Voir la source de Blazar

Let's experiment [https://docs.openstack.org/blazar/latest/ Blazar], Openstack dedicated service for resource reservation.

== Concept ==

Imagine this situation : you provides two services, one with high priority, the other one with low priority. During the week, each service runs VMs on multiple node with auto-scaling capability (i.e. another VMs are automatically provisionned if the workload increases). You know that during the week-end, your higher priority service will have more demand and you don't want your lower priority service starving it from resources.<br>
Blazar brings the possibility to reserve dedicated compute nodes for your high prority service for a time period, say, the week-end.<br>
Best of all, unreserved compute nodes managed by Blazar can run preemptible VMs, avoiding unused computing power.

== Installation / Configuration ==

[https://docs.openstack.org/kolla-ansible/latest/ Kolla-ansible] is used to deploy our private cloud.

=== Enable ''Blazar'' in ''globals.yml'' ===

<syntaxhighlight lang="yaml">
enable_blazar: "yes"
kolla_enable_tls_internal: "no"
kolla_enable_tls_backend: "no"
</syntaxhighlight>

Note that TLS should be disabled (especially for internal traffic). This is a [https://bugs.launchpad.net/blazar/+bug/2045281 current limitation identified].

=== Activate ''preemptible instances'' in ''nova-scheduler'' ===

On the Ansible deploy host, the file should be ''config/nova/nova-scheduler.conf''

<syntaxhighlight lang="yaml">
[blazar:physical:host]
allow_preemptibles = true
</syntaxhighlight>

=== Create a dedicated flavor for preemptible instances ===

For the sake of simplicity, only two flavors are going to be used :
* a "normal" (no preemption)
* a preemptible

<syntaxhighlight lang="bash">
# normal flavor
openstack flavor create --id 1 --ram 512 --disk 1 --vcpus 1 g1
# preemptible flavor
openstack flavor create --id 2 --ram 512 --disk 1 --vcpus 1 --property blazar:preemptible=true g1.preempt
</syntaxhighlight>

== Action ==

=== Book hosts for blazar ===

The hosts you want to reserve for blazar must not belong to aggregates.

<syntaxhighlight lang="bash">
openstack reservation host create compute1.cloud.ld
openstack reservation host create compute4.cloud.ld
openstack reservation host list
+----+---------------------+-------+-----------+----------+
| id | hypervisor_hostname | vcpus | memory_mb | local_gb |
+----+---------------------+-------+-----------+----------+
| 8  | compute1.cloud.ld   |     2 |      9664 |       52 |
| 4  | compute4.cloud.ld   |     2 |      5632 |       22 |
+----+---------------------+-------+-----------+----------+
</syntaxhighlight>

[[Fichier:blazar1.png|800px|thumb|center|visualization of compute resources in Horizon]]

=== Create some instances ===

Creation of 8 instances : one "normal" and seven "preemptible"

<syntaxhighlight lang="bash">
openstack server create --image cirros --flavor g1 --network Ext-Net vm1
for i in $(seq 2 8); do
  openstack server create --image cirros --flavor g1.preempt --network Ext-Net vm${i}
done
</syntaxhighlight>

[[Fichier:blazar2.png|800px|thumb|center|visualization of instances in Horizon]]

Notes :
* Preemptible instances are distributed across ''compute1'' and ''compute4''
* The normal instance is hosted by a compute node not managed by Blazar

=== Make a reservation ===

Reservation of one compute node for 20 minutes in 5 minutes from now. The compute node should have at leat 2 CPUs. The reservation is called ''lease-1'' :
<syntaxhighlight lang="bash">
openstack reservation lease create \
--reservation resource_type=physical:host,min=1,max=1,hypervisor_properties='[">=", "$vcpus", "2"]' \
--start-date "$(date --date '+5 min' +"%Y-%m-%d %H:%M")" \
--end-date "$(date --date '+20 min' +"%Y-%m-%d %H:%M")" lease-1
+--------------+-------------------------------------------------------------+
| Field        | Value                                                       |
+--------------+-------------------------------------------------------------+
| created_at   | 2024-01-21 22:00:57                                         |
| degraded     | False                                                       |
| end_date     | 2024-01-21T22:20:00.000000                                  |
| events       | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": null,                                     |
|              |     "id": "1b4700d4-960d-46c0-8022-af743bd778ce",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "end_lease",                              |
|              |     "time": "2024-01-21T22:20:00.000000",                   |
|              |     "status": "UNDONE"                                      |
|              | }                                                           |
|              | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": null,                                     |
|              |     "id": "3f8a4928-a360-495d-826d-4b92a5b7a003",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "start_lease",                            |
|              |     "time": "2024-01-21T22:05:00.000000",                   |
|              |     "status": "UNDONE"                                      |
|              | }                                                           |
|              | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": null,                                     |
|              |     "id": "564bd93c-e157-4dcb-825a-2258d882a4d2",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "before_end_lease",                       |
|              |     "time": "2024-01-21T22:05:00.000000",                   |
|              |     "status": "UNDONE"                                      |
|              | }                                                           |
| id           | 7180e34e-2718-47c9-8616-590e6a3585b2                        |
| name         | lease-1                                                     |
| project_id   | e1bbe999a4a84d91bbf79eaf54adc60d                            |
| reservations | {                                                           |
|              |     "created_at": "2024-01-21 22:00:57",                    |
|              |     "updated_at": "2024-01-21 22:00:58",                    |
|              |     "id": "e379e7c5-b708-4822-80a3-d9e9a0c573a7",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "resource_id": "80c24e3a-beb5-4f72-a566-31a1be252ba5",  |
|              |     "resource_type": "physical:host",                       |
|              |     "status": "pending",                                    |
|              |     "missing_resources": false,                             |
|              |     "resources_changed": false,                             |
|              |     "hypervisor_properties": "[\">=\", \"$vcpus\", \"2\"]", |
|              |     "resource_properties": "",                              |
|              |     "before_end": "default",                                |
|              |     "min": 1,                                               |
|              |     "max": 1                                                |
|              | }                                                           |
| start_date   | 2024-01-21T22:05:00.000000                                  |
| status       | PENDING                                                     |
| trust_id     | 9e5864d9805b4ff1bb452730fef859ab                            |
| updated_at   | 2024-01-21 22:00:58                                         |
| user_id      | e2cde8831daf4285b148499159c4c14e                            |
+--------------+-------------------------------------------------------------+
</syntaxhighlight>

Note the ''reservation id'' for future use : e379e7c5-b708-4822-80a3-d9e9a0c573a7
<br>
The reservation is ''PENDING'', i.e. not ''ACTIVE'' yet.
<br>
After a few minutes, the reservation becomes ''ACTIVE'' :
<syntaxhighlight lang="bash">
openstack reservation lease show lease-1
+--------------+-------------------------------------------------------------+
| Field        | Value                                                       |
+--------------+-------------------------------------------------------------+
| created_at   | 2024-01-21 22:00:57                                         |
| degraded     | False                                                       |
| end_date     | 2024-01-21T22:20:00.000000                                  |
| events       | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": null,                                     |
|              |     "id": "1b4700d4-960d-46c0-8022-af743bd778ce",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "end_lease",                              |
|              |     "time": "2024-01-21T22:20:00.000000",                   |
|              |     "status": "UNDONE"                                      |
|              | }                                                           |
|              | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": "2024-01-21 22:05:11",                    |
|              |     "id": "3f8a4928-a360-495d-826d-4b92a5b7a003",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "start_lease",                            |
|              |     "time": "2024-01-21T22:05:00.000000",                   |
|              |     "status": "DONE"                                        |
|              | }                                                           |
|              | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": "2024-01-21 22:05:12",                    |
|              |     "id": "564bd93c-e157-4dcb-825a-2258d882a4d2",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "before_end_lease",                       |
|              |     "time": "2024-01-21T22:05:00.000000",                   |
|              |     "status": "DONE"                                        |
|              | }                                                           |
| id           | 7180e34e-2718-47c9-8616-590e6a3585b2                        |
| name         | lease-1                                                     |
| project_id   | e1bbe999a4a84d91bbf79eaf54adc60d                            |
| reservations | {                                                           |
|              |     "created_at": "2024-01-21 22:00:57",                    |
|              |     "updated_at": "2024-01-21 22:05:11",                    |
|              |     "id": "e379e7c5-b708-4822-80a3-d9e9a0c573a7",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "resource_id": "80c24e3a-beb5-4f72-a566-31a1be252ba5",  |
|              |     "resource_type": "physical:host",                       |
|              |     "status": "active",                                     |
|              |     "missing_resources": false,                             |
|              |     "resources_changed": false,                             |
|              |     "hypervisor_properties": "[\">=\", \"$vcpus\", \"2\"]", |
|              |     "resource_properties": "",                              |
|              |     "before_end": "default",                                |
|              |     "min": 1,                                               |
|              |     "max": 1                                                |
|              | }                                                           |
| start_date   | 2024-01-21T22:05:00.000000                                  |
| status       | ACTIVE                                                      |
| trust_id     | 9e5864d9805b4ff1bb452730fef859ab                            |
| updated_at   | 2024-01-21 22:05:11                                         |
| user_id      | e2cde8831daf4285b148499159c4c14e                            |
+--------------+-------------------------------------------------------------+
</syntaxhighlight>

Let's see the impact on host aggregates with Horizon (''compute4.cloud.ld'' is now reserved and belongs to a special aggregate created for the purpose) :
[[Fichier:blazar3.png|800px|thumb|center|compute4.cloud.ld is now reserved and belongs to a special aggregate created for the purpose]]

The preemptibles instances on ''compute4.cloud.ld'' are gone :
[[Fichier:blazar4.png|800px|thumb|center|state of instances in Horizon when the reservation becomes active on compute4.cloud.ld]]

Let's create an instance with our ''reservation id'' :
<syntaxhighlight lang="bash">
openstack server create --image cirros --flavor g1 --network Ext-Net --hint reservation=e379e7c5-b708-4822-80a3-d9e9a0c573a7 vm9
</syntaxhighlight>

And verify the result with Horizon (''compute4.cloud.ld'' is now hosting ''vm9'') :
[[Fichier:blazar5.png|800px|thumb|center|compute4.cloud.ld is now hosting vm9]]

At the end of the reservation, ''lease-1'' becomes ''TERMINATED'' :
<syntaxhighlight lang="bash">
openstack reservation lease show lease-1
+--------------+-------------------------------------------------------------+
| Field        | Value                                                       |
+--------------+-------------------------------------------------------------+
| created_at   | 2024-01-21 22:00:57                                         |
| degraded     | False                                                       |
| end_date     | 2024-01-21T22:20:00.000000                                  |
| events       | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": "2024-01-21 22:20:11",                    |
|              |     "id": "1b4700d4-960d-46c0-8022-af743bd778ce",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "end_lease",                              |
|              |     "time": "2024-01-21T22:20:00.000000",                   |
|              |     "status": "DONE"                                        |
|              | }                                                           |
|              | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": "2024-01-21 22:05:11",                    |
|              |     "id": "3f8a4928-a360-495d-826d-4b92a5b7a003",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "start_lease",                            |
|              |     "time": "2024-01-21T22:05:00.000000",                   |
|              |     "status": "DONE"                                        |
|              | }                                                           |
|              | {                                                           |
|              |     "created_at": "2024-01-21 22:00:58",                    |
|              |     "updated_at": "2024-01-21 22:05:12",                    |
|              |     "id": "564bd93c-e157-4dcb-825a-2258d882a4d2",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "event_type": "before_end_lease",                       |
|              |     "time": "2024-01-21T22:05:00.000000",                   |
|              |     "status": "DONE"                                        |
|              | }                                                           |
| id           | 7180e34e-2718-47c9-8616-590e6a3585b2                        |
| name         | lease-1                                                     |
| project_id   | e1bbe999a4a84d91bbf79eaf54adc60d                            |
| reservations | {                                                           |
|              |     "created_at": "2024-01-21 22:00:57",                    |
|              |     "updated_at": "2024-01-21 22:20:11",                    |
|              |     "id": "e379e7c5-b708-4822-80a3-d9e9a0c573a7",           |
|              |     "lease_id": "7180e34e-2718-47c9-8616-590e6a3585b2",     |
|              |     "resource_id": "80c24e3a-beb5-4f72-a566-31a1be252ba5",  |
|              |     "resource_type": "physical:host",                       |
|              |     "status": "deleted",                                    |
|              |     "missing_resources": false,                             |
|              |     "resources_changed": false,                             |
|              |     "hypervisor_properties": "[\">=\", \"$vcpus\", \"2\"]", |
|              |     "resource_properties": "",                              |
|              |     "before_end": "default",                                |
|              |     "min": 1,                                               |
|              |     "max": 1                                                |
|              | }                                                           |
| start_date   | 2024-01-21T22:05:00.000000                                  |
| status       | TERMINATED                                                  |
| trust_id     | 9e5864d9805b4ff1bb452730fef859ab                            |
| updated_at   | 2024-01-21 22:20:11                                         |
| user_id      | e2cde8831daf4285b148499159c4c14e                            |
+--------------+-------------------------------------------------------------+
</syntaxhighlight>

And ''compute4.cloud.ld'' returns to the ''freepool'' aggregate :
[[Fichier:blazar6.png|800px|thumb|center|compute4.cloud.ld in freepool aggregate]]