Workload Migration Complexity Analysis

Approach

Categorizing workload complexity will help us prioritize the migration plans and give us an estimate of the effort. We base our evaluation on the following:

  • Workload environment

  • Operating system and version

  • Workload type

  • Resource capacity and requirement

  • Disk size

In the sections below, you will see the results of Red Hat’s evaluation of the financial company’s workloads.

Workload Environment

Prioritizing lab and nonproduction workloads for migration will help ensure that we perform production migration as efficiently and smoothly as possible.

RHEL and other Linux distributions

  • In the scenario for this module, we calculated that our financial services firm had about 69,000 workloads from VMware that were eligible for migration. These eligible workloads must first be categorized into supported operating systems and version or not. You can refer the article on certified guest operating systems - Certified Guest Operating Systems in Red Hat OpenStack Platform, Red Hat Virtualization, Red Hat OpenShift Virtualization and Red Hat Enterprise Linux with KVM

  • RHEL and RHEL-derivatives such as CentOS, Rocky, and Oracle Linux that are newer than RHEL 5 will be placed into the easy bucket. These versions are heavily tested and officially supported by Red Hat. The older versions will require upgrades before migration so they will be placed in the medium bucket.

  • SUSE is also a supported distribution starting with version 12+.

  • Debian and Ubuntu are not supported distributions, but are considered Technology Preview. We will place these in the hard bucket.

  • Various Linux VMs with unlabelled distribution will need to be determined by other means. The effort level will be determined on a case-by-case basis.

Operating Systems Easy Medium Hard

RHEL 5

-

41

-

RHEL 6, 7, 8, 9

53521

-

-

CentOS 4, 5

-

73

-

CentOS 6, 7, 8

683

-

-

Oracle Linux 4, 5

-

13

-

Oracle Linux 7, 8

53

-

-

Rocky Linux 8, 9

3790

-

-

SUSE 11

-

-

7

SUSE 12, 15

-

21

-

Ubuntu 18, 20, 22, 24

-

-

739

Debian 8, 9, 10

-

-

35

Other Linux (kernel 2.6+)

-

-

926

Total

58047

148

1707

Windows

Microsoft Windows and Microsoft Windows Servers are certified by Microsoft SVVP to run on Openshift Virtualization’s KVM hypervisor. The drivers will need to be changed out to virtio, so that increases the challenge. We assume these Windows VMs run on the VMware hypervisor and are possible to migrate. If they are running on Hyper-V, Red Hat does not have a direct migration solution from Hyper-V to Openshift Virtualization.

Operating Systems Easy Medium Hard

Windows 10

-

8631

-

Windows Server 2016, 2019, 2022

-

467

-

Total

0

9098

0

Workload Type

When we examine our financial client’s workload types, we are looking at the level of complexity. Here, you can see that we have identified database, message bus, Hadoop, and observability VMs as having higher complexity to migrate due to required persistence of objects in their runtime. They will be required to be quiesced and written to disk before migrating.

Workload Type Easy Medium Hard

Low Complexity Types; App & Web Servers, Frameworks, etc.

52763

-

-

Database

-

8765

-

Message Bus

-

2168

-

Hadoop VMs

-

427

-

Observability

-

274

-

Total

52763

11634

0

Resource Requirements

CPU and memory requirements will limit what we can send to each cluster. The financial company has a requirement that we utilize no more than 80% of the total physical memory and overcommit more than 4:1 vCPUs to physical CPUs. Additionally, two nodes of the cluster cannot be counted in the total available resources. They are assigned solely to handle node failures.

Disk Size

The size of the VM disk affects the time to copy the vdmk to the cluster and the time it takes to convert the disk. These are controlled by the migration network bandwidth and the CPUs available during conversion. In the table below, you can see the varying disk sizes utilized by the financial company.

Disk Size (TB) Easy Medium Hard

1-2 TB

67563

-

-

3-9 TB

-

3672

-

10-20 TB

-

-

104

21-40 TB

-

-

68

Total

67563

3672

172