--- name: vpc-vsi_is_creating_auto_scale_group title: Creating an instance group for auto scaling description: With Auto Scale for VPC, you can create an instance group to scale according to your requirements. Based on the target utilization metrics that you define, the instance group can dynamically add or remove instances to achieve your specified instance availability. last-updated: 2026-06-26 --- > ## Documentation Index > The table of contents for this documentation set is at https://cloud.ibm.com/docs/vpc?format=markdown > The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt > Use these files to discover more information as needed. # Creating an instance group for auto scaling {: #creating-auto-scale-instance-group} With Auto Scale for VPC, you can create an instance group to scale according to your requirements. Based on the target utilization metrics that you define, the instance group can dynamically add or remove instances to achieve your specified instance availability. {: shortdesc} If you are going to use a custom image in a private catalog, you must first create a service-to-service policy to `globalcatalog-collection.instance.retrieve` before you can create the instance group. For more information, see [Using a custom image in a private catalog with an instance group](https://cloud.ibm.com/docs/vpc?topic=vpc-private-catalog-image-instance-group&interface=ui&format=markdown). {: important} ## Auto scale for VPC {: #auto-scale-vpc} With Auto Scale for VPC, you can improve performance and costs by dynamically creating virtual server instances to meet the demands of your environment. You set scaling policies that define the average utilization that you want to achieve for metrics like CPU, memory, and network usage. The policies that you define determine when virtual server instances are added or removed from your instance group. As an example, imagine that the fictitious company, Acme Web Retailer, sets up an instance group for auto scaling. They define that they want to maintain a minimum of three instances and a maximum of seven instances. They create a dynamic scaling policy for CPU usage with their specified average utilization for instances at 70%. They set an aggregation window of 10 minutes, so the instance group manager monitors each instance for 10 minutes before it calculates the average utilization. If adjustments are needed to meet the target utilization across instances, the instance group manager provisions or reclaims more instances as needed. Auto scale uses the following computation to determine how many instances are running at any time: ```text Σ(Current average utilization of each instance)/target utilization = membership count ``` If Acme Web Retailer has four virtual server instances that are running when the aggregation window elapses, the formula is similar to this example: _VSI1 + VSI2 + VSI3 + VSI4 / 70% = membership count_. CPU utilization for the four running instances is 80%, 70%, 65%, and 85%, so the following computation takes place: ```text 80% + 70% + 65% + 85% / 70% = 4.29 ``` Based on this calculation, the instance group manager rounds **4.29** up to **5** and provisions another instance. Now Acme Web Retailer has a total of five instances and maintains their specified average CPU utilization across the instances in the group. ![Image showing an instance that is being added to an instance group](images/VPC_Autoscaling_Docs.png "Image showing an instance that is being added to an instance group after computation"){: caption="Auto scale instance group adds new instance" caption-side="bottom"} When an instance group scales up to create an instance, a subnet is selected randomly from the subnets that are defined for the instance group. When an instance group scales down to remove instances, it uses a first in first out (FIFO) strategy. The oldest instances are deleted first. If at any time an instance in the instance group fails, it is replaced with a new instance. You can configure your instance group with a load balancer to balance incoming requests across instances. With a load balancer, you can configure specific health checks for the pool members that are associated with instances in your instance group. If an instance fails health checks, a new instance is created in the instance group to replace the failed membership. When the new instance is available, the instance that failed health checks is deleted. The monitoring service reflects the same health information for instances that health checks access. ## Setting up auto scale with the UI {: #setting-up-autoscale-overview} {: ui} Before you can create an instance group, you need to [create an IBM Cloud VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-creating-a-vpc-using-the-ibm-cloud-console&format=markdown). {: important} To create an instance group for auto scale, you must complete the following tasks. 1. Create an instance template that is used to provision instances in your group. 2. Create an instance group in a single region that is made up of like virtual server instances. 3. Choose a scaling method (static or dynamic) and create scaling policies. ### Creating an instance template {: #creating-instance-template} An instance template is required before you can create an instance group for auto scaling. The instance template defines the details of the virtual server instances that are created for your instance group. For example, specify the profile (vCPU and memory), image, attached volumes, and network interfaces for the image template. All of the virtual server instances that are created for an instance group use the instance template that is defined in the instance group. All resources that are defined in an instance template must all be in the same resource group as the instance group. {: tip} To create an instance template, complete the following steps. 1. In the [IBM Cloud console](https://cloud.ibm.com/login){: external}, go to **Navigation Menu** icon ![menu icon](../../icons/icon_hamburger.svg) **> Infrastructure** ![VPC icon](../../icons/vpc.svg) **> Compute > Instance templates**. 2. Click **New instance template** and enter the information that is in Table 1. 3. Click **Create an instance template** when the information is complete. {{site.data.content.create-instance-template-table}} **Important:** Instance groups don't support instance templates that have the following configurations: - Secondary network interfaces aren't supported. Only one primary network interface for an instance template is supported in an instance group. - A primary IP address or floating IP address that is assigned to the primary interface isn't supported. When you create an instance template, validation steps are performed to make sure that you can use this template to provision a virtual server instance. ### Creating an instance group {: #creating-instance-group} An instance group is a collection of like virtual server instances. You define how many instances to maintain in the group. You can set a static number of instances or choose to dynamically scale instances according to your requirements. If you want to include a load balancer for your instance group to balance incoming requests across instances and configure specific health checks, you must create the load balancer before you create the instance group. For more information, see the following topics: - [About application load balancers](https://cloud.ibm.com/docs/vpc?topic=vpc-load-balancers-about&format=markdown) and [Creating an IBM Cloud Application Load Balancer for VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-load-balancers&format=markdown) - [About network load balancers](https://cloud.ibm.com/docs/vpc?topic=vpc-network-load-balancers&format=markdown), [Creating an IBM Cloud Network Load Balancer for VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-nlb-ui-creating-network-load-balancer&format=markdown), and [Creating an IBM Cloud Private Network Load Balancer with routing mode for VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-nlb-vnf&format=markdown) For more information about health checks for load balancer pools, see the following topics: - [Working with health checks (ALB)](https://cloud.ibm.com/docs/vpc?topic=vpc-alb-health-checks&format=markdown) - [Working with health checks (NLB)](https://cloud.ibm.com/docs/vpc?topic=vpc-nlb-health-checks&format=markdown) Not all network load balancer offerings support integration with instance groups. Before you attach an instance group to a network load balancer pool, make sure that the `instance_groups_supported` property of the [load balancer detail](https://cloud.ibm.com/docs/apis/vpc/latest#get-load-balancer) is `true`. {: important} 1. Make sure that you have the required IBM Cloud Identity and Access Management (IAM) permissions to create an instance group. For more information, see [Managing IAM access for VPC Infrastructure Services](https://cloud.ibm.com/docs/vpc?topic=vpc-iam-getting-started&interface=ui&format=markdown). 2. In the [IBM Cloud console](https://cloud.ibm.com/login){: external}, go to **Navigation Menu** icon ![menu icon](../../icons/icon_hamburger.svg) **> Infrastructure** ![VPC icon](../../icons/vpc.svg) **> Compute > Instance groups**. 3. Click **New instance group** and enter the information in Table 2. 4. If you want to create dynamic scaling policies as part of instance group creation, see [Creating scaling policies](#creating-scaling-policies). You can also [add policies later](https://cloud.ibm.com/docs/vpc?topic=vpc-managing-instance-group&format=markdown#creating-target-policies) after you create your instance group. 5. Click **Create an instance group** when the information is complete. | Field | Value | |-------|-------| | Name | A name is required for your virtual server instance. | | Resource group | Select a resource group for the instance. | | Region | Select the location where you want your virtual server instance to be created. | | Placement group | Select a placement group for the instance. If you add a placement group, the instance is placed according to the placement group policy. For more information, see [About placement groups](https://cloud.ibm.com/docs/vpc?topic=vpc-about-placement-groups-for-vpc&format=markdown). | | Subnets | Select the subnets where you want to create your instance group. To maximize the availability of your applications, select subnets in different zones. For the best performance of an auto scale instance group, make sure that you use a subnet size of 32 or greater. | | Use a load balancer | Select this checkbox if you plan to use a load balancer to balance incoming requests across instances in your instance group. The load balancer must already be configured, attached to the subnets that you select for this instance group, and have at least one back-end pool. | | Instance template | Select the instance template that you want to use for provisioning the virtual server instances in your auto-scale instance group. All virtual server instances in the group are provisioned with the same instance template. | | Scaling method | Select whether you want to use a dynamic or static scaling method. With the dynamic scaling method, instances are added or removed based on the metric targets that you specify. With the static scaling method, you can specify a fixed number of instances that you want to maintain. | | Instance group size | For a static group, enter the number of instances that you want to constantly have in this instance group. For a dynamic group, enter the minimum and maximum number of instances for your group. The number of instances automatically scale automatically within that range based on the target metrics that you define. | | Aggregation window (seconds) | For a dynamic group, this value determines the time period that the instance group manager monitors each instance and determines the average utilization. | | Cooldown period (seconds) | For a dynamic group, the cooldown period is the time in seconds to pause further scaling actions after scaling takes place. | {: caption="Instance group selections" caption-side="bottom"} ### Creating scaling policies {: #creating-scaling-policies} For the dynamic scaling method, you define certain metrics (like CPU utilization %) and the target utilization that you want to achieve for that metric. Together, the metric and the average target utilization determine when your instance group needs to dynamically add or remove virtual server instances from your group. To add scaling policies, complete the following fields on the **New instance group for VPC** page. If you need to add policies after your instance group is already created, see [add policies](https://cloud.ibm.com/docs/vpc?topic=vpc-managing-instance-group&format=markdown#creating-target-policies). | Field | Value | |-------|-------| | Metric type | Select the metric type that you want to associate with a target utilization value to use for adding or removing instances from your group. You can choose one of these metrics: CPU utilization (%), RAM utilization (%), Network in (Mbps), Network out (Mbps). You can define more than one target metric policy, but only one policy for each type of metric. | | Average target utilization | Specify the average utilization that you want to achieve for the metric that you select. This target value defines when the instance group manager needs to scale up instances or scale down instances in your group. At the end of each aggregation window, the instance group manager adds the current utilization of each instance and divides it by this target utilization value to determine the membership count. | {: caption="Scaling policies selections" caption-side="bottom"} ## Setting up auto scale with the CLI {: #setting-up-autoscale-cli} {: cli} You can create an instance group in your IBM Cloud VPC to auto scale according to your requirements by using the IBM Cloud CLI. ### Before you begin {: #before-cli-tutorial-autoscale} Make sure that you set up your [IBM Cloud® CLI environment](https://cloud.ibm.com/docs/vpc?topic=vpc-set-up-environment&format=markdown#cli-prerequisites-setup) and your [IBM Cloud VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-creating-vpc-resources-with-cli-and-api&interface=cli&format=markdown). {: important} To create an auto scale instance group by using the CLI, you must complete the following tasks: 1. Make sure that you have the required IBM Cloud Identity and Access Management (IAM) permissions to create instance group resources. For more information, see * [Managing IAM access for VPC Infrastructure Services](https://cloud.ibm.com/docs/vpc?topic=vpc-iam-getting-started&interface=ui&format=markdown). 2. Create an instance template that is used to provision instances in your group. 3. Create an instance group in a single region that is made up of like virtual server instances. 4. Create an instance group manager so that you can apply your scaling policies. 5. Create scaling policies to dynamically add or remove instances from your group based on the target utilization metrics that you define. ### Creating an instance template {: #creating-instance-template-cli} All resources that are defined in an instance template must all be in the same resource group as the instance group. {: tip} #### Gathering information to create an instance template {: #cli-command-options-instance-template-create} Ready to create an instance template? Before you can run the `ibmcloud is instance-template-create` command, you need to know the details about your instance template and command options, such as what profile or image you want to use. Use the following steps to prepare for running the command. Verify that the profile that you want to use is available in the zone where you plan to create the instance. Gather the following required instance template details. | Instance template details | Listing command | | ----------------------------- | -------------------------------- | | VPC | `ibmcloud is vpcs` | | Zone | `ibmcloud is zones` | | Profile | `ibmcloud is instance-profiles` | | Subnet | `ibmcloud is subnets` | | Image | `ibmcloud is images` | {: caption="Required instance template details" caption-side="bottom"} Use the following commands to determine the required information to create an instance template. 1. List the regions that are associated with your account. ```sh ibmcloud is regions ``` {: pre} See the following example. ```sh $ ibmcloud is regions Listing regions under account Test Account as user test.user@ibm.com... Name Endpoint Status au-syd https://au-syd.iaas.cloud.ibm.com available br-sao https://br-sao.iaas.cloud.ibm.com available ca-tor https://ca-tor.iaas.cloud.ibm.com available eu-de https://eu-de.iaas.cloud.ibm.com available eu-es https://eu-es.iaas.cloud.ibm.com available eu-gb https://eu-gb.iaas.cloud.ibm.com available jp-osa https://jp-osa.iaas.cloud.ibm.com available jp-tok https://jp-tok.iaas.cloud.ibm.com available us-east https://us-east.iaas.cloud.ibm.com available us-south https://us-south.iaas.cloud.ibm.com available ``` {: screen} 1. Switch to your target region. ```sh ibmcloud target -r ``` {: pre} 1. List the zones that are associated with the target region. ```sh ibmcloud is zones ``` {: pre} In the following example, the command is run in the `us-south` region and the output shows the available zones that are in the region. ```sh $ ibmcloud is zones Listing zones in target region us-south under account Test Account as user test.user@ibm.com... Name Region Status us-south-1 us-south available us-south-2 us-south available us-south-3 us-south available ``` {: screen} 1. List the IBM Cloud VPCs that are associated with your account. ```sh ibmcloud is vpcs ``` {: pre} For this example, you see a response similar to the following output: ```sh ID Name Default Status Tags 0738-xxx1xx23-4xx5-6789-12x3-456xx7xx123x my-vpc yes available - 0738-xxxx1234-5678-9x12-x34x-567x8912x3xx my-other-vpc no available - ``` {: screen} If you don't have one available, you can create an IBM Cloud VPC by using the `ibmcloud is vpc-create` command. For more information about creating an IBM Cloud VPC, see [IBM Cloud VPC CLI reference](https://cloud.ibm.com/docs/vpc?topic=vpc-vpc-reference&format=markdown#vpc-create). 1. List the available profiles for creating your instance template. ```sh ibmcloud is instance-profiles ``` {: pre} For this example, you see a response similar to the following output: ```text Name Architecture Family vCPUs Memory(G) Network Performance (Gbps) GPUs bx2-2x8 amd64 balanced 2 8 4 - bx2-4x16 amd64 balanced 4 16 8 - bx2-8x32 amd64 balanced 8 32 16 - bx2-16x64 amd64 balanced 16 64 32 - bx2-32x128 amd64 balanced 32 128 64 - bx2-48x192 amd64 balanced 48 192 80 - cx2-2x4 amd64 compute 2 4 4 - cx2-4x8 amd64 compute 4 8 8 - cx2-8x16 amd64 compute 8 16 16 - cx2-16x32 amd64 compute 16 32 32 - cx2-32x64 amd64 compute 32 64 64 - mx2-2x16 amd64 memory 2 16 4 - mx2-4x32 amd64 memory 4 32 8 - mx2-8x64 amd64 memory 8 64 16 - ``` {: screen} 1. List the subnets that are associated with the IBM Cloud VPC. ```sh ibmcloud is subnets ``` {: pre} For this example, you see a response similar to the following output: ```text ID Name Status 0076-2249dabc-8c71-4a54-bxy7-953701ca3999 subnet1 available 0767-173bn4aa-060b-47e7-am45-b3395a593897 subnet2 available ``` {: screen} For the best performance of an auto scale instance group, make sure that you use a subnet size of 32 or greater. If you don't have one available, you can create a subnet by using the `ibmcloud is subnet-create` command. For more information about creating a subnet, see [IBM Cloud VPC CLI reference](https://cloud.ibm.com/docs/vpc?topic=vpc-vpc-reference&format=markdown#subnet-create). 1. List the available images for creating your instance template. You can create an instance by using a stock image, a custom image from your account, or an image that was shared with your account from a private catalog. Run one of the following commands based on the image that you plan to use. - Select a stock image or image from your account for your instance. To list all available images, run the following command: ```sh ibmcloud is images ``` {: pre} Deprecated images do not include the most current support. {: tip} Select the image `ibm-debian-11-11-minimal-amd64-4`. To get the image ID, run the following command: ```sh image=$(ibmcloud is images | grep -i "debian.*available.*amd64.*public" | cut -d" " -f1) ``` {: pre} Save the image ID as a variable, which is used later to provision an instance. - Select an image that is shared from a private catalog for the instance To list all available images, run the following command. ```sh ibmcloud is catalog-image-offerings ``` {: pre} This command returns both the `offering_crn` and the `offering_version_crn` for the available images. When you create an instance, you can either provision an instance from the private catalog image at the most recent version in a catalog product offering by using the `offering_crn` or from a specific version in the catalog product offering by using the `offering_version_crn`. Save the `offering_crn` and `offering_version_crn`in variables, which is used later to provision an instance. ```sh offering_crn="crn:v1:bluemix:public:globalcatalog-collection:global:a/a1234567:0b322820-dafd-4b5e-b694-6465da6f008a:offering:136559f6-4588-4af2-8585-f3c625eee09d" offering_version_crn="crn:v1:bluemix:public:globalcatalog-collection:global:a/a1234567:0b322820-dafd-4b5e-b694-6465da6f008a:version:136559f6-4588-4af2-8585-f3c625eee09d/8ae92879-e253-4a7c-b09f-8d30af12e518" ``` {: pre} After you know these values, use them to run the `instance-template-create` command. In addition to the information that you gathered, you must specify a name for the instance. The following example creates an instance template by using a stock image or a custom image from your account. ```sh ibmcloud is instance-template-create INSTANCE_TEMPLATE_NAME VPC ZONE_NAME PROFILE_NAME SUBNET --image-id IMAGE_ID ``` {: pre} For example, if you create an instance template that is called _my-instance-template_ in _us-south-1_, use the _bx2-2x8_ profile, with a custom image `_r008-54e9238a-feaa-4f90-9742-7424cb2b9ff1_` your `instance-template-create` command is similar to the following example. ```sh ibmcloud is instance-template-create my-instance-template r006-680c56cb-7fbb-41e6-833b-029beb7b6ba3 us-south-3 bx2-2x8 0076-2249dabc-8c71-4a54-bxy7-953701ca3999 --image-id r008-54e9238a-feaa-4f90-9742-7424cb2b9ff1 ``` {: pre} Where: - `INSTANCE_TEMPLATE_NAME` is _my-instance-template_ - `VPC` is _r006-680c56cb-7fbb-41e6-833b-029beb7b6ba3_ - `ZONE_NAME` is _us-south-3_ - `PROFILE_NAME` is _bx2-2x8_ - `SUBNET_ID` is _0076-2249dabc-8c71-4a54-bxy7-953701ca3999_ - `--image_ID` is _r008-54e9238a-feaa-4f90-9742-7424cb2b9ff1_ For this example, you see a response similar to the following output. Keep in mind that the following response varies depending on what values you use. ```text ID 0738-c3809e5b-8d48-4629-b258-33d5b14fa84f Name my-instance-template CRN crn:v1:bluemix:public:is:us-south-3:a/a1234567::instance-template:0738-c3809e5b-8d48-4629-b258-33d5b14fa84f Resource group Default VPC ID r006-680c56cb-7fbb-41e6-833b-029beb7b6ba3 Image ID r008-54e9238a-feaa-4f90-9742-7424cb2b9ff1 Profile bx2-2x8 Primary Network Interface ID Name Subnet ID Security Groups primary 0076-2249dabc-8c71-4a54-bxy7-953701ca3999 r006-9fd0b586-6876-4e8a-a0a1-586aeff5167c ``` {: screen} If you want to create an instance template from an image that is shared from a private catalog, replace `--image_ID` with either `--catalog-offering` or `catalog-offering_version`. {: note} For more examples of the `ibmcloud is instance-template-create` command, see the [VPC CLI reference](https://cloud.ibm.com/docs/vpc?topic=vpc-vpc-reference&format=markdown#instance-template-create). When you create an instance template, validation steps are performed that make sure that you can use your template to provision a virtual server instance. Need more help? You can run `ibmcloud is help instance-template-create` to display help for creating an instance template. {: tip} ### Creating an instance group {: #creating-instance-group-cli} After you have your instance template, you can create an instance group. Before you can run the `instance-group-create` command, you must specify a name for the instance group and determine values for the command options, such as what instance template you want to use. If you want to include a load balancer for your instance group to balance incoming requests across instances and configure specific health checks, you must create the load balancer before you create the instance group. For more information, see - [About application load balancers](https://cloud.ibm.com/docs/vpc?topic=vpc-load-balancers-about&format=markdown) and [Creating an IBM Cloud Application Load Balancer for VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-load-balancers&format=markdown). - [About network load balancers](https://cloud.ibm.com/docs/vpc?topic=vpc-network-load-balancers&format=markdown) and [Creating an IBM Cloud Network Load Balancer for VPC](https://cloud.ibm.com/docs/vpc?topic=vpc-nlb-ui-creating-network-load-balancer&format=markdown). For more information about health checks for load balancer pools, see the following topics. - [Working with health checks](https://cloud.ibm.com/docs/vpc?topic=vpc-alb-health-checks&format=markdown) - [Working with health checks](https://cloud.ibm.com/docs/vpc?topic=vpc-nlb-health-checks&format=markdown) {: important} Gather the following information. | Instance group details | Description | | -------------------------- | -------------------------------- | | Instance template | ID of the instance template that you created in the previous task | | Subnet IDs | Comma-separated IDs of subnets that you must select from the `ibmcloud is subnets` command in the previous task | | --membership-count | Number of members that are in the instance group | {: caption="Required instance group details" caption-side="bottom"} After you know these values, use them to run the `instance-group-create` command. In addition to the information that you gathered, you must specify a name for the instance group. ```sh ibmcloud is instance-group-create INSTANCE_GROUP_NAME --instance-template INSTANCE_TEMPLATE --subnet-ids IDS --membership-count MEMBERS ``` {: pre} For example, if you create an instance group that is called _my-instance-group_ with instance template ID _72251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ and _1_ member initially, your `instance-group-create` command would look similar to the following example. ```sh ibmcloud is instance-group-create my-instance-group --instance-template 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479 --subnet-ids 0076-2249dabc-8c71-4a54-bxy7-953701ca3999,0767-173bn4aa-060b-47e7-am45-b3395a593897 --membership-count 1 ``` {: pre} Where: - `INSTANCE_GROUP_NAME` is _my-instance-group_ - `--instance-template` is _72251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ - `--subnet IDs` are _0076-2249dabc-8c71-4a54-bxy7-953701ca3999_ and _0767-173bn4aa-060b-47e7-am45-b3395a593897_ - `--membership-count` is 1 initially For this example, you see a response that is similar to the following output: ```text ID r006-4f7d0010-33f5-40bf-9f21-ab5bee04fd71 Name my-instance-group Status healthy Instances 1 Instance Template 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479 Subnets Name Subnet ID subnet-1 0076-2249dabc-8c71-4a54-bxy7-953701ca3999 subnet-2 0767-173bn4aa-060b-47e7-am45-b3395a593897 Resource group ID Name 11caaa983d9c4beb82690daab08717e9 Default ``` {: screen} For more examples of the `ibmcloud is instance-group-create` command, see the [VPC CLI reference](https://cloud.ibm.com/docs/vpc?topic=vpc-vpc-reference&format=markdown#instance-group-create). Need more help? You can run `ibmcloud is instance-group-create --help` to display help for creating an instance group. {: tip} ### Creating an instance group manager {: #creating-instance-group-manager-cli} Now you can create an instance group manager so that you can apply your scaling policies in the next and final task. Before you can run the `ibmcloud is instance-group-manager-create` command, you need to determine values for the command options, such as what instance group you want to manage. Gather the following information. | Instance group manager option | Description | | --------------------------------- | -------------------------------- | | INSTANCE_GROUP | ID of the instance group you created in the previous task | | --max-members | The maximum number of members that are in a managed instance group; range 1 - 100 | {: caption="Required instance group manager details" caption-side="bottom"} After you know these values, use them to run the `instance-group-manager-create` command. ```sh ibmcloud is instance-group-manager-create INSTANCE_GROUP --max-members MAX_MEMBERS ``` {: pre} For example, if you create an instance group manager with instance group ID _72251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ and options --max-members = _20_, your `instance-group-manager-create` command is similar to the following example. ```sh ibmcloud is instance-group-manager-create 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479 --max-members 20 ``` {: pre} Where: - `INSTANCE_GROUP` is _72251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ - `--max-members` is _20_ For this example, you see a response that is similar to the following output: ```text ID r006-bcf54494-f63a-41a7-8368-9f7d002c9020 Status enabled Max Membership Count 20 ``` {: screen} For more examples of the `ibmcloud is instance-group-manager-create` command, see the [VPC CLI reference](https://cloud.ibm.com/docs/vpc?topic=vpc-vpc-reference&format=markdown#instance-group-manager-create). Need more help? You can run `ibmcloud is instance-group-manager-create --help` to display help for creating an instance group manager. {: tip} ### Creating scaling policies {: #creating-scaling-policies-cli} Now you're ready to take full advantage of autoscaling! For the dynamic scaling method, you define certain metrics like CPU utilization % and the target utilization that you want to achieve for that metric. Together, the metric and the average target utilization determine when your instance group needs to dynamically add or remove virtual server instances from your group. This target value defines when the auto scale manager needs to scale up instances or scale down instances in your group. At the end of each aggregation window, the auto scale manager adds the current utilization of each instance and divides it by the target utilization value that you specify to determine the membership count. Before you can run the `group-manager-policy-create` command, you need to specify an instance group and a group manager, then specify values for the metric type and the average target utilization. Gather the following information. | Instance group manager policy option | Description | | ---------------------------------------- | -------------------------------- | | INSTANCE_GROUP | ID of the instance group | | MANAGER | ID of the manager | | --metric-type | The type of metric to evaluate: cpu (utilization %), memory (utilization %), network_in (Mbps), network_out (Mbps) | | --metric-value | The metric target value to evaluate | {: caption="Required instance group manager policy details" caption-side="bottom"} Use the following commands to determine the required information that you need to create an instance template. 1. List the available instance groups to create your scaling policy. ```sh ibmcloud is instance-groups ``` {: pre} For this example, you see a response that is similar to the following output: ```text ID Name Status Instances 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479 my-instance-group healthy 1 72271a2e-d6c7-64b6-99c7-ac7426ew3495 my-other-instance-group healthy 1 ``` {: screen} 2. List the available instance groups managers to create your scaling policy. ```sh ibmcloud is instance-group-managers 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479 ``` {: pre} Where: - `INSTANCE_GROUP` is _2251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ For this example, you see a response that is similar to the following output: ```text ID Status Aggregation Window Cooldown Max Membership Count Min Membership Count 72b27b5c-f4b0-48bb-b954-5becc7c1dcb3 enabled 90 300 20 1 ``` {: screen} After you know these values, run the following command to create a scaling policy. ```sh ibmcloud is instance-group-manager-policy-create INSTANCE_GROUP MANAGER --metric-type METRIC_TYPE --metric-value METRIC_VALUE ``` {: pre} For example, if you create a scaling policy with instance group ID _72251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ and manager ID _72b27b5c-f4b0-48bb-b954-5becc7c1dcb3_ with options --metric-type _cpu_ and --metric-value = _50_, your `ibmcloud is instance-group-manager-policy-create` command is similar to the following example. ```sh ibmcloud is instance-group-manager-policy-create 2251a2e-d6c5-42b4-97b0-b5f8e8d1f479 72b27b5c-f4b0-48bb-b954-5becc7c1dcb3 --metric-type cpu --metric-value 50 ``` {: pre} Where: - `INSTANCE_GROUP` is _2251a2e-d6c5-42b4-97b0-b5f8e8d1f479_ - `MANAGER` is _72b27b5c-f4b0-48bb-b954-5becc7c1dcb3_ - `--metric-type` is _cpu_ - `--metric-value` is _50_ For this example, you see a response that is similar to the following output: ```text ID r006-5f5c1127-da5c-4c7a-a8ae-9a539b56fa56 Metric Type cpu Metric Value 50 Policy Type target ``` {: screen} The response indicates that the auto scale manager needs to scale up the number of instances in your group when the average CPU utilization reaches 50 %. Likewise, the auto scale manager also scales down the number of instances in your group when the average CPU utilization drops to less than 50 %. For more examples of the `ibmcloud is instance-group-manager-policy-create` command, see the [VPC CLI reference](https://cloud.ibm.com/docs/vpc?topic=vpc-vpc-reference&format=markdown#instance-group-manager-policy-create). You can define more than one target metric policy, but only one policy for each type of metric. Need more help? You can run `ibmcloud is instance-group-manager-policy-create --help` to display help for creating a scaling policy. {: tip} ## Next steps {: #next-steps-instance-groups} You can use [Activity tracking events](https://cloud.ibm.com/docs/vpc?topic=vpc-at_events&format=markdown) to find specific details that are related to instance group events. For more information, see [Instance group events](https://cloud.ibm.com/docs/vpc?topic=vpc-at_events&format=markdown#events-compute-instance-group).