Creating an instance group for auto scaling

Creating an 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.

To create an instance template, complete the following steps.

1. In the IBM Cloud console, go to Navigation Menu icon > Infrastructure > Compute > Instance templates.
2. Click New instance template and enter the information that is in Table 1.
3. Click Create instance template when the information is complete.

Instance template selections

Field	Value
Location	Locations are composed of regions (specific geographic areas) and zones (fault tolerant data centers within a region). Select the geography, region, and zone where you want your virtual server instance to be created.
Name	A name is required for your virtual server instance.
Resource group	Select a resource group for the instance.
Image	Click Change image to select an image. On the Select an image page, you can select a stock image, custom image, catalog image, snapshot, or an existing volume. If the geographic location where you are provisioning an instance supports it, you can select an x86 or s390x architecture. After you select your image, click Save. Stock images: You can select from available stock images. For more information, see x86 virtual server images and s390x virtual server images. Custom images: A custom image can be an image that you customize and upload to IBM Cloud Object Storage, which you can then import into IBM Cloud VPC. You can also use a custom image that was created from a boot volume. For more information about custom images, see Getting started with custom images. Catalog images: A catalog image is a custom image that is imported into a private catalog. For more information about catalog images, see VPC considerations when using custom images in a private catalog. Snapshot: You can select from available snapshots. For more information, see About Block Storage Snapshots for VPC. Existing volume: You can select from existing volumes. The specified volume must be unattached, and must have an operating system with the same architecture as the instance profile.
Profile	Click Change profile to select from all available vCPU and RAM combinations. The profile families are Balanced, Compute, Memory, and GPU. For more information, see Profiles.
SSH Key	You must select an existing public SSH key or click Create an SSH key to create a new one. You can create only RSA SSH keys. For ED25519 SSH keys, you must upload the key information. For more information about creating an SSH key, see Creating your SSH key by using the UI. SSH keys are used to securely connect to the instance after it's running. Note:** Alpha-numeric combinations are limited to 100 characters. SSH keys can be either RSA or ED25519. ED25519 can be used only if the operating system supports this key type. ED25519 can't be used with Windows or VMware images. For more information, see Getting started with SSH keys.
Boot volume	The default boot volume size for all profiles is 100 GB. You can specify a larger boot volume capacity, up to 250 GB, depending on what the image allows. You can also specify user tags.
Data volumes	You can add one or more secondary data volumes to be included when you provision the instance. To add volumes, click Create. You can specify customer-managed encryption and user tags for the volume.
Virtual private cloud	Specify the IBM Cloud VPC where you want to create your instance. You can use an existing VPC or you can create a new VPC. To create a new VPC, click New VPC.
Network interfaces	Defines the networking connection into the IBM Cloud VPC. By default, the new option Network attachment with a virtual network interface is selected for your instance template. Alternatively, you can select the legacy option Instance network interface. Whichever type of network interface option that you select when you provision the virtual server persists through the lifecycle of the virtual server. After you selected your network interface type, you can click the Edit icon to update the details of the network interface, for example, the subnet or the associated security group.
User data	You can add user data that automatically performs common configuration tasks or runs scripts. For more information, see User data.
Metadata	Disabled by default, lets the instance that is created from this template gather metadata about itself. Click the toggle to turn on the metadata service. For more information, see About Instance Metadata for VPC.
Add to dedicated host	You can add the virtual server instance to a dedicated host, creating the instance in a single-tenant space. To provision a dedicated instance, you must have a dedicated host available or create one.
Add to placement group	You can select a placement group for the instance. To enable placement groups, click the toggle. Then, select or create a placement group for the instance. If you add a placement group, the instance is placed according to the placement group strategy. For more information, see About placement groups.
Host failure auto restart	This setting is enabled by default. To disable host failure auto restart, click the toggle. For more information, see Host failure recovery policies.

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

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 and Creating an IBM Cloud Application Load Balancer for VPC
• About network load balancers, Creating an IBM Cloud Network Load Balancer for VPC, and Creating an IBM Cloud Private Network Load Balancer with routing mode for VPC

For more information about health checks for load balancer pools, see the following topics:

• Working with health checks (ALB)
• Working with health checks (NLB)

Not all network load balancer offerings support integration with instance groups. Before attaching an instange group to a network load balancer pool, ensure that the instance_groups_supported property of the load balancer detail is true.

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.
2. In the IBM Cloud console, go to Navigation Menu icon > Infrastructure > 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. You can also add policies later after you create your instance group.
5. Click Create instance group when the information is complete.

Creating scaling policies

For the dynamic scaling method, you define certain metrics (like CPU utilization percent) 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.

Before you begin

Make sure that you set up your IBM Cloud® CLI environment and your IBM Cloud VPC.

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.
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

All resources that are defined in an instance template must all be in the same resource group as the instance group.

ibmcloud is instance-template-create INSTANCE_TEMPLATE_NAME VPC ZONE_NAME PROFILE_NAME SUBNET --image-id IMAGE_ID

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

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

Creating an instance group

After you have your instance template in hand, your next step is to 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 and Creating an IBM Cloud Application Load Balancer for VPC.
• About network load balancers and Creating an IBM Cloud Network Load Balancer for VPC.

For more information about health checks for load balancer pools, see

• Working with health checks.
• Working with health checks.

Gather the following information.

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.

ibmcloud is instance-group-create INSTANCE_GROUP_NAME --instance-template INSTANCE_TEMPLATE --subnet-ids IDS --membership-count MEMBERS

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 sample.

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

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 similar to the following output:

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

For more examples of the ibmcloud is instance-group-create command, see the VPC CLI reference.

Need more help? You can always run ibmcloud is instance-group-create --help to display help for creating an instance group.

Creating an instance group manager

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.

After you know these values, use them to run the instance-group-manager-create command.

ibmcloud is instance-group-manager-create INSTANCE_GROUP --max-members MAX_MEMBERS

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 would look similar to the following sample.

ibmcloud is instance-group-manager-create 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479 --max-members 20

Where:

• INSTANCE_GROUP is 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479
• --max-members is 20

For this example, you see a response similar to the following output:

ID                     r006-bcf54494-f63a-41a7-8368-9f7d002c9020
Status                 enabled
Max Membership Count   20

For more examples of the ibmcloud is instance-group-manager-create command, see the VPC CLI reference.

Need more help? You can always run ibmcloud is instance-group-manager-create --help to display help for creating an instance group manager.

Creating scaling policies

Now you're ready to take full advantage of autoscaling! For the dynamic scaling method, you define certain metrics like CPU utilization percent 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.

Use the following commands to determine the required information for creating a new instance template.

1. List the available instance groups for creating your scaling policy.

   ibmcloud is instance-groups
   

   For this example, you see a response similar to the following output:

   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
   
   

2. List the available instance groups managers for creating your scaling policy.

   ibmcloud is instance-group-managers 72251a2e-d6c5-42b4-97b0-b5f8e8d1f479
   

   Where:

   • INSTANCE_GROUP is 2251a2e-d6c5-42b4-97b0-b5f8e8d1f479

   For this example, you see a response similar to the following output:

   ID                                          Status    Aggregation Window   Cooldown   Max Membership Count   Min Membership Count
   72b27b5c-f4b0-48bb-b954-5becc7c1dcb3        enabled   90                   300        20                     1
   
   

After you know these values, run the following command to create a scaling policy.

ibmcloud is instance-group-manager-policy-create INSTANCE_GROUP MANAGER --metric-type METRIC_TYPE --metric-value METRIC_VALUE

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 would look similar to the following sample.

ibmcloud is instance-group-manager-policy-create 2251a2e-d6c5-42b4-97b0-b5f8e8d1f479 72b27b5c-f4b0-48bb-b954-5becc7c1dcb3 --metric-type cpu --metric-value 50

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 similar to the following output:

ID             r006-5f5c1127-da5c-4c7a-a8ae-9a539b56fa56
Metric Type    cpu
Metric Value   50
Policy Type    target

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 percent. 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 percent.

For more examples of the ibmcloud is instance-group-manager-policy-create command, see the VPC CLI reference.

You can define more than one target metric policy, but only one policy for each type of metric. Need more help? You can always run ibmcloud is instance-group-manager-policy-create --help to display help for creating a scaling policy.