Virtualization Adapted Adapting Business Processes for Virtual Infrastrcuture (and vice-versa)

2009/03/19

how to reset root password on vmware esx classic

Filed under: virtualization — Tags: , , , , , , — iben @ 11:15

Follow these steps if you need to reset the root password on an ESX classic.

Note: Ignore the “quote marks” in the instructions below.

1 – turn on system (if it’s on then reboot it with Ctrl-Alt-Del from console)
2 – when grub appears press the “tab” key
3 – highlight VMware ESX line using the “arrow” keys
4 – press the “e” key
5 – scroll to kernel line using the “arrow” keys
6 – press the “e” key (again, I know!)
7 – press the “end” key to move cursor to end of the kernel line
8 – type the word “single” (using the keys)
9 – press the “b” key to boot the ESX host into single user mode
10 – eventually a “sh-3.2#” root prompt will appear
11 – use the command “passwd” to reset the password
12 – use the command “reboot” to reboot the ESX machine
13 – login to the console or the vic using the new password!

That’s it! I hope this procedure works for you. Your feedback is appreciated.

Morale of this story is:
1 – always protect the physical environment where you ESX host is located.
2 – always secure the Lights Out/Remote Access/IP-KVM/console access to your host.
3 – consider using a GRUB password on your ESX host so as to prevent password resets.

2009/03/09

Overhead Memory Table on ESX Virtual Machines

Filed under: virtualization — Tags: , , , , — iben @ 13:46

Refer to page 30 of http://www.vmware.com/pdf/vsphere4/r40/vsp_40_resource_mgmt.pdf or page 136 of http://www.vmware.com/pdf/vi3_35/esx_3/r35/vi3_35_25_resource_mgmt.pdf

Memory overhead usage chart

Memory overhead usage chart

Some examples:

With 1 vcpu and 256MB of RAM; the VM kernel requires 87MB for 32 bit VM’s and 108MB for 64 bit VM’s.

With 8GM of RAM and 1 vCPU you’ll need 188MB and 209MB for 32 and 64 bit.

With 4 vCPU’s and 8GB of RAM you’re looking at ~360MB for a 32 bit VM and 431MB for a 64 bit VM.

Note: memory overhead for 32-bit VMs generally increased between 3.0.1 and 3.5 while 64-bit overhead generally decreased.

ESX 3.5 Overhead

ESX
3.5 Update 2
Virtual CPUs Virtual Memory (MB) Overhead for 32-bit VM
(MB)
% Overhead for 32-bit VM Overhead for 64-bit VM
(MB)
% Overhead for 64-bit VM
1 256 87.56 34.20% 107.54 42.01%
1 512 90.82 17.74% 110.81 21.64%
1 1,024 97.35 9.51% 117.35 11.46%
1 2,048 110.40 5.39% 130.42 6.37%
1 4,096 136.50 3.33% 156.57 3.82%
1 8,192 188.69 2.30% 208.85 2.55%
1 16,384 293.07 1.79% 313.42 1.91%
1 32,768 501.84 1.53% 522.56 1.59%
1 65,536 919.37 1.40% 940.84 1.44%
2 256 108.73 42.47% 146.41 57.19%
2 512 114.49 22.36% 152.20 29.73%
2 1,024 126.04 12.31% 163.79 16.00%
2 2,048 149.11 7.28% 186.96 9.13%
2 4,096 195.27 4.77% 233.30 5.70%
2 8,192 287.57 3.51% 325.98 3.98%
2 16,384 472.18 2.88% 511.34 3.12%
2 32,768 841.40 2.57% 882.06 2.69%
2 65,536 1579.84 2.41% 1623.50 2.48%
4 256 146.75 57.32% 219.82 85.87%
4 512 153.52 29.98% 226.64 44.27%
4 1,024 167.09 16.32% 240.30 23.47%
4 2,048 194.20 9.48% 267.61 13.07%
4 4,096 248.45 6.07% 322.22 7.87%
4 8,192 356.91 4.36% 431.44 5.27%
4 16,384 573.85 3.50% 649.88 3.97%
4 32,768 1007.73 3.08% 1086.75 3.32%
4 65,536 1875.48 2.86% 1960.52 2.99%
Averages 408.30 11.51% 453.30 15.29%

ESX 3.0 Overhead

vcpu vRAM 32 bit overhead 64 bit overhead
1 256 79 174
1 512 79 176
1 1024 84 180
1 2048 91 188
1 4096 107 204
1 8192 139 236
1 16384 203 300
2 256 97 288
2 512 101 292
2 1024 101 300
2 2048 125 316
2 4096 157 349
2 8192 221 413
2 16384 349 541
4 256 129 511
4 512 133 515
4 1024 141 523
4 2048 157 540
4 4096 189 572
4 8192 222 605
4 16384 350 734

TCP Wrappers for ESX Classic

Filed under: virtualization — Tags: , , , , , , , — iben @ 08:50

Here’s an example hosts.allow:
#begin
sshd:management.host.com:allow
sshd:ALL:deny
xinetd:management-host-ip-or-fqdn-hostname:allow
xinetx:ALL:deny
httpd:management-host-ip-or-fqdn-hostname:allow
httpd:ALL:deny
#eof
But even this may be too simple.

Reference:
http://www.dell.com/downloads/global/…/tnc/dell_vmware_certified_deploy.pdf

http://communities.vmware.com/thread/182964?tstart=0
What this will do is allow all hosts to ssh into the system while only allowing VI client connections from the virtualcenter server. This means you pretty much have to go through virtualcenter to manage the system.

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