Vmware Vcenter Operations Manager Unregister a Vcenter Server via the CLI

Vmware-workstation-17-535x535So my Windows based Vmware Vcenter Server went belly up again. Something to do with the SSO database not starting. Not being a lover of Windows I decided to give the Vcenter Server Appliance a shot. Install was great and I am kicking myself a bit as to why I spent so much time fighting with Windows. My new Vcenter Server, which has a different IP address then the original Windows box (might make a great Veeam server) was not registered with Vcenter Operations Manager. I was not prepared to reinstall that thing again. So I needed to figure out how to manually unregister a Vcenter instance and add register another one in its place.

Since VCOPs runs Linux, I decided to ssh into the server and see if I could figure it out. First thing I found that I needed to do was figure out the registered Vcenter Server name and Vcenter Name (whatever that's supposed to be) I was able to do this using the vcops-admin command.

admin@vcops:~> vcops-admin summary


This command output a bunch of stuff, but the important bits for this task are below.

Registration Details
vCenter Server address  = https://vc00.lab.localdomain/sdk
vCenter Server name = Lab Vcenter


So now we need to unregister the sucker above. Note that this command takes a bit to unregister

admin@vcops:~> vcops-admin unregister –vc-name Lab\ Vcenter –vc-server https://vc00.lab.localdomain/sdk –user LAB\\userid –password mypassword–force

vCenter Server unregister = success


So flip on over to your browser and log in. The unregister process will cause the webUI to reload, so if you were already logged in you will find that you still need to log in again.

Now you can register your new Vcenter Server via the webUI.

Related articles

Vmware VCenter Virtual Appliance – Death to Windows.. I think.
ESX 5: How to Power On A Virtual Machine from the Command Line
vCenter Operations Manager: VMware's move into cloud monitoring?
VCOPs – VMware's Move into Cloud Monitoring

ESX 5: How to Power On A Virtual Machine from the Command Line

Avengers_lego___captain_america_by_robking21-d4wjhwtSo lately I have been noticing some strange issues with my home lab. Every so often I find my all my virtuall machines are down, however the ESX box is up and running fine. Checking the logs on the ESX server has not helped me get to the bottom of the issue, rather I can just see the messages that the server has rebooted. So at the very least I know that something is happening to the ESX server causing it to crash.

This morning I happned to get lucky as I was sitting in my office when the basement airconditioner turned on around the same time that the whole home dehumidifier kicked on. Bleep when all my UPSs, and then I heard my ESX server power off and power back on again.

So now I am on a mission to figure out how to get my ESX server and my UPS to communicate so i can get at least 30 seconds of power during brownout. However this is an issue for another day, right now I just need to get my Vcenter Server back up and running, however my challenge is how to do so despite the fact that I do not have a Windows machine that I can use to connect directly to my ESX server via Vcenter Client.

Thanfully I can power up my Virtual Machines on the Command Line Via SSH. First step is to log into the ESX Server and get a list of all the Virtual Machines that are currently registerd on it. You can do this using the command below.


 # vim-cmd vmsvc-getallvms

Now that I have a list of all my registered Virtual Machines, I need to check its current power state and ensure that it is in fact powered off.

~ # vim-cmd vmsvc/power.getstate 1
Retrieved runtime info
Powered off

Yup – its down. Now lets power it back on.

~ # vim-cmd vmsvc/power.on 1
Powering on VM:
~ #

Now wait a minute or so to allow the Virtual Machine time to boot… Now I should be able to RDP from my Linux Workstation to the Vcenter Server. No extra Windows Workstations needed.

Related articles

Vmware VCenter Virtual Appliance – Death to Windows.. I think.
HomeLab: Simple DHCP Service Configuration on a Cisco Router
NEW VMSA-2013-0016 VMware ESXi and ESX unauthorized file access through vCenter Server and ESX
Anonymous leaks VMware ESX Server Kernel source code

Install and Configure SNMP on the Asus RT-AC66U Router

ASUS_RT-AC66U_newsOk first off let me start by saying that this is probably the coolest piece of home computing hardware that I have ever laid my hands on. Yes the setup was easy, and yes the thing is rock solid, and yes wireless range is awesome. But for approx $200 USD you really should not expect anything less.  I’m not going to go into its specs or features, as I’ll leave that to the professionals. Read up on it here.

Anyway out of the box it supported telnet, but I wanted ssh, so I dropped the default firmware and went with Asuswrt-Merlin. It was at this point I started to explore the Busybox OS and decided I wanted to monitor the device via my HomeLab Zenoss install.

However, much to my chagrin net-snmp was not installed out of the box.

So how do you install it you ask? Would you believe via a package manager?

First, you need to find the package name

#ipkg list | grep snmp

Then install the snmp package

#ipkg install net-snmp

Then configure it to start at boot time.

#app_set_enabled.sh net-snmp yes

In order to configure it, you are going to have to search for the snmp.conf

#find / -name snmpd.conf

I found two files and one of them clearly states that you should not edit it directly. The other one does not so this is the one that I modified to include my custom rocommunity. See below.

rocommunity  lab

Now I just need to figure out how to allow port 161 udp/tcp on my local LAN segment and I am in business. However, I will probably tackle that tomorrow.


Additional Info (2016)

Note, you can restart snmp as shown below.


admin@RT-AC66U:/tmp/home/root# app_stop.sh net-snmp
killall: dm2_transmission-daemon: no process killed
killall: asus_lighttpd: no process killed
killall: dm2_snarfmaster: no process killed
killall: dm2_nzbget: no process killed
killall: dm2_amuled: no process killed
iptables: No chain/target/match by that name
iptables: Bad rule (does a matching rule exist in that chain?)


admin@RT-AC66U:/tmp/home/root# app_set_enabled.sh net-snmp yes
The field(Enabled) was set “yes” already.
Restarting the package…


2016 Update – Configuring SNMP via the WebUI

Figured that I would add an update to this post as it seems that there are plenty of folks who are looking to setup SNMP on their Asus routers. Note that SNMP can now be configured directly from the WebUI.

In the left pane, click on “Advanced Setting”. Then click on the “SNMP” tab. See example below. Note that the webui does not seem to pick up your configuration if you have configured it via the cli. I have not tested to see if the WebUI overwrites the CLI configuration or if it creates another configuration file.


Additional Resources

Fatmin: How to Add a Static Route on the Asus RT-AC66U

Fatmin: Install and Configure SNMP on the Asus RT-AC66U

Cisco UCS Failover Via 6248 CLI

Ucs_6248_lg1Need to fail over Cisco UCS Manager from one 6248 to another. Oh did I mention that you are in a hurry because you are going to have to sift through pages and pages of pdfs to get the information. I found this out the hard way. Anyway, out of the kindness of my heart I have documented this process below.

First log into one of your 6248s and figure out which one is the primary by running the command below.

ucs01-A# show cluster state
Cluster Id: 0x4b05e6042b6111e1-0x8c9e547fee4bbf24


Note that UCS01-B is our primary. So log into UCS-B and issue the command below.

ucs01-B# connect local-mgmt

Then run the command to make UCS-A our primary.

ucs01-B(local-mgmt)# cluster lead a
Cluster Id: 0x4b05e6042b6111e1-0x8c9e547fee4bbf24

Note that you must issue the failover command on the node that is the primary, otherwise this happens.

ucs01-A(local-mgmt)# cluster lead a
Cluster Id: 0x4b05e6042b6111e1-0x8c9e547fee4bbf24
request failed: local node is subordinate

During the failover process you will see the output below when checking the cluster state.

ucs01-B(local-mgmt)# show cluster state

Cluster Id: 0x4b05e6042b6111e1-0x8c9e547fee4bbf24 B: UP, PRIMARY, (Management services: SWITCHOVER IN PROGRESS) A: UP, SUBORDINATE,

(Management services: SWITCHOVER IN PROGRESS) HA NOT READY Management services: switchover in progress on local Fabric Interconnect

Forcibly Remove a Host From XenCenter via CLI

PicklePD3Welcome back to another XenServer adventure. Today we are going to review the process of removing an orphaned XenServer host from XenCenter via the command line.

A few days ago one of my Xen hosts died due to an issue with the raid controller. In order to revive it I had to rebuild it, and add it back into the pool. However there was a problem; the original entry for this host in XenCenter appeared in red, which indicated that it was disconnected, and another entry for the same exact host with the same exact hostname appeared next to it in the host list for this particular cluster. I was unable to remove the orphaned host via XenCenter as there was no remove option.

I was in a pickle.

However I was able to find a solution.

First and formost it appears that there are actually two ways to do this; the first one being from the Windows command line where you are running Xencenter, or on the master node in the cluster.

This example is from the Windows CLI. Note that the UUID that is output to the command line is the UUID of the Host that is unreachable — the orphaned host.

C:\Program Files\Citrix\XenCenter>xe -s <Hostname_of_master> -u root -pw <root_password> pool-sync-database
You attempted an operation which involves a host which could not be contacted.
host: 560e233b-0e8b-4c2f-a641-cf1876630a6b (virt04.atlc1)

C:\Program Files\Citrix\XenCenter>xe -s <Hostname_of_master> -u root -pw <root_password> host-foget uuid=560e233b-0e8b-4c2f-a641-cf1876630a6b
WARNING: A host should only be forgotten if it is physically unrecoverable;
WARNING: if possible, Hosts should be 'ejected' from the Pool instead.
WARNING: Once a host has been forgotten it will have to be re-installed.
WARNING: This operation is irreversible.
Type 'yes' to continue

Returning to XenCenter I found that the orphaned host entry had been removed.


Removing a Virtual Disk from CentOS/RHEL via vSphere Client

PxdxaDisco08 When you right click on a VM via the vSphere client and click edit setting you will see your hard disk enumerated as follows:

Hard disk 1 - Virtual Disk

Hard disk 2 - Virtual Disk

However CentOS/RHEL enumerates your disks using a different nomenclature. See below:

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        1044     8385898+  83  Linux
/dev/sda2            1045        2349    10482412+  83  Linux
/dev/sda3            2350        2610     2096482+  82  Linux swap

Disk /dev/sdb: 268.4 GB, 268435456000 bytes
255 heads, 63 sectors/track, 32635 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       32635   262140606   83  Linux


While you can assume that the your first disk listed in ESX is your first disk listed via the OS, this is not always the case. You can attempt to compare disk sizes to further determine which disk is which, however the sizes do not always match up.

The best way to identify disks is via the Virtual Device Node, which is visible via the virtual disk properties in ESX and via the command lsscsi in Centos/OS.

More than likely lsscsi is not installed via default so you are going to either need to install via yum, or download a rpm and install. Once installed run as seen below

[0:0:0:0]    disk    VMware   Virtual disk     1.0   /dev/sda
[0:0:1:0]    disk    VMware   Virtual disk     1.0   /dev/sdb
[0:0:2:0]    disk    VMware   Virtual disk     1.0   /dev/sdc
[0:0:3:0]    disk    VMware   Virtual disk     1.0   /dev/sdd

The first two numbers are unique to the scsi controller and the second two numbers indicate the disk number which can be seen in the disk properties in the vsphere client properties.

For example in vmware Hard disk 4 has a virtual device id of “SCSI (0:3) Hard Disk 4, and by running lsscsi I know for sure that this disk is /dev/sdd. Now I can remove the disk with confidence from esx and have to worry that I removed the wrong disk.

Reset HP ILO Via the Command Line

Gary_the_snail Its not unheard of that an HP ILO (Integrated Lights Out) can become sick and slow down to a crawl. When this occurs, a restart of the ILO is in order, which is easily accomplished via the ILO cli interface. Note that you need to make sure that that you have enabled ssh access in ilo.

The steps to reset an ilo via ssh are below.

</>hpiLO-> cd /map1

</map1>hpiLO-> reset
Resetting iLO.

CLI session stopped

Additional Resources: