Offering High Availability to Users

Overview#

No additional subscription is required for administrators to use High Availability (HA) directly. You can also include HA in plans offered to end users, either for free or as a paid add-on.

An HA-capable plan makes HA available, but does not enable it automatically. You enable HA per virtual server, and you can turn it on or off at any time in the server’s settings.

How you set HA at creation depends on how you create the virtual server:

• In the SolusVM interface: select the Include in failover domain option when you create the virtual server. If you do not select it, the virtual server starts without HA protection, and you can enable it later.
• In WHMCS: configure HA in the product settings. For more information, see the Enable High Availability documentation.

HA does not evacuate virtual servers that do not have HA enabled. Those virtual servers remain on the offline compute resource until an administrator intervenes manually.

Add High Availability to a Plan#

To include the High Availability feature in a plan:

1. Go to Compute Resources > Plans.
2. Click Add Plan to create a new plan, or click the corresponding button to edit an existing plan.
3. Under Additional Offers, select the Offer high availability per CR checkbox.
4. (Optional) To make High Availability a paid feature, enter a value in the High availability price in % field. This is the percentage of the virtual server price that customers pay additionally for enabling High Availability per compute resource. By default, the value is zero.
5. Click Save.

Enable High Availability for a Virtual Server#

Before you can enable HA for a virtual server, make sure you meet the following conditions:

• The virtual server’s plan offers HA.
• The virtual server’s compute resource belongs to a failover domain.
• That failover domain is active.
• The virtual server uses the same storage as the failover domain.
• The virtual server does not use a primary disk offer, and any additional disk offer it uses does not have a storage tag.

To enable or disable HA protection for an individual virtual server, perform the following steps:

1. Go to Virtual Servers and select the virtual server. The Settings tab opens.
2. In the High availability card, set the toggle to on or off.
3. Confirm the action in the interface that appears.

You can also change the setting from the Virtual Servers list. Open the Actions menu for the virtual server, click Edit Server, and then set the Enable HA toggle.

The Virtual Servers interface displays the HA status of each virtual server with an icon:

• Virtual servers with active HA protection display the icon.
• Virtual servers eligible for HA that do not yet have protection enabled display the icon.
• Virtual servers not eligible for HA protection display the icon.
• Virtual servers that lack sufficient resources to guarantee successful evacuation display the icon.
• Virtual servers with HA protection that an administrator has disabled display the icon.
• Virtual servers that SolusVM cannot currently reach display the icon.

High Availability Priority#

Within a single evacuation event, SolusVM recovers virtual servers in descending order of their High Availability priority. The system recovers servers with a higher priority first, and recovers servers with equal priority in order of their ID.

You set the priority with the ha_priority parameter, which accepts a value from 0 to 65535. To set it, send a PATCH request to /servers/{id}. You can set the priority only for virtual servers whose plan offers High Availability. For more information, see the RESTful API documentation.