Manage GCP Instant Snapshot IAM Bindings

The gcp:compute/instantSnapshotIamBinding:InstantSnapshotIamBinding resource, part of the Pulumi GCP provider, grants IAM roles to multiple members on instant snapshots while preserving other role assignments. This guide focuses on three capabilities: binding roles to multiple members, adding time-based conditional access, and incrementally adding single members.

IAM bindings reference existing instant snapshots by name, zone, and project. The snapshot must exist before you attach policies. The examples are intentionally small. Combine them with your own snapshot resources and identity management.

Grant a role to multiple members at once

Teams managing snapshot access often need to grant the same role to multiple users or service accounts simultaneously.

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 role property specifies which permission set to grant. The members array lists all identities that receive the role. InstantSnapshotIamBinding is authoritative for this specific role, meaning it replaces any previous member list for this role while leaving other roles untouched. The name, zone, and project properties identify which snapshot receives the binding.

Add time-based access with IAM Conditions

Temporary access grants expire automatically when you attach IAM Conditions to role bindings, preventing manual cleanup.

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"],
    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.InstantSnapshotIamBinding("binding",
    project=default["project"],
    zone=default["zone"],
    name=default["name"],
    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\")",
    })

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"),
			},
			Condition: &compute.InstantSnapshotIamBindingConditionArgs{
				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.InstantSnapshotIamBinding("binding", new()
    {
        Project = @default.Project,
        Zone = @default.Zone,
        Name = @default.Name,
        Role = "roles/compute.storageAdmin",
        Members = new[]
        {
            "user:jane@example.com",
        },
        Condition = new Gcp.Compute.Inputs.InstantSnapshotIamBindingConditionArgs
        {
            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.InstantSnapshotIamBinding;
import com.pulumi.gcp.compute.InstantSnapshotIamBindingArgs;
import com.pulumi.gcp.compute.inputs.InstantSnapshotIamBindingConditionArgs;
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")
            .condition(InstantSnapshotIamBindingConditionArgs.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:InstantSnapshotIamBinding
    properties:
      project: ${default.project}
      zone: ${default.zone}
      name: ${default.name}
      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 temporal constraints to the role binding. The expression property uses CEL (Common Expression Language) to define when access is valid. Here, the timestamp comparison automatically revokes access after December 31, 2019. The title and description properties document the condition’s purpose for auditing.

Add a single member to an existing role

When you need to grant access to one additional user without affecting existing members, InstantSnapshotIamMember adds the new identity 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 member property specifies a single identity to add. Unlike InstantSnapshotIamBinding, this resource is non-authoritative: it adds one member without replacing the existing member list for the role. Use this when you want to grant access without knowing or affecting who else has the role.

Beyond these examples

These snippets focus on specific IAM binding features: role binding with multiple members, time-based conditional access, and incremental member addition. They’re intentionally minimal rather than complete access control configurations.

The examples reference pre-existing infrastructure such as instant snapshots (by name, zone, project) and IAM principals (users, service accounts, groups). They focus on configuring access rather than creating the underlying resources.

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

Full policy replacement (InstantSnapshotIamPolicy)
Custom role definitions and formatting
Condition limitations and troubleshooting
Policy conflict resolution between resource types

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

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Frequently Asked Questions

Resource Conflicts & Compatibility

Can I use InstantSnapshotIamPolicy with InstantSnapshotIamBinding or InstantSnapshotIamMember?

No, gcp.compute.InstantSnapshotIamPolicy cannot be used with gcp.compute.InstantSnapshotIamBinding or gcp.compute.InstantSnapshotIamMember because they will conflict over the policy state.

Can I use InstantSnapshotIamBinding and InstantSnapshotIamMember together?

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

IAM Configuration & Roles

What properties can't be changed after creation?

The role, name, project, zone, and condition properties are all immutable and cannot be modified after the resource is created.

How do I specify custom IAM roles?

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

Can I create multiple InstantSnapshotIamBinding resources for the same instant snapshot?

Yes, but only one gcp.compute.InstantSnapshotIamBinding per role. Each binding manages a different role’s member list.

Access Control & Members

What types of identities can I grant access to in the members list?

You can grant access to:

Users: user:alice@gmail.com
Service accounts: serviceAccount:my-app@appspot.gserviceaccount.com
Groups: group:admins@example.com
Domains: domain:example.com
Project roles: projectOwner:my-project, projectEditor:my-project, projectViewer:my-project
Special identifiers: allUsers, allAuthenticatedUsers
Federated identities: principal://iam.googleapis.com/locations/global/workforcePools/...

Advanced Features

How do I add time-based or conditional access restrictions?

Use the condition property with title, description, and expression fields. For example, to expire access at a specific date: expression: "request.time < timestamp(\"2020-01-01T00:00:00Z\")".

What are the limitations of IAM Conditions?

IAM Conditions have known limitations that may affect functionality. Review the limitations before implementing conditional access controls.

Using a different cloud?

Explore security guides for other cloud providers:

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