Run shutdown scripts (original) (raw)

Linux Windows

Create and run shutdown scripts that execute commands right before a virtual machine (VM) instance is stopped or restarted. This is useful if you rely on automated scripts to start up and shut down instances, allowing instances time to clean up or perform tasks, such as exporting logs, or syncing with other systems.

Shutdown scripts are especially useful for VMs in amanaged instance group with anautoscaler. If the autoscaler shuts down a VM in the group, the shutdown script runs before the VM stops and the shutdown script performs any actions that you define. The script runs during the limited shutdown period before the VM stops. For example, your shutdown script might copy processed data to Cloud Storage or back up any logs.

Shutdown scripts function very similarly to startup scripts. Much of the documentation for startup scripts also applies for shutdown scripts.

For both shutdown and reboot tasks, VMs always run shutdown scripts as follows:

Prerequisites

To run scripts stored in metadata on a VM instance, the guest environment must be installed and running.

Before you begin

Console

When you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication.

gcloud

  1. Install the Google Cloud CLI. After installation,initialize the Google Cloud CLI by running the following command:
    gcloud init
    If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.
  2. Set a default region and zone.

Terraform

To use the Terraform samples on this page in a local development environment, install and initialize the gcloud CLI, and then set up Application Default Credentials with your user credentials.
Install the Google Cloud CLI.
If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.
If you're using a local shell, then create local authentication credentials for your user account:
gcloud auth application-default login
You don't need to do this if you're using Cloud Shell.
If an authentication error is returned, and you are using an external identity provider (IdP), confirm that you have signed in to the gcloud CLI with your federated identity.
For more information, see Set up authentication for a local development environment.

REST

To use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI.
Install the Google Cloud CLI.
If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.
For more information, seeAuthenticate for using REST in the Google Cloud authentication documentation.

Permissions required for this task

To perform this task, you must have the following permissions:

Specifications

The following sections outline the specifications for shutdown scripts.

Limitations

There are some limitations to note when using shutdown scripts:

Shutdown script invocation

Shutdown scripts are triggered when the instance shuts down after any of the following events happen:

A shutdown script can be of any file type. If there is a shutdown script present in the instance, then Compute Engine does the following:

  1. Copies the script to a local file in the instance.
  2. Sets permissions on the file to make the script executable.
  3. Executes the file when the instance shuts down.

You could, for example, provide a Python script instead of a bash script. Keep in mind that Compute Engine runs the script verbatim, regardless of the type of script.

To execute a script that is not bash, add a shebang line at the top of the file to let the operating system know which interpreter to use. For example, for a Python script, you can add a shebang line like:

#!/usr/bin/python

Shutdown script running time

Your shutdown scripts start running when Compute Engine sets the instance state to STOPPING. Your scripts must complete before the instance is fully stopped, which is when its state changes to TERMINATED. The time the instance takes to reach the TERMINATED state varies depending on theinstance type.

If your scripts take longer than the time it takes for the instance to stop, then Compute Engine forcefully stops the scripts, which can lead to data loss or incomplete tasks. To prevent this,stop the instance from within its guest OS. This approach keeps the instance state to STOPPING until your shutdown scripts finish running.

Use a local shutdown script

A local shutdown script is a script that lives on your local computer. Pass in a local shutdown script either as a file or by giving the contents directly to Compute Engine.

Shutdown scripts can perform as many actions as you need, but if you are passing in the file locally, your script cannot exceed the metadata value length limit of 256 KB. To use a script that exceeds the length limit, store your file on Cloud Storage. SeeUse shutdown script from Cloud Storage for more information.

Provide a shutdown script file

You can only pass in a local shutdown script file through the gcloudcommand-line tool.

gcloud

To pass in a local shutdown script file, supply the --metadata-from-fileflag, followed by a metadata key pair, shutdown-script=PATH/TO/FILE, wherePATH/TO/FILE is a relative path to the shutdown script. For example:

gcloud compute instances create example-instance \
    --metadata-from-file shutdown-script=examples/scripts/install.sh

Terraform

To specify a shutdown script directly, use the google_compute_instanceresource with the path to the shutdown script in the metadata.

Provide shutdown script contents directly

Alternatively, you can pass in the contents of your shutdown script directly.

Console

In Google Cloud console, specify a shutdown script directly using theshutdown-script metadata key:

  1. Go to the Create an instance page.
    Go to Create an instance
  2. Specify the VM details.
  3. Expand the Advanced options section.
  4. Expand Management, and do the following:
    1. In the Metadata section, click Add item.
    2. In the Key field, enter shutdown-script for the metadata key.
    3. In the Value field, add the contents of your shutdown script.
  5. Continue with the VM creation process.

gcloud

Using the Google Cloud CLI, use the --metadata flag to provide the contents of your shutdown script, followed by theshutdown-script=CONTENTS key pair, where CONTENTS is the content of your shutdown script.

gcloud compute instances create example-instance --metadata shutdown-script="#! /bin/bash
> # Shuts down Apache server
> /etc/init.d/apache2 stop"

Terraform

To specify a shutdown script directly, use the google_compute_instanceresource with the shutdown script in the metadata.

REST

In the API, provide a shutdown script as part of the metadata property in your request when you create an instance. Use shutdown-script as the metadata key:

POST https://compute.googleapis.com/compute/v1/projects/myproject/zones/us-central1-a/instances

{...
  "metadata": {
    "items": [
      {
       "key": "shutdown-script",
       "value": "#! /bin/bash\n\n# Shuts down Apache server\n/etc/init.d/apache2 stop"
      }
    ]
  }...
}

Provide a shutdown script on Windows instances

Run shutdown scripts on Windows instances using the following Windows-specific metadata keys. Choose from any of the specialized keys listed below. Each key should match the type of script you want to run.

You can specify multiple shutdown scripts by passing in different keys to your instance but each key can only be specified once per virtual machine.

The following keys can be used with a local shutdown script, using thesame instructionsearlier in this document.

cmd shutdown scripts bat shutdown scripts ps1 shutdown scripts
windows-shutdown-script-cmd windows-shutdown-script-bat windows-shutdown-script-ps1

Use a shutdown script from Cloud Storage

You can store and use a shutdown script from Cloud Storage. Follow the instructions in the Startup scriptsdocumentation but replace startup-script-url with shutdown-script-url.

For Windows instances, replace windows-startup-script-url withwindows-shutdown-script-url.

Apply a shutdown script to running instances

To add a shutdown script to a running instance, follow the instructions in theApplying a startup script to running instancesdocumentation but replace the metadata keys with one of the following keys:

Viewing the output of a shutdown script

Linux

You can view the output from a Linux shutdown script by doing any of the following:

sudo journalctl -u google-shutdown-scripts.service

Windows

View the output from a Windows Server shutdown script by using any of the following and checking for GCEMetadataScripts events: