Manage GCP Instant Snapshot IAM Policies

The gcp:compute/instantSnapshotIamPolicy:InstantSnapshotIamPolicy resource, part of the Pulumi GCP provider, manages IAM permissions for Compute Engine instant snapshots. This guide focuses on four capabilities: authoritative policy replacement, role-based member binding, incremental member addition, and time-based conditional access.

These resources reference existing instant snapshots by name, project, and zone. The examples are intentionally small. Combine them with your own snapshot infrastructure and organizational IAM policies.

Replace the entire IAM policy for a snapshot

When you need complete control over snapshot 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/compute.storageAdmin",
        members: ["user:jane@example.com"],
    }],
});
const policy = new gcp.compute.InstantSnapshotIamPolicy("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/compute.storageAdmin",
    "members": ["user:jane@example.com"],
}])
policy = gcp.compute.InstantSnapshotIamPolicy("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/compute.storageAdmin",
					Members: []string{
						"user:jane@example.com",
					},
				},
			},
		}, nil)
		if err != nil {
			return err
		}
		_, err = compute.NewInstantSnapshotIamPolicy(ctx, "policy", &compute.InstantSnapshotIamPolicyArgs{
			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/compute.storageAdmin",
                Members = new[]
                {
                    "user:jane@example.com",
                },
            },
        },
    });

    var policy = new Gcp.Compute.InstantSnapshotIamPolicy("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.InstantSnapshotIamPolicy;
import com.pulumi.gcp.compute.InstantSnapshotIamPolicyArgs;
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.storageAdmin")
                .members("user:jane@example.com")
                .build())
            .build());

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

    }
}

resources:
  policy:
    type: gcp:compute:InstantSnapshotIamPolicy
    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/compute.storageAdmin
            members:
              - user:jane@example.com

The InstantSnapshotIamPolicy resource is authoritative: it replaces the entire IAM policy for the snapshot. The policyData property accepts output from getIAMPolicy, which defines roles and members. The project, zone, and name properties identify which snapshot to configure. This approach gives you full control but removes any permissions not explicitly listed.

Grant a role to multiple members at once

Teams often need to grant the same role to several users or service accounts without affecting other roles.

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

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

import pulumi
import pulumi_gcp as gcp

binding = gcp.compute.InstantSnapshotIamBinding("binding",
    project=default["project"],
    zone=default["zone"],
    name=default["name"],
    role="roles/compute.storageAdmin",
    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.NewInstantSnapshotIamBinding(ctx, "binding", &compute.InstantSnapshotIamBindingArgs{
			Project: pulumi.Any(_default.Project),
			Zone:    pulumi.Any(_default.Zone),
			Name:    pulumi.Any(_default.Name),
			Role:    pulumi.String("roles/compute.storageAdmin"),
			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.InstantSnapshotIamBinding("binding", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        Name = @default.Name,
        Role = "roles/compute.storageAdmin",
        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.InstantSnapshotIamBinding;
import com.pulumi.gcp.compute.InstantSnapshotIamBindingArgs;
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 InstantSnapshotIamBinding("binding", InstantSnapshotIamBindingArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .name(default_.name())
            .role("roles/compute.storageAdmin")
            .members("user:jane@example.com")
            .build());

    }
}

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

The InstantSnapshotIamBinding resource is authoritative for a single role: it sets the complete member list for that role while preserving other roles on the snapshot. The members property accepts a list of identities (users, service accounts, groups). This approach works well when you manage all members for a role together, but conflicts with Policy resources on the same snapshot.

Add a single member to a role incrementally

When you need to grant access to one additional user without modifying existing members, non-authoritative resources let you add permissions incrementally.

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

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

import pulumi
import pulumi_gcp as gcp

member = gcp.compute.InstantSnapshotIamMember("member",
    project=default["project"],
    zone=default["zone"],
    name=default["name"],
    role="roles/compute.storageAdmin",
    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.NewInstantSnapshotIamMember(ctx, "member", &compute.InstantSnapshotIamMemberArgs{
			Project: pulumi.Any(_default.Project),
			Zone:    pulumi.Any(_default.Zone),
			Name:    pulumi.Any(_default.Name),
			Role:    pulumi.String("roles/compute.storageAdmin"),
			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.InstantSnapshotIamMember("member", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        Name = @default.Name,
        Role = "roles/compute.storageAdmin",
        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.InstantSnapshotIamMember;
import com.pulumi.gcp.compute.InstantSnapshotIamMemberArgs;
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 InstantSnapshotIamMember("member", InstantSnapshotIamMemberArgs.builder()
            .project(default_.project())
            .zone(default_.zone())
            .name(default_.name())
            .role("roles/compute.storageAdmin")
            .member("user:jane@example.com")
            .build());

    }
}

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

The InstantSnapshotIamMember resource is non-authoritative: it adds one member to a role without affecting other members. The member property specifies a single identity. This approach works well for incremental access grants and can coexist with Binding resources as long as they target different roles.

Set time-based access with IAM Conditions

Access requirements sometimes include expiration dates or other conditional logic. IAM Conditions let you attach restrictions to permissions.

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

const admin = gcp.organizations.getIAMPolicy({
    bindings: [{
        role: "roles/compute.storageAdmin",
        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\")",
        },
    }],
});
const policy = new gcp.compute.InstantSnapshotIamPolicy("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/compute.storageAdmin",
    "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\")",
    },
}])
policy = gcp.compute.InstantSnapshotIamPolicy("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/compute.storageAdmin",
					Members: []string{
						"user:jane@example.com",
					},
					Condition: {
						Title:       "expires_after_2019_12_31",
						Description: pulumi.StringRef("Expiring at midnight of 2019-12-31"),
						Expression:  "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
					},
				},
			},
		}, nil)
		if err != nil {
			return err
		}
		_, err = compute.NewInstantSnapshotIamPolicy(ctx, "policy", &compute.InstantSnapshotIamPolicyArgs{
			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/compute.storageAdmin",
                Members = new[]
                {
                    "user:jane@example.com",
                },
                Condition = new Gcp.Organizations.Inputs.GetIAMPolicyBindingConditionInputArgs
                {
                    Title = "expires_after_2019_12_31",
                    Description = "Expiring at midnight of 2019-12-31",
                    Expression = "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
                },
            },
        },
    });

    var policy = new Gcp.Compute.InstantSnapshotIamPolicy("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.InstantSnapshotIamPolicy;
import com.pulumi.gcp.compute.InstantSnapshotIamPolicyArgs;
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.storageAdmin")
                .members("user:jane@example.com")
                .condition(GetIAMPolicyBindingConditionArgs.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())
            .build());

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

    }
}

resources:
  policy:
    type: gcp:compute:InstantSnapshotIamPolicy
    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/compute.storageAdmin
            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")

The condition block adds time-based or attribute-based restrictions to IAM bindings. The expression property uses CEL (Common Expression Language) to define when access is granted. Here, the condition expires at midnight on 2020-01-01. IAM Conditions work with all three resource types (Policy, Binding, Member) but have known limitations documented by Google Cloud.

Beyond these examples

These snippets focus on specific IAM management features: authoritative and non-authoritative IAM management, and IAM Conditions for time-based access. They’re intentionally minimal rather than full access control solutions.

The examples reference pre-existing infrastructure such as instant snapshots (by name, project, zone). They focus on configuring IAM permissions rather than creating the snapshots themselves.

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

  • Combining Policy with Binding or Member resources (causes conflicts)
  • Multiple Binding resources for the same role (causes conflicts)
  • IAM Conditions limitations and workarounds
  • Custom role definitions and references

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 InstantSnapshotIamPolicy resource reference for all available configuration options.

Let's manage GCP Instant Snapshot IAM Policies

Get started with Pulumi Cloud, then follow our quick setup guide to deploy this infrastructure.

Try Pulumi Cloud for FREE

Frequently Asked Questions

Resource Selection & Conflicts
What's the difference between InstantSnapshotIamPolicy, InstantSnapshotIamBinding, and InstantSnapshotIamMember?
InstantSnapshotIamPolicy is authoritative and replaces the entire IAM policy. InstantSnapshotIamBinding is authoritative for a specific role, preserving other roles. InstantSnapshotIamMember is non-authoritative, adding a single member while preserving other members for that role.
Can I use these IAM resources together?
No, InstantSnapshotIamPolicy cannot be used with InstantSnapshotIamBinding or InstantSnapshotIamMember as they will conflict. You can use InstantSnapshotIamBinding and InstantSnapshotIamMember together only if they manage different roles.
Why am I seeing policy conflicts or unexpected changes?
Mixing InstantSnapshotIamPolicy with InstantSnapshotIamBinding or InstantSnapshotIamMember causes resources to fight over policy state. Choose one approach: use Policy for full control, or use Binding/Member for granular management.
IAM Conditions & Advanced Features
How do I add time-based or conditional access restrictions?
Use the condition property with title, description, and expression. For example, set expression to request.time < timestamp("2020-01-01T00:00:00Z") to expire access at a specific time.
Are there limitations with IAM Conditions?
Yes, IAM Conditions are supported but have known limitations. Review GCP’s IAM Conditions documentation if you encounter issues with conditional access policies.
Configuration & Immutability
What properties can't be changed after creation?
The name, project, and zone properties are immutable. Changing these requires recreating the resource.

Using a different cloud?

Explore security guides for other cloud providers:

AWS Guides Azure Guides