-2 Ready <none> 36m v1.10.2
说明:kubelet充当了一个agent的角色,安装好kubelet就可以在master上查看到节点信息。kubelet的配置文件是一个yaml格式文件,对master的指定需要在配置文件中说明。默认监听10248、10250、10255、4194端口。
4、 kube-proxy
1、创建systemd启动文件:
# cat /usr/lib/systemd/system/kube-proxy.service
[Unit]
Description=Kubernetes kubelet agent
Documentation=https://kubernetes.io/doc
After=network.service
Requires=network.service
[Service]
EnvironmentFile=/etc/kubernetes/proxy
ExecStart=/usr/bin/kube-proxy $KUBE_PROXY_ARGS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
2、创建参数文件:
# cat /etc/kubernetes/proxy
KUBE_PROXY_ARGS="--master=https://10.0.0.1:6443 --kubeconfig=/etc/kubernetes/kubeconfig.yaml"
3、启动服务:
# systemctl daemon-reload
# systemctl start kube-proxy
# systemctl enable kube-proxy
说明:启动服务后默认监听10249,10256.
创建应用
完成上述的部署后,就可以创建应用了,但是在开始前,每个Node节点上必须要有pause的镜像,否则国内由于无法访问谷歌镜像,创建不会成功。
在Node节点执行如下命令,解决镜像问题:
docker pull mirrorgooglecontainers/pause-amd64:3.1
docker tag mirrorgooglecontainers/pause-amd64:3.1 k8s.gcr.io/pause-amd64:3.1
下面会用一个创建简单的应用,来验证我们的集群是否能正常工作。
创建一个nginx的应用
1、编辑nginx.yaml文件:
apiVersion: v1
kind: ReplicationController
metadata:
name: myweb
spec:
replicas: 2
selector:
app: myweb
template:
metadata:
labels:
app: myweb
spec:
containers:
- name: myweb
image: nginx
ports:
- containerPort: 80
2、执行:
# kubectl create -f nginx.yaml
3、查看状态:
[[email protected] ~]# kubectl get rc
NAME DESIRED CURRENT READY AGE
myweb 2 2 2 3h
[[email protected] ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
myweb-qtgrv 1/1 Running 0 1h
myweb-z9d2c 1/1 Running 0 1h
[[email protected] ~]# docker ps|grep nginx
067db96d0c97 [email protected]:0fb320e2a1b1620b4905facb3447e3d84ad36da0b2c8aa8fe3a5a81d1187b884 "nginx -g ‘daemon ..." About an hour ago Up About an hour k8s_myweb_myweb-qtgrv_default_3213ec67-5fef-11e8-9e43-000c295f81fb_0
dd8f7458e410 [email protected]:0fb320e2a1b1620b4905facb3447e3d84ad36da0b2c8aa8fe3a5a81d1187b884 "nginx -g ‘daemon ..." About an hour ago Up About an hour k8s_myweb_myweb-z9d2c_default_3214600e-5fef-11e8-9e43-000c295f81fb_0
4、创建一个service,映射到本地端口:
# cat nginx-service.yaml
apiVersion: v1
kind: Service
metadata:
name: myweb
spec:
type: NodePort # 定义外网访问模式
ports:
- port: 80
nodePort: 30001 # 外网访问的端口,映射的本地宿主机端口
selector:
app: myweb
# 创建service
# kubectl create -f nginx-service.yaml
# 验证:
[[email protected] ~]# kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.222.0.1 <none> 443/TCP 1d
myweb NodePort 10.222.35.97 <none> 80:30001/TCP 1h
5、会在所有安装proxy服务的节点上映射一个30001的端口,访问此端口就可以访问到nginx的默认起始页。
# netstat -lntp|grep 30001
tcp6 0 0 :::30001 :::* LISTEN 7713/kube-proxy
原文地址:http://blog.51cto.com/tryingstuff/2120374