Expand an AIStor Deployment on Kubernetes

The following procedure adds a server pool to an existing AIStor cluster running on Kubernetes infrastructure. Each pool expands the total available storage capacity of the cluster with new nodes and persistent volumes while maintaining the overall availability of the cluster. Pay particular attention to the parity (EC:M) value of the existing cluster and the new pool.

MinIO strongly recommends seeking an architecture review from MinIO Engineering through SUBNET to analyze potential performance impacts before committing to a new pool for your cluster.

All commands provided below use example values. Replace these values with those appropriate for your cluster.

1. Retrieve and review the existing object store Helm chart.

   The objectStore.pools key describes the current cluster’s topology and pool configuration. Each element in the pools array describes a single server pool in the AIStor cluster.

   Review this file and take a timestamped backup as object-store-NAME-values.yaml.TIMESTAMP-bak before proceeding.

2. Prepare new worker nodes.

   Add or configure the new worker nodes for supporting AIStor. Ensure the worker nodes have the necessary storage and compute resources for supporting the target architecture.

3. Modify the objectStore.pools array with the new pool.

   The following example adds a new pool pool-1 to an existing cluster with a single pool pool-0. Each pool uses a nodeSelector to restrict the cluster to specific worker nodes based on label:

   objectStore:
      name: primary-object-store # name of the AIStor Server
      pools:
      - name: pool-0
        servers: 8 # Number of servers/pods to deploy
        volumesPerServer: 8 # Number of Persistent Volumes per Server/Pod
        size: 2Ti # Size of each PV
        storageClassName: directpv-min-io # Storage Class assigned to each PV
        nodeSelector: {
          aistor-label: "primary-object-store-pool-0"
   
        }
      - name: pool-1
        servers: 32
        volumesPerServer: 32
        size: 2Ti
        storageClassName: directpv-min-io
        nodeSelector: {
          aistor-label: "primary-object-store-pool-1"
        }
      services:
         minio:
            serviceType: NodePort
            nodePort: 31000 # Select an available NodePort in the supported range of 30000-32767
   

4. Deploy the chart with the updated values.

   Use the helm upgrade command to upgrade the chart with the new values.yaml:

   helm upgrade primary-object-store minio/aistor-objectstore \
     -n aistor-primary-object-store \
     -f primary-object-store-values.yaml
   

   You can use kubectl get events -n NAMESPACE --watch to monitor the progress of expansion.

   Once the expansion completes, use the mc admin info command to validate the expanded topology and status.

After validating cluster health and expanded storage, you can update any load balancers, reverse proxies, or other network management tools with the new hostnames of the added server pool. This ensures that incoming connections balance appropriately across the expanded topology.