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+.. This work is licensed under a Creative Commons Attribution 4.0 International License.
+.. http://creativecommons.org/licenses/by/4.0
+
+=========================================
+OpenStack NOVA API for marking host down.
+=========================================
+
+Related Blueprints:
+===================
+
+ https://blueprints.launchpad.net/nova/+spec/mark-host-down
+ https://blueprints.launchpad.net/python-novaclient/+spec/support-force-down-service
+
+What the API is for
+===================
+
+ This API will give external fault monitoring system a possibility of telling
+ OpenStack Nova fast that compute host is down. This will immediately enable
+ calling of evacuation of any VM on host and further enabling faster HA
+ actions.
+
+What this API does
+==================
+
+ In OpenStack the nova-compute service state can represent the compute host
+ state and this new API is used to force this service down. It is assumed
+ that the one calling this API has made sure the host is also fenced or
+ powered down. This is important, so there is no chance same VM instance will
+ appear twice in case evacuated to new compute host. When host is recovered
+ by any means, the external system is responsible of calling the API again to
+ disable forced_down flag and let the host nova-compute service report again
+ host being up. If network fenced host come up again it should not boot VMs
+ it had if figuring out they are evacuated to other compute host. The
+ decision of deleting or booting VMs there used to be on host should be
+ enhanced later to be more reliable by Nova blueprint:
+ https://blueprints.launchpad.net/nova/+spec/robustify-evacuate
+
+REST API for forcing down:
+==========================
+
+ Parameter explanations:
+ tenant_id: Identifier of the tenant.
+ binary: Compute service binary name.
+ host: Compute host name.
+ forced_down: Compute service forced down flag.
+ token: Token received after successful authentication.
+ service_host_ip: Serving controller node ip.
+
+ request:
+ PUT /v2.1/{tenant_id}/os-services/force-down
+ {
+ "binary": "nova-compute",
+ "host": "compute1",
+ "forced_down": true
+ }
+
+ response:
+ 200 OK
+ {
+ "service": {
+ "host": "compute1",
+ "binary": "nova-compute",
+ "forced_down": true
+ }
+ }
+
+ Example:
+ curl -g -i -X PUT http://{service_host_ip}:8774/v2.1/{tenant_id}/os-services
+ /force-down -H "Content-Type: application/json" -H "Accept: application/json
+ " -H "X-OpenStack-Nova-API-Version: 2.11" -H "X-Auth-Token: {token}" -d '{"b
+ inary": "nova-compute", "host": "compute1", "forced_down": true}'
+
+CLI for forcing down:
+=====================
+
+ nova service-force-down <hostname> nova-compute
+
+ Example:
+ nova service-force-down compute1 nova-compute
+
+REST API for disabling forced down:
+===================================
+
+ Parameter explanations:
+ tenant_id: Identifier of the tenant.
+ binary: Compute service binary name.
+ host: Compute host name.
+ forced_down: Compute service forced down flag.
+ token: Token received after successful authentication.
+ service_host_ip: Serving controller node ip.
+
+ request:
+ PUT /v2.1/{tenant_id}/os-services/force-down
+ {
+ "binary": "nova-compute",
+ "host": "compute1",
+ "forced_down": false
+ }
+
+ response:
+ 200 OK
+ {
+ "service": {
+ "host": "compute1",
+ "binary": "nova-compute",
+ "forced_down": false
+ }
+ }
+
+ Example:
+ curl -g -i -X PUT http://{service_host_ip}:8774/v2.1/{tenant_id}/os-services
+ /force-down -H "Content-Type: application/json" -H "Accept: application/json
+ " -H "X-OpenStack-Nova-API-Version: 2.11" -H "X-Auth-Token: {token}" -d '{"b
+ inary": "nova-compute", "host": "compute1", "forced_down": false}'
+
+CLI for disabling forced down:
+==============================
+
+ nova service-force-down --unset <hostname> nova-compute
+
+ Example:
+ nova service-force-down --unset compute1 nova-compute