Moving an instance group to a different availability zone

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Yandex Cloud

Updated at December 16, 2024

If your instance group is attached to a load balancer, follow these guides:

Moving an instance group with a network load balancer to a different availability zone
Moving an instance group with an L7 load balancer to a different availability zone

To move an instance group to a different availability zone:

Create a subnet in the availability zone you want to move your instance group to.
Add the group instances to the new availability zone:
Management console

CLI

Terraform

API
1. In the management console, open the folder containing the instance group you need.
2. Select Compute Cloud.
3. In the left-hand panel, select Instance groups.
4. Select the instance group to update.
5. In the top-right corner, click Edit.
6. Under Allocation, add the availability zone where you want to move the instance group.
7. If your instance group is a manually scaled one, under Scaling, specify a group size sufficient to place instances in all the selected availability zones.
  
  You will be able to reset the number of instances back to the initial one after all the instances in the group are moved to the new availability zone and deleted from the old one.
8. If your instance group is an autoscaled one and has the OPPORTUNISTIC shutdown strategy, change the strategy to PROACTIVE in the Stop VMs by strategy field.
  
  You will be able to reset the shutdown strategy back to OPPORTUNISTIC after all the instances in the group are moved to the new availability zone and deleted from the old one.
9. Click Save.
If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.
1. Open the instance group specification file and edit the VM template:
  - Under allocation_policy, add a new availability zone.
  - Under network_interface_specs, add the ID of the previously created subnet.
  - If your instance group is a manually scaled one, under scale_policy, specify a group size sufficient to place instances in all the selected availability zones.
    
    You will be able to reset the number of instances back to the initial one after all the instances in the group are moved to the new availability zone and deleted from the old one.
  - If your instance group is an autoscaled one and has the OPPORTUNISTIC shutdown strategy, change the strategy to PROACTIVE under deploy_policy.
    
    You will be able to reset the shutdown strategy back to OPPORTUNISTIC after all the instances in the group are moved to the new availability zone and deleted from the old one.
2. View a description of the CLI command to update an instance group:
  yc compute instance-group update --help
3. Get a list of all instance groups in the default folder:
  yc compute instance-group list
  Result:
  +----------------------+---------------------------------+--------+--------+ | ID | NAME | STATUS | SIZE | +----------------------+---------------------------------+--------+--------+ | cl15sjqilrei******** | first-fixed-group-with-balancer | ACTIVE | 3 | | cl19s7dmihgm******** | test-group | ACTIVE | 2 | +----------------------+---------------------------------+--------+--------+
4. Update the instance group:
  yc compute instance-group update \ --id <instance_group_ID> \ --file <VM_specification_file>
  Where:
  - --id: Instance group ID.
  - --file: Path to the instance group specification file.
  Result:
  id: cl15sjqilrei******** ... allocation_policy: zones: - zone_id: <old_availability_zone> - zone_id: <new_availability_zone> ...
If you do not have Terraform yet, install it and configure the Yandex Cloud provider.
1. Open the Terraform configuration file for the instance group. Under allocation_policy, specify the new availability zone; under network_interface, specify the ID of the previously created subnet.
  ... network_interface { subnet_ids = [ "<subnet_ID_in_old_availability_zone>", "<subnet_ID_in_new_availability_zone>" ] } ... allocation_policy { zones = [ "<old_availability_zone>", "<new_availability_zone>" ] } ...
  Where:
  - zones: Availability zones the instance group will reside in (new and old).
  - subnet_ids: IDs of subnets in the availability zones the instance group will reside in.
  If your instance group is a manually scaled one, under scale_policy, specify a group size sufficient to place instances in all the selected availability zones.
  ... scale_policy { fixed_scale { size = <number_of_VMs_in_group> } } ...
  You will be able to reset the number of instances back to the initial one after all the instances in the group are moved to the new availability zone and deleted from the old one.
  
  If your instance group is an autoscaled one and has the OPPORTUNISTIC shutdown strategy, change the strategy to PROACTIVE:
  ... deploy_policy { strategy = "proactive" } ...
  You will be able to reset the shutdown strategy back to OPPORTUNISTIC after all the instances in the group are moved to the new availability zone and deleted from the old one.
  
  For more information about resource parameters in Terraform, see the provider documentation.
2. Apply the changes:
  1. In the terminal, change to the folder where you edited the configuration file.
  2. Make sure the configuration file is correct using the command:
    
    terraform validate
    
    If the configuration is correct, the following message is returned:
    
    Success! The configuration is valid.
  3. Run the command:
    
    terraform plan
    
    The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.
  4. Apply the configuration changes:
    
    terraform apply
  5. Confirm the changes: type yes in the terminal and press Enter.
  This will add a new availability zone for an instance group. You can check the update using the management console or this CLI command:
  yc compute instance-group get <VM_group_name>
Use the update REST API method for the InstanceGroup resource or the InstanceGroupService/Update gRPC API call.

If your instance group is a manually scaled one, specify a group size sufficient to place instances in all the selected availability zones. You will be able to reset the number of instances back to the initial one after all the instances in the group are moved to the new availability zone and deleted from the old one.

If your instance group is an autoscaling one and has the OPPORTUNISTIC shutdown strategy, change the strategy to PROACTIVE. You will be able to reset the shutdown strategy back to OPPORTUNISTIC after all the instances in the group are moved to the new availability zone and deleted from the old one.
Wait until the instances appear in the new availability zone and switch to the Running Actual status.
Delete the group instances from the previous availability zone:
Management console

CLI

Terraform

API
1. In the management console, open the folder containing the instance group you need.
2. Select Compute Cloud.
3. In the left-hand panel, select Instance groups.
4. Select the instance group to update.
5. In the top-right corner, click Edit.
6. Under Allocation, disable the old availability zone.
7. Click Save.
1. Open the instance group specification file and edit the VM template:
  - Delete the old availability zone in the allocation_policy section.
  - Remove the subnet ID in the old availability zone from the network_interface_specs section.
2. Update the instance group:
```
yc compute instance-group update \
  --id <instance_group_ID> \
  --file <VM_specification_file>
```
Where:
- --id: Instance group ID.
- --file: Path to the instance group specification file.
Result:
```
id: cl15sjqilrei********
...
allocation_policy:
zones:
- zone_id: <new_availability_zone>
...
```
1. Open the Terraform configuration file for the instance group. Delete the old availability zone from the allocation_policy section, and the subnet ID in the old availability zone from the network_interface section.
  ... network_interface { subnet_ids = ["<subnet_ID_in_new_availability_zone>"] } ... allocation_policy { zones = ["<new_availability_zone>"] } ...
  Where:
  - zones: Availability zone to move the instance group to. You can specify multiple availability zones.
  - subnet_ids: ID of the subnet in the availability zone you want to move your instance group to.
  For more information about resource parameters in Terraform, see the provider documentation.
2. Apply the changes:
  1. In the terminal, change to the folder where you edited the configuration file.
  2. Make sure the configuration file is correct using the command:
    
    terraform validate
    
    If the configuration is correct, the following message is returned:
    
    Success! The configuration is valid.
  3. Run the command:
    
    terraform plan
    
    The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.
  4. Apply the configuration changes:
    
    terraform apply
  5. Confirm the changes: type yes in the terminal and press Enter.
  The group instances will be deleted from the old availability zone. You can check the update using the management console or this CLI command:
  yc compute instance-group get <VM_group_name>
Use the update REST API method for the InstanceGroup resource or the InstanceGroupService/Update gRPC API call.

Moving an instance group to a different availability zone

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