# Creating an instance group connected to a file storage One of the ways to handle [stateful workloads](../../concepts/instance-groups/stateful-workload.md) is to store the application state in a [file storage](../../concepts/filesystem.md) independent of the instance group. To create an instance group that will automatically connect a common file storage to each of its instances: 1. In Instance Groups, all operations are performed under a service account. If you don't have a service account, [create one](../../../iam/operations/sa/create.md). 1. If you do not have a file storage, [create one](../filesystem/create.md). 1. To be able to create, update, and delete VM instances in the instance group, [assign](../../../iam/operations/sa/assign-role-for-sa.md) the [compute.editor](../../security/index.md#compute-editor) role to the service account. 1. Create an instance group: {% list tabs group=instructions %} - CLI {#cli} If you do not have the Yandex Cloud CLI yet, [install and initialize it](../../../cli/quickstart.md#install). The folder used by default is the one specified when [creating](../../../cli/operations/profile/profile-create.md) the CLI profile. To change the default folder, use the `yc config set folder-id ` command. You can also specify a different folder for any command using `--folder-name` or `--folder-id`. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions. 1. See the description of the [CLI](../../../cli/index.md) command for creating an instance group: ```bash yc compute instance-group create --help ``` 1. Check whether the [folder](../../../resource-manager/concepts/resources-hierarchy.md#folder) contains any [networks](../../../vpc/concepts/network.md#network): ```bash yc vpc network list ``` If there are no networks, [create one](../../../vpc/operations/network-create.md). 1. Select one of the Yandex Cloud Marketplace public images, e.g., [Ubuntu 22.04 LTS](https://yandex.cloud/en/marketplace/products/yc/ubuntu-22-04-lts). To get a list of available images using the CLI, run this command: ```bash yc compute image list --folder-id standard-images ``` Result: ```text +----------------------+-------------------------------------+--------------------------+----------------------+--------+ | ID | NAME | FAMILY | PRODUCT IDS | STATUS | +----------------------+-------------------------------------+--------------------------+----------------------+--------+ ... | fdvk34al8k5n******** | centos-7-1549279494 | centos-7 | dqni65lfhvv2******** | READY | | fdv7ooobjfl3******** | windows-2016-gvlk-1548913814 | windows-2016-gvlk | dqnnc72gj2is******** | READY | | fdv4f5kv5cvf******** | ubuntu-1604-lts-1549457823 | ubuntu-1604-lts | dqnnb6dc7640******** | READY | ... +----------------------+-------------------------------------+--------------------------+----------------------+--------+ ``` Where: * `ID`: Image ID. * `NAME`: Image name. * `FAMILY`: ID of the [image family](../../concepts/image.md#family) the image belongs to. * `PRODUCT IDS`: IDs of Yandex Cloud Marketplace [products](../../../marketplace/concepts/product.md) associated with the image. * `STATUS`: Current status of the image. It may take one of the following values: * `STATUS_UNSPECIFIED`: Image status is not defined. * `CREATING`: Image is being created. * `READY`: Image is ready to use. * `ERROR`: You cannot use the image due to an issue. * `DELETING`: Image is being deleted. 1. Prepare a file with the [YAML specification](../../concepts/instance-groups/specification.md) of the instance group and give it a name, e.g., `specification.yaml`. To connect a file storage to instances in the instance group, add the following to the specification: * In the `instance_template` field, a nested `filesystem_specs` field containing the description of the file storage: ```yml instance_template: ... filesystem_specs: - mode: READ_WRITE device_name: filesystem_id: ``` Where: * `mode`: File storage access mode, `READ_WRITE` (read and write). * `device_name`: Device name for connecting the [file storage](../../concepts/filesystem.md) to the VM instance, e.g., `sample-fs`. It can only contain lowercase Latin letters, numbers, and hyphens. The first character must be a letter. The last character cannot be a hyphen. The name may be up to 63 characters long. * `filesystem_id`: File storage ID. You can view the ID in the [management console](https://console.yandex.cloud) or using the `yc compute filesystem list` CLI command. * In the `#cloud-config` section of the `instance_template.metadata.user-data` field, commands for mounting the file storage to the VM: ```yml instance_template: ... metadata: user-data: |- #cloud-config ... runcmd: - mkdir - mount -t virtiofs - echo "test-fs virtiofs rw 0 0" | tee -a /etc/fstab ``` Where: * ``: Instance directory to mount the connected file storage to, e.g., `/mnt/vfs0`. * ``: Device name for connecting the file storage to the VM instance. The value must match the one specified earlier in the `instance_template.filesystem_specs.device_name` field. Here is a YAML specification example: ```yml name: my-vm-group-with-fs service_account_id: description: "This instance group was created using a YAML configuration file." instance_template: platform_id: standard-v3 resources_spec: memory: 2g cores: 2 boot_disk_spec: mode: READ_WRITE disk_spec: image_id: fd8dlvgiatiqd8tt2qke type_id: network-hdd size: 32g network_interface_specs: - network_id: enp9mji1m7b3******** primary_v4_address_spec: { one_to_one_nat_spec: { ip_version: IPV4 } } security_group_ids: - enpuatgvejtn******** filesystem_specs: - mode: READ_WRITE device_name: sample-fs filesystem_id: epdccsrlalon******** metadata: user-data: |- #cloud-config datasource: Ec2: strict_id: false ssh_pwauth: no users: - name: my-user sudo: ALL=(ALL) NOPASSWD:ALL shell: /bin/bash ssh_authorized_keys: - runcmd: - mkdir /mnt/vfs0 - mount -t virtiofs sample-fs /mnt/vfs0 - echo "sample-fs /mnt/vfs0 virtiofs rw 0 0" | tee -a /etc/fstab deploy_policy: max_unavailable: 1 max_expansion: 0 scale_policy: fixed_scale: size: 2 allocation_policy: zones: - zone_id: ru-central1-a instance_tags_pool: - first - second ``` This example shows a specification for [creating a fixed-size instance group](create-fixed-group.md) with a file storage connected to the instances. For more information about the instance group specification parameters, see [Specification of an instance group in YAML format](../../concepts/instance-groups/specification.md). 1. Create an instance group in the default folder: ```bash yc compute instance-group create --file specification.yaml ``` This command will create a group of two same-type instances with the following configuration: * Name: `my-vm-group-with-fs`. * OS: `Ubuntu 22.04 LTS`. * Availability zone: `ru-central1-a`. * vCPU: 2, RAM: 2 GB. * Network [HDD](../../concepts/disk.md#disks-types): 32 GB. * Connected to a file storage. The file storage will be mounted to the `/mnt/vfs0` directory of the group instances. * Each VM of the group will have а [public IP address](../../../vpc/concepts/address.md#public-addresses) assigned. This way, you can easily [connect](../vm-connect/ssh.md#vm-connect) to the group VM over SSH when checking the result. If you create an instance group without public IP addresses, you can still connect to a group VM over SSH by specifying its [internal IP address](../../../vpc/concepts/address.md#internal-addresses) or [FQDN](../../../vpc/concepts/address.md#fqdn) instead of the public IP address. However, you can only make such a connection from another virtual machine that has a public IP address and is located in the same Yandex Cloud [cloud network](../../../vpc/concepts/network.md#network) as the group VM. - Terraform {#tf} If you do not have Terraform yet, [install it and configure the Yandex Cloud provider](../../../tutorials/infrastructure-management/terraform-quickstart.md#install-terraform). To manage infrastructure using Terraform under a service account or user accounts (a Yandex account, a federated account, or a local user), [authenticate](../../../terraform/authentication.md) using the appropriate method. 1. In the configuration file, describe the resources you want to create: ```hcl resource "yandex_iam_service_account" "ig-sa" { name = "ig-sa" description = "Service account for managing the instance group" } resource "yandex_resourcemanager_folder_iam_member" "compute_editor" { folder_id = "" role = "compute.editor" member = "serviceAccount:${yandex_iam_service_account.ig-sa.id}" depends_on = [ yandex_iam_service_account.ig-sa, ] } resource "yandex_compute_instance_group" "ig-1" { name = "fixed-ig" folder_id = "" service_account_id = "${yandex_iam_service_account.ig-sa.id}" deletion_protection = "" depends_on = [yandex_resourcemanager_folder_iam_member.compute_editor] instance_template { platform_id = "standard-v3" resources { memory = cores = } boot_disk { mode = "READ_WRITE" initialize_params { image_id = "" } } filesystem { mode = "READ_WRITE" device_name = "" filesystem_id = "" } network_interface { network_id = "${yandex_vpc_network.network-1.id}" subnet_ids = ["${yandex_vpc_subnet.subnet-1.id}"] security_group_ids = [""] nat = true } metadata = { user-data = "#cloud-config\n datasource:\n Ec2:\n strict_id: false\n ssh_pwauth: no\n users:\n - name: \n sudo: ALL=(ALL) NOPASSWD:ALL\n shell: /bin/bash\n ssh_authorized_keys:\n - \n runcmd:\n - mkdir \n - mount -t virtiofs \n - echo \"sample-fs virtiofs rw 0 0\" | tee -a /etc/fstab" } } scale_policy { fixed_scale { size = } } allocation_policy { zones = ["ru-central1-a"] } deploy_policy { max_unavailable = 1 max_expansion = 0 } } resource "yandex_vpc_network" "network-1" { name = "network1" } resource "yandex_vpc_subnet" "subnet-1" { name = "subnet1" zone = "ru-central1-a" network_id = "${yandex_vpc_network.network-1.id}" v4_cidr_blocks = ["192.168.10.0/24"] } ``` Where: * `yandex_iam_service_account`: [Service account](../../../iam/concepts/users/service-accounts.md) description. All operations in Instance Groups are performed on behalf of the service account. You cannot delete a service account while it is linked to an instance group. * `yandex_resourcemanager_folder_iam_member`: Description of access permissions for the [folder](../../../resource-manager/concepts/resources-hierarchy.md#folder) the service account belongs to. To be able to create, update, and delete VM instances in the instance group, assign the [compute.editor](../../security/index.md#compute-editor) role to the service account. * `yandex_compute_instance_group`: Instance group description: * General information about the instance group: * `name`: Instance group name. * `folder_id`: Folder ID. * `service_account_id`: Service account ID. * `deletion_protection`: Instance group protection against deletion, `true` or `false`. You cannot delete a group while the value is `true`. The default value is `false`. * [Instance template](../../concepts/instance-groups/instance-template.md): * `platform_id`: [Platform](../../concepts/vm-platforms.md). * `resources`: Number of vCPUs and amount of RAM available to the VM instance. The values must match the selected [platform](../../concepts/vm-platforms.md). * `boot_disk`: Boot [disk](../../concepts/disk.md) settings. * `mode`: Disk access mode, `READ_ONLY` or `READ_WRITE`. * `image_id`: ID of the selected image. You can get the image ID from the [list of public images](../images-with-pre-installed-software/get-list.md). * `filesystem`: [File storage](../../concepts/filesystem.md) settings. * `mode`: File storage access mode, `READ_WRITE` (read and write). * `device_name`: Device name for connecting the file storage to the VM instance, e.g., `sample-fs`. It can only contain lowercase Latin letters, numbers, and hyphens. The first character must be a letter. The last character cannot be a hyphen. The name may be up to 63 characters long. * `filesystem_id`: File storage ID. You can view the ID in the [management console](https://console.yandex.cloud) or using the `yc compute filesystem list` CLI command. * `network_interface`: [Network](../../../vpc/concepts/network.md#network) settings. Specify the IDs of your network, [subnet](../../../vpc/concepts/network.md#subnet), and [security groups](../../../vpc/concepts/security-groups.md). * `metadata`: In [metadata](../../concepts/vm-metadata.md), provide the following: * Instance username and public key to enable this user to access the instance over SSH. * Instance mount point for the file storage, i.e., instance directory to mount the connected file storage to, e.g., `/mnt/vfs0`. * Instance device name, i.e., device name for connecting the file storage to the VM instance. The value must match the one specified earlier in the `device_name` field of the `filesystem` section. For more information, see [VM metadata](../../concepts/vm-metadata.md). * [Policies](../../concepts/instance-groups/policies/index.md): * `deploy_policy`: Instance [deployment policy](../../concepts/instance-groups/policies/deploy-policy.md) for the group. * `scale_policy`: Instance [scaling policy](../../concepts/instance-groups/policies/scale-policy.md) for the group. * `allocation_policy`: [Policy for allocating](../../concepts/instance-groups/policies/allocation-policy.md) instances across [availability zones](../../../overview/concepts/geo-scope.md) and regions. * `yandex_vpc_network`: Cloud network description. * `yandex_vpc_subnet`: Description of the subnet to which you connect the instance group. {% note info %} If you already have suitable resources, such as a service account, cloud network, and subnet, you do not need to redefine them. Specify their names and IDs in the appropriate parameters. {% endnote %} For more information about the resources you can create with Terraform, see [this provider guide](../../../terraform/index.md). 1. Create the resources: 1. In the terminal, navigate to the configuration file directory. 1. Make sure the configuration is correct using this command: ```bash terraform validate ``` If the configuration is valid, you will get this message: ```bash Success! The configuration is valid. ``` 1. Run this command: ```bash terraform plan ``` You will see a list of resources and their properties. No changes will be made at this step. Terraform will show any errors in the configuration. 1. Apply the configuration changes: ```bash terraform apply ``` 1. Type `yes` and press **Enter** to confirm the changes. This will create all the resources you need in the specified folder. You can check the new resources and their settings using the [management console](https://console.yandex.cloud). Each VM of the group will have а [public IP address](../../../vpc/concepts/address.md#public-addresses) assigned. This way, you can easily [connect](../vm-connect/ssh.md#vm-connect) to the group VM over SSH when checking the result. If you create an instance group without public IP addresses, you can still connect to a group VM over SSH by specifying its [internal IP address](../../../vpc/concepts/address.md#internal-addresses) or [FQDN](../../../vpc/concepts/address.md#fqdn) instead of the public IP address. However, you can only make such a connection from another virtual machine that has a public IP address and is located in the same Yandex Cloud [cloud network](../../../vpc/concepts/network.md#network) as the group VM. - API {#api} Use the [create](../../instancegroup/api-ref/InstanceGroup/create.md) REST API method for the [InstanceGroup](../../instancegroup/api-ref/InstanceGroup/index.md) resource or the [InstanceGroupService/Create](../../instancegroup/api-ref/grpc/InstanceGroup/create.md) gRPC API call. {% endlist %} Make sure the file storage is connected to the group instances. For this, [connect](../vm-connect/ssh.md#vm-connect) to the instances over SSH and navigate to the directory you specified as the mount point.