This document describes some helpful usage tips for gcutil. Note that this is not a comprehensive list. For a comprehensive list of all available gcutil flags and commands, run:
$ gcutil $ gcutil --help
Listing available gcutil commands
To list all available gcutil commands, run:
Similarly, you can list all global gcutil flags by running:
$ gcutil --help
For help on a specific command and list non-global flags for that command:
$ gcutil help <command-name>
Filtering list results
When you list resources, you might want to filter your list results based on a set
of criteria. This can help so that you have a shorter list of more relevant
results. To do so, use the
<expression> must contain the following:
<field-name> <comparison-string> <literal-string>
- The name of the field you want to compare. The field name must be valid for
the type of resource being filtered. Field names are named using camel-case,
operationType. Only atomic field types are supported (string, number, boolean). Array and object fields are not currently supported.
- The comparison string, either
- The literal string value to filter to. The literal value must be valid for the
type of field (string, number, boolean). For string fields, the literal
value is interpreted as a regular expression using
RE2 syntax. The literal
value must match the entire field. For example, when filtering instances
name eq my-instance-won't work, but
name eq my-instance-.*will work.
$ gcutil listoperations --filter="operationType eq delete" \ --project=myproject \ --zone=us-central1-a
The above filter causes gcutil to return only operations in the zone
operation-type field equals
delete. Here is a more complex example:
$ gcutil listinstances --filter="name eq 'my-instance-[0-9]+'" --project=myproject
This would list all instances whose name matches the given regular expression.
Formatting list results
gcutil allows you format your list results into one of several display options, including:
For example, if you wanted to just list the names of a certain resource, you can use the
$ gcutil listinstances --format=names --project=<project-id>
Moving instances across zones
gcutil offers a helper function to move instances across zones using the
gcutil moveinstances command. The command copies your instance configuration,
takes snapshots of any persistent disks attached to the instance, deletes the
existing instances, and then recreates the instances in your destination zone.
This particular feature takes a snapshot of all your existing persistent disk data, shuts down your instance, recreates your persistent disks in the new zone, and starts new instances with your instance configurations. It is possible that this process could fail before it completes your move. For this reason, we encourage that you also backup your data before running this command, so that you can keep track of your backup resources in case you need to perform recovery. In particular, you should create snapshots of any persistent disk data you want to keep and also create custom images of the instances you are moving.
Other warnings to keep in mind:
This command deletes and recreates instances for you, but does not preserve any ephemeral IP addresses or contents of memory. Before executing this command, make sure you have backed up any data you want to keep.
You should not modify your project while a move is in progress. In particular, any changes that affect quotas, introduce naming conflicts, or deletes required resources, such as snapshots, will cause unpredictable behavior from gcutil.
You must fulfill the following prerequisites before you use this feature:
The desired zone must have enough quota to handle the number of new instances and disks that are created.
To see how much quota is available in a zone using gcutil, use the
gcutil getregion <region>command.
If you want to move instances that have persistent disks attached, you must move all instances that are using those persistent disks.
For example, if
instance-2are both using
persistent-disk-1, you must move both instances together to be able to successfully move the persistent disk. If you attempt to move one instance and not the other, gcutil won't perform the move.
If the above preconditions are not met, gcutil won't perform the move at all and your instances won't be modified.
When you run this command, almost all data that is accessible through the API, such as persistent disk data, is copied to your new instances. Server-generated data and data that is not accessible through the API, such as selfLinks, ephemeral IP addresses, and any contents of memory, are not preserved. Generally, startup scripts and storing data on persistent disks are the ideal ways reinstall software and store persistent data.
To move an instance:
$ gcutil --project=<project-id> moveinstances <name-regex> [<name-regex> ... <name-regex>] \ --source_zone=<zone-name> \ --destination_zone=<zone-name> \ [--force] [--keep_snapshots]
Import flags and parameters:
- [Required] The project ID for this request.
- [Required] One or more regular expressions matched to instance names that should be moved to the new zone. If any instance names match any of these regex expression, they will be moved.
- [Required] The current zone where the instances live.
- [Required] The new zone where you want your instances to be recreated.
- [Optional] Overrides the confirmation prompt.
- [Optional] After a successful move, all generated snapshots from the move are deleted. If you want to keep these snapshots, specify this flag.
Also, as part of the move process, gcutil creates snapshots of any attached persistent disks and recreates these disks in the new zone. After the move is complete, the snapshots are automatically deleted. It is possible that users might experience some charges for these snapshots. For information how snapshots are priced, see the price sheet.
Resuming a move
gcutil generates a log file every time you start the
command. If the move fails, you can use the log file to resume a move.
$ gcutil --project=<project-id> resumemove <log-path> \ [--force] [--keep_log_file] [--keep_snapshots]
Important flags and parameters:
- [Required] The project ID for this request.
- [Optional] Override the confirmation prompt.
- [Optional] By default, gcutil deletes the log file after the command is completely successfully. If you want to keep the log file, include this flag.
- [Optional] After a successful move, all generated snapshots from the move are deleted. If you want to keep these snapshots, set this flag.
[Required] The path to the log file that gcutil should use. When running
gcutil moveinstances, look for the following line:
If the move fails, you can re-attempt it using:
$ gcutil resumemove $HOME/.gcutil.move.20130201231024
$HOME/.gcutil.move.<datetime>is the log path.
Checking which user you are authorized as
$ gcutil --project=<project-id> auth --just_check_auth INFO: Authorization succeeded for user <user>
Printing a REST request and its corresponding JSON response
To see the details of the REST request and its corresponding JSON response sent
and received by gcutil, use the
$ gcutil --dump_request_response <command> <command_flags>
To see only the JSON response to your request, use the
$ gcutil <command> <command_flags> --print_json
Saving and reusing flag values
When you run gcutil commands, there are certain flags that you must always
specify. For example, every gcutil command requires a
--project flag so that
gcutil knows for which project it should execute the command. To make this more
convenient, gcutil provides a
--cache_flag_values flag which saves all your
specified flags for that command into a .gcutil.flags file. To save and use
gcutil flag values, run:
$ gcutil <command> <command_flags> --cache_flag_values=True
By default, gcutil creates a
.gcutil.flags file in your home directory. If you
would like to save your
.gcutil.flags file elsewhere, you can specify a file
path using the
$ gcutil <command> <command_flags> --cache_flag_values=True [--cached_flags_file=<some_file_path>]
<some_file_path> is your desired file path. You can specify the file
path in a variety of manners:
gcutil will always look for an existing
.gcutil.flags value in the following
- If the
--cached_flags_valueflag is specified with a file path, gcutil the file path provided.
- If the
--cached_flags_valueflag is not specified, or is specified only with a file name rather than a file path, gcutil looks for the file name in the current directory. If it doesn't find the file in the current directory, it looks for the file in the parent directories, and lastly, it looks for the file in the home directory if the file is not found in the parent directories. gcutil uses the first instance of the file it finds.
This behavior allows you to create multiple
.gcutil.flag values for easy access
to more than one project. For example, if you use multiple projects with gcutil,
you can save a customized cached flag file in each directory to use for each
project and gcutil automatically selects the right cached flag file for you.
Revoking a refresh token
If your refresh tokens are compromised, you can revoke them so that they can no longer be used. To revoke a refresh token:
- Log into your Google account page.
- Click Security and then click the Edit button next to Authorizing applications and sites.
- Click Revoke Access next to Google Cloud SDK.
Resetting an instance
For information on how to reset an instance, review the Instances documentation.
Performing requests in asynchronous mode
To perform a request in asynchronous mode, meaning gcutil returns immediately
after posting a request, regardless of whether or not the request has been
completed, use the
--[no]synchronous_mode flag. This can be useful if you know
a request will take a while to complete and you want to be able to perform other
tasks. By default, gcutil will perform requests in synchronous mode.
Using gcutil with multiple accounts
You will need a different authorization token for each Google account with which
you want to access Google Compute Engine. gcutil provides a
flag for this purpose. When specifying a new
--credentials_file that does not
yet exist, gcutil prompts you through the authorization process again. Sign into
the intended Google account in your browser, and authorize gcutil to access your
account. For example:
- Sign into Google with email@example.com on your browser.
gcutil auth --credentials_file=$HOME/.user1_credentials.
- Follow the authorization steps.
- Sign into Google with firstname.lastname@example.org on your browser.
gcutil auth --credentials_file=$HOME/.user2_credentials.
- Follow the authorization steps
Isolating your scripts from future changes
If you use applications or scripts that depend on a certain API version, image, or disk location, you might find that your scripts break from time to time as Google Compute Engine releases a new API, releases a new default image, or changes the disk path. If you don't always have the time to resolve these breaking changes as they happen, here are some tips on how to isolate your scripts and applications from changes until you have time to resolve these conflicts:
Always reference your persistent disks using the disk alias path rather than linking to it using
/dev/vd*path can change at anytime and is not a reliable path to use. Use the disk alias path, which always points to the correct location of the disk:
For more information, see attaching a persistent disk.
Hard coding an API version or image name in your script:
If your scripts or applications depend on a particular API version
Consider hard coding the API version number using the gcutil
--service_version=<api-version-number>flag. If you don’t specify an API version number, Google Compute Engine automatically uses the most current version. As versions change, there might be changes that break your script. To help with this, hard code the API version number so that your script continues to run until you have time to address any conflicts. Deprecated APIs are supported for 3 months from the deprecation date, providing a relatively large time frame to convert your scripts.
If your scripts or applications depend on a particular image
Consider hard coding the image name into your script. The default image does change from time to time, and your script might not work or run correctly if it relies on certain capabilities of an older image that is not available in newer images. To prevent your script from breaking until you have time to resolve conflicts, you can hard code the image name and change it when you have updated your script to use the new images. In gcutil, you can specify an image using the