# Masakari service overview

Masakari provides Virtual Machines High Availability(VMHA), and rescues KVM-based Virtual Machines(VM) from a failure events described below:

- `VM process down` - restart vm (use nova stop API, and nova start API). Libvirt events will be also emitted by other failures.

- `Provisioning process down` - restarts process, changes nova-compute service status to maintenance mode (use nova service-disable).

- `nova-compute host failure` - evacuate all the VMs from failure host according to the following recovery methods (use nova evacuate API).

  - `auto` - evacuate all the VMs with no destination node for nova scheduler.

  - `reserved_host` - evacuate all the VMs with reserved hosts as the destination nodes for nova scheduler.

  - `auto_priority` - evacuate all the VMs by using `auto` recovery method firstly. If failed, then using `reserved_host` recovery method.

  - `rh_priority` - evacuate all the VMs by using `reserved_host` recovery method firstly. If failed, then using `auto` recovery method.

The below services enables deplores to integrate with the Masakari directly or through custom plug-ins.

The Masakari service consists of the following components:

`masakari-api`

  An OpenStack-native REST API that processes API requests by sending them to the `masakari-engine` over Remote Procedure Call (RPC).

`masakari-engine`

  Processes the notifications received from `masakari-api` by executing the recovery workflow in asynchronous way.

this page last updated: 2026-04-01 20:28:51

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