前言
目前 kubernetes 正式版本已经到1.10版本。因为前面有大佬(漠然)已经采完坑，所以自己也试着部署 kubernetes 1.9 体验下该版本的新特性。对于前面部署的 kubernetes 1.7 HA版本而言，本质上变化不大。主要是总结一下某些参数的变动以及其他组件的部署。
一、相关配置变更
1.1 关于 API SERVER 配置出现的变动
- 移除了 --runtime-config=rbac.authorization.k8s.io/v1beta1 配置，因为 RBAC 已经稳定，被纳入了 v1 api，不再需要指定开启；
- --authorization-mode 授权模型增加了 Node 参数，因为 1.8 后默认 system:node role 不会自动授予 system:nodes 组；
- 其中准入控制器(admission control)选项名称变为了 --enable-admission-plugins，--admission-control 同时增加了NodeRestriction 参数;
- 增加 --audit-policy-file 参数用于指定高级审计配置;
- 移除 --experimental-bootstrap-token-auth 参数，更换为 --enable-bootstrap-token-auth;
个人apiserver配置参考如下：
[root@master01 ~]# cat /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="--advertise-address=192.168.133.128 --insecure-bind-address=127.0.0.1 --bind-address=192.168.133.128"
# The port on the local server to listen on.
KUBE_API_PORT="--insecure-port=8080 --secure-port=6443"
# Port minions listen on
# KUBELET_PORT="--kubelet-port=10250"
# Comma separated list of nodes in the etcd cluster
KUBE_ETCD_SERVERS="--etcd-servers=https://192.168.133.128:2379,https://192.168.133.129:2379,https://192.168.133.130:2379"
# 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,LimitRanger,ServiceAccount,DefaultStorageClass,DefaultTolerationSeconds,ResourceQuota,NodeRestriction"
# Add your own!
KUBE_API_ARGS="--authorization-mode=RBAC,Node \
--anonymous-auth=false \
--kubelet-https=true \
--enable-bootstrap-token-auth \
--token-auth-file=/etc/kubernetes/ssl/token.csv \
--service-node-port-range=30000-50000 \
--tls-cert-file=/etc/kubernetes/ssl/kubernetes.pem \
--tls-private-key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
--client-ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem \
--service-account-key-file=/etc/kubernetes/ssl/k8s-root-ca.pem \
--audit-policy-file=/etc/kubernetes/ssl/audit-policy.yaml \
--etcd-quorum-read=true \
--storage-backend=etcd3 \
--etcd-cafile=/etc/etcd/ssl/etcd-root-ca.pem \
--etcd-certfile=/etc/etcd/ssl/etcd.pem \
--etcd-keyfile=/etc/etcd/ssl/etcd-key.pem \
--etcd-compaction-interval=5m0s \
--enable-swagger-ui=true \
--enable-garbage-collector \
--enable-logs-handler \
--kubelet-timeout=3s \
--apiserver-count=3 \
--audit-log-maxage=30 \
--audit-log-maxbackup=3 \
--audit-log-maxsize=100 \
--audit-log-path=/var/log/kube-audit/audit.log \
--event-ttl=1h \
--enable-swagger-ui \
--log-flush-frequency=5s"
1.2 关于 controller-manager 配置变动
- 默认已开启了证书轮换能力用于自动签署 kueblet 证书，并且证书时间也设置了 10 年，可自行调整(--experimental-cluster-signing-duration=86700h0m0s)；
- 增加了 --controllers (--controllers=*,bootstrapsigner,tokencleaner)选项以指定开启全部控制器；
个人controller-manager配置参考如下：
# The following values are used to configure the kubernetes controller-manager
# defaults from config and apiserver should be adequate
# Add your own!
KUBE_CONTROLLER_MANAGER_ARGS="--address=0.0.0.0 \
--service-cluster-ip-range=10.254.0.0/16 \
--cluster-name=kubernetes \
--cluster-signing-cert-file=/etc/kubernetes/ssl/k8s-root-ca.pem \
--cluster-signing-key-file=/etc/kubernetes/ssl/k8s-root-ca-key.pem \
--service-account-private-key-file=/etc/kubernetes/ssl/k8s-root-ca-key.pem \
--controllers=*,bootstrapsigner,tokencleaner \
--deployment-controller-sync-period=10s \
--experimental-cluster-signing-duration=86700h0m0s \
--root-ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem \
--leader-elect=true \
--node-monitor-grace-period=40s \
--node-monitor-period=5s \
--pod-eviction-timeout=5m0s \
--feature-gates=RotateKubeletServerCertificate=true"
1.3 关于 scheduler 配置变动
- 恢复默认的领导选举(leader-elect=true),参考v1.9.5变更日志；
个人scheduler配置参考如下：
[root@master01 ~]# cat /etc/kubernetes/scheduler ### # kubernetes scheduler config # default config should be adequate # Add your own! KUBE_SCHEDULER_ARGS="--leader-elect=true --address=0.0.0.0 \ --algorithm-provider=DefaultProvider"
更多细节请关注changelog以及官方手册：https://v1-9.docs.kubernetes.io/docs/reference/generated/kubelet/
二、网络插件部署
2.1 Calico 简介
Calico 是一个纯三层的数据中心网咯方案，不需要overlay。并且对OpenStack、kubernetes、AWS等有良好的集成。Calico 在每个节点利用Linux Kernel实现一个高效的vRouter来负责数据转发，而每个vRouter通过BGP协议负责把自己运行的workload路由信息向整个Calico网络内传播。小规模部署可以直接互联，大规模部署下可通过制定的BGP route reflector来完成。这样保证最终所有的workload之间的数据流量都可以通过IP路由的方式完成互联。Calico节点组网可以直接利用数据中心的网络结构(无论是L2还是L3)，无需额外的NAT或者Overlay Network。
此外，Calico基于iptables还提供了丰富而灵活的网络Policy，保证通过各个节点上的ACLs来提供Workload的多租户隔离、安全组以及其他可达性限制等功能。
Calico 核心组件：
- Felix，Calico Agent，跑在每台需要运行Workload节点上，主要负责配置路由及ACL等信息来确保Endpoint的连通状态；
- etcd，分布式键值存储，主要负责网络元数据一致性，确保Calico网络状态的准确性；
- BGP Client(BIRD)，主要负责把Felix写入Kernel的路由信息分发到当前Calico网络，确保Workload间的通信有效性；
- BGP Route Reflector(BIRD)，大规模部署时使用，摒弃所有节点互联的mesh模式，通过一个或者多个BGP Route Reflector来完成集中式的路由分发；
- calico/calico-ipam，主要用作kubernetes的CNI插件；
IP-in-IP
Calico控制平面的设计要求物理网络得是L2 Fabric，这样vRouter间都是直接可达的，路由不需要把物理设备当做下一跳。为了支持L3 Fabric，Calico推出了IPinIP的选项。
2.2 Calico 安装
关于calico的部署，官方推荐 "Standard Hosted Install" 安装方式，及所有组件通过kubernetes去管理服务。还有另一种就是在Kubernetes上安装Calico以集成定制配置管理所需的组件。关于Standard Hosted Install方式安装就是将 calico-node/calico-cni/calico-kube-controller 全部通过kubernetes去管理、部署，而另一种方式 systemd 通过 docker 启动calico-node，而 calico-cni 则是通过二进制文件以及手动设置网络来实现的。calico-kube-controller 还是通过 kubernetes 部署。具体安装配置参考 Calico 官方文档。
2.2.1 创建 calico-node systemd文件
cat << EOF > /usr/lib/systemd/system/calico-node.service
[Unit]
Description=calico node
After=docker.service
Requires=docker.service
[Service]
User=root
Environment=ETCD_ENDPOINTS=https://172.16.204.131:2379
PermissionsStartOnly=true
ExecStart=/usr/bin/docker run --net=host --privileged --name=calico-node \\
-e ETCD_ENDPOINTS=${ETCD_ENDPOINTS} \\
-e ETCD_CA_CERT_FILE=/etc/etcd/ssl/etcd-root-ca.pem \\
-e ETCD_CERT_FILE=/etc/etcd/ssl/etcd.pem \\
-e ETCD_KEY_FILE=/etc/etcd/ssl/etcd-key.pem \\
-e NODENAME=node01 \\
-e IP= \\
-e IP6= \\
-e NO_DEFAULT_POOLS= \\
-e AS= \\
-e CALICO_IPV4POOL_CIDR=10.20.0.0/16 \\
-e CALICO_IPV4POOL_IPIP=always \\
-e CALICO_LIBNETWORK_ENABLED=true \\
-e CALICO_NETWORKING_BACKEND=bird \\
-e CALICO_DISABLE_FILE_LOGGING=true \\
-e FELIX_IPV6SUPPORT=false \\
-e FELIX_DEFAULTENDPOINTTOHOSTACTION=ACCEPT \\
-e FELIX_LOGSEVERITYSCREEN=info \\
-v /etc/etcd/ssl/etcd-root-ca.pem:/etc/etcd/ssl/etcd-root-ca.pem \\
-v /etc/etcd/ssl/etcd.pem:/etc/etcd/ssl/etcd.pem \\
-v /etc/etcd/ssl/etcd-key.pem:/etc/etcd/ssl/etcd-key.pem \\
-v /var/run/calico:/var/run/calico \\
-v /lib/modules:/lib/modules \\
-v /run/docker/plugins:/run/docker/plugins \\
-v /var/run/docker.sock:/var/run/docker.sock \\
-v /var/log/calico:/var/log/calico \\
calico/node:v2.6.9
ExecStop=/usr/bin/docker rm -f calico-node
Restart=always
RestartSec=10
[Install]
WantedBy=multi-user.target
EOF
启动calico-node服务
systemctl daemon-reload systemctl start calico-node
2.2.2 编辑calico.yml文件
下载相关文件
wget https://docs.projectcalico.org/v2.6/getting-started/kubernetes/installation/rbac.yaml wget https://docs.projectcalico.org/v2.6/getting-started/kubernetes/installation/hosted/calico.yaml
修改calico.yml文件
## 更改为自己的etcd集群
sed -i 's@.*etcd_endpoints:.*@\ \ etcd_endpoints:\ \"https://172.16.204.131:2379\"@gi' calico.yaml
export ETCD_CERT=`cat /etc/etcd/ssl/etcd.pem | base64 | tr -d '\n'`
export ETCD_KEY=`cat /etc/etcd/ssl/etcd-key.pem | base64 | tr -d '\n'`
export ETCD_CA=`cat /etc/etcd/ssl/etcd-root-ca.pem | base64 | tr -d '\n'`
sed -i "s@.*etcd-cert:.*@\ \ etcd-cert:\ ${ETCD_CERT}@gi" calico.yaml
sed -i "s@.*etcd-key:.*@\ \ etcd-key:\ ${ETCD_KEY}@gi" calico.yaml
sed -i "s@.*etcd-ca:.*@\ \ etcd-ca:\ ${ETCD_CA}@gi" calico.yaml
sed -i 's@.*etcd_ca:.*@\ \ etcd_ca:\ "/calico-secrets/etcd-ca"@gi' calico.yaml
sed -i 's@.*etcd_cert:.*@\ \ etcd_cert:\ "/calico-secrets/etcd-cert"@gi' calico.yaml
sed -i 's@.*etcd_key:.*@\ \ etcd_key:\ "/calico-secrets/etcd-key"@gi' calico.yaml
## 禁止kubernetes启动calico-node容器
sed -i '106,197s@.*@#&@gi' calico.yaml
2.2.3 修改 kubelet 配置文件
[root@node01 ~]# cat /etc/kubernetes/kubelet
###
# kubernetes kubelet (minion) config
# The address for the info server to serve on (set to 0.0.0.0 or "" for all interfaces)
KUBELET_ADDRESS="--address=172.16.204.132"
# 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=172.16.204.132"
# location of the api-server
# KUBELET_API_SERVER="--api-servers=http://127.0.0.1:8080"
# Add your own!
# KUBELET_ARGS="--cgroup-driver=systemd"
KUBELET_ARGS="--cgroup-driver=systemd \
--network-plugin=cni \
--cni-conf-dir=/etc/cni/net.d \
--cni-bin-dir=/opt/cni/bin \
--cluster-dns=10.254.0.2 \
--resolv-conf=/etc/resolv.conf \
--experimental-bootstrap-kubeconfig=/etc/kubernetes/bootstrap.kubeconfig \
--kubeconfig=/etc/kubernetes/kubelet.kubeconfig \
--fail-swap-on=false \
--cert-dir=/etc/kubernetes/ssl \
--cluster-domain=cluster.local. \
--hairpin-mode=promiscuous-bridge \
--serialize-image-pulls=false \
--pod-infra-container-image=gcr.io/google_containers/pause-amd64:3.0"
添加如上内容，然后重启服务
systemctl daemon-reload systemctl restart kubelet
2.2.4 启动相关容器
## 创建RBAC kubectl apply -f rbac.yaml ## 启动calico-cni以及kube-controller容器 kubectl create -f calico.yaml
2.2.5 Calico 网络测试
创建一个简单demo进行测试
cat << EOF > demo.deploy.yml
apiVersion: apps/v1beta1
kind: Deployment
metadata:
name: demo-tomcat
spec:
replicas: 3
template:
metadata:
labels:
app: demo
spec:
containers:
- name: demo
image: tomcat:9.0.7
ports:
- containerPort: 80
EOF
kubectl create -f demo.deploy.yml
kubetcl get pods -o wide --all-namespaces
测试
[root@master01 calico]# kubectl get pods --all-namespaces -o wide NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE default demo-tomcat-56697dcc5b-2jv69 1/1 Running 0 34s 10.20.196.136 192.168.133.129 default demo-tomcat-56697dcc5b-lmc2h 1/1 Running 0 35s 10.20.140.74 192.168.133.130 default demo-tomcat-56697dcc5b-whbg7 1/1 Running 0 34s 10.20.140.73 192.168.133.130 kube-system calico-kube-controllers-684fcf8587-66kxn 1/1 Running 0 43m 192.168.133.129 192.168.133.129 kube-system calico-node-hpr9c 1/1 Running 0 43m 192.168.133.129 192.168.133.129 kube-system calico-node-jvpf2 1/1 Running 0 43m 192.168.133.130 192.168.133.130 [root@master01 calico]# kubectl exec -it demo-tomcat-56697dcc5b-2jv69 bash root@demo-tomcat-56697dcc5b-2jv69:/usr/local/tomcat# pin pinentry pinentry-curses ping ping6 pinky root@demo-tomcat-56697dcc5b-2jv69:/usr/local/tomcat# ping 10.20.140.74 PING 10.20.140.74 (10.20.140.74): 56 data bytes 64 bytes from 10.20.140.74: icmp_seq=0 ttl=62 time=0.673 ms 64 bytes from 10.20.140.74: icmp_seq=1 ttl=62 time=0.398 ms ^C--- 10.20.140.74 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.398/0.536/0.673/0.138 ms root@demo-tomcat-56697dcc5b-2jv69:/usr/local/tomcat# ping 10.20.140.73 PING 10.20.140.73 (10.20.140.73): 56 data bytes 64 bytes from 10.20.140.73: icmp_seq=0 ttl=62 time=0.844 ms 64 bytes from 10.20.140.73: icmp_seq=1 ttl=62 time=0.348 ms ^C--- 10.20.140.73 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.348/0.596/0.844/0.248 ms root@demo-tomcat-56697dcc5b-2jv69:/usr/local/tomcat# ping 10.20.196.136 PING 10.20.196.136 (10.20.196.136): 56 data bytes 64 bytes from 10.20.196.136: icmp_seq=0 ttl=64 time=0.120 ms 64 bytes from 10.20.196.136: icmp_seq=1 ttl=64 time=0.068 ms ^C--- 10.20.196.136 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 0.068/0.094/0.120/0.026 ms
总结：
关于 k8s 网络插件的选择，没有什么完整的方案。主要还是根据自己的环境进行决策，主要是 Calico 坑其实比较多。这里提供几个实质性比较强的参考链接：
https://feisky.gitbooks.io/sdn/basic/tcpip.html#tcpip%E7%BD%91%E7%BB%9C%E6%A8%A1%E5%9E%8B
http://www.shushilvshe.com/data/kubernete-calico.html#data/kubernete-calico
http://www.51yimo.com/2017/09/26/calico-install-on-kubernetes/
三、安装CoreDNS
3.1 CoreDNS 简介
没啥说的，其实就是一个取代kube-dns插件的。
3.2 部署安装
首先下载 delopy.sh和coredns.yaml.sed 文件，然后直接安装
./deploy.sh -r 10.254.0.0/16 -i 10.254.0.2 -d cluster.local | kubectl apply -f -
提示：关于脚本的内容可能会因为你使用的版本不同而参数不同，所以尽量在做的时候撸一眼脚本的内容。
[root@master01 coredns]# kubectl get pods --all-namespaces NAMESPACE NAME READY STATUS RESTARTS AGE kube-system calico-kube-controllers-684fcf8587-5ndks 1/1 Running 1 11d kube-system calico-node-4wskw 1/1 Running 1 11d kube-system calico-node-sbngf 1/1 Running 1 11d kube-system coredns-64b597b598-fmh85 1/1 Running 0 57s kube-system coredns-64b597b598-jf88d 1/1 Running 0 57s
3.3 验证CoreDNS的可用性
部署测试nginx pod进行测试
cat > my-nginx.yaml << EOF
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 2
template:
metadata:
labels:
run: my-nginx
spec:
containers:
- name: my-nginx
image: nginx:1.7.9
ports:
- containerPort: 80
EOF
kubectl create -f my-nginx.yaml
创建my-nginx pod的service并且查看当前的cluster ip
##创建my-nginx pod service kubectl expose deploy my-nginx ##查看创建的service [root@master01 ~]# kubectl get services --all-namespaces NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE default kubernetes ClusterIP 10.254.0.1 <none> 443/TCP 12d default my-nginx ClusterIP 10.254.37.75 <none> 80/TCP 13s kube-system kube-dns ClusterIP 10.254.0.2 <none> 53/UDP,53/TCP 4m
验证CoreDNS可用性
[root@master01 ~]# kubectl exec -it my-nginx-56b48db847-g8fr2 /bin/bash
root@my-nginx-56b48db847-g8fr2:/# cat /etc/resolv.conf
nameserver 10.254.0.2
search default.svc.cluster.local. svc.cluster.local. cluster.local.
options ndots:5
root@my-nginx-56b48db847-g8fr2:/# ping my-nginx
PING my-nginx.default.svc.cluster.local (10.254.37.75): 48 data bytes
^C--- my-nginx.default.svc.cluster.local ping statistics ---
7 packets transmitted, 0 packets received, 100% packet loss
root@my-nginx-56b48db847-g8fr2:/# ping kubernetes
PING kubernetes.default.svc.cluster.local (10.254.0.1): 48 data bytes
^C--- kubernetes.default.svc.cluster.local ping statistics ---
5 packets transmitted, 0 packets received, 100% packet loss
root@my-nginx-56b48db847-g8fr2:/# ping kube-dns.kube-system.svc.cluster.local
PING kube-dns.kube-system.svc.cluster.local (10.254.0.2): 48 data bytes
^C--- kube-dns.kube-system.svc.cluster.local ping statistics ---
6 packets transmitted, 0 packets received, 100% packet loss
root@my-nginx-56b48db847-g8fr2:/# curl -I my-nginx
HTTP/1.1 200 OK
Server: nginx/1.7.9
Date: Tue, 08 May 2018 07:27:13 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 23 Dec 2014 16:25:09 GMT
Connection: keep-alive
ETag: "54999765-264"
Accept-Ranges: bytes
root@my-nginx-56b48db847-g8fr2:/# curl my-nginx.default.svc.cluster.local
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
...省略其他...
从上面可以看出，当前是能够解析service对应的cluster ip;