1 什么是K8ssandra
Cassandra是一款十分优良的开源的分布式NoSQL数据库,被许多优良的大公司采纳,具备高可用、弹性扩大、性能好等特点。
正应Cassandra的劣势,咱们常常须要在云上服务应用,则须要部署Cassandra到K8s上,这就有了K8ssandra。K8ssandra不仅帮忙咱们能够疾速牢靠地在Kubernetes上部署Cassandra,同时提供了许多组件,如监控、备份、同步、拜访等。而这些都是一个Production-Ready的产品不可或缺的。
K8ssandra的组件架构图如下:
- Cass-operator:保障整个集群失常运行;
- Reaper:保障一致性的同步工具;
- Medusa:数据备份工具,反对S3、GCP Cloud Storage等;
- Stargate:对数据拜访提供API;
- Prometheus+Grafana:云原生的罕用监控组件。
2 装置K8ssandra
2.1 装置Kubenetes
如何在Ubuntu上通过Minikube疾速启动一个Kubernetes,在文章《服务网格Istio入门-具体记录Kubernetes装置Istio并应用》曾经有具体的介绍,这里不再赘述。为了更好的兼容性,咱们指定了Kubernetes的版本,命令如下:
<code class="bash">minikube start --driver=none --kubernetes-version=v1.19.13
因为要用到PVC,咱们创立一个StorageClass:
<code class="bash">$ kubectl apply -f https://raw.githubusercontent.com/rancher/local-path-provisioner/master/deploy/local-path-storage.yaml
2.2 装置helm3
咱们须要应用Helm来部署K8ssandra,下载Helm3如下:
<code class="bash"># 下载安装包 curl -LO https://get.helm.sh/helm-v3.7.0-linux-amd64.tar.gz # 解压 tar -zxvf helm-v3.7.0-linux-amd64.tar.gz # 挪动到bin目录 mv linux-amd64/helm /usr/local/bin/helm
增加Helm的仓库:
<code class="bash">helm repo add k8ssandra https://helm.k8ssandra.io/stable $ helm repo list NAME URL k8ssandra https://helm.k8ssandra.io/stable traefik https://helm.traefik.io/traefik
查找一下K8ssandra相干的包:
<code class="bash">$ 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...
咱们装置k8ssandra/k8ssandra就能够了。
2.3 用Helm装置K8ssandra
Helm是一个Chart+Value的治理形式,咱们筹备一个yaml文件(k8ssandra-values.yaml)来放一些变量:
<code class="yaml">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
装置K8ssandra:
<code class="bash">$ 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
做一些必要的查看如下:
<code class="bash">$ 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
检查一下Pod和Service:
获取K8ssandra超级用户的用户名和明码
<code class="bash">$ kubectl get secret k8ssandra-superuser -o jsonpath="{.data.username}" | base64 --decode ; echo k8ssandra-superuser $ kubectl get secret k8ssandra-superuser -o jsonpath="{.data.password}" | base64 --decode ; echo TNE5xOk45C1aQsj29qxw
2.4 减少节点
咱们为了高可用和容量,创立更多的Cassandra Node,间接批改k8ssandra-values.yaml如下:
<code class="bash">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: 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
批改完之后,降级配置:
<code class="bash">$ 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
查看Kubernetes的相干资源:
3 查看监控
咱们对外裸露Grafana服务来看看:
<code class="bash">kubectl expose deployment k8ssandra-grafana --type=NodePort --name=grafana-out
找到对应的NodePort的端口30348,拜访:http://外网IP:30348
账号:admin/admin123
界面如下,提供良好的监控界面:
4 总结
K8ssandra真是一个不错的开源我的项目,后续再介绍如何在开发中通过K8ssandra应用Cassandra吧。
代码请查看:https://github.com/LarryDpk/p…