简介: Kubernetes(k8s)是自动化容器操作的开源平台,这些操作包括部署,调度和节点集群间扩展。如果你曾经用过Docker容器技术部署容器,那么可以将Docker看成Kubernetes内部使用的低级别组件。Kubernetes不仅仅支持Docker,还支持Rocket,这是另一种容器技术。
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基本概念
- pod 最小的基本单位,就像一个个对应的容器。对于一个简单的网站来说,一个POD是前台,一个POD是后台,一个POD是数据库。三个包含容器的POD各自独立运行。
- replicationController 是对于POD的抽象组合,用于解决POD的伸缩问题。一般情况下,rc能够保持部分POD失效时自动维持可用POD数量的机制。
- service 是对一些列POD以及访问这些POD的策略的一层抽象。service 通过label找到POD组,对外提供访问端口。
- label POD中的label就是一个键值对,用来传递用户自定义的属性。简单说就是用来标记的,而且可以使用选择器选择特定的POD。
- deployment 是对于RC的升级,提供了一种更加简单有效更新POD和RC的机制。通过yml文件中描述的期望的集群状态,deployment会将现在的集群状态在可控的速度下逐步更新成所期望的状态。集成了上线部署、滚动升级、创建副本、暂停上线任务,恢复上线任务,回滚到以前某一版本(成功/稳定)的Deployment等功能,在某种程度上,Deployment可以实现无人值守的上线,大大降低上线过程的复杂沟通、操作风险。
- node 所有的服务都运行在node上,是一切服务的基础,就像虚拟机的宿主机。
安装配置
版本
- OS:CentOS Linux release 7.3.1611 (Core) 3.10.0-514.16.1.el7.x86_64
- Kubernetes 1.5.2
- Docker 1.12.6(使用yum安装)
- Etcd 3.1.5
- Flannel 0.7.1 vxlan或者host-gw 网络
- TLS 认证通信 (所有组件,如 etcd、kubernetes master 和 node)
- kubedns、dashboard、heapster(influxdb、grafana)、EFK(elasticsearch、fluentd、kibana) 集群插件
环境准备
关闭防火墙
systemctl disable iptables-services firewalld
systemctl stop iptables-services firewalld
主机名
hosts
centos-master = 10.10.30.102
centos-minion-1 = 10.10.30.102
centos-minion-2 = 10.10.30.103
centos-minion-3 = 10.10.30.104
配置主机名,如果没有的话
echo "10.10.30.102 centos-master
10.10.30.102 centos-minion-1
10.10.30.103 centos-minion-2
10.10.30.104 centos-minion-3" >> /etc/hosts
yum 源
vim /etc/yum.repos.d/virt7-docker-common-release.repo
[virt7-docker-common-release]
name=virt7-docker-common-release
baseurl=http://cbs.centos.org/repos/virt7-docker-common-release/x86_64/os/
gpgcheck=0
安装
yum -y install --enablerepo=virt7-docker-common-release kubernetes etcd flannel
版本
[root@localhost ~]# docker version
Client:
Version: 1.12.6
API version: 1.24
Package version: docker-1.12.6-68.gitec8512b.el7.centos.x86_64
Go version: go1.8.3
Git commit: ec8512b/1.12.6
Built: Mon Dec 11 16:08:42 2017
OS/Arch: linux/amd64
Server:
Version: 1.12.6
API version: 1.24
Package version: docker-1.12.6-68.gitec8512b.el7.centos.x86_64
Go version: go1.8.3
Git commit: ec8512b/1.12.6
Built: Mon Dec 11 16:08:42 2017
OS/Arch: linux/amd64
配置文件
/etc/kubernetes/config
修改以下内容
KUBE_LOGTOSTDERR="--logtostderr=true"
# journal message level, 0 is debug
KUBE_LOG_LEVEL="--v=0"
# Should this cluster be allowed to run privileged docker containers
KUBE_ALLOW_PRIV="--allow-privileged=false"
# How the controller-manager, scheduler, and proxy find the apiserver
KUBE_MASTER="--master=http://centos-master:8080"
KUBE_ETCD_SERVERS=”–etcd_servers=http://centos-master:4001″
主节点配置
/etc/kubernetes/apiserver
###
# kubernetes system config
#
# The following values are used to configure the kube-apiserver
#
# The address on the local server to listen to.
KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0"
# The port on the local server to listen on.
KUBE_API_PORT="--port=8080"
# Port minions listen on
KUBELET_PORT="--kubelet-port=10250"
# Comma separated list of nodes in the etcd cluster
KUBE_ETCD_SERVERS="--etcd-servers=http://centos-master:2379"
# Address range to use for services
KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
# default admission control policies
#KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota"
# Add your own!
KUBE_API_ARGS=""
/etc/etcd/etcd.conf
# [member]
ETCD_NAME=default
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379"
#[cluster]
ETCD_ADVERTISE_CLIENT_URLS="http://0.0.0.0:2379"
配置etcd
systemctl start etcd
etcdctl mkdir /kube-centos/network
etcdctl mk /kube-centos/network/config "{ \"Network\": \"172.30.0.0/16\", \"SubnetLen\": 24, \"Backend\": { \"Type\": \"vxlan\" } }"
启动服务
for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do
systemctl restart $SERVICES
systemctl enable $SERVICES
systemctl status $SERVICES
done
节点配置
/etc/kubernetes/kubelet
node 增加
# The address for the info server to serve on
KUBELET_ADDRESS=”–address=0.0.0.0″
# The port for the info server to serve on
KUBELET_PORT=”–port=10250″
# You may leave this blank to use the actual hostname
KUBELET_HOSTNAME=”–hostname_override=centos-minion”
# Add your own!
KUBELET_ARGS=””
启动节点服务
for SERVICES in kube-proxy kubelet docker; do
systemctl restart $SERVICES
systemctl enable $SERVICES
systemctl status $SERVICES
done
Configure kubectl
kubectl config set-cluster default-cluster --server=http://centos-master:8080
kubectl config set-context default-context --cluster=default-cluster --user=default-admin
kubectl config use-context default-context
检查状态
$ kubectl get nodes
NAME LABELS STATUS
centos-minion <none> Ready
更多参考:
Kubernetes + Dashboard + Heapster (一) 安装配置
Kubernetes + Dashboard + Heapster (二) 监控部署
Kubernetes + Dashboard + Heapster (三) ingress负载均衡
Kubernetes + Dashboard + Heapster (四) 慢慢填坑
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