Workload Balance Migration Strategy

updated: 2017-07-27 13:37

Workload Balance Migration Strategy¶

Synopsis¶

display name: workload_balance

goal: workload_balancing

[PoC]Workload balance using live migration

Description

This strategy migrates a VM based on the VM workload of the hosts. It makes decision to migrate a workload whenever a host’s CPU utilization % is higher than the specified threshold. The VM to be moved should make the host close to average workload of all hosts nodes.

Requirements

Hardware: compute node should use the same physical CPUs
Software: Ceilometer component ceilometer-agent-compute running in each compute node, and Ceilometer API can report such telemetry “cpu_util” successfully.
You must have at least 2 physical compute nodes to run this strategy.

Limitations

This is a proof of concept that is not meant to be used in production.
We cannot forecast how many servers should be migrated. This is the reason why we only plan a single virtual machine migration at a time. So it’s better to use this algorithm with CONTINUOUS audits.

Requirements¶

None.

Metrics¶

The workload_balance strategy requires the following metrics:

metric	service name	plugins	comment
`cpu_util`	ceilometer	none

Cluster data model¶

Default Watcher’s Compute cluster data model:

Nova cluster data model collector

The Nova cluster data model collector creates an in-memory representation of the resources exposed by the compute service.

Actions¶

Default Watcher’s actions:

action description
migration
Migrates a server to a destination nova-compute host

This action will allow you to migrate a server to another compute destination host. Migration type ‘live’ can only be used for migrating active VMs. Migration type ‘cold’ can be used for migrating non-active VMs as well active VMs, which will be shut down while migrating.

The action schema is:
schema = Schema({
 'resource_id': str,  # should be a UUID
 'migration_type': str,  # choices -> "live", "cold"
 'destination_node': str,
 'source_node': str,
})
The resource_id is the UUID of the server to migrate. The source_node and destination_node parameters are respectively the source and the destination compute hostname (list of available compute hosts is returned by this command: nova service-list --binary nova-compute).

action	description
`migration`	Migrates a server to a destination nova-compute host This action will allow you to migrate a server to another compute destination host. Migration type ‘live’ can only be used for migrating active VMs. Migration type ‘cold’ can be used for migrating non-active VMs as well active VMs, which will be shut down while migrating. The action schema is: schema = Schema({ 'resource_id': str, # should be a UUID 'migration_type': str, # choices -> "live", "cold" 'destination_node': str, 'source_node': str, }) The resource_id is the UUID of the server to migrate. The source_node and destination_node parameters are respectively the source and the destination compute hostname (list of available compute hosts is returned by this command: `nova service-list --binary nova-compute`).

Planner¶

Default Watcher’s planner:

Weight planner implementation

This implementation builds actions with parents in accordance with weights. Set of actions having a higher weight will be scheduled before the other ones. There are two config options to configure: action_weights and parallelization.

Limitations

This planner requires to have action_weights and parallelization configs tuned well.

Configuration¶

Strategy parameters are:

parameter	type	default Value	description
`threshold`	Number	25.0	Workload threshold for migration
`period`	Number	300	Aggregate time period of ceilometer

Efficacy Indicator¶

None

Algorithm¶

For more information on the Workload Balance Migration Strategy please refer to: https://specs.openstack.org/openstack/watcher-specs/specs/mitaka/implemented/workload-balance-migration-strategy.html

How to use it ?¶

$ openstack optimize audittemplate create \
  at1 workload_balancing --strategy workload_balance

$ openstack optimize audit create -a at1 -p threshold=26.0 \
        -p period=310

External Links¶

None.

updated: 2017-07-27 13:37

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.