Migrating VMware ESXi Workloads to OpenStack Using MigrateKit

This guide describes a practical, production-tested workflow to migrate virtual machines from VMware ESXi to OpenStack using MigrateKit — an open-source migration tool developed by VEXXHOST.

The approach focuses on:

• Near-zero downtime

• Full data integrity

• Repeatable and automated execution

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Objectives

• Migrate virtual machines from VMware ESXi to OpenStack

• Minimize service downtime (typically 5–10 minutes)

• Preserve data integrity

• Enable repeatable and automated migration runs

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Architecture Overview

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Prerequisites

MigrateKit Server

• OS: Ubuntu 22.04 LTS

• Memory: minimum 4 GB

• Disk: minimum 50 GB

• Network access to both VMware and OpenStack endpoints

VMware VDDK

• Version: 8.0.3 or later

• Download from VMware Developer Portal

Source Environment (VMware)

• ESXi 6.7+ or vCenter-managed environment

• Change Block Tracking (CBT) must be enabled

Target Environment (OpenStack)

• OpenStack Bobcat (2023.2) or later

• Required services: Cinder, Nova, Neutron

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Part 1: MigrateKit Server Setup

Install Docker

sudo apt update && sudo apt upgrade -y
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh
docker --version

Install VMware VDDK

scp VMware-vix-disklib-8.0.3-*.tar.gz root@migratekit:/tmp/
ssh root@migratekit

cd /tmp
tar -xzf VMware-vix-disklib-8.0.3-*.tar.gz
sudo mkdir -p /usr/lib64/vmware-vix-disklib
sudo cp -r vmware-vix-disklib-distrib/lib64/* /usr/lib64/vmware-vix-disklib/
ls -la /usr/lib64/vmware-vix-disklib/

Configure OpenStack Credentials

cat > ~/openstack-credentials.env << 'EOF'
export OS_AUTH_URL=https://your-openstack.com:5000
export OS_PROJECT_NAME=your-project
export OS_PROJECT_ID=your-project-id
export OS_USERNAME=your-username
export OS_PASSWORD=your-password
export OS_REGION_NAME=RegionOne
export OS_INTERFACE=public
export OS_IDENTITY_API_VERSION=3
export OS_USER_DOMAIN_NAME=default
export OS_PROJECT_DOMAIN_NAME=default
EOF

source ~/openstack-credentials.env

Validate connectivity:

docker run --rm \
  --env-file <(env | grep OS_) \
  python:3-slim bash -c \
  "pip install python-openstackclient && openstack token issue"

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Part 2: Preparing the VMware Source

Enable Change Block Tracking (CBT)

ssh root@esxi-host
vim-cmd vmsvc/getallvms | grep your-vm-name
vim-cmd vmsvc/power.off <VM_ID>

vi /vmfs/volumes/datastore1/your-vm/your-vm.vmx
# Add:
ctkEnabled = "TRUE"
scsi0:0.ctkEnabled = "TRUE"

vim-cmd vmsvc/reload <VM_ID>
vim-cmd vmsvc/power.on <VM_ID>

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Part 3: Migration Workflow

Phase 1: Initial Full Sync

docker run -it --rm --privileged \
  --network host \
  -v /dev:/dev \
  -v /usr/lib64/vmware-vix-disklib/:/usr/lib64/vmware-vix-disklib:ro \
  --env-file <(env | grep OS_) \
  ghcr.io/vexxhost/migratekit:main \
  migrate \
  --vmware-endpoint <ESXI_IP> \
  --vmware-username root \
  --vmware-password "<ESXI_PASSWORD>" \
  --vmware-path /ha-datacenter/vm/<VM_NAME> \
  --debug

Expected output:

INFO[0001] Creating snapshot
INFO[0003] Volume created and set bootable
Full copy 100% (25 GiB, 533 MiB/s)
INFO[0061] Migration completed

Phase 2: Incremental Sync

Re-run the migrate command to copy only changed blocks.
This phase can be repeated multiple times to reduce final cutover time.

Phase 3: Final Cutover

openstack network list
openstack subnet list

docker run -it --rm --privileged \
  --network host \
  -v /usr/lib64/vmware-vix-disklib/:/usr/lib64/vmware-vix-disklib:ro \
  --env-file <(env | grep OS_) \
  ghcr.io/vexxhost/migratekit:main \
  cutover \
  --vmware-endpoint <ESXI_IP> \
  --vmware-username root \
  --vmware-password "<ESXI_PASSWORD>" \
  --vmware-path /ha-datacenter/vm/<VM_NAME> \
  --flavor <FLAVOR_ID> \
  --network-mapping mac=<MAC>,network-id=<NETWORK_ID>,subnet-id=<SUBNET_ID> \
  --debug

Cutover sequence:

1. Create Neutron port

2. Perform final incremental sync

3. Power off source VM

4. Create volume and Nova instance

5. Boot the migrated VM

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Verification

openstack volume list
openstack server list
openstack console url show <INSTANCE_NAME>
ssh ubuntu@<INSTANCE_IP>

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Troubleshooting

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Performance Observations

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Operational Best Practices

Before migration

• Test with non-production workloads

• Enable CBT early

• Maintain backups

• Perform multiple sync cycles

During migration

• Monitor network throughput

• Keep source VM running until cutover

• Review logs in debug mode

After migration

• Validate application behavior

• Update DNS and routing

• Monitor system performance

• Retain source VM temporarily for rollback

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Conclusion

MigrateKit provides a clean and reliable migration path from VMware ESXi to OpenStack when Change Block Tracking is available.

Key strengths:

• Minimal downtime

• Deterministic workflow

• Open-source and production-ready

Limitations:

• Requires CBT support

• Dependent on ESXi API access

• Network performance impacts total time

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References

• MigrateKit GitHub

• VEXXHOST: Introducing MigrateKit

• VMware VDDK Documentation

• OpenStack Official Documentation