What is the difference between profiles and reservations?

A profile defines the shape of an instance (vCPU, RAM, network bandwidth) — picking one is like picking an EC2 instance type. A reservation is a commitment to a specific quantity of profile capacity in advance, giving you discounted hourly pricing and guaranteed capacity. Use profiles for ad-hoc workloads; use reservations for steady-state production.

Can I attach more storage after the instance is created?

Yes. Boot volumes are fixed size by image, but additional block storage volumes can be attached after creation. Block storage on IBM Cloud VPC supports online resize (no detach required) for filesystems that support it. For new data volumes, the workflow is: provision the volume, attach it to the instance, format/mount.

IBM Virtual Server Config Builder

ComputeIBM Cloud

Build VPC virtual server instance configurations with profiles, networking, volumes, and placement targets.

Last verified: May 2026

IBM Cloud VPC Virtual Servers Configuration

Build VPC virtual server instance configurations with profiles, networking, boot/data volumes, and placement targets.

Required Fields

namevpcIdzoneprofileimageprimaryNetworkInterface

{
  "name": "prod-web-server-01",
  "vpcId": "vpc-prod-us-south",
  "zone": "us-south-1",
  "resourceGroup": "prod-resources",
  "profile": "bx2-8x32",
  "image": {
    "id": "ibm-ubuntu-24-04-minimal-amd64-3",
    "os": "ubuntu-24-04-amd64"
  },
  "keys": ["ssh-key-prod-deploy"],
  "primaryNetworkInterface": {
    "name": "eth0",
    "subnetId": "subnet-web-us-south-1",
    "securityGroups": ["web-sg", "management-sg"],
    "allowIpSpoofing": false
  },
  "networkInterfaces": [
    {
      "name": "eth1",
      "subnetId": "subnet-app-us-south-1",
      "securityGroups": ["app-sg"]
    }
  ],
  "bootVolume": {
    "name": "boot-prod-web-01",
    "size": 250,
    "profile": "general-purpose",
    "encryption": "provider_managed"
  },
  "dataVolumes": [
    {
      "name": "data-prod-web-01",
      "size": 500,
      "profile": "5iops-tier",
      "encryption": "provider_managed"
    }
  ],
  "userData": "#!/bin/bash\napt-get update && apt-get install -y nginx",
  "placementTarget": {
    "type": "dedicated_host_group",
    "id": "dhg-prod-us-south-1"
  },
  "metadataService": {
    "enabled": true,
    "protocol": "https",
    "responseHopLimit": 1
  }
}

Generated Output

Output will appear here...

See It in Action

A new database workload needs four instances with identical configuration: bx2-8x32 profile, 100 GB boot, 500 GB data volume, in a private subnet without floating IP. You define the spec once in the builder, copy the Terraform into a `count`-based block, and apply. Four instances come up in three minutes with consistent configuration. Changes (resize, add disk) apply to all four with a one-line edit.

What This Tool Does

IBM Cloud VPC virtual server instances are the equivalent of EC2 instances or Azure VMs — sized by profile, networked by subnet, attached to volumes, and placed by zone. The Virtual Server Config Builder generates a complete instance spec including profile, image, networking (VPC, subnet, security groups, floating IP), block storage, and placement target. Output is `ibm_is_instance` Terraform-ready and supports both standalone instances and template-based instance groups.

Technical Details

The builder collects instance name, zone, profile, image, VPC and subnet, security groups, optional floating IP, boot volume size, attached block storage volumes, and placement target (default scheduler or dedicated host/group). Output is an `ibm_is_instance` Terraform resource with nested `volume_attachments` and `network_interfaces` blocks, plus separate `ibm_is_floating_ip` and `ibm_is_volume` resources as needed.

Common Use Cases

1Spinning up a new compute instance with a standard image, dedicated boot volume, and properly-attached secondary data volume.
2Generating an instance template for use with an instance group (IBM Cloud's autoscaling primitive) where instances need consistent configuration.
3Sizing an instance for a specific workload — picking between general-purpose, balanced, compute, memory, GPU, or VPU profiles.
4Migrating a baremetal or VMware workload spec into the equivalent IBM Cloud VPC instance configuration.

Common Questions

What is the difference between profiles and reservations?: A profile defines the shape of an instance (vCPU, RAM, network bandwidth) — picking one is like picking an EC2 instance type. A reservation is a commitment to a specific quantity of profile capacity in advance, giving you discounted hourly pricing and guaranteed capacity. Use profiles for ad-hoc workloads; use reservations for steady-state production.
Can I attach more storage after the instance is created?: Yes. Boot volumes are fixed size by image, but additional block storage volumes can be attached after creation. Block storage on IBM Cloud VPC supports online resize (no detach required) for filesystems that support it. For new data volumes, the workflow is: provision the volume, attach it to the instance, format/mount.

Expert Tips

TIP

Pick the profile family based on the bottleneck, not the gut feel. Most workloads are memory-bound or network-bound long before they're CPU-bound, and the balanced profiles are usually the most cost-effective default.

TIP

Use a dedicated host or reservation for compliance-sensitive workloads where the underlying hardware must be exclusive. Compliance auditors increasingly ask for this and it's much cheaper to plan for it than to retrofit.

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