K8ssandra入門教程之Linux上部署K8ssandra到Kubernetes的過程
阿新 • • 發佈：2021-10-08
目錄
- 1 什麼是K8ssandra
- 2 安裝K8ssandra
- 2.1 安裝Kubenetes
- 2.2 安裝helm3
- 2.3 用Helm安裝K8ssandra
- 2.4 增加節點
- 3 檢視監控
- 4 總結
1 什麼是K8ssandra
Cassandra是一款非常優秀的開源的分散式NoSQL，被許多優秀的大公司採用，具有高可用、彈性擴充套件、效能好等特點。
正應Cassandra的優勢，我們經常需要在雲上服務使用，則需要部署Cassandra到K8s上，這就有了K8ssandra。K8ssandra不僅幫助我們可以快速可靠地在Kubernetes上部署Cassandra，同時提供了許多元件，如監控、備份、同步、訪問等。而這些都是一個Production-Ready的產品不可或缺的。
K8ssandra的元件架構圖如下：
- Cass-operator：保證整個叢集正常執行；
- Reaper：保證一致性的同步工具；
- Medusa：資料備份工具，支援S3、GCP Cloud Storage等；
- Stargate：對資料訪問提供API；
- Prometheus+Grafana：雲原生的常用監控元件。
2 安裝K8ssandra
2.1 安裝Kubenetes
如何在Ubuntu上搭建Kubernetes，在文章《VirtualBox+Ubuntu16搭建Kubernetes叢集的實現》已經有詳細的介紹，這裡不再贅述。為了更好的相容性，我們指定了Kubernetes的版本，命令如下：
minikube start --driver=none --kubernetes-version=v1.19.13
因為要用到PVC，我們建立一個StorageClass：
$ kubectl apply -f https://raw.usercontent.com/rancher/local-path-provisioner/master/deploy/local-path-storage.yaml
2.2 安裝helm3
我們需要使用Helm來部署K8ssandra，下載Helm3如下：
# 下載安裝包 curl -LO https://get.helm.sh/helm-v3.7.0--amd64.tar.gz # 解壓 tar -zxvf helm-v3.7.0-linux-amd64.tar.gz # 移動到bin目錄 mv linux-amd64/helm /usr/local/bin/helm
新增Helm的倉庫：
helm repohttp://www.cppcns.com add k8ssandra https://helm.k8ssandra.io/stable $ helm repo list NAME URL k8ssandra https://helm.k8ssandra.io/stable traefik https://helm.traefik.io/traefik
查詢一下K8ssandra相關的包：
$ helm search repo k8ssandra NAME CHART VERSION APP VERSION DESCRIPTION k8ssandra/k8ssandra 1.3.1 Provisions and configures an instance of the en... k8ssandra/k8ssandra-common 0.28.4 Helper library containing functions used by man... k8ssandra/k8ssandra-operator 0.31.0 1.0.0 Kubernetes operator which handles the provision... k8ssandra/backup 0.26.0 Creates a CassandraBackup custom resource insta... k8ssandra/cass-operator 0.31.0 1.8.0 Kubernetes operator which handles the provision... k8ssandra/medusa-operator 0.30.1 0.1.0 Installs and configures the Medusa Operator for... k8ssandra/reaper-operator 0.32.1 0.1.0 Configures and installs the Reaper Operator for... k8ssandra/restore 0.27.1 Creates a CassandraRestore custom resource inst...
我們安裝k8ssandra/k8ssandra就可以了。
2.3 用Helm安裝K8ssandra
Helm是一個Chart+Value的管理方式，我們準備一個yaml檔案（k8ssandra-values.yaml）來放一些變數：
cassandra:
version: "4.0.0"
cassandraLibDirVolume:
storageClass: local-path
size: 5Gi
allowMultipleNodesPerWorker: true
heap:
size: 1G
newGenSize: 1G
resources:
requests:
cpu: 1000m
memory: 2Gi
limits:
cpu: 1000m
memory: 2Gi
datacenters:
- name: dc1
size: 1
racks:
- name: default
kube-prometheus-stack:
grafana:
adminUser: admin
adminPassword: admin123
stargate:
enabled: true
replicas: 1
heapMB: 256
cpuReqMillicores: 200
cpuLimMillicores: 1000
安裝K8ssandra：
$ helm install -f k8ssandra-values.yaml k8ssandra k8ssandra/k8ssandra NAME: k8ssandra LAST DEPLOYED: Thu Sep 30 21:20:49 2021 NAMESPACE: default STATUS: deployed REVISION: 1
做一些必要的檢查如下：
$ helm list NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION k8ssandra default 1 2021-09-30 21:20:49.409672869 +0800 CST deployed k8ssandra-1.3.1 $ kubectl get cassandradatacenters NAME AGE dc1 4m34s $ kubectl describe CassandraDataCenter dc1 | grep "Cassandra Operator Progress:" Cassandra Operator Progress: Ready
檢查一下Pod和Service：
獲取K8ssandra超級使用者的使用者名稱和密碼
$ kubectl get secret k8ssandra-superuser -o onpath="{.data.username}" | base64 --decode ; echo
k8ssandra-superuser
$ kubectl get secret k8ssandra-superuser -o jsonpath="{.data.password}" | base64 --decode ; echo
TNE5xOk45C1aQsj29qxw
2.4 增加節點
我們為了高可用和容量，建立更多的Cassandra Node，直接修改k8ssandra-values.yaml如下：
cassandra:
version: "4.0.0"
cassandraLibDirVolume:
storageClass: local-path
size: 5Gi
allowMultipleNodesPerWorker: true
heap:
size: 1G
newGenSize: 1G
resources:
requests:
cphttp://www.cppcns.comu: 1000m
memory: 2Gi
limits:
cpu: 1000m
memory: 2Gi
datacenters:
- name: dc1
size: 3
racks:
- name: racks1
- name: racks2
- name: racks3
kube-prometheus-stack:
grafana:
adminUser: admin
adminPassword: admin123
stargate:
enabled: true
replicas: 1
heapMB: 256
cpuReqMillicores: 200
cpuLimMillicores: 1000
修改完之後，升級配置：
$ helm upgrade -f k8ssandra-values.yaml k8ssandra k8ssandra/k8ssandra Release "k8ssandra" has been upgraded. Happy Helming! NAME: k8ssandra LAST DEPLOYED: Fri Oct 1 00:40:08 2021 NAMESPACE: default STATUS: deployed REVISION: 2
檢視Kubernetes的相關資源：
3 檢視監控
我們對外暴露Grafana服務來看看：
kubectl expose deployment k8ssandra-grafana --type=NodePort --name=grafana-out
找到對應的NodePort的埠30348，訪問：http://外網IP:30348
賬號：admin/admin123
介面如下，提供良好的監控介面：
4 總結
K8ssandra真是一個不錯的開源專案，後續再介紹如何在開發中通過K8ssandra使用Cassandra吧。
程式碼請檢視：https://github.com/LarryDpk/pkslow-samples
Reference:
Apache Cassandra Operations in Kubernetes
K8ssandra Get Started
Install K8ssandra on GKE
K8ssandra Helm Chart
用Helm部署Kubernetes應用，支援多環境部署與版本回滾
附：
使用到的映象：
root@k8ssandra:~# images | sort | grep -v REPOSITORY | grep -v k8s.gcr.io alpine 3.12.2 b14afc6dfb98 9 months ago 5.57MB busybox 1.33.1 16ea53ea7c65 2 weeks ago 1.24MB busybox latest 16ea53ea7c65 2 weeks ago 1.24MB datastax/cass-config-builder 1.0.4 907e52ff2f78 4 months ago 354MB gcr.io/k8s-minikube/storage-provisioner v5 6e38f40d628d 6 months ago 31.5MB grafana/grafana 7.3.5 71716d95fc52 9 months ago 187MB jettech/kube-webhook-certgen v1.5.0 344297e197b6 11 months ago 44.7MB k8ssandra/cass-management-api 3.11.10-v0.1.27 e88cc3a8ce75 2 months ago 877MB k8ssandra/cass-management-api 4.0.0-v0.1.28 59b9869dd160 7 weeks ago 726MB k8ssandra/cass-operator v1.7.1 dd57363b0794 4 months ago 49.4MB k8ssandra/k8ssandra-tools latest 43e4bd91cf9b 42 hours ago 49MB k8ssandra/reaper-operator v0.3.3 b4cb9084a5e5 2 months ago 45.9MB k8ssandra/system-logger 9c4c3692 4dda0db106cb 4 months ago 5.66MB kiwigrid/k8s-sidecar 1.1.0 f4bb3bf1ddc7 11 months ago 82MB quay.io/prometheus-operator/prometheus-config-reloader v0.44.0 73bc771f8028 10 months ago 13.4MB quay.io/prometheus-operator/prometheus-operator v0.44.0 f5ab8d7a1a64 10 months ago 42.6MB quay.io/prometheus/prometheus v2.22.1 7cc97b58fb0e 10 months ago 168MB rancher/local-path-provisioner v0.0.20 933989e1174c 2 months ago 35MB stargateio/stargate-3_11 SASQmKqjx v1.0.29 c276fffd9964 3 months ago 537MB stargateio/stargate-4_0 v1.0.29 be4bae3748e1 3 months ago 546MB thelastpickle/cassandra-reaper 2.3.1 8ad2c2784ead 2 months ago 418MB
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