chore(core): set live migrations defaults

[fl64]

Description

Set the default live migration parameters as follows:

• Migration bandwidth: 5 Gbps (approximately 640 MiB/s)
• Limit one outbound migration stream per node
• The total number of concurrent migrations in a cluster is limited to the number of nodes that are running virtual machines

Why do we need it, and what problem does it solve?

Previously, the defaults were set to:

• 0.5 Gbps per migration
• 2 outbound migrations per node
• Maximum of 5 concurrent migrations cluster-wide

This setup could lead to several issues:

• Low per-migration bandwidth (0.5 Gbps) slowed down migration operations unnecessarily.
• Multiple outbound migrations per node (2) could cause network contention and resource starvation on the source node.
• Hard limit of 5 total migrations per cluster did not scale well with larger clusters and created bottlenecks during large-scale maintenance or rebalancing.

The new defaults address these limitations by:

• Increasing bandwidth for faster migrations
• Limiting each node to one outbound migration at a time to prevent local resource overuse
• Scaling the total number of concurrent migrations based on the number of nodes in use, enabling better throughput in larger clusters

What is the expected result?

• Live migrations will run with up to 5 Gbps of bandwidth allocated per operation
• Each node will perform at most one outbound migration at a time
• The total number of concurrent migrations across the cluster will be equal to the number of nodes hosting VMs

Checklist

• [ ] The code is covered by unit tests.
• [ ] e2e tests passed.
• [ ] Documentation updated according to the changes.
• [x] Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: core
type: fix
summary: set live migrations defaults