1 什么是K8ssandra
Cassandra是一款非常优秀的开源的分布式NoSQL数据库，被许多优秀的大公司采用，具有高可用、弹性扩展、性能好等特点。
正应Cassandra的优势，我们经常需要在云上服务使用，则需要部署Cassandra到K8s上，这就有了K8ssandra。K8ssandra不仅帮助我们可以快速可靠地在Kubernetes上部署Cassandra，同时提供了许多组件，如监控、备份、同步、访问等。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：保证整个集群正常运行；
- Reaper：保证一致性的同步工具；
- Medusa：数据备份工具，支持S3、GCP Cloud Storage等；
- Stargate：对数据访问提供API；
- Prometheus+Grafana：云原生的常用监控组件。
2 安装K8ssandra
2.1 安装Kubenetes
如何在Ubuntu上搭建Kubernetes，在文章《VirtualBox+Ubuntu16搭建Kubernetes集群的实现》已经有详细的介绍，这里不再赘述。为了更好的兼容性，我们指定了Kubernetes的版本，命令如下：
minikube start --driver=none --kubernetes-version=v1.19.13因为要用到PVC，我们创建一个StorageClass：
$ kubectl apply -f https://raw.githubusercontent.com/rancher/local-path-provisioner/master/deploy/local-path-storage.yaml
2.2 安装helm3
我们需要使用Helm来部署K8ssandra，下载Helm3如下：
# 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
# 移动到bin目录
mv linux-amd64/helm /usr/local/bin/helm添加Helm的仓库：
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相关的包：
$ 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... 我们安装k8ssandra/k8ssandra就可以了。
2.3 用Helm安装K8ssandra
Helm是一个Chart+Value的管理方式，我们准备一个yaml文件（k8ssandra-values.yaml）来放一些变量：
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安装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做一些必要的检查如下：
$ 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检查一下Pod和Service：
获取K8ssandra超级用户的用户名和密码
$ 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
TNE5xOk45C1aQsj29qxw2.4 增加节点
我们为了高可用和容量，创建更多的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:
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修改完之后，升级配置：
$ 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查看Kubernetes的相关资源：
3 查看监控
我们对外暴露Grafana服务来看看：
kubectl expose deployment k8ssandra-grafana --type=NodePort --name=grafana-out找到对应的NodePort的端口30348，访问：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项目，后续再介绍如何在开发中通过K8ssandra使用Cassandra吧。
代码请查看：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应用，支持多环境部署与版本回滚
附：
使用到的镜像：
root@k8ssandra:~# docker 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 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到此这篇关于K8ssandra入门教程之Linux上部署K8ssandra到Kubernetes的过程的文章就介绍到这了,更多相关K8ssandra部署Kubernetes内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
