Changing vCenter Hostname

Changing vCenter Hostname

Why?!?! Cause I gotta!

Source: Changing your vCenter Server’s FQDN – VMware vSphere Blog

PreReqs, AKA Checklist

  • Backup all vCenter Servers that are in the SSO Domain before changing the FQDN of the vCenter Server(s)
  • Supports Enhanced Linked Mode (ELM)
  • Changing the FQDN is only supported for embedded vCenter Server nodes
  • Products which are¬†registered with vCenter Server will first need to be unregistered prior to an FQDN change. Once the FQDN change is complete they can then be reregistered.
  • vCenter HA (VCHA)¬†should be destroyed prior to an FQDN change and¬†reconfigured after changes
  • All custom¬†certificates will need to be regenerated
  • Hybrid Linked Mode¬†with Cloud vCenter Server must be recreated
  • vCenter Server that has been renamed will need to be rejoined back to Active Directory
  • Make sure that the new FQDN/Hostname is resolvable to the provided IP address (DNS A records)

NOTE: If the vCenter Server was deployed using the IP as PNID/FQDN, then the following should also be considered:

  • The PNID change workflow cannot be used to change the IP address of vCenter Server
  • The PNID change workflow cannot be used to change the FQND of vCenter Server

In this scenario, use the vCenter Server Appliance Management Interface (VAMI) to update hostnames or IP changes directly. 

The main thing I was expecting was the certificate issue. In my home lab, I removed SSO domain before this change (just using vpshere.local), no ELM, already using embedded (all-in-one), no VCHA, no Hybird, oh yeah…. not sure if you “leave an SSO domain”, before joining back to AD…

My Only Pre-Req

I went into DNS and pre-created A host records for the new server hostname: vCenter.zewwy.ca

Steps

Basically log into VAMI, and change the name.

Then

and and…. well WTF…

No matter what I do it’s greyed out… I thought maybe the untrusted cert, might be an issue so tried from a machine with full trusted chain, and same issue!

Like…. Why… why is Next greyed out? It’s like whatever Button Validation code is written for it is not being triggered, is this a browser version issue? I can’t find anything online with anyone having this issue…. Why? Cause I was right, it was the input validation…

Honestly, this is one of those MASSIVE facepalm moments in my life. I only realized after the fact the username field was NOT auto filled, it was only a label that was greyed and provided as a suggestion… Fill both fields and the next is ungreyed…

Step 4, check the checkbox to acknowledge the warning, and away… she goes!

At which point I clicked redirect now (both web addresses were still available as it didn’t seem to matter which you came from, the cert was untrusted either way, cause the CA not in my trusted ca store)

5 minutes later….

I tell ya nothing more annoying than a spinning circle and the warning “don’t refresh” when the status bar simply does not move… sure got some conflicting messages here….

*Starts to sweat*…

after about 10 minutes time…

More Certificate Fun!

Alright so after this, quick take always… when I went to check the site it was “untrusted” but not for the reason I had thought, I thought it would have been from the same issue as the source blog, and be the hostname on the cert but that was not the case, instead it was imply the the cert chain seemed to be missing, and the issuer could not be verified:

as well as:

So what to do about this… You can download the CA cert from vcenter/certs/download.zip (some reason I had to use IE). Then install the CA cert. (I noticed even after I did this I still had cert warning, error, but after the next day, maybe cache clearing or update, it reported green in the web browser).

Now when I logged in, I got the ol Cert Alert in the vCenter UI

first thing to try is removing old CA’s

Which I did, following this VMware KB

I simply followed my other post about this, and just cleared reset to green on the alert. (Still good days later).

Backup Solutions

Don’t forget to change the server in your backup software, such as I had to do this in Veeam.

These were my results…

Which go figure errored out…

So right click, go to properties of the object… Next, next…

Accept the certs new certificate

Now you figure all is well, but when I went to create a new backup job, when I attempted to expand the vcenter server in Veeam. It just hung there…

I ended up rebooting the server, and then waiting for all the Veeam services to be started. I reopened Veeam, and when to Inventory, clicked the vCenter server, took a second and then showed all the hosts, and the VMs. I clicked it and rescanned to be safe and got this result which was a bit different then the applied settings confirmation above. I think maybe I forgot to rescan the host after applying the new settings, assuming it would have done that as part of the properties change wizard.

which lucky for me now worked, and I was able to select a VM in the Veeam backup wizard, and it successfully backed up the VM.

Final Caveats

like what the heck, everywhere else its changed except at the shell. Let’s see if we change change this.

Well that was easy enough, no reboot required. ūüôā

I also found the local hosts file doesn’t update either, in the file it states it managed by VAMI, so many have to look there for potential solutions:

I noticed this since I had to do a work around for something else, and sure enough caught it. I’ll change it manually with vi for now and see what changes after a reboot.

Summary

Overall, literally quick n easy.

  1. Verify DNS records exist.
  2. Use VAMI to edit hostname via editing the Network MGMT settings and change the hostname, click apply and wait.
  3. Manually clear out the old Certs that were created under the old hostname.
  4. Reconfigure you backup solution, which is vender specific (I provided step for Veeam as that is the Backup Vender I like to use)

Overall the task seemed to go pretty smooth. I’ll follow up with any other issue I might come across in the future. Cheers.

 

 

Activating Windows Offline

Story

Quick Story here, Installed a copy of Server 2019. System is completely offline, how to activate it?

I found a couple guides to help along the way, and even a nice thread post.

Issue

Main thing I found was a command to get your started:

slui 4

To my dismay I was greeted with a greeting, much like the thread poster:

"Can't activate Windows by phone."

If you keep reading there are other potential reasons for activation to fail, but that usually happens afterwards with a dedicated error code. E.G Attempting to activate a evail edition, or using a MAK key instead of a retail one, or using the wrong key with the wrong edition (Standard vs Datacenter).

In the first example it makes sense, as well as the last one. In my case I was using the proper image downloaded from VLSC with the key from the same web portal, So I knew I was good on the first and second examples. The middle example of requiring the use of a retail key didn’t seem right, as I would assume any version would suffice. *NOTE* At this point I was merely assuming, as I couldn’t fully verify my key as I wasn’t utilizing a VMAT server. Again this is an offline activation.

Solution

Now for my realization, I had made yet another assumption, and that was I’d assume slui 4 would provide a pop-up that would allow you to enter your product key before starting, and the error message doesn’t exactly convey that with an incorrect error message of: “Can’t activate Windows by phone.”

When in reality it should have simply stated “Please set a product key first”.

as it turns out you have to use: Windows Software Licensing Management Tool and can be accesses via elevated command line using slmgr.vbs.

Yes that’s right a Visual Basic script. ;P.

C:\Windows\System32> slmgr.vbs /ipk <Key>

/dli (This will show basic license and activation information.)
/dlv (This will show detailed license and activation information.)
/xpr (This will show the current expiration date of the license installed which is most useful when using a KMS key with a local KMS activation server on the network.)
/upk (Be careful with this one as it will uninstall your current license key.)
/cpky (Also be careful with this one as this removes license key information from the registry.)
/ipk *****-*****-*****-*****-***** (This will change your license key to the one entered. If there was no key entered previously this command will also attempt to activate the license based on the license key type.)
/ato (This will force an online activation immediately. This could be useful if you have already entered the new key but was not online with either the KMS server for the network or unable to reach Microsoft’s activation servers.)

After doing this, then running slui 4 again, I was prompted with a screen asking me to select my Region. I then proceeded to use a Phone to call the toll free number provided and follow the IVR prompts to get a confirmation ID.

After entering the confirmation ID, I successfully activated Windows Offline. I did note one thing, that I told the IVR I did not have a smartphone so I did not get the web link as mentioned by others in the comment area. You can save this link and use it to do offline activations without calling in to the phone number from another machine that is online. If I manage to get this link I will share it as the commenters in that other post did not do the same.

Hope this helps someone.

 

Change vCenter FQDN or IP on Veeam

Story

I recently did a infrastructure upgrade on my home lab, which included moving all my esxi hosts into a dedicate subnet, and making them all more dependent on DNS. This has it’s pros n cons, after all my ESXi host had their IP addresses changed. I also moved my vCenter and changed it IP address, which is now supported yay.

Now I had to move Veeam along with it, originally it was in the same subnet as the esxi hosts, and vCenter which have all moved, instead of trying to manage cross subnet comms, I changed Veaam’s IP address and pointed it’s DNS settings to my AD DNS which has all the ESXi and vCenter host records. Was easy enough just changing the Windows NIC Ip address, and changing the VM’s VMPG.

 How to

Now when I went to scan the vCenter instance in Veeam, it complained about the certificate, since it was renewed from the vCEnter upgrade. I decided I’d change it to be based on DNS now that everything else is as well. When I went to edit the object in Veeam it was greyed out.¬† Lucky for me Veeam had a KB ready to go.

Challenge

The Name/FQDN/IP of the vCenter Server has changed, and needs to be updated within Veeam Backup & Replication.

Solution

Solves Name Change Only
This solution applies ONLY if the vCenter Server database has not changed.
(I did an upgrade so yes, which you’d want to preserve VM-IDs, and chains)

If the Name/FQDN/IP of the vCenter changed due to a reinstall or upgrade, and a new vCenter database was used, the Ref-IDs will have changed. Due to the changed Ref-IDs you will need to follow the documented process in www.veeam.com/KB1299

Step 1

Prior to running the commands below you need to identify the Name\FQDN\IP Veeam is using to communicate with the VC currently. To do this, edit the entry for the vCenter under Backup Infrastructure and note the ‚ÄúName:‚ÄĚ.

Next perform the following steps to change that VMware Server’s name.

Step 2

Launch PowerShell from inside the Veeam Backup & Replication console. You can find the “PowerShell” button under the File-menu’s “Console” section.
openpsconsole
The Veeam Backup & Replication PowerShell Tookit will load.

Step 3

Run the following command:

$Servers = Get-VBRServer -name "old-name"

Replace old-name with the “Name” current set for the vCenter in the Veeam Backup and Replication Console

Step 4

Run the following command next to change the name:

$Servers.SetName("new-name")

Replace new-name with the new name for the vCenter, this can be an IP, Hostname, or FQDN.
Do not remove the quotes on either side.
This change will go in to effect as soon as the command in Step 4 completes.

How I did it – One Liner

Verify:

Get-VBRServer -name "Name from Step 1"

Change:

(Get-VBRServer -name "Name From Step 1").SetName("new.domain.com")

Results:

Now you can click next, Apply, should get right past checking certificate if the certificates are all good… and end up with the follow after rescan:

That was easy enough, I don’t fully understand why the grey out the UI to make this change, but there you have it. Happy Backups!

vSphere HA Agent cannot be correctly installed or configured… again

Story

Another vCenter Patch, Another problem ūüėÄ

This seems to be a reoccurring story these last couple posts…

Error on Host

This time after updating again a host in the cluster had the error message.

Troubleshooting

Un like the last time this happened, the event log wasn’t as blatant (flooded) complaining about the /tmp being full. and checking the host with

vdf -h

which showed only 90% full, which was still pretty high, which might have explained the one log event that I did see about it:

The ramdisk 'tmp' is full. As a result, the file /tmp/img-stg/data/vmware_f.v00 could not be written

Which was in the log right after this event of attempting to install a base ESXi image?

Installing image profile '(Updated) HPE-ESXi-Image' with acceptance level checking disabled

This seemed a bit weird but I could find any info other than what’s usuallly a very Microsoft type answer of “you can just ignore it” or “usually this is not an issue, just it says vCenter saying it is connecting to esxi host and installing it’s agent

OK I guess… moving on… the very next error event was:

Could not stage image profile '(Updated) HPE-ESXi-Image': ('VMware_bootbank_vmware-fdm_7.0.2-18455184', '[Errno 28] No space left on device')

Huh, Now note this host was installed running the official VMware Image provided by HPE for this exact hardware supported by the VMware HCL. So there should be no funny business. However I feel maybe there’s a bit of the known HPE bug as mentioned the last time this happened. It just hasn’t fully flooded /tmp just yet.

Lil Side Trail

So couple things to note here, first the ESXi image is installed on a USB/SD Card style setup as such it should be well know to define the persistent log location, as well as the scratch location. However, not many source specify changing the system swap location.

  1. Persistent Log; VMware KB; Tech Blogger
    (Most standard ESXi Log info)
  2. Scratch Log: VMware KB; Tech Blogger 1; Tech Blogger 2
    (Crash Logs, Support log creations)
  3. Swap Location: VMware Doc 1 (Configure), VMware Doc2 (About), Tech Blogger Who seem to regurgitate the exact about page from VMware.

However, researching this even more lots of posts on reddit mentioned the swap file for VM’s being on their VM directories, so if using a shared datastore they will reside there, and I shouldn’t see issues around swap usage at all at the host level.

Which if you look on the vCenter Web UI on a ESXi hosts there are two options available: VM – Swap, and System Swap.

The VMware docs doesn’t seem to describe accurately the difference between these two options.

Lookup up the error about not being able to stage the file I found this one blog post which of course mentioned changing the swap location to get past the error…

The main thing mentioned by the blogger is “The problem is caused by ESXi not having enough free space available to extract the installation packages.” but failed to specify where that exactly is, and the event log didn’t specify that either. Now since his solution was to adjust the system swap location, it begs the question. Is the package extraction location the System Swap location?

Since the host settings seem to be only specified with the alternative option checkboxes as:

Can use host cache
Can use datastore specified by host for swap files

It’s still not fully clear to me where the swap is actually located with these, assumed default settings. Or if extraction of the image actually using swap, or why the same imagine already on the ESXi host is being re-applied when your upgrade vCenter?

Resolution

So many question, so little answers, so unfortunately I’m going to go on a bit of a whim, and simply try exactly what I did before, clear the file from the /tmp location that was takin up a lot of it’s space, install the HPE patch for the known bug, in hopes it resolves the issue….

Sure enough the exact same thing happened, as in my initial post it just seems it wasn’t fully full. So the symptoms were just a bit different.

  1. vMotion all VMs to another host in the cluster (amazing vMotion works without issue)
  2. Ignore the HA warning on the VMs migrated
  3. Place Host into Maintenance mode (This clears the HA warnings on the VMs and cluster)
  4. Verify /tmp has room. Update any ESXi packages from the hardware vendor if applicable.
  5. Reboot the host.
  6. Exit Maintenance mode.

Hope this helps someone who might see the same type of error events in their ESXi event logs.

Clear vCenter Alert Certificate Status

Story

So lately updated a couple vCenter server servers, and in my process I hit a couple errors that required some resolving…

  1. Expired Certs on Source vCenter
  2. Error [500] Auth Provider, due to something, potentially bad certs.
  3. An HPE Bug, filling up ramdisk, causing HA config issues.
  4. Change in security process; preventing login.

The Problem

So a couple hiccups along the way. And now it’s time to resolve this one…

Yeahhhh and alert on Certificates… Seems like VMware and certificate management is like Oil n Water. They don’t mix well.

I’ve had some terrible times managing certificates¬† with VMware. However as blogged about here, seems there’s finally a way to use your own certificates via the WebUI.

Anyway… to the point, you figured you simply navigate to the vCenter WebUI -> Home -> Administration -> Certificates. Only to realize there’s nothing reporting as invalid or expired.

Checking for Expired Certs

What gives? Ahhh yes, more hidden secret stuff that is not in your face when it comes to the WebUI. Can you guess? That’s right another VMware KB

So while the other issues I’ve mentioned does have references and script in relation to certs, the only “check” in those previous posts was using openssl on the VCSA shell to grab the certificate from the listening service on the dedicated port. Which was based on a particular symptom which spurred that check. So here’s the KB telling you how to actually check the certificates the easiest way I found so far (no check.py; python script needed)

for store in $(/usr/lib/vmware-vmafd/bin/vecs-cli store list | grep -v TRUSTED_ROOT_CRLS); do echo "[*] Store :" $store; /usr/lib/vmware-vmafd/bin/vecs-cli entry list --store $store --text | grep -ie "Alias" -ie "Not After";done;

That’s it! :D…. which just like the KB indicated which cert was bad, in this case, an old Root CA that was used in previous deployments of vCenter before upgrades, So it turns out even though you follow the required KB to get past the pre-check of expired certs. It doesn’t delete the old certificates CA Cert.

There it is, the second CA Cert with expiry in 2019… OK so… You figured it would be easy to clean this up, but remember you couldn’t even see it in the WebUI, so you best believe there is no WebUI way to do this that protects you from human error.

Removing old Expired Certs

Instead, very brilliantly, you get… yes another KB! Booo Yeah… So let’s do this!

The main thing to note about this is…

Certificates are copied back to the VECS store because the CA Certificate which is expiring is published to the VMware Directory Service (VMDIR). When the Certificate is removed from VECS, VMDIR adds the Certificate back to VECS during a sync operation. This is done in order to ensure the integrity of the TRUSTED_ROOTS Certificate store, as deletion of an incorrect Certificate from this store could cause the environment to be irreparably damaged.

OK…. All I take away from this is Certs are important so they have a second cert store as a backup to the first cert store… that’s all I can take away form this odd statement.

/usr/lib/vmware-vmafd/bin/vecs-cli entry list --store TRUSTED_ROOTS --text | less

“Find the Certificate you wish to remove and make a note of the Alias and the X509v3 Subject Key Identifier.

Note: There Could be several Certificates to remove. Any expired and not in use certificates should be removed to avoid certificate related alarms.”

Yes that is the plan…

List the trusted certs published to the VMware Directory Service using the following command (administrator@vsphere.local password required). This command is in the same location as vecs-cli:

/usr/lib/vmware-vmafd/bin/dir-cli trustedcert list

Huh… in this case it looks like it is not here, so I should be safe to delete it from the normal store and it shouldn’t auto populate back in.

If you do see it (CN equal to x509v3 Key Identifier) then follow the linked KB to remove it, which seems to save a copy of the cert and use that saved copy to run another command to remove it from the store… super weird.

/usr/lib/vmware-vmafd/bin/vecs-cli entry delete --store TRUSTED_ROOTS --alias 3276134ad93b3688b5dc5dcfaa402e9bfd7af12f

Restart all services on the PSCs and on the vCenter Servers and ensure that all services start and respond normally and that you can log in and manage the environment.

service-control --stop --all
service-control --start --all

Took a liil while, then logging in… alert still there, I guess I just have to Reset to Green?

For Now Clicked the Reset to Green link. Even after Yet another vCenter patch, it still did not show up anymore. Yay.

Fixing [400] An error occurred while sending an authentication request to the vCenter Single Sign-On server

So After the last two blog posts about fixing vCenter7’s access issues due to it’s due certificate monument work flows. I was greeted with this error when trying to sign into the web UI on vCenter.

[400] An error occurred while sending an authentication request to the vCenter Single Sign-On server- An error occurred when processing meta data during vCenter Single Sign-On setup:the service provider validation failed. Verify that the server URL is correct and is in FQDN format, or that the hostname is a trusted service provider alias.

After a a quick google search I found yet another VMware KB discussing it.

 Resolution
This is an expected behavior.
VMware vSphere 7.0 enforce FQDN or IP address reverse resolvable to FQDN to allow authentication for Single-Sign on.
Greeeeeeeeeeeeeeaaaaaaaaat! Thanks VMware, just another example of security destroying functionality.
What did I do? Exactly what it stated, I navigated to the WebUI URL using the hostnames Fully Qualified Domain Name E.G: Hostname.domain.end
Cause I was attempting to access it just by just the hostname as domain info was being auto resolved by the domain suffix during queries.

vSphere HA Agent cannot be correctly installed or configured

I updated a vCenter server to 7.0.x when logging into the newly updated vCenter one host in the cluster state the following alert.

Error: “vSphere HA agent cannot be correctly installed or configured” (2056299) (vmware.com)

The KB didn’t sound promising. Checking the hosts event logs. a bunch of errors about /tmp ramdisk being full…

The ramdisk ‘tmp’ is full – VMware ESXi on HPE ProLiant – Davoud Teimouri – Virtualization and Data Center

For real? Wow, not gettin’ lucky last couple weeks. Sure enough exact same issue, cleared /tmp temporality, and downloaded the patch. When I vMotion the VMs from this host onto another host the VMs themselves showed alerts.

Virtual machine failed to become vSphere HA Protected and HA may not attempt to restart it after a failure.

I kept chugging alone in hopes I’d resolve each VM later. However as soon as I placed the issued host into maintenance mode, the alerts from all VMs disappeared. Applied to patch exactly as the HPE KB stated for the ESXi version it was on.

With luck on my side, the host came up clean, and came out of maintenance mode without an issue, and all error and alerts were resolved. Woooo!

Hope this helps anyone doing a vCenter upgrade to 7.x

Fixing vCenter [500] An error occurred while fetching identity providers.

Story

So The other day I posted about upgrading vCenter to 7.0.x while everything went fine during the upgrade. For some odd reason a couple days later when I went to navigate to the vCenter login page I was greeted with:

[500] An error occurred while fetching identity providers.

Kinda wished I had read this reddit post right off the hope, cause the first reply was is going to be my answer at the of this post.

I did however first hit this KB about it as well I was a bit thrown off has it indicated to only do it if you see the following in the logs:

(/var/log/vmware/trustmanagement/trustmanagement-svcs.log)

2021-03-10T09:27:03.474Z [tomcat-exec-14  INFO  com.vmware.identity.token.impl.X509TrustChainKeySelector  opId=] Failed to find trusted path to signing certificate <STS Certificate Subject, example - C=US,CN=ssoserverSign\,dc\=vsphere\,dc\=local>
java.security.cert.CertPathBuilderException: Unable to find certificate chain.

Which I could not see, so I wasn’t sure if this was the issue or not. What I did see in my logs was the following:

2021-09-17T23:58:03.945Z [tomcat-exec-14 WARN com.vmware.vcenter.trustmanagement.impl.VcIdentityProviders opId=] com.vmware.sso.interop.ldap.NoSuchObjectLdapException: No such object
LDAP error [code: 32]

and

2021-09-18T01:19:01.322Z [tomcat-exec-26 INFO com.vmware.vapi.security.AuthenticationFilter opId=] Not successful authentication
java.lang.RuntimeException: Authentication data not found
Caused by: com.vmware.vapi.dsig.json.SignatureException: Cannot verify the signature over the provided data

So it wasn’t matching. Looking at my firewall I couldn’t see any LDAP connections from vCenter to my LDAP server since the upgrade. So I decided instead to try a reboot. This simply made things worse.

No Healthy Upsteam

Now when I’d try access vCEnter Web UI I was greeted with a blank white web page with simple text stating “No Healthy Upstream”, now looking into this, people reached this problem for several different reasons. As mentioned here and here and for some odd reason this guy just changed his IP address?! Weird.

For me I checked the local Hosts file and it was fine, and couple other mentioned fixes and they all didn’t work for me.

Try Anyway

For some reason at this point I decided to double the mentioned work around in the initial VMware KB I found as the main login symptom was exactly the same even though I couldn’t validate the same log entries within the logs.

How to Copy Files to VCSA via WinSCP

Now a couple real quick things to note here. You need to copy a script to the VCSA. If you get unable to agree on a cipher suite, you’ll need to update your copy of WinSCP to a newer version. Also instead of doing what VMware says to change the shell on the VCSA, do what this guy suggests instead:

“In the new connection dialog, specify the Host name, User name and then click the Advanced button,

(VCSA 6.5)

Choose the Environment/SFTP option

Specify for SFTP server: shell /usr/libexec/sftp-server”

so much easier.

I decided to take a look at the script after copying it to the VCSA, and it had this line which had me hopeful it would actually work to resolve my issue:

/opt/likewise/bin/ldapmodify -x -h localhost -p 389 -D "cn=administrator,cn=users,$DOMAINCN" -w "$DOMAINPASSWORD" -f sso-sts.ldif | tee -a $LOGFILE

So I followed along with the workaround specified in the KB…

1) Download the attached fixsts.sh script from this article and upload to the impacted PSC or vCenter Server with Embedded PSC to the /tmp folder.

2) If the connection to upload to the vCenter by the SCP client is rejected, run this from an SSH session to the vCenter:

chsh -s /bin/bash

3) Connect to the PSC or vCenter Server with an SSH session if you have not already per Step 2.

4) Navigate to the /tmp directory:

cd /tmp

5) Run chmod +x fixsts.sh to make the file executable.

chmod +x ./fixsts.sh

6) Run ./fixsts.sh.

./fixsts.sh

Restart services on all vCenters and/or PSCs in your SSO domain by using below commands:

service-control --stop --all
service-control --start --all

my results:

To my Amazement it actually worked, and I was able to login into the vCenter server!! Wooo!

*Update* Here’s a great blog post covering managing or creating custom certificates with vCenter 7

Kinda funny that 7.0 is stated as 6.8 in the scripts.. mhmm

ESXi Update Network Config Failed
Set ESXi IP via CLI

Real quick post here. I was moving my ESXi hosts and vCenter to a new dedicated subnet. I did the usual; had a temp Windows System in the new subnet, create VMK with temp IP in new subnet, connect to ESXi Web UI via new Temp IP in new Subnet via temp Windows machine. Reconfigure default TCP/IP stack default gateway, change VMK0 IP address (and edit management port group VLAN id if applicable). and Away I’d go.

However on this one host for some unknown stupid reason it would simply fail “Failed – An Error occurred during host configuration”, and the detailed log was just as vague “operation failed diagnostics report unable to set network unreachable” OK… whatever, that shouldn’t matter do as I tell you! Here’s a snippet of the error, and the CLI command that simply worked without bitching.

I just figured let’s try the CLI way and see if it worked, and it turns out it did. The source I used to figure out the command syntax.

The commands I used:

Get IPs:

esxcli network ip interface ipv4 get

Set new IP:

esxcli network ip interface ipv4 set -i vmk1 -I 1.1.1.1 -N 255.255.255.0 -t static

Hope this helps someone.