How to use placement groups

Placement groups allow you specify that you want certain Instances to either run on different physical hypervisors for maximum availability, or else as physically close together as possible for minimum latency.

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. To find the tab you may need to click More at the top right of the dashboard first.

   

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 means that, if the group cannot be applied, only Instances on hypervisors matching the group settings will boot
     • Optional ensures that the settings of the Placemet Group are applied wherever possible, but lets Instances boot on hypervisors that don’t match the group policy.
   • Add Instances to the placement group.
   Important:

   Instances must be powered off to be available to be added 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, where your new placement group now displays.

How to add Instances to a placement group

1. Navigate to the Placement Groups tab (via the Instances page accessible from the Compute section of the side menu). A list of your placement groups displays.
2. Click the placement group you wish 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. Navigate to the Placement Groups tab (via the Instances page accessible from 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 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. A list of your Instances displays.

2. Click the name of the Instance in question. The Instance Overview tab displays.

3. Scroll down to Placement Groups

   

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

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

   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 slider at the top right of the page.

How to modify a placement group’s type

1. Navigate to the Placement Groups tab (via the Instances page accessible from 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’s 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. Navigate to the Placement Groups tab (via the Instances page accessible from 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’s 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 that are attached to it. They will continue to run on their current hypervisors until you reboot them.

1. Navigate to the Placement Groups tab (via the Instances page accessible from 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 just deleted no longer displays.