Copy from https://github.com/georgechang/sitecore-k8s

SolrKustomization

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

images:
- name: solr-zk-waiter
  newName: sandbox.azurecr.io/sandbox-linux-solr-8.4.0
  newTag: test  
- name: solr
  newName: sandbox.azurecr.io/sandbox-linux-solr-8.4.0
  newTag: test
  

resources:
  - solr-service.yaml
  - solr-statefulset.yaml

SolrService

apiVersion: v1
kind: Service
metadata:
  name: solr-service
  namespace: default
  labels:
    app: solr
  annotations:
    service.beta.kubernetes.io/azure-load-balancer-internal: "true"
spec:
  type: LoadBalancer
  ports:
    - port: 8983
  selector:
    app: solr

SolrStatefulset

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: solr-statefulset
  namespace: default
  labels:
    app: solr
spec:
  replicas: 3 # set this to the number of Solr pod instances you want
  selector:
    matchLabels:
      app: solr
  serviceName: solr-service
  template:
    metadata:
      namespace: default
      labels:
        app: solr
    spec:
      securityContext:
        runAsUser: 1001
        fsGroup: 1001
      nodeSelector:
        kubernetes.io/os: linux
        agentpool: solr
      affinity:
        # this causes K8s to only schedule only one Solr pod per node
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values:
                      - solr
              topologyKey: "kubernetes.io/hostname"
      containers:
        - name: solr
          image: solr
          env:
            # ZK_HOST lists all of the hostnames for all of the Zookeeper instances - this should correspond to however many ZK instances you have running.
            - name: ZK_HOST
              value: "zookeeper-statefulset-0.zookeeper-service:2181,zookeeper-statefulset-1.zookeeper-service:2181,zookeeper-statefulset-2.zookeeper-service:2181"
            - name: SOLR_JAVA_MEM
              value: "-Xms4g -Xmx4g" # set the JVM memory usage and limit
          ports:
            - name: solr
              containerPort: 8983
          volumeMounts:
            - name: solr-pvc
              mountPath: /var/solr
          livenessProbe:
            # runs a built-in script to check for Solr readiness/liveness
            exec:
              command:
                - /bin/bash
                - -c
                - "/opt/docker-solr/scripts/wait-for-solr.sh"
            initialDelaySeconds: 20
            timeoutSeconds: 5
          readinessProbe:
            # runs a built-in script to check for Solr readiness/liveness
            exec:
              command:
                - /bin/bash
                - -c
                - "/opt/docker-solr/scripts/wait-for-solr.sh"
            initialDelaySeconds: 20
            timeoutSeconds: 5
      initContainers:
        # runs a built-script to wait until all Zookeeper instances are up and running
        - name: solr-zk-waiter
          image: solr-zk-waiter
          command:
            - /bin/bash
            - "-c"
            - "/opt/docker-solr/scripts/wait-for-zookeeper.sh"
          securityContext:
            allowPrivilegeEscalation: false
            runAsUser: 0    
          env:
            - name: ZK_HOST
              value: "zookeeper-statefulset-0.zookeeper-service:2181,zookeeper-statefulset-1.zookeeper-service:2181,zookeeper-statefulset-2.zookeeper-service:2181"
        
  volumeClaimTemplates:
    - metadata:
        name: solr-pvc
      spec:
        accessModes:
          - ReadWriteOnce
        storageClassName: managed-premium
        resources:
          requests:
            storage: 10Gi

ZookeeperStatefulset

# this allows for max 3 instance of ZK to be unavailable
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: zookeeper-pdb
  namespace: default
spec:
  selector:
    matchLabels:
      app: zookeeper
  maxUnavailable: 3
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: zookeeper-statefulset
  namespace: default
  labels:
    app: zookeeper
spec:
  replicas: 3
  updateStrategy:
    type: RollingUpdate
  podManagementPolicy: Parallel
  selector:
    matchLabels:
      app: zookeeper
  serviceName: zookeeper-service
  template:
    metadata:
      labels:
        app: zookeeper
    spec:
      nodeSelector:
        kubernetes.io/os: linux
        agentpool: solr
      affinity:
        # this causes K8s to only schedule only one Zookeeper pod per node
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values:
                      - zookeeper
              topologyKey: "kubernetes.io/hostname"
      containers:
        - name: zookeeper
          image: zookeeper
          env:
            - name: ZK_REPLICAS
              value: "3" # informs Zookeeper of the number of intended replicas
            - name: ZK_TICK_TIME
              value: "2000"
            - name: ZOO_4LW_COMMANDS_WHITELIST
              value: "mntr,conf,ruok"
            - name: ZOO_STANDALONE_ENABLED
              value: "false"
            - name: ALLOW_ANONYMOUS_LOGIN
              value: "yes"  
            # lists all of the Zookeeper servers that are part of this cluster
            - name: ZOO_SERVERS
              value: "server.1=zookeeper-statefulset-0.zookeeper-service:2888:3888;2181 server.2=zookeeper-statefulset-1.zookeeper-service:2888:3888;2181 server.3=zookeeper-statefulset-2.zookeeper-service:2888:3888;2181"
            - name: ZOO_CFG_EXTRA
              value: "quorumListenOnAllIPs=true electionPortBindRetry=0" # quorumListenOnAllIPs allows ZK to listen on all IP addresses for leader election/follower, electionPortBindRetry disables the max retry count as other ZK instances are spinning up
          ports:
            - name: client
              containerPort: 2181
              protocol: TCP
            - name: server
              containerPort: 2888
              protocol: TCP
            - name: election
              containerPort: 3888
              protocol: TCP
          volumeMounts:
            - name: zookeeper-pv
              mountPath: /data
          livenessProbe:
            # runs a shell script to ping the running local Zookeeper instance, which responds with "imok" once the instance is ready
            exec:
              command:
                - sh
                - -c
                - 'OK=$(echo ruok | nc 127.0.0.1 2181); if [ "$OK" = "imok" ]; then	exit 0; else exit 1; fi;'
            initialDelaySeconds: 20
            timeoutSeconds: 5
          readinessProbe:
            # runs a shell script to ping the running local Zookeeper instance, which responds with "imok" once the instance is ready
            exec:
              command:
                - sh
                - -c
                - 'OK=$(echo ruok | nc 127.0.0.1 2181); if [ "$OK" = "imok" ]; then	exit 0; else exit 1; fi;'
            initialDelaySeconds: 20
            timeoutSeconds: 5
      initContainers:
        # each ZK instance requires an ID specification - since we can't set the ID using env variables, this init container sets the ID for each instance incrementally through a file on a volume mount
        - name: zookeeper-id
          image: zookeeper-id
          command:
            - sh
            - -c
            - echo $((${HOSTNAME##*-}+1)) > /data-new/myid
          volumeMounts:
            - name: zookeeper-pv
              mountPath: /data-new
  volumeClaimTemplates:
    - metadata:
        name: zookeeper-pv
      spec:
        accessModes:
          - ReadWriteOnce
        storageClassName: managed-premium
        resources:
          requests:
            storage: 10Gi

ZookeperKustomization

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

images:
- name: zookeeper
  newName: zookeeper
  newTag: 3.5.9
  
- name: zookeeper-id
  newName: busybox
  newTag: latest  

resources:
- zookeeper-service.yaml
- zookeeper-statefulset.yaml

ZookeperService

apiVersion: v1
kind: Service
metadata:
  name: zookeeper-service
  namespace: default
  labels:
    app: zookeeper
spec:
  ports:
    - port: 2888
      name: server
    - port: 3888
      name: leader-election
    - port: 2181
      name: client
  clusterIP: None
  selector:
    app: zookeeper