$ gcloud beta compute instances set-machine-type example-instance \
    --zone us-central1-b --machine-type n1-standard-4

POSITIONAL ARGUMENTS

INSTANCE_NAME

Name of the instance to operate on.

FLAGS

--machine-type=MACHINE_TYPE

Specifies the machine type used for the instances. To get a list of available machine types, run 'gcloud compute machine-types list'. Either this flag, --custom-cpu, or --custom-memory must be specified.

--zone=ZONE

Zone of the instance to operate on. If not specified, you may be prompted to select a zone. gcloud will attempt to identify the zone by searching for resources in your project. If the zone cannot be determined, you will then be prompted with all Google Cloud Platform zones.
To avoid prompting when this flag is omitted, you can set the compute/zone property:

$ gcloud config set compute/zone ZONE

A list of zones can be fetched by running:

$ gcloud compute zones list

To unset the property, run:

$ gcloud config unset compute/zone

Alternatively, the zone can be stored in the environment variable CLOUDSDK_COMPUTE_ZONE.

Custom machine type extensions.

--custom-cpu=CUSTOM_CPU

A whole number value indicating how many cores are desired in the custom machine type. This flag must be specified if any of the other arguments in this group are specified.

--custom-memory=CUSTOM_MEMORY

A whole number value indicating how much memory is desired in the custom machine type. A size unit should be provided (eg. 3072MB or 9GB) - if no units are specified, GB is assumed. This flag must be specified if any of the other arguments in this group are specified.

--custom-extensions

Use the extended custom machine type.

GCLOUD WIDE FLAGS

NOTES

$ gcloud compute instances set-machine-type $ gcloud alpha compute instances set-machine-type