在Kubernetes上创建副本数据库

如何使用数据库控制器创建和自动化数据库副本

您可以通过在Redis Enterprise数据库规范的replicaSources部分创建一个项目来配置数据库的副本。replicaSourceType的值必须为'SECRET'；replicaSourceName必须是一个包含副本源URL的密钥的名称。

必须使用包含副本源URI的stringData部分来创建秘密，如下所示：

apiVersion: v1
kind: Secret
metadata:
   name: my-replica-source
stringData:
   uri: replica-source-uri-goes-here

可以通过在管理界面中转到“UI > 数据库 > 配置 > 按下获取源URL副本的按钮”来检索副本源URL。但是，这些信息也可以直接从REST API中检索。

数据库CR的副本只需使用replicaSources部分中的密钥：

apiVersion: app.redislabs.com/v1alpha1
kind: RedisEnterpriseDatabase
metadata:
   name: name-of-replica
spec:
   redisEnterpriseCluster:
      name: name-of-cluster
   replicaSources:
   - replicaSourceType: SECRET
     replicaSourceName: my-replica-source

在上述情况下，只要源数据库存在于源集群上并且密钥包含该数据库的正确副本源URL，name-of-replica数据库将作为源数据库的副本被创建。

通过kubectl检索副本源URL

您需要安装kubectl、curl和jq来完成此过程。

  1. 设置您的元数据：

    CLUSTER_NAME=test
SOURCE_DB=db1
TARGET_DB=db2
TARGET_CLUSTER_NAME=test

  2. 检索集群认证：

    CLUSTER_USER=`kubectl get secret/${CLUSTER_NAME} -o json | jq -r .data.username | base64 -d`
CLUSTER_PASSWORD=`kubectl get secret/${CLUSTER_NAME} -o json | jq -r .data.password | base64 -d`

  3. 转发源集群的REST API服务端口：

    kubectl port-forward pod/${CLUSTER_NAME}-0 9443

  4. 从REST API请求信息：

    JQ='.[] | select(.name=="'
JQ+="${SOURCE_DB}"
JQ+='") | ("redis://admin:" +  .authentication_admin_pass + "@"+.endpoints[0].dns_name+":"+(.endpoints[0].port|tostring))'
URI=`curl -sf -k -u "$CLUSTER_USER:$CLUSTER_PASSWORD" "https://localhost:9443/v1/bdbs?fields=uid,name,endpoints,authentication_admin_pass" | jq "$JQ" | sed 's/"//g'`

    注意：URI 现在包含副本源 URI。

  5. 构建副本的密钥：

    cat << EOF > secret.yaml
apiVersion: v1
kind: Secret
metadata:
  name: ${SOURCE_DB}-url
stringData:
  uri: ${URI}
EOF
kubectl apply -f secret.yaml

  6. 创建副本数据库：

    cat << EOF > target.yaml
apiVersion: app.redislabs.com/v1alpha1
kind: RedisEnterpriseDatabase
metadata:
  name: ${TARGET_DB}
spec:
  redisEnterpriseCluster:
    name: ${TARGET_CLUSTER_NAME}
  replicaSources:
  - replicaSourceType: SECRET
    replicaSourceName: ${SOURCE_DB}-url
EOF
kubectl apply -f target.yaml

通过作业自动化创建

以下过程使用ConfigMap和Job从源数据库构建副本源URL密钥并配置目标数据库。

有四个参数：

  • source - 源数据库的名称
  • cluster - 源数据库的集群名称
  • target - 目标数据库的名称
  • targetCluster - 目标数据库的集群名称

这些参数可以通过以下方式设置：

kubectl create configmap replica-of-database-parameters \
--from-literal=source=name-of-source \
--from-literal=cluster=name-of-cluster \
--from-literal=target=name-of-target \
--from-literal=targetCluster=name-of-cluster

其中 "name-of-..." 被替换为数据库源、源集群、数据库目标和目标集群的名称。

下面的Job和ConfigMap在提交时，将创建secret和副本数据库：

apiVersion: batch/v1
kind: Job
metadata:
  name: replica-of-database
spec:
  backoffLimit: 4
  template:
    spec:
      serviceAccountName: redis-enterprise-operator
      restartPolicy: Never
      volumes:
        - name: scripts
          configMap:
            name: replica-of-database
      containers:
        - name: createdb
          image: debian:stable-slim
          env:
            - name: MY_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
            - name: SCRIPT
              value: create.sh
            - name: SOURCE_DB
              valueFrom:
                configMapKeyRef:
                  name: replica-of-database-parameters
                  key: source
            - name: TARGET_DB
              valueFrom:
                configMapKeyRef:
                  name: replica-of-database-parameters
                  key: target
            - name: CLUSTER_SERVICE
              value: .svc.cluster.local
            - name: CLUSTER_NAME
              valueFrom:
                configMapKeyRef:
                  name: replica-of-database-parameters
                  key: cluster
            - name: CLUSTER_PORT
              value: "9443"
            - name: TARGET_CLUSTER_NAME
              valueFrom:
                configMapKeyRef:
                  name: replica-of-database-parameters
                  key: targetCluster
          volumeMounts:
            - mountPath: /opt/scripts/
              name: scripts
          command:
            - /bin/bash
            - -c
            - |
              apt-get update; apt-get install -y curl jq apt-transport-https gnupg2
              apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6A030B21BA07F4FB
              curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
              echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | tee -a /etc/apt/sources.list.d/kubernetes.list
              apt-get update
              apt-get install -y kubectl
              bash /opt/scripts/$SCRIPT              
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: replica-of-database
data:
  create.sh: |
    CLUSTER_USER=`kubectl get secret/${CLUSTER_NAME} -o json | jq -r .data.username | base64 -d`
    CLUSTER_PASSWORD=`kubectl get secret/${CLUSTER_NAME} -o json | jq -r .data.password | base64 -d`
    CLUSTER_HOST=${CLUSTER_NAME}.${MY_NAMESPACE}${CLUSTER_SERVICE}
    JQ='.[] | select(.name=="'
    JQ+="${SOURCE_DB}"
    JQ+='") | ("redis://admin:" +  .authentication_admin_pass + "@"+.endpoints[0].dns_name+":"+(.endpoints[0].port|tostring))'
    URI=`curl -sf -k -u "$CLUSTER_USER:$CLUSTER_PASSWORD" "https://${CLUSTER_HOST}:${CLUSTER_PORT}/v1/bdbs?fields=uid,name,endpoints,authentication_admin_pass" | jq "$JQ" | sed 's/"//g'`
    echo "URL: ${URL}"
    echo ""
    cat << EOF > /tmp/secret.yaml
    apiVersion: v1
    kind: Secret
    metadata:
      name: ${SOURCE_DB}-url
    stringData:
      uri: ${URI}
    EOF
    cat /tmp/secret.yaml
    cat << EOF > /tmp/target.yaml
    apiVersion: app.redislabs.com/v1alpha1
    kind: RedisEnterpriseDatabase
    metadata:
      name: ${TARGET_DB}
    spec:
      redisEnterpriseCluster:
        name: ${TARGET_CLUSTER_NAME}
      replicaSources:
      - replicaSourceType: SECRET
        replicaSourceName: ${SOURCE_DB}-url
    EOF
    echo "---"
    cat /tmp/target.yaml
    echo ""
    kubectl -n ${MY_NAMESPACE} apply -f /tmp/secret.yaml
    kubectl -n ${MY_NAMESPACE} apply -f /tmp/target.yaml
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