Kubernetes高可用Master節點安裝
前言 這是和我一步步部署kubernetes叢集專案((fork自opsnull))中的一篇文章,下文是結合我之前部署kubernetes的過程產生的kuberentes環境,部署master節點的kube-apiserver、kube-controller-manager和kube-scheduler的過程。 高可用Kubernetes Master節點安裝 kubernetes master 節點包含的元件:
kube-apiserver kube-scheduler kube-controller-manager
目前這三個元件需要部署在同一臺機器上。
kube-scheduler、kube-controller-manager 和 kube-apiserver 三者的功能緊密相關; 同時只能有一個 kube-scheduler、kube-controller-manager 程序處於工作狀態,如果執行多個,則需要通過選舉產生一個 leader;
本文件記錄部署一個三個節點的高可用 kubernetes master 叢集步驟。(後續建立一個 load balancer 來代理訪問 kube-apiserver 的請求) TLS 證書檔案 pem和token.csv證書檔案我們在TLS證書和祕鑰這一步中已經建立過了。我們再檢查一下。 $ ls /etc/kubernetes/ssl admin-key.pem admin.pem ca-key.pem ca.pem kube-proxy-key.pem kube-proxy.pem kubernetes-key.pem kubernetes.pem 下載最新版本的二進位制檔案 有兩種下載方式 方式一 從 github release 頁面 下載釋出版 tarball,解壓後再執行下載指令碼 $ wget https://github.com/kubernetes/kubernetes/releases/download/v1.6.0/kubernetes.tar.gz $ tar -xzvf kubernetes.tar.gz ... $ cd kubernetes $ ./cluster/get-kube-binaries.sh ... 方式二 從 CHANGELOG頁面 下載 client 或 server tarball 檔案 server 的 tarball kubernetes-server-linux-amd64.tar.gz 已經包含了 client(kubectl) 二進位制檔案,所以不用單獨下載kubernetes-client-linux-amd64.tar.gz檔案; $ # wget https://dl.k8s.io/v1.6.0/kubernetes-client-linux-amd64.tar.gz $ wget https://dl.k8s.io/v1.6.0/kubernetes-server-linux-amd64.tar.gz $ tar -xzvf kubernetes-server-linux-amd64.tar.gz ... $ cd kubernetes $ tar -xzvf kubernetes-src.tar.gz 將二進位制檔案拷貝到指定路徑 $ cp -r server/bin/{kube-apiserver,kube-controller-manager,kube-scheduler,kubectl,kube-proxy,kubelet} /root/local/bin/ 配置和啟動 Kube-Apiserver 建立 kube-apiserver的service配置檔案 serivce配置檔案/usr/lib/systemd/system/kube-apiserver.service內容: [Unit] Description=Kubernetes API Service Documentation=https://github.com/GoogleCloudPlatform/kubernetes After=network.target After=etcd.service [Service] EnvironmentFile=-/etc/kubernetes/config EnvironmentFile=-/etc/kubernetes/apiserver ExecStart=/usr/bin/kube-apiserver
$KUBE_LOGTOSTDERR
$KUBE_LOG_LEVEL
$KUBE_ETCD_SERVERS
$KUBE_API_ADDRESS
$KUBE_API_PORT
$KUBELET_PORT
$KUBE_ALLOW_PRIV
$KUBE_SERVICE_ADDRESSES
$KUBE_ADMISSION_CONTROL
$KUBE_API_ARGS Restart=on-failure Type=notify LimitNOFILE=65536 [Install] WantedBy=multi-user.target /etc/kubernetes/config檔案的內容為:
# kubernetes system config # # The following values are used to configure various aspects of all # kubernetes services, including # # kube-apiserver.service # kube-controller-manager.service # kube-scheduler.service # kubelet.service # kube-proxy.service # logging to stderr means we get it in the systemd journal 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=true" # How the controller-manager, scheduler, and proxy find the apiserver #KUBE_MASTER="--master=http://sz-pg-oam-docker-test-001.tendcloud.com:8080" KUBE_MASTER="--master=http://172.20.0.113:8080"
該配置檔案同時被kube-apiserver、kube-controller-manager、kube-scheduler、kubelet、kube-proxy使用。 apiserver配置檔案/etc/kubernetes/apiserver內容為:
## 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=sz-pg-oam-docker-test-001.tendcloud.com"
KUBE_API_ADDRESS="--advertise-address=172.20.0.113 --bind-address=172.20.0.113 --insecure-bind-address=172.20.0.113" # ## 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=https://172.20.0.113:2379,172.20.0.114:2379,172.20.0.115:2379" # ## 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=ServiceAccount,NamespaceLifecycle,NamespaceExists,LimitRanger,ResourceQuota" # ## Add your own! KUBE_API_ARGS="--authorization-mode=RBAC --runtime-config=rbac.authorization.k8s.io/v1beta1 --kubelet-https=true --experimental-bootstrap-token-auth --token-auth-file=/etc/kubernetes/token.csv --service-node-port-range=30000-32767 --tls-cert-file=/etc/kubernetes/ssl/kubernetes.pem --tls-private-key-file=/etc/kubernetes/ssl/kubernetes-key.pem --client-ca-file=/etc/kubernetes/ssl/ca.pem --service-account-key-file=/etc/kubernetes/ssl/ca-key.pem --etcd-cafile=/etc/kubernetes/ssl/ca.pem --etcd-certfile=/etc/kubernetes/ssl/kubernetes.pem --etcd-keyfile=/etc/kubernetes/ssl/kubernetes-key.pem --enable-swagger-ui=true --apiserver-count=3 --audit-log-maxage=30 --audit-log-maxbackup=3 --audit-log-maxsize=100 --audit-log-path=/var/lib/audit.log --event-ttl=1h"
--authorization-mode=RBAC 指定在安全埠使用 RBAC 授權模式,拒絕未通過授權的請求; kube-scheduler、kube-controller-manager 一般和 kube-apiserver 部署在同一臺機器上,它們使用非安全埠和 kube-apiserver通訊; kubelet、kube-proxy、kubectl 部署在其它 Node 節點上,如果通過安全埠訪問 kube-apiserver,則必須先通過 TLS 證書認證,再通過 RBAC 授權; kube-proxy、kubectl 通過在使用的證書裡指定相關的 User、Group 來達到通過 RBAC 授權的目的; 如果使用了 kubelet TLS Boostrap 機制,則不能再指定 --kubelet-certificate-authority、--kubelet-client-certificate 和 --kubelet-client-key 選項,否則後續 kube-apiserver 校驗 kubelet 證書時出現 ”x509: certificate signed by unknown authority“ 錯誤;
--admission-control 值必須包含 ServiceAccount;
--bind-address 不能為 127.0.0.1;
runtime-config配置為rbac.authorization.k8s.io/v1beta1,表示執行時的apiVersion;
--service-cluster-ip-range 指定 Service Cluster IP 地址段,該地址段不能路由可達; 預設情況下 kubernetes 物件儲存在 etcd /registry 路徑下,可以通過 --etcd-prefix引數進行調整;
完整 unit 見 kube-apiserver.service 啟動kube-apiserver $ systemctl daemon-reload $ systemctl enable kube-apiserver $ systemctl start kube-apiserver $ systemctl status kube-apiserver 配置和啟動 Kube-Controller-Manager 建立 kube-controller-manager的serivce配置檔案 檔案路徑/usr/lib/systemd/system/kube-controller-manager.service Description=Kubernetes Controller Manager Documentation=https://github.com/GoogleCloudPlatform/kubernetes [Service] EnvironmentFile=-/etc/kubernetes/config EnvironmentFile=-/etc/kubernetes/controller-manager ExecStart=/usr/bin/kube-controller-manager
$KUBE_LOGTOSTDERR
$KUBE_LOG_LEVEL
$KUBE_MASTER
$KUBE_CONTROLLER_MANAGER_ARGS Restart=on-failure LimitNOFILE=65536 [Install] WantedBy=multi-user.target 配置檔案/etc/kubernetes/controller-manager。
# 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=127.0.0.1 --service-cluster-ip-range=10.254.0.0/16 --cluster-name=kubernetes --cluster-signing-cert-file=/etc/kubernetes/ssl/ca.pem --cluster-signing-key-file=/etc/kubernetes/ssl/ca-key.pem --service-account-private-key-file=/etc/kubernetes/ssl/ca-key.pem --root-ca-file=/etc/kubernetes/ssl/ca.pem --leader-elect=true"
--service-cluster-ip-range 引數指定 Cluster 中 Service 的CIDR範圍,該網路在各 Node 間必須路由不可達,必須和 kube-apiserver 中的引數一致;
--cluster-signing-* 指定的證書和私鑰檔案用來簽名為 TLS BootStrap 建立的證書和私鑰;
--root-ca-file 用來對 kube-apiserver 證書進行校驗,指定該引數後,才會在Pod 容器的 ServiceAccount 中放置該 CA 證書檔案;
--address 值必須為 127.0.0.1,因為當前 kube-apiserver 期望 scheduler 和 controller-manager 在同一臺機器,否則:
$ kubectl get componentstatuses NAME STATUS MESSAGE ERROR scheduler Unhealthy Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused controller-manager Healthy ok etcd-2 Unhealthy Get http://172.20.0.113:2379/health: malformed HTTP response "\x15\x03\x01\x00\x02\x02" etcd-0 Healthy {"health": "true"} etcd-1 Healthy {"health": "true"} 參考:https://github.com/kubernetes-incubator/bootkube/issues/64 完整 unit 見 kube-controller-manager.service 啟動 Kube-Controller-Manager $ systemctl daemon-reload $ systemctl enable kube-controller-manager $ systemctl start kube-controller-manager 配置和啟動 Kube-Scheduler 建立 kube-scheduler的serivce配置檔案 檔案路徑/usr/lib/systemd/system/kube-scheduler.serivce。 [Unit] Description=Kubernetes Scheduler Plugin Documentation=https://github.com/GoogleCloudPlatform/kubernetes [Service] EnvironmentFile=-/etc/kubernetes/config EnvironmentFile=-/etc/kubernetes/scheduler ExecStart=/usr/bin/kube-scheduler
$KUBE_LOGTOSTDERR
$KUBE_LOG_LEVEL
$KUBE_MASTER
$KUBE_SCHEDULER_ARGS Restart=on-failure LimitNOFILE=65536 [Install] WantedBy=multi-user.target 配置檔案/etc/kubernetes/scheduler。
# kubernetes scheduler config # default config should be adequate # Add your own!
KUBE_SCHEDULER_ARGS="--leader-elect=true --address=127.0.0.1"
--address 值必須為 127.0.0.1,因為當前 kube-apiserver 期望 scheduler 和 controller-manager 在同一臺機器; 完整 unit 見 kube-scheduler.service 啟動 Kube-Scheduler $ systemctl daemon-reload $ systemctl enable kube-scheduler $ systemctl start kube-scheduler 驗證 Master 節點功能 $ kubectl get componentstatuses NAME STATUS MESSAGE ERROR scheduler Healthy ok controller-manager Healthy ok etcd-0 Healthy {"health": "true"} etcd-1 Healthy {"health": "true"} etcd-2 Healthy {"health": "true"} 後記 當時在配置過程中遇到了問題TLS認證相關的問題,其實就是因為配置apiserver時候etcd的協議寫成了http導致的,應該是用https。 Opsnull寫的kubernetes高可用master叢集部署過程中似乎並沒有包括高可用的配置,才雲科技的唐繼元分享過Kubernetes Master High Availability 高階實踐。 究竟如何實現kubernetes master的高可用還需要繼續探索。 本文轉自中文社群-Kubernetes高可用Master節點安裝