How to use placement groups

Placement groups allow you to define if you want certain Instances to run on different physical hypervisors for maximum availability or as physically close together as possible for minimum latency.

Before you start

To complete the actions presented below, you must have:

• A Scaleway account logged into the console
• Owner status or IAM permissions allowing you to perform actions in the intended Organization
• An Instance

How to create a placement group

1. Click Instances in the Compute section of the side menu. The Instances page displays.

2. Click the Placement groups tab.

3. Click Create placement group. The creation wizard displays.

4. Complete the following steps in the wizard:

   • Enter a name for your placement group, or leave the randomly-generated name in place.
   • Choose an Availability Zone, which is the geographical region where your placement group will be created. You can only add Instances from this same Availability Zone to the placement group.
   • Choose the type of placement group:
     • Low Latency groups ensure that Instances are located as close as possible to each other
     • Maximum Availability groups ensure that Instances do not run on the same physical hypervisor
   • Choose the policy for your placement group:
     • Enforced: if the group cannot be applied, only Instances on hypervisors matching the group settings will boot.
     • Optional: ensures the application of the placement group’s settings wherever possible, but lets Instances boot on hypervisors that do not match the group policy.
   • Add Instances to the placement group.
   Important

   You can only add powered off Instances to a placement group.

5. Click Create placement group to finish. Your placement group is created, and you are returned to the list of your placement groups.

How to add Instances to a placement group

1. Go to the Placement groups tab, accessible from the Instances page under the Compute section of the side menu. A list of your placement groups displays.
2. Click the placement group you want to add Instances to. You are taken to the Overview for that placement group.
3. Click the Instances tab.
4. Use the drop-down menu to select the Instance you want to add, then click Add Instance
   Note

   You can add up to 20 Instances to each of your placement groups.

You are returned to the list of Instances attached to your placement group, where the Instance you added now displays. If you wish to power the Instance you added back on, you can do so by clicking «See more Icon», and selecting Power on from the drop-down menu.

How to remove Instances from a placement group

1. Go to the Placement groups tab, accessible from the Instances page under the Compute section of the side menu. A list of your placement groups displays.

2. Click the placement group you wish to remove Instances from. You are taken to the Overview for that placement group.

3. Click the Instances tab.

4. Click «See more Icon» next to the Instance you want to remove, then click Remove. A pop-up displays.

5. Confirm that you want to remove the Instance by clicking the Remove from placement group button.

   You are returned to the list of Instances attached to your placement group, where the Instance you removed no longer displays.

How to change an Instance’s placement group

1. Click Instances in the Compute section of the side menu. The Instances page displays.

2. Click the name of the Instance you want to edit. The Instance Overview tab displays.

3. Scroll down to Placement groups.

4. Click «See more Icon» next to the placement group name, and select Switch from the drop-down menu. A pop-up displays.

5. Select another placement group from the drop-down list, then click Save settings.

   Your Instance’s placement group is changed, and you are returned to the Instance Overview page. If you wish to power the Instance back on, you can do so using the «Toogle Icon» button at the top right of the page.

How to modify a placement group’s type

1. Go to the Placement groups tab, accessible from the Instances page under the Compute section of the side menu. A list of your placement groups displays.
2. Click the placement group in question. You are taken to the placement group’s Overview tab.
3. Scroll down to the Placement group type section, and choose the required type for your group.

The new group type will be applied immediately, and Instances of the group will boot according to the new settings once they are powered back on.

How to modify a placement group’s policy

1. Go to the Placement groups tab, accessible from the Instances page under the Compute section of the side menu. A list of your placement groups displays.
2. Click the placement group in question. You are taken to the placement group’s Overview tab.
3. Scroll down to the Placement group policy section, and choose the required policy for your group.

The new group policy will be applied immediately, and Instances of the group will boot according to the new settings once they are powered back on.

How to delete a placement group

Deleting a placement group will have no direct impact on the Instances attached to it. They will continue to run on their current hypervisors until you reboot them.

1. Go to the Placement groups tab, accessible from the Instances page under the Compute section of the side menu. A list of your placement groups displays.

2. Click «See more Icon» next to the placement group you want to delete, and select Delete from the drop-down menu that displays.

   A pop-up appears asking you to confirm this action.

3. Click Delete placement group.

   You are returned to the list of your placement groups, where the group you deleted no longer displays.