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Cache

Introduction​

This guide walks you through migrating a Redis cache from Heroku to Azure using Massdriver, with an emphasis on using private network access to enhance security. We’ll use Azure’s services, and Massdriver will handle most of the infrastructure setup and orchestration.

Prerequisites​

Before starting, ensure you have the following:

Step 1: Set Up Azure Infrastructure with Massdriver​

If you haven't done so already from the database guide, we will start by configuring the Azure infrastructure using Massdriver.

  1. Create a Massdriver environment:

    • Navigate to your Massdriver dashboard and create a new project if you don’t already have one. Create a new environment, naming it something appropriate for this migration (e.g., staging).

  2. Deploy a Private Virtual Network:

    • In Massdriver, search for the Azure Virtual Network bundle and deploy it. This will provide network isolation for your infrastructure.
    • Choose a region, configure CIDR blocks, and other network settings.
    • Deploy the virtual network and wait for it to complete.

  3. Set Up an Azure Cache for Redis:

    • Using the Azure Cache for Redis bundle in Massdriver, set up the cache instance (Premium or Enterprise SKU). Make sure it’s in the same region as your network.
    • Configure the resource group, redis version (ensure it's compatible with your current Redis version on Heroku), and enable private network access.
    • You may also enable automatic alarms and monitoring if needed.
    • Save and deploy the Redis cache.

Step 2: Create a Backup of Redis​

  1. Log into Heroku CLI:

    heroku login

  2. Fetch the Heroku Redis credentials:

    heroku redis:credentials -a <app-name>

  3. Create a backup of the Heroku Redis instance:

    redis-cli -h <host> -p <port> -a <password> --rdb dump.rdb
    note

    If you are using a tier higher than Mini, you may need to add --tls --insecure to the command.

Step 3: Upload Backup to Azure Storage​

Migrating your Redis cache data to Azure requires the use of page or block blobs in Azure Storage.

Create a Storage Account​

  1. Setup environment variables:

    accountName="herokutoazure"
    accountRg="herokutoazure"
    containerName="herokutoazure"
    blobName="herokutoazure"
    location="eastus"

  2. Log into Azure CLI:

    az login

  3. Set your Azure subscription:

    az account set --subscription <subscription-id>

  4. Create a resource group and a storage account:

    az group create --name $accountRg --location $location
    az storage account create --name $accountName --resource-group $accountRg --location $location --sku Standard_LRS

  5. Create a container:

    az storage container create --name $containerName --account-name $accountName

Step 4: Upload the RDB File to Azure Storage​

  1. Upload the Redis dump file to Azure storage:

    az storage blob upload --account-name $accountName --container-name $containerName --name $blobName --file dump.rdb

  2. Generate the SAS (Shared Access Signature) URL for the blob:

    # Linux:
    end=$(date -u -d "60 minutes" '+%Y-%m-%dT%H:%MZ')

    # MacOS:
    end=$(date -u -v+60M '+%Y-%m-%dT%H:%MZ')
    az storage blob generate-sas --account-name $accountName --container-name $containerName --name $blobName --permissions r --expiry $end
    caution

    Set an expiry date for the SAS URL to ensure the data is not accessible after migration.

Step 5: Configure Kubernetes Cluster on Azure​

  1. Deploy Azure Kubernetes Service (AKS):

    • In Massdriver, deploy an AKS cluster using the appropriate bundle. Select the region to match your existing infrastructure and network settings.
    • Enable ingress controllers and DNS if necessary.

  2. Access the Kubernetes Cluster:

    • Download the kubeconfig file from Massdriver and connect to the cluster by following this guide.

  3. Set Up a Jump Box Pod for Cache Migration:

    • Create a new file called haiku-havoc-hero.yaml with the following content:
    apiVersion: v1
    kind: Pod
    metadata:
      name: haiku-havoc-hero
      namespace: default
    spec:
      containers:
        - name: redis
          image: mclacore/haiku-havoc-hero:redis-v1
    info

    haiku-havoc-hero is a simple Docker image that deploys a Redis container packed with toos like redis-cli, heroku, aws cli, az cli, gcloud cli, and more. Designed to make your migration from Heroku to the cloud as smooth as possible.

  4. Deploy the pod:

    kubectl apply -f haiku-havoc-hero.yaml

Step 6: Import data from Azure Storage to Azure Cache for Redis using AKS​

  1. Set up your environment variables (modify as needed):

    cacheRg="<resource-group>"
    cacheName="<cache-name>"

  2. Exec into the pod:

    kubectl exec -it haiku-havoc-hero -c redis -- sh

  3. Import the data from Azure Storage into Azure Cache for Redis:

az redis import --name $cacheName --resource-group $cacheRg --files $sasUrl

Step 7: Verify and Clean Up​

  1. Verify the import by connecting to the Azure Cache for Redis instance using redis-cli:

    redis-cli -h <cache-name>.redis.cache.windows.net -p 6380 -a <password> --tls --insecure

  2. Check that the keys have been imported:

    keys *

  3. Once verified, delete the jump box pod:

    kubectl delete pod haiku-havoc-hero

Conclusion​

You have successfully migrated your Redis cache from Heroku to Azure Cache for Redis while ensuring data security through private network access using Massdriver.