Tag: esxi

Posted on

VMWare: How to Change the ESXi System Time and HW Clock on the CLI

This article details how to change the ESXi system time and HW clock on your ESXi hypervisor machine via the CLI.

Ideally we want to use NTP to set the system time but if your clock is too far out from the actual time then this will fail and you may see something like this in the syslog file:
ntpd[263140]: synchronized to <46.249.47.127>, stratum 1
ntpd[263140]: time correction of <54423> seconds exceeds sanity limit (1000); set clock manually to the correct UTC time.
[info 'ha-eventmgr'] Event 91 : NTP daemon stopped. Time correction 1206 > 1000 seconds. Manually set the time and restart ntpd.
The situation was that my VMs were synchronising their time to the ESXi host’s on every reboot, meaning that some important secure system services (in Windows 2008 in particular) were not starting. There isn’t the facility to do this on the DCUI (Direct Console User Interface – the yellow and black screen) so here’s the gen on how to achieve this using the command line.

My first endeavours were using the “date” command, as I’m used to doing in Linux, unfortunately these were met with the error:

~ # date 100410112014
date: can't set date: Function not implemented
Sat Oct  4 10:11:00 UTC 2014

OK, it’s being pernickety so lets use the “-s” flag to SET the time:

~ # date -s 041010112014
date: Setting date not supported; use <esxcli system time set>

Now we’re getting somewhere. The command takes the following parameters:

Usage: esxcli system time set [cmd options]
Description:
set                   Set the system clock time. Any missing parameters will default to the current time
Cmd options:
-d|--day=<long>       Day
-H|--hour=<long>      Hour
-m|--min=<long>       Minute
-M|--month=<long>     Month
-s|--sec=<long>       Second
-y|--year=<long>      Year

So, to set the system time to 10th April 2014, 10:18 (am):
~ # esxcli system time set -d 10 -H 10 -m 18 -M 04 -y 2014

Also, make sure that we also set the hardware clock time as the system time will revert to this on a reboot:

~ # esxcli hardware clock set -d 10 -H 10 -m 18 -M 04 -y 2014     <- sets the hardware clock to 10th April 2014, 10:18 (am)

To check the hardware and system time we can use the following commands:

esxcli hardware clock get
esxcli system time get

Job done! Now move on to setting the time automatically using NTP.

Related posts:

Posted on

Linux: Hot Clone a Live *nix Machine

This article describes how to clone a live production linux server to a VM on ESX infrastructure although it is the same process to clone to another physical machine.

Prepare the Target Machine

Prepare a new server on ESX debian 32 bit machine, same hdd size etc:

In the past I’ve always used the DSL (Damn Small Linux) distro to boot from but this time I noticed that it didn’t pick up the hard drive on ESX so rather than mess around I tried Puppy Linux – it’s 160 MB compared to DSL’s 50MB but the hassle factor decided it for me and I’m very happy with it 🙂 

 

Check your fstab:

 

root@localhost:~# cat /etc/fstab
LABEL=DOROOT       /               ext4    errors=remount-ro 0       1


root@localhost:~# blkid /dev/disk/by-label/DOROOT
/dev/disk/by-label/DOROOT: LABEL="DOROOT" UUID="2c342fc9-3fcd-42fb-a837-1135ce07fe9c" TYPE="ext4"

Here we only have one filesystem to worry about – “/” – so it should be a straightforward exercise.

Make a single partition on our new VM (no swap partition on original – might need to address this)

Commands:

# fdisk /dev/sda (may be different to sda in your case, check your dmesg output)

Then “n” to add a new partition and accept the defaults for the start and finish – these will be the whole device. When done, enter “w” to write the partition to disk.

We also need to make it bootable so back into fdisk. “p” will print the partition table and here we can see /dev/sda1. Enter “a” to make a partition bootable and then the partition number; in this case we only have one partition butbasically you make the partition that contains “/boot” bootable. Again, enter “w” to write the partition to disk:

Format our partition using the same filesystem as our source machine – ext4 in this case:

Make a mount directory (remember we’re still in puppy linux in memory) and mount the hard drive partition(s) to it. Then create our other parts of the filesystem – dev, sys, proc and tmp:

Copy the Live System to the Target Machine

Make sure VM has connectivity to live source machine and perform the rysnc:

    rsync -aHxvz root@1.2.3.4:/* /mount --exclude=/dev --exclude=/proc --exclude=/sys --exclude=/tmp

The switches used are as follows:

  • -a – archive mode – a shortcut to avoid using multiple switches and ideal for backups – serverfault has a good description.
  • -H – preserve hard links – not necessary for a backup but certainly for cloning
  • -x – preserve extended attributes
  • -v – verbose output – keep an eye on what’s going on
  • -z – although it’s not on the screenshot above, use this to enable end-to-end compression.

Modify the Filesystem Table (fstab) and Install Grub

Update the filesystem table (fstab) if necessary. This is currently under /mount/etc/fstab – info on the format can be found here.

Install the grub bootmanager using the following command:

# grub-install --root-directory=/mnt/sda1 /dev/sda

Once it’s done, say a quick prayer and reboot, hopefully job done!

** If, however, you run into errors (like the “/dev/sda does not have any corresponding BIOS drive” error) and you don’t have enough time or experience with grub configuration, my advice would be to download the most illustrious Boot Repair Disk and allow it to install / reconfigure your grub.

And then it really is job done 🙂

Cleaning Up!

Keyboard Map

For some reason, the keyboard map had changed, meaning that I my root password appeared to be wrong. Once I got logged in, a quick keyboard mapping sorted it out – easily done using the following command:

dpkg-reconfigure console-data

NIC Configuration

Your new machine will also have the same network configuration as your live one and will most likely need reconfigured – see the debian wiki for step-by-step instructions on how to achieve what you need. The main config file is /etc/network/interfaces.

/tmp Permissions

Make sure your /tmp directory has correct permissions set; you may not notice this until a daemon fails e.g. mysqld because it can’t write to the directory

# chown root:root /tmp
# chmod 1777 /tmp

 

Related posts:

Posted on

Checkpoint: Gaia on ESX – “No Hard Drives Have Been Found” Error

 

This article describes how to fix the error “No Hard Drives Have Been Found” when installing Checkpoint Gaia on ESX.

This is a simple one – I used to work round it by implementing an IDE drive instead of SCSI but actually it’s just due to the SCSI controller type. It happens when you choose a Red Hat machine which in turn sets the SCSI controller type to VMware Paravirtual as shown here below:

 

All you need to do is go into the VM Settings, SCSI Controller, and change the SCSI controller type from “VMware Paravirtual” to “LSI Logic Parallel” or to “LSI Logic SAS.”

Job done! Screenshots available in SecureKnowledge here.

 

Related posts:

Exit mobile version
%%footer%%