Manage GCP Compute Disk IAM Permissions

The gcp:compute/diskIamMember:DiskIamMember resource, part of the Pulumi GCP provider, manages IAM permissions for Compute Engine disks by adding individual members to roles without affecting other permissions. This guide focuses on three capabilities: adding single members to roles, managing complete member lists per role, and replacing entire IAM policies.

GCP provides three related resources for disk IAM management: DiskIamMember (non-authoritative, adds one member), DiskIamBinding (authoritative for one role), and DiskIamPolicy (authoritative for entire policy). DiskIamPolicy cannot coexist with the other two; DiskIamBinding and DiskIamMember can coexist only if they manage different roles. The examples are intentionally small. Choose the resource that matches your authorization model.

Grant a single user access to a disk

Most IAM configurations add individual users or service accounts to roles incrementally, preserving existing permissions.

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 member property specifies one identity using GCP’s identity format (user:, serviceAccount:, group:, etc.). The role property defines the permission level. DiskIamMember is non-authoritative: it adds this member without removing others who already have the role.

Grant multiple users the same role

When multiple identities need identical permissions, you can manage the complete member list for a single role.

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 members property lists all identities that should have this role. DiskIamBinding is authoritative for the specified role: it replaces any existing members with this list. Other roles on the disk remain unchanged.

Replace the entire IAM policy for a disk

Some workflows require complete control over all IAM bindings, replacing any existing policy.

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 policyData property accepts a complete IAM policy document, typically constructed using getIAMPolicy. This resource is authoritative for the entire policy: it replaces all existing bindings. DiskIamPolicy cannot be used alongside DiskIamBinding or DiskIamMember, as they would conflict over policy ownership.

Beyond these examples

These snippets focus on specific IAM management approaches: incremental member addition, role-level member management, and complete policy replacement. They’re intentionally minimal rather than full access control systems.

The examples reference pre-existing infrastructure such as Compute Engine disks in specified zones. They focus on configuring IAM permissions rather than provisioning the disks themselves.

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

Conditional IAM bindings (condition property)
Custom role definitions
Cross-project or organization-level policies
Federated identity configuration details

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 Compute Disk IAM Member resource reference for all available configuration options.

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Frequently Asked Questions

Resource Selection & Conflicts

Why are my disk IAM resources conflicting with each other?

gcp.compute.DiskIamPolicy cannot be used with gcp.compute.DiskIamBinding or gcp.compute.DiskIamMember, as they will fight over the policy. Use DiskIamPolicy alone for full control, or use DiskIamBinding and DiskIamMember together.

Can I use DiskIamBinding and DiskIamMember together?

Yes, but only if they don’t grant privileges to the same role. Each role must be managed by only one resource type to avoid conflicts.

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

DiskIamPolicy is authoritative and replaces the entire policy. DiskIamBinding is authoritative for a given role and preserves other roles. DiskIamMember is non-authoritative and preserves other members for the role.

Which disk IAM resource should I use?

Use DiskIamPolicy for full policy control, DiskIamBinding to manage all members for specific roles, or DiskIamMember to add individual members to roles while preserving existing members.

Configuration & Identity Formats

What member identity formats are supported?

Supported formats include allUsers, allAuthenticatedUsers, user:{email}, serviceAccount:{email}, group:{email}, domain:{domain}, projectOwner:{projectid}, projectEditor:{projectid}, projectViewer:{projectid}, and federated identities like principal://iam.googleapis.com/....

How do I specify custom roles for disk IAM?

Custom roles must use the format [projects|organizations]/{parent-name}/roles/{role-name}. For example, projects/my-project/roles/my-custom-role or organizations/my-org/roles/my-custom-role.

Using a different cloud?

Explore security guides for other cloud providers:

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