内容简介：在 centos 7 上 直接运行Kubernetes 依赖 Etcd 服务来维护所有主节点的状态。系统自带的etcd 版本是3.2.11 kubernetes 的版本是 1.5.2
在 centos 7 上 直接运行
yum -y install etcd kubernetes
Kubernetes 依赖 Etcd 服务来维护所有主节点的状态。
系统自带的etcd 版本是3.2.11 kubernetes 的版本是 1.5.2
测试状态
[root@centos ~]# curl 127.0.0.1:8080
{
"paths": [
"/api",
"/api/v1",
"/apis",
"/apis/apps",
"/apis/apps/v1beta1",
"/apis/authentication.k8s.io",
"/apis/authentication.k8s.io/v1beta1",
"/apis/authorization.k8s.io",
"/apis/authorization.k8s.io/v1beta1",
"/apis/autoscaling",
"/apis/autoscaling/v1",
"/apis/batch",
"/apis/batch/v1",
"/apis/batch/v2alpha1",
"/apis/certificates.k8s.io",
"/apis/certificates.k8s.io/v1alpha1",
"/apis/extensions",
"/apis/extensions/v1beta1",
"/apis/policy",
"/apis/policy/v1beta1",
"/apis/rbac.authorization.k8s.io",
"/apis/rbac.authorization.k8s.io/v1alpha1",
"/apis/storage.k8s.io",
"/apis/storage.k8s.io/v1beta1",
"/healthz",
"/healthz/ping",
"/healthz/poststarthook/bootstrap-controller",
"/healthz/poststarthook/extensions/third-party-resources",
"/healthz/poststarthook/rbac/bootstrap-roles",
"/logs",
"/metrics",
"/swaggerapi/",
"/ui/",
"/version"
]
}
修改配置文件
修改
# vim /etc/sysconfig/docker OPTIONS='--selinux-enabled=false --insecure-registry gcr.io'
修改 k8s apiserver 的配置文件
vim /etc/kubernetes/apiserver
把
KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota"
中的 ServiceAccount 删掉。
启动服务
1.设置为开机自启动
systemctl enable docker systemctl enable etcd systemctl enable kube-apiserver systemctl enable kube-controller-manager systemctl enable kube-scheduller systemctl enable kube-scheduler systemctl enable kubelet systemctl enable kube-proxy
2.启动
systemctl start docker systemctl start etcd systemctl start kube-apiserver systemctl start kube-controller-manager systemctl start kube-scheduller systemctl start kube-scheduler systemctl start kubelet systemctl start kube-proxy
至此，一个单机版的k8s 集群就安装好了。
1.查看版本
kubectl version
输出
[root@centos ~]# kubectl version
Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState:"clean", BuildDate:"2017-07-03T15:31:10Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState:"clean", BuildDate:"2017-07-03T15:31:10Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
2.查看服务
[root@centos ~]# kubectl get service
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes 10.254.0.1 <none> 443/TCP 12h
[root@centos ~]# kubectl describe services kubernetes
Name: kubernetes
Namespace: default
Labels: component=apiserver
provider=kubernetes
Selector: <none>
Type: ClusterIP
IP: 10.254.0.1
Port: https 443/TCP
Endpoints: 192.168.10.115:6443
Session Affinity: ClientIP
No events.
定义 MYSQL RC 配置
我们创建一个 mysql-rc.yaml 的文件，内容如下：
apiVersion: v1
kind: ReplicationController # 副本控制器 RC
metadata:
name: mysql # RC名称，全局唯一
spec:
replicas: 1 # Pod副本期待数量
selector:
app: mysql # 符合目标 Pod拥有此标签
template: # 根据此模板创建 Pod 的副本（实例）
metadata:
labels:
app: mysql # Pod 副本拥有的标签，对应 RC 的Selector
spec:
containers: # Pod 内容的定义部分
- name: mysql #容器的名称
image: mysql #容器对应的 Docker Image
ports:
- containerPort: 3306 # 容器暴露的端口号
env: # 注入到容器的环境变量
- name: MYSQL_ROOT_PASSWORD
value: "123456"
说明
-
kind 用来表示此资源对象的类型
-
spec 定义 RC 的相关属性，比如spec.selector 是 RC 的 Pod 标签选择器，即表示监控和管理这些标签的pod实例。
- replicas = 1 表示只能运行一个mysql Pod 实例，当Pod 数量小于replicas 时，RC会根据spec.template 一节中定义的 Pod 来生成新的Pod实例
- spec.template.labels 指定了该pod的标签，需要注意这里的app 必须与selector中的app相同，否则无法创建匹配label的pod
创建好 mysql-rc.yaml 文件以后，为了将它发布到 k8s 集群中，我们在 Master 节点执行命令：
kubectl create -f mysql-rc.yaml
提示如下
[root@centos ~]# kubectl create -f mysql-rc.yaml replicationcontroller "mysql" created
提示如下错误请注意yaml 文件的格式是否正确以及配置参数是否输入正确
error: error validating "mysql-rc.yaml": error validating data: kind not set; if you choose to ignore these errors, turn validation off with --validate=false
查看 RC
[root@centos ~]# kubectl get rc NAME DESIRED CURRENT READY AGE mysql 1 1 0 1m
查看 Pod
[root@centos ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-cvg6c 0/1 ContainerCreating 0 3m
我们看到一个名为 mysql-xxxx的 Pod 实例，这是 k8s 根据 mysql 的这个 RC 文件的定义自动创建的 Pod。 由于其创建需要一些时间，因此我们一开始看到的 Pod 状态是 Pending，待最终完成会被更新为 Running
但是我们这边看到的状态是 ContainerCreating ,我们执行
[root@centos ~]# kubectl describe pod mysql
Name: mysql-cvg6c
Namespace: default
Node: 127.0.0.1/127.0.0.1
Start Time: Sat, 03 Mar 2018 09:22:42 +0800
Labels: app=mysql
Status: Pending
IP:
Controllers: ReplicationController/mysql
Containers:
mysql:
Container ID:
Image: mysql
Image ID:
Port: 3306/TCP
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Volume Mounts: <none>
Environment Variables:
MYSQL_ROOT_PASSWORD: 123456
Conditions:
Type Status
Initialized True
Ready False
PodScheduled True
No volumes.
QoS Class: BestEffort
Tolerations: <none>
Events:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
8m 8m 1 {default-scheduler } Normal Scheduled Successfully assigned mysql-cvg6c to 127.0.0.1
8m 3m 6 {kubelet 127.0.0.1} Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request. details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"
8m 12s 35 {kubelet 127.0.0.1} Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "POD" with ImagePullBackOff: "Back-off pulling image \"registry.access.redhat.com/rhel7/pod-infrastructure:latest\""
可以看出是镜像下载失败了
Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request. details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"
解决办法:
yum install *rhsm*
因为没有这个文件或目录，这个解决办法，来自 这里
然后删除 RC
[root@centos ~]# kubectl delete -f mysql-rc.yaml replicationcontroller "mysql" deleted
重新创建
[root@centos ~]# kubectl create -f mysql-rc.yaml replicationcontroller "mysql" created [root@centos ~]# kubectl get rc NAME DESIRED CURRENT READY AGE mysql 1 1 0 10s [root@centos ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-7blh0 0/1 ContainerCreating 0 13s mysql-cvg6c 0/1 Terminating 0 21m
发现还是不行
[root@centos ~]# kubectl describe pods mysql
Name: mysql-j6vpx
Namespace: default
Node: 127.0.0.1/127.0.0.1
Start Time: Sat, 03 Mar 2018 09:51:30 +0800
Labels: app=mysql
Status: Pending
IP:
Controllers: ReplicationController/mysql
Containers:
mysql:
Container ID:
Image: mysql
Image ID:
Port: 3306/TCP
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Volume Mounts: <none>
Environment Variables:
MYSQL_ROOT_PASSWORD: 123456
Conditions:
Type Status
Initialized True
Ready False
PodScheduled True
No volumes.
QoS Class: BestEffort
Tolerations: <none>
Events:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
59m 59m 1 {default-scheduler } Normal Scheduled Successfully assigned mysql-j6vpx to 127.0.0.1
32m 32m 1 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.
32m 32m 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Pulling pulling image "mysql"
1m 1m 1 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.
59s 59s 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Pulling pulling image "mysql"
镜像一直在下载，原因是因为gcr.io 被傻逼墙给干了，草他妈的，耽误我折腾一个小时。
解决办法，修改配置文件/etc/sysconfig/docker
OPTIONS='--selinux-enabled=false --registry-mirror=https://olzwzeg2.mirror.aliyuncs.com --insecure-registry gcr.io'
这个是我搜到的镜像加速地址，可以使用
然后重启docker
systemctl restart docker
后再次查看，发现状态是 Running 了。
[root@centos ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-j6vpx 1/1 Running 0 1h
然后 在使用 kubectl describe pods mysql 查看
[root@centos ~]# kubectl describe pods mysql
Name: mysql-j6vpx
Namespace: default
Node: 127.0.0.1/127.0.0.1
Start Time: Sat, 03 Mar 2018 09:51:30 +0800
Labels: app=mysql
Status: Running
IP: 172.17.0.2
Controllers: ReplicationController/mysql
Containers:
mysql:
Container ID: docker://0f1032ef9bd08438996e76c98f7f313b73a07ade76bf6b4b6b5c42de8dcba053
Image: mysql
Image ID: docker-pullable://docker.io/mysql@sha256:227d5c3f54ee3a70c075b1c3013e72781564000d34fc8c7ec5ec353c5b7ef7fa
Port: 3306/TCP
State: Running
Started: Sat, 03 Mar 2018 10:51:26 +0800
Ready: True
Restart Count: 0
Volume Mounts: <none>
Environment Variables:
MYSQL_ROOT_PASSWORD: 123456
Conditions:
Type Status
Initialized True
Ready True
PodScheduled True
No volumes.
QoS Class: BestEffort
Tolerations: <none>
Events:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
33m 33m 1 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.
33m 33m 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Pulling pulling image "mysql"
2m 2m 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Pulling pulling image "mysql"
2m 1m 2 {kubelet 127.0.0.1} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.
1m 1m 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Pulled Successfully pulled image "mysql"
1m 1m 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Created Created container with docker id 0f1032ef9bd0; Security:[seccomp=unconfined]
1m 1m 1 {kubelet 127.0.0.1} spec.containers{mysql} Normal Started Started container with docker id 0f1032ef9bd0
使用docker ps -a 查看
[root@centos ~]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 0f1032ef9bd0 mysql "docker-entrypoint.sh" 6 minutes ago Up 6 minutes k8s_mysql.f6601b53_mysql-j6vpx_default_64fa560c-1e85-11e8-b481-fa163eee21c2_2999ac54 19334c061120 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 7 minutes ago Up 7 minutes k8s_POD.1d520ba5_mysql-j6vpx_default_64fa560c-1e85-11e8-b481-fa163eee21c2_3a9e5664 f72b01ab8585 registry.access.redhat.com/rhel7/pod-infrastructure:latest "/usr/bin/pod" 38 minutes ago Exited (0) 7 minutes ago k8s_POD.1d520ba5_mysql-j6vpx_default_64fa560c-1e85-11e8-b481-fa163eee21c2_a7bd20de
节点状态
节点的状态主要是用来描述处于 Running 的节点。当前可用的有 NodeReachable 和 NodeReady。以后可能会增加其他状态。NodeReachable 表示集群可达。NodeReady 表示 kubelet 返回 Status Ok 并且 HTTP 状态检查健康。
定义 MYSQL Service 配置
[root@centos ~]# cat mysql-
mysql-rc.yaml mysql-svc.yaml
[root@centos ~]# cat mysql-svc.yaml
apiVersion: v1
kind: Service #表明是kubernetes Service
metadata:
name: mysql
spec:
ports:
- port: 3306
selector:
app: mysql
创建 Service
[root@centos ~]# kubectl create -f mysql-svc.yaml service "mysql" created
查看刚刚创建的Service
[root@centos ~]# kubectl get svc NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes 10.254.0.1 <none> 443/TCP 13h mysql 10.254.248.63 <none> 3306/TCP 1m
注意 Mysql 已经被分配了一个 10.254.248.63 的IP,我们可以通过 CLUSTER-IP+PORT的方式访问
[root@centos ~]# telnet 10.254.248.63 3306 Trying 10.254.248.63... Connected to 10.254.248.63. Escape character is '^]'. J 5.7.21[8e-7}H8e;-bigi3mysql_native_password
定义 Tomcat RC 配置
创建Tomcat，创建一个 RC 文件 myweb-rc.yaml，内容如下
kind: ReplicationController
metadata:
name: myweb
spec:
replicas: 5
selector:
app: myweb
template:
metadata:
labels:
app: myweb
spec:
containers:
- name: myweb
image: kubeguide/tomcat-app:v1
ports:
-containerPort: 8080
env:
#此处如果在未安装域名解析的情况下，会无法将mysql对应的IP解析到env环境变量中，因此先注释掉！
# - name: MYSQL_SERVICE_HOST
# value: 'mysql'
- name: MYSQL_SERVICE_PORT
value: '3306'
执行
kubectl create -f myweb-rc.yaml
查看 pods
[root@centos ~]# kubectl get pods NAME READY STATUS RESTARTS AGE mysql-j6vpx 1/1 Running 0 10h myweb-2bswt 1/1 Running 0 1m myweb-5wq91 1/1 Running 0 1m myweb-67j9n 1/1 Running 0 1m myweb-r74qq 1/1 Running 0 1m myweb-svz49 1/1 Running 0 1m
定义 Tomcat Service 配置
然后继续创建 myweb-svc.yaml，内容如下
apiVersion: v1
kind: Service
metadata:
name: myweb
spec:
type: NodePort
ports:
- port: 8080 # 容器端口
nodePort: 30001 # 外网映射的端口，可以通过30001 访问容器的8080端口
selector:
app: myweb
创建 Service
[root@centos ~]# kubectl create -f myweb-svc.yaml service "myweb" created
查看 Service
[root@centos ~]# kubectl get services NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes 10.254.0.1 <none> 443/TCP 22h mysql 10.254.248.63 <none> 3306/TCP 9h myweb 10.254.193.35 <nodes> 8080:30001/TCP 32s
删除 rc
[root@centos ~]# kubectl delete -f myweb-rc.yaml
查看 rc
[root@centos ~]# kubectl get rc NAME DESIRED CURRENT READY AGE mysql 1 1 1 11h myweb 5 5 0 4s
访问，需要防火墙放行 30001 端口
以上所述就是小编给大家介绍的《K8s 的环境安装》，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持！
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