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Migrating Existing VMware Environment to a New vCenter

Migrating Existing VMware Environment to a New vCenter

New hardware, vCenter consolidation, or upgrading: a few examples where you’ might have the requirement to migrate your existing, managed VMware environment to a brand new vCenter server. In my case, we have multiple vCenter servers and want to consolidate into a single server, allowing us to manage our ESXi hosts across multiple sites in one place.  Sure you can use Linked-Mode to help accomplish this but you begin to complicate the SSO install and, in the end, you still have to upgrade two servers down the road. At the same time, the migration will allow us to make a smooth transition to vCenter 5.5 and ultimately upgrade hosts to ESXi 5.5.

This step-by-step process, as outlined below, takes into consideration that the existing environment is using advanced features such as the vDistributed Switch and Datastore clusters. It also assumes that the environment is using HA, DRS, etc.

*Note: Hosts CAN absolutely be migrated from one vCenter to another without any downtime to the running VMs on the host.


The first step is to prepare the new environment. Items such as vCenter installation, configuration, and prepare existing hosts are part of the preparation stage.


1). Provision new vCenter server (minimum requirements found here).

2). Install VMware vCenter – the Simple Install now works much better than in the past (documentation found here).

3). Install VMware Update Manager – Requires separate database connected using a 32-bit DSN (documentation found here).

4). Configure VMware vCenter

  1. Create Datacenter Object(s)
  2. Create and Configure Cluster(s)
  3. Create and Configure Distributed Virtual Switch(es)
  4. Configure Additional Options such as SMTP, Alerts, etc as required.

Prepare Hosts to be Migrated (Removing vCenter Dependencies)

1). Migrate VMs to Standard Switches

  1. On each host, create a new Standard Switch.
  2. Remove at least one uplink from VDSwitch and add to standard switch
  3. Migrate VMs using “Migrate Networking Wizard” or manually by changing the connected network on each VM. You can also use Drag & Drop to migrate multiple VMs at once. See my post here for more information.
  4. Migrate VMkernel adapters from VDS to VSS.
  5. Move other uplink(s) from VDSwitch to standard switch
  6. Remove Host from VDSwitch – detailed information here.

2). Remove any local Datastores from configured Datastore Clusters.

3). Ensure you have the local ‘root’ password for each host – test each host by logging in via SSH. If you don’t know the password for your hosts, you can find details on updating them on my post here.

Migrate Hosts to new vCenter Server

1). Set DRS to Partially Automated or Manual

2). Remove Host from existing vCenter server – see more details here.

3). Add Host to new vCenter server

Other Tasks to Consider are Below

Upgrade Hosts to Latest Build

1). Put single host into maintenance mode

2). Upgrade to latest ESXi build (using Update Manager or fresh install)

3). Exit Maintenance Mode, set DRS to Manual and test host by migrating a test VM to it.

There are definitely easier/faster ways to upgrade hosts, such as using vSphere Auto Deploy, but in a smaller environment this process works fine and limits mistakes.

Additional Tasks

1). Upgrade VMware Tools on VMs

2). Upgrade Virtual Hardware on VMs (Important: you must upgrade VMware Tools first)

3). Migrate Backup & Monitoring Jobs to reflect vCenter change.

4). Decommission old vCenter server – remove from monitoring, archive and delete old database, etc

Optional Tasks

1). Deploy and Configure VMware Operations Manager

2). Deploy and Configure vMA and/or Syslog Collector

3). Configure VMware Orchestrator

About The Author

Bryan Krausen

Bryan Krausen is currently working as a Sr. Solutions Architect with experience in a vast number of platforms, specializing in AWS and HashiCorp tools.


  1. Avatar

    It’s a very good document.

  2. Avatar

    Dear Sir,

    Great doc. I have some questions for the VDS. Is it necessary to change the VDS to vSS in old vcenter? and I don`t see the step after the migration that you change the vss back to vds? Thanks.

  3. Avatar

    Would VMs be able to be migrated without the hosted apps losing any downtime?

    • Bryan Krausen

      Absolutely. As mentioned above, the VMs don’t go down, therefore the applications see no downtime as a result.

  4. Avatar

    What about the datastores the vm’s are hosted on?
    In our case vm’s are hosted on iSCSI volumes mounted on hosts that are member of vCenter server A.
    What happens with these datastores when I remove a host from vcenter A and add it to vcenter B?

  5. Avatar

    Thanks you so much.
    How about VMs folders? How can i move the folders infrastructure i build under “VMs and Templates” from old vcenter server to the new one?

  6. Avatar

    How much time this entire process takes from phase 1 to final phase completion?


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