Manage GCP Compute Disk IAM Policies

The gcp:compute/diskIamPolicy:DiskIamPolicy resource, part of the Pulumi GCP provider, manages IAM permissions for Compute Engine disks using three distinct approaches: full policy replacement (DiskIamPolicy), role-level binding (DiskIamBinding), or individual member grants (DiskIamMember). This guide focuses on three capabilities: authoritative policy replacement, role-level member binding, and individual member grants.

These resources reference existing Compute Engine disks and require project/zone configuration. The examples are intentionally small. Combine them with your own disk resources and organizational IAM structure.

Replace the entire IAM policy for a disk

When you need complete control over disk access, you can set the entire IAM policy at once, replacing any existing permissions.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const admin = gcp.organizations.getIAMPolicy({
    bindings: [{
        role: "roles/viewer",
        members: ["user:jane@example.com"],
    }],
});
const policy = new gcp.compute.DiskIamPolicy("policy", {
    project: _default.project,
    zone: _default.zone,
    name: _default.name,
    policyData: admin.then(admin => admin.policyData),
});

import pulumi
import pulumi_gcp as gcp

admin = gcp.organizations.get_iam_policy(bindings=[{
    "role": "roles/viewer",
    "members": ["user:jane@example.com"],
}])
policy = gcp.compute.DiskIamPolicy("policy",
    project=default["project"],
    zone=default["zone"],
    name=default["name"],
    policy_data=admin.policy_data)

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/compute"
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/organizations"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		admin, err := organizations.LookupIAMPolicy(ctx, &organizations.LookupIAMPolicyArgs{
			Bindings: []organizations.GetIAMPolicyBinding{
				{
					Role: "roles/viewer",
					Members: []string{
						"user:jane@example.com",
					},
				},
			},
		}, nil)
		if err != nil {
			return err
		}
		_, err = compute.NewDiskIamPolicy(ctx, "policy", &compute.DiskIamPolicyArgs{
			Project:    pulumi.Any(_default.Project),
			Zone:       pulumi.Any(_default.Zone),
			Name:       pulumi.Any(_default.Name),
			PolicyData: pulumi.String(admin.PolicyData),
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var admin = Gcp.Organizations.GetIAMPolicy.Invoke(new()
    {
        Bindings = new[]
        {
            new Gcp.Organizations.Inputs.GetIAMPolicyBindingInputArgs
            {
                Role = "roles/viewer",
                Members = new[]
                {
                    "user:jane@example.com",
                },
            },
        },
    });

    var policy = new Gcp.Compute.DiskIamPolicy("policy", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        Name = @default.Name,
        PolicyData = admin.Apply(getIAMPolicyResult => getIAMPolicyResult.PolicyData),
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.organizations.OrganizationsFunctions;
import com.pulumi.gcp.organizations.inputs.GetIAMPolicyArgs;
import com.pulumi.gcp.compute.DiskIamPolicy;
import com.pulumi.gcp.compute.DiskIamPolicyArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        final var admin = OrganizationsFunctions.getIAMPolicy(GetIAMPolicyArgs.builder()
            .bindings(GetIAMPolicyBindingArgs.builder()
                .role("roles/viewer")
                .members("user:jane@example.com")
                .build())
            .build());

        var policy = new DiskIamPolicy("policy", DiskIamPolicyArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .name(default_.name())
            .policyData(admin.policyData())
            .build());

    }
}

resources:
  policy:
    type: gcp:compute:DiskIamPolicy
    properties:
      project: ${default.project}
      zone: ${default.zone}
      name: ${default.name}
      policyData: ${admin.policyData}
variables:
  admin:
    fn::invoke:
      function: gcp:organizations:getIAMPolicy
      arguments:
        bindings:
          - role: roles/viewer
            members:
              - user:jane@example.com

The DiskIamPolicy resource is authoritative: it replaces the disk’s entire IAM policy with the one you provide. The policyData comes from the getIAMPolicy data source, which constructs a policy from bindings (role-to-members mappings). This approach gives you full control but conflicts with DiskIamBinding and DiskIamMember resources on the same disk.

Grant a role to multiple members at once

When multiple users or service accounts need the same level of access, you can bind them all to a single role while preserving other role assignments.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const binding = new gcp.compute.DiskIamBinding("binding", {
    project: _default.project,
    zone: _default.zone,
    name: _default.name,
    role: "roles/viewer",
    members: ["user:jane@example.com"],
});

import pulumi
import pulumi_gcp as gcp

binding = gcp.compute.DiskIamBinding("binding",
    project=default["project"],
    zone=default["zone"],
    name=default["name"],
    role="roles/viewer",
    members=["user:jane@example.com"])

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/compute"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := compute.NewDiskIamBinding(ctx, "binding", &compute.DiskIamBindingArgs{
			Project: pulumi.Any(_default.Project),
			Zone:    pulumi.Any(_default.Zone),
			Name:    pulumi.Any(_default.Name),
			Role:    pulumi.String("roles/viewer"),
			Members: pulumi.StringArray{
				pulumi.String("user:jane@example.com"),
			},
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var binding = new Gcp.Compute.DiskIamBinding("binding", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        Name = @default.Name,
        Role = "roles/viewer",
        Members = new[]
        {
            "user:jane@example.com",
        },
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.compute.DiskIamBinding;
import com.pulumi.gcp.compute.DiskIamBindingArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var binding = new DiskIamBinding("binding", DiskIamBindingArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .name(default_.name())
            .role("roles/viewer")
            .members("user:jane@example.com")
            .build());

    }
}

resources:
  binding:
    type: gcp:compute:DiskIamBinding
    properties:
      project: ${default.project}
      zone: ${default.zone}
      name: ${default.name}
      role: roles/viewer
      members:
        - user:jane@example.com

The DiskIamBinding resource is authoritative for a specific role: it sets the complete member list for that role but leaves other roles untouched. The members array accepts user accounts, service accounts, groups, and domains. You can use multiple DiskIamBinding resources on the same disk as long as they target different roles.

Add a single member to a role incrementally

When you need to grant access to one additional user without affecting existing permissions, you can add individual members to a role.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const member = new gcp.compute.DiskIamMember("member", {
    project: _default.project,
    zone: _default.zone,
    name: _default.name,
    role: "roles/viewer",
    member: "user:jane@example.com",
});

import pulumi
import pulumi_gcp as gcp

member = gcp.compute.DiskIamMember("member",
    project=default["project"],
    zone=default["zone"],
    name=default["name"],
    role="roles/viewer",
    member="user:jane@example.com")

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/compute"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := compute.NewDiskIamMember(ctx, "member", &compute.DiskIamMemberArgs{
			Project: pulumi.Any(_default.Project),
			Zone:    pulumi.Any(_default.Zone),
			Name:    pulumi.Any(_default.Name),
			Role:    pulumi.String("roles/viewer"),
			Member:  pulumi.String("user:jane@example.com"),
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var member = new Gcp.Compute.DiskIamMember("member", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        Name = @default.Name,
        Role = "roles/viewer",
        Member = "user:jane@example.com",
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.compute.DiskIamMember;
import com.pulumi.gcp.compute.DiskIamMemberArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var member = new DiskIamMember("member", DiskIamMemberArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .name(default_.name())
            .role("roles/viewer")
            .member("user:jane@example.com")
            .build());

    }
}

resources:
  member:
    type: gcp:compute:DiskIamMember
    properties:
      project: ${default.project}
      zone: ${default.zone}
      name: ${default.name}
      role: roles/viewer
      member: user:jane@example.com

The DiskIamMember resource is non-authoritative: it adds one member to a role without removing existing members. This is the most granular approach, useful when you manage permissions incrementally or across multiple Pulumi stacks. You can combine DiskIamMember with DiskIamBinding as long as they don’t target the same role.

Beyond these examples

These snippets focus on specific IAM management approaches: authoritative vs non-authoritative IAM management, role-based access control, and policy data sources. They’re intentionally minimal rather than full access control systems.

The examples reference pre-existing infrastructure such as Compute Engine disks and GCP project and zone configuration. They focus on configuring IAM permissions rather than provisioning the underlying resources.

To keep things focused, common IAM patterns are omitted, including:

Conditional IAM bindings (attribute-based access)
Custom role definitions
Service account creation and management
Audit logging configuration

These omissions are intentional: the goal is to illustrate how each IAM resource type is wired, not provide drop-in access control modules. See the Disk IAM Policy resource reference for all available configuration options.

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Frequently Asked Questions

Resource Selection & Conflicts

What's the difference between DiskIamPolicy, DiskIamBinding, and DiskIamMember?

DiskIamPolicy is authoritative and replaces the entire IAM policy. DiskIamBinding is authoritative for a specific role but preserves other roles. DiskIamMember is non-authoritative and adds a single member while preserving existing members for that role.

Can I use DiskIamPolicy with DiskIamBinding or DiskIamMember?

No, DiskIamPolicy cannot be used with DiskIamBinding or DiskIamMember because they’ll conflict over the policy state. Use DiskIamPolicy alone, or use DiskIamBinding and DiskIamMember together.

Can I use DiskIamBinding and DiskIamMember together?

Yes, but only if they manage different roles. Using both for the same role will cause conflicts.

Configuration & Setup

How do I generate the policyData for DiskIamPolicy?

Use the gcp.organizations.getIAMPolicy data source to generate policy data, then pass it to the policyData property.

What properties can't I change after creating a DiskIamPolicy?

The name, project, and zone properties are immutable and cannot be changed after creation.

Import & Migration

How do I import a disk IAM resource with a custom role?

Use the full custom role name in the format [projects/my-project|organizations/my-org]/roles/my-custom-role when importing.

Using a different cloud?

Explore security guides for other cloud providers:

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