Manage GCP Compute Instance IAM Policies

The gcp:compute/instanceIAMPolicy:InstanceIAMPolicy resource, part of the Pulumi GCP provider, manages IAM policies for Compute Engine instances through three resource types with different update behaviors. This guide focuses on four capabilities: authoritative policy replacement (InstanceIAMPolicy), role-level member management (InstanceIAMBinding), single-member grants (InstanceIAMMember), and time-based access with IAM Conditions.

All three resource types reference existing Compute Engine instances by name, project, and zone. InstanceIAMPolicy cannot be used with InstanceIAMBinding or InstanceIAMMember because they conflict over policy ownership. InstanceIAMBinding and InstanceIAMMember can coexist if they manage different roles. The examples are intentionally small. Combine them with your own instance infrastructure and access requirements.

Grant a role to multiple members with InstanceIAMBinding

When you need to grant the same role to multiple users or service accounts, InstanceIAMBinding manages all members for a specific role while preserving other roles on the instance.

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

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

import pulumi
import pulumi_gcp as gcp

binding = gcp.compute.InstanceIAMBinding("binding",
    project=default["project"],
    zone=default["zone"],
    instance_name=default["name"],
    role="roles/compute.osLogin",
    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.NewInstanceIAMBinding(ctx, "binding", &compute.InstanceIAMBindingArgs{
			Project:      pulumi.Any(_default.Project),
			Zone:         pulumi.Any(_default.Zone),
			InstanceName: pulumi.Any(_default.Name),
			Role:         pulumi.String("roles/compute.osLogin"),
			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.InstanceIAMBinding("binding", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        InstanceName = @default.Name,
        Role = "roles/compute.osLogin",
        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.InstanceIAMBinding;
import com.pulumi.gcp.compute.InstanceIAMBindingArgs;
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 InstanceIAMBinding("binding", InstanceIAMBindingArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .instanceName(default_.name())
            .role("roles/compute.osLogin")
            .members("user:jane@example.com")
            .build());

    }
}

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

InstanceIAMBinding is authoritative for the specified role. The members list defines everyone who has that role; anyone not in the list loses access. Other roles on the instance remain unchanged. The instanceName, project, and zone properties identify which instance to configure.

Add a single member to a role with InstanceIAMMember

When you need to grant access to one user without affecting other members of the same role, InstanceIAMMember provides non-authoritative updates that preserve existing grants.

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

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

import pulumi
import pulumi_gcp as gcp

member = gcp.compute.InstanceIAMMember("member",
    project=default["project"],
    zone=default["zone"],
    instance_name=default["name"],
    role="roles/compute.osLogin",
    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.NewInstanceIAMMember(ctx, "member", &compute.InstanceIAMMemberArgs{
			Project:      pulumi.Any(_default.Project),
			Zone:         pulumi.Any(_default.Zone),
			InstanceName: pulumi.Any(_default.Name),
			Role:         pulumi.String("roles/compute.osLogin"),
			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.InstanceIAMMember("member", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        InstanceName = @default.Name,
        Role = "roles/compute.osLogin",
        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.InstanceIAMMember;
import com.pulumi.gcp.compute.InstanceIAMMemberArgs;
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 InstanceIAMMember("member", InstanceIAMMemberArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .instanceName(default_.name())
            .role("roles/compute.osLogin")
            .member("user:jane@example.com")
            .build());

    }
}

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

InstanceIAMMember adds one member to a role without replacing existing members. Multiple InstanceIAMMember resources can target the same role, each adding a different member. The member property uses the format “type:identifier” (e.g., “user:jane@example.com”, “serviceAccount:my-sa@project.iam.gserviceaccount.com”).

Replace the entire IAM policy with InstanceIAMPolicy

Some deployments require complete control over instance IAM policies, replacing any existing grants with a new authoritative policy document.

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

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

import pulumi
import pulumi_gcp as gcp

admin = gcp.organizations.get_iam_policy(bindings=[{
    "role": "roles/compute.osLogin",
    "members": ["user:jane@example.com"],
}])
policy = gcp.compute.InstanceIAMPolicy("policy",
    project=default["project"],
    zone=default["zone"],
    instance_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/compute.osLogin",
					Members: []string{
						"user:jane@example.com",
					},
				},
			},
		}, nil)
		if err != nil {
			return err
		}
		_, err = compute.NewInstanceIAMPolicy(ctx, "policy", &compute.InstanceIAMPolicyArgs{
			Project:      pulumi.Any(_default.Project),
			Zone:         pulumi.Any(_default.Zone),
			InstanceName: 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/compute.osLogin",
                Members = new[]
                {
                    "user:jane@example.com",
                },
            },
        },
    });

    var policy = new Gcp.Compute.InstanceIAMPolicy("policy", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        InstanceName = @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.InstanceIAMPolicy;
import com.pulumi.gcp.compute.InstanceIAMPolicyArgs;
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/compute.osLogin")
                .members("user:jane@example.com")
                .build())
            .build());

        var policy = new InstanceIAMPolicy("policy", InstanceIAMPolicyArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .instanceName(default_.name())
            .policyData(admin.policyData())
            .build());

    }
}

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

InstanceIAMPolicy replaces the entire IAM policy for the instance. The policyData property comes from the getIAMPolicy data source, which constructs a policy document from bindings. This approach gives you full control but conflicts with InstanceIAMBinding and InstanceIAMMember; use only one approach per instance.

Apply time-based access with IAM Conditions

Temporary access grants often require expiration dates to limit permissions to specific time windows.

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

const binding = new gcp.compute.InstanceIAMBinding("binding", {
    project: _default.project,
    zone: _default.zone,
    instanceName: _default.name,
    role: "roles/compute.osLogin",
    members: ["user:jane@example.com"],
    condition: {
        title: "expires_after_2019_12_31",
        description: "Expiring at midnight of 2019-12-31",
        expression: "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
    },
});

import pulumi
import pulumi_gcp as gcp

binding = gcp.compute.InstanceIAMBinding("binding",
    project=default["project"],
    zone=default["zone"],
    instance_name=default["name"],
    role="roles/compute.osLogin",
    members=["user:jane@example.com"],
    condition={
        "title": "expires_after_2019_12_31",
        "description": "Expiring at midnight of 2019-12-31",
        "expression": "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
    })

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.NewInstanceIAMBinding(ctx, "binding", &compute.InstanceIAMBindingArgs{
			Project:      pulumi.Any(_default.Project),
			Zone:         pulumi.Any(_default.Zone),
			InstanceName: pulumi.Any(_default.Name),
			Role:         pulumi.String("roles/compute.osLogin"),
			Members: pulumi.StringArray{
				pulumi.String("user:jane@example.com"),
			},
			Condition: &compute.InstanceIAMBindingConditionArgs{
				Title:       pulumi.String("expires_after_2019_12_31"),
				Description: pulumi.String("Expiring at midnight of 2019-12-31"),
				Expression:  pulumi.String("request.time < timestamp(\"2020-01-01T00:00:00Z\")"),
			},
		})
		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.InstanceIAMBinding("binding", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        InstanceName = @default.Name,
        Role = "roles/compute.osLogin",
        Members = new[]
        {
            "user:jane@example.com",
        },
        Condition = new Gcp.Compute.Inputs.InstanceIAMBindingConditionArgs
        {
            Title = "expires_after_2019_12_31",
            Description = "Expiring at midnight of 2019-12-31",
            Expression = "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
        },
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.compute.InstanceIAMBinding;
import com.pulumi.gcp.compute.InstanceIAMBindingArgs;
import com.pulumi.gcp.compute.inputs.InstanceIAMBindingConditionArgs;
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 InstanceIAMBinding("binding", InstanceIAMBindingArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .instanceName(default_.name())
            .role("roles/compute.osLogin")
            .members("user:jane@example.com")
            .condition(InstanceIAMBindingConditionArgs.builder()
                .title("expires_after_2019_12_31")
                .description("Expiring at midnight of 2019-12-31")
                .expression("request.time < timestamp(\"2020-01-01T00:00:00Z\")")
                .build())
            .build());

    }
}

resources:
  binding:
    type: gcp:compute:InstanceIAMBinding
    properties:
      project: ${default.project}
      zone: ${default.zone}
      instanceName: ${default.name}
      role: roles/compute.osLogin
      members:
        - user:jane@example.com
      condition:
        title: expires_after_2019_12_31
        description: Expiring at midnight of 2019-12-31
        expression: request.time < timestamp("2020-01-01T00:00:00Z")

IAM Conditions add temporal constraints to role bindings through the condition block. The expression property uses Common Expression Language (CEL) to define when the binding applies. Here, the condition checks that the request time is before midnight on January 1, 2020. The title and description properties document the condition’s purpose.

Beyond these examples

These snippets focus on specific IAM management features: authoritative vs non-authoritative IAM management, role binding and member management, and time-based access with IAM Conditions. They’re intentionally minimal rather than full access control systems.

The examples reference pre-existing infrastructure such as Compute Engine instances (referenced by name, project, zone). They focus on configuring IAM policies rather than provisioning the instances themselves.

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

IAM Condition limitations and edge cases
Custom role definitions and management
Service account impersonation patterns
Conflict resolution between resource types

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 Instance IAM Policy resource reference for all available configuration options.

Let's manage GCP Compute Instance IAM Policies

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Frequently Asked Questions

Resource Selection & Conflicts

What's the difference between InstanceIAMPolicy, InstanceIAMBinding, and InstanceIAMMember?

gcp.compute.InstanceIAMPolicy is authoritative and replaces the entire IAM policy. gcp.compute.InstanceIAMBinding is authoritative for a specific role, preserving other roles. gcp.compute.InstanceIAMMember is non-authoritative, adding a single member while preserving other members for that role.

Can I use InstanceIAMPolicy with InstanceIAMBinding or InstanceIAMMember?

No, gcp.compute.InstanceIAMPolicy cannot be used with gcp.compute.InstanceIAMBinding or gcp.compute.InstanceIAMMember because they will conflict over the policy.

Can I use InstanceIAMBinding and InstanceIAMMember together?

Yes, but only if they don’t grant privileges to the same role. Using both for the same role causes conflicts.

IAM Conditions

How do I add time-based conditions to IAM policies?

Add a condition block with title, description, and expression. For example, use expression: "request.time < timestamp(\"2020-01-01T00:00:00Z\")" for time-based expiration.

What are the limitations of IAM Conditions?

IAM Conditions are supported but have known limitations. If you’re experiencing issues, review the Google Cloud IAM Conditions limitations documentation.

Configuration & Import

How do I import existing IAM policies?

Use pulumi import with the resource identifier. Four forms are supported:

Full path: projects/{{project}}/zones/{{zone}}/instances/{{name}}
Project/zone/name: {{project}}/{{zone}}/{{name}}
Zone/name: {{zone}}/{{name}}
Name only: {{name}}

For IAM member imports, add the role and member identity (space-delimited). For IAM binding imports, add the role.

Using a different cloud?

Explore security guides for other cloud providers:

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