Load balancer resizing¶
Link to blueprint: https://blueprints.launchpad.net/octavia/+spec/octavia-resize-loadbalancer
This spec’s goal is to describe the functionality of resizing of load balancers. The main aim of this new feature is to enable you to change the flavor directly from the API.
Problem description¶
Today’s users can’t easily change the flavor. They have to recreate their load balancer with the new flavor and migrate their configurations such as l7 rules, listeners, etc. This can be very tedious for a user who wants to quickly resize his load balancer. It can be especially complicated to script.
Proposed change¶
The proposed change would be to add an endpoint to allow load balancer resizing. It would also be easy to cancel a resize in progress and return to the previous flavor.
To achieve this, the endpoint will launch a workflow to initiate a failover with the new flavor ID. This will involve patching the get_failover_LB_flow to add the flavorId parameter. At the end of the workflow the flavor_id will be updated in the loadbalancer table.
A check will be added before the start of the failover to prevent migration to a flavor profile topology different from the original one. A user cannot migrate from a flavorprofile standalone to active/passive.
If a problem occurs during resizing, the load balancer status will be set to ERROR. The flavor will remain the same in database, allowing the user to perform a failover or retry the same call.
Alternatives¶
Rebuild the vm of the loadbalancer with the new flavor compute.
Use the “backup” and “restore”.
Data model impact¶
None
REST API impact¶
Add one endpoint in /v2.0/lbaas/loadbalancers.
To run this endpoint, the user must have the role load-balancer:write”.
Start a resize of a load balancer:
PUT /v2.0/lbaas/loadbalancers/{loadbalancer_id}/resize
{
"new_flavor_id": "6d425a5e-429f-4848-b240-ab31c6d211e4"
}
Code |
Description |
|---|---|
202 Accepted |
Resize starting |
400 Bad request |
Resize object is invalid |
401 Unauthorized |
X-Auth-Token is invalid |
403 Forbidden |
X-Auth-Token is valid, but the associated project does not have the appropriate role/scope |
404 Not Found |
Load balancer not found |
Security impact¶
None
Notifications impact¶
Add a notification to announce a loadbalancer resize.
Other end user impact¶
Add one command to launch resize in CLI client.
- Start a resize: openstack loadbalancer resize
–flavor <flavor-id|flavor-name> <lb-id|lb-name>
Add functions to resize in the openstacksdk.
Performance Impact¶
None
Other deployer impact¶
None
Developer impact¶
None
Implementation¶
Assignee(s)¶
TBD
Work Items¶
Create endpoints
Patch the get_failover_LB_flow to add flavorId parameter.
Add unit tests
Add API functional tests
Add tempest tests
Update Octavia CLI and OpenstackSDK
Write Documentation
Dependencies¶
None
Testing¶
- Tempest tests should be added for testing this new feature:
Create a loadbalancer
Try to resize
Documentation Impact¶
A user guide to explain how that works.
Add a note on the fact that some flavor changes can cause data plane downtime. Similarly, going from a newer image tag to an older one may cause failures or features to be disabled.
References¶
None
