Virtual Machines

Basic Virtual Machine Tasks

Start / Stop / Bounce a VM

1. Log into the Virtual Infrastructure - Management Access
2. Under the Inventory button, ensure Hosts and Clusters is ticked
3. Highlight the VM you want to affect
4. Either right-click or use the commands in the right hand pane to Power off, Power on, Reset as required

This is the same as using the Power or Reset buttons on the front of a physical server. It's possible to send Windows shut down etc commands to the VM; right click over the VM and select the appropriate Shut Down Guest, Restart Guest command. This tells VM Tools to attempt to perform the required action, obviously open applications etc can inhibit the successful shutdown of an OS.

Remote Console (KVM like) Access

If possible, its preferable to use normal remote access software (eg RDP, or VNC). This ensures that load caused by remote access is contained within the VM, rather than the ESX.

1. Log into the Virtual Infrastructure - Management Access
2. Under the Inventory button, ensure Hosts and Clusters is ticked
3. Highlight the VM you want and either right click Open Console or use the Open Console command in the right hand pane

CD-ROM Access

There are essentially two ways to present a CD-ROM image to a VM, using an ISO image is by far and away the most flexible. Even if you only have a physical CD and expect to use it once, its still recommended that you create an ISO image from the CD and use that instead. The alternative is to put the physical media into the ESX hosting the VM (use Host Device when adding the CD to the VM).

To present an ISO image to a VM

1. If its not already there, copy the ISO image to the Virtual Centre server's NFS share - \\uklonvcp1\NFS_Share
2. Log into the Virtual Infrastructure - Management Access
3. Under the Inventory button, ensure Hosts and Clusters is ticked
4. Highlight the VM you want to attach the ISO image to
5. Right-click and select Edit Settings...
6. Highlight the CD/DVD Drive, and select the Datastore ISO file
7. Hit Browse and go into the UKLONVCP1 NFSShare datastore
8. Select the required ISO file
9. Tick the Connected check box
10. Hit OK, the ISO will be attached to the VM's CDROM drive as if you'd inserted a CD into a physical drive

• Once you've finished using the ISO, go back into the VM's settings and untick the Connected check box
• To boot a VM to a CDROM ISO, check the "Connected at power on" checkbox and restart the VM's OS

To create an ISO image

You'll need to download an ISO creator, there are many freeware utilities available, however one that's tried and tested is ISORecorder. Generally you can create ISO images from both a physical CD, or just the contents of a folder (if you have ISORecorder installed, right-click over the disk or folder and select "Create ISO image")

Change Network Connection

In similar fashion to being able to swap over a network cable for a physical server, the network connection of a virtual machine can be changed on the fly

1. Log into the Virtual Infrastructure - Management Access
2. Under the Inventory button, ensure Hosts and Clusters is ticked
3. Highlight the VM you want to change the network connection on
4. Right-click and select Edit Settings...
5. Hightlight the appropriate Network Adapter, and select the new Network Connection
6. Change takes effect as soon as OK is hit

Add an Additional Network Connection

When adding additional network connections to any system you must consider network security, for example no system should ever be given access to both Private and Public networks.

1. Shut down the Application and OS of the virtual machine
2. Log into the Virtual Infrastructure - Management Access
3. Under the Inventory button, ensure Hosts and Clusters is ticked
4. Highlight the VM you want to add the network connection to
5. Right-click and select Edit Settings...
6. Hit the Add... button and select Ethernet Adapter, and hit Next
7. Select the appropriate network connection and hit Next, and then Finish
8. Power on the virtual machine

Change Physical Memory / CPU's Allocation

1. Shut down the Application and OS of the virtual machine
2. Log into the Virtual Infrastructure - Management Access
3. Under the Inventory button, ensure Hosts and Clusters is ticked
4. Highlight the VM you want to change the network connection on
5. Right-click and select Edit Settings...
6. Hightlight the appropriate setting, Memory or CPUs, and edit as required.
7. Apply the change by hitting OK
8. Power on the virtual machine

Increase Disk Size

Increasing the virtual disk size provided to a VM is straight forward...

1. Go into the VM's settings
2. Increase the size of the disk and apply
3. Within the VM's OS, rescan the disk, and the new space will be visible

The trick is to extend the logical partition, and depending on the original partition type, the options vary. Generally boot or system disks cannot be extended whilst the OS is up, whereas normal data disk can be in later OS's, but this is still not ideal. Its generally most reliable to plan for system down time, and use a utility to extend the partition whilst its offline. Especially in a virtual environment there is no excuse for not making a backup of the partition 1st. For older Windows machines (excluding Win7 and Win2k8)...

Partition	Type	Options
System	Either	Cannot be extended
Data	Basic	Cannot be extended, can convert to Dynamic, but this will require a brief IO interruption.
Data	Dynamic	Can be extended on the fly, but a new volume is tagged onto the end of the existing partition to create a larger one made up of two volumes

Increase Logical Partition

Download a copy of the GParted Live CD - http://gparted.sourceforge.net/livecd.php, this will need to be booted to by the VM

• Note There is a bug in some recent versions of GParted (v0.5.0-3 and v0.5.1-1 are known to have issues), whereby the boot fails with the following error, v0.4.6-1 is known to work
  • Unable to find a medium containing a live file system

1. Increase the relevant VMDK size through the VM's options
2. Start snapshoting (or take a full backup of the machine)
3. Attach GParted ISO to VM and restart
   • If VM doesn't boot to the ISO, force the VM to boot to BIOS (Options | Advanced | Boot Options in VM Settings) and change the VM's boot order
4. Boot into GParted Live (accepting the default options, except setting language to English UK)
5. Once in GParted, follow the interface, and apply changes to action
6. Restart VM and verify all is good
7. Turn off snapshotting

Troubleshooting

Can't Connect to VM Console

Error connecting: Cannot connect to host...

• This is caused by a TCP connection failure to the ESX server the VM is hosted on. Using telnet or a port test utility, confirm you can connect on both TCP 902 and 903 from your machine to the ESX server.

Can't Deploy VM

The VirtualCenter server is unable to decrypt passwords stored in the customization specification

• Bizarrely caused by the Virtual Centre running out of disk space, free up some space and all will be well.

A general system error occurred: Failed to create journal file provider

• Check ESX disks are not full

Can't Start VM

HA Admission Control

• Can't start VM as doing so wouldn't leave enough failover capacity in order to be able to restart failed VM's should an ESX fail. Options are to
  • Reduce resource usage of VM's that are already running
  • Increase cluster capacity
  • Reduce the cluster's failover capacity, or allow constraints violations

Access to VMFS storage

• ESX may have lost connectivity to VMFS partition on which VM resides

VMFS full

• If VMFS is full, the ESX won't be able to write to the VM's logs when it starts it up, causing VM start-up to fail

ESX licensing

• Either ESX isn't licensed, or has lost contact with the license server (VI3) for a long period of time

Waiting for question to be answered

• Generally after changes (such as cold migrations or new deployments), a VM may need to have a question answered before it can continue to power on

Can't VMotion a VM

VM network doesn't exist at destination

• VM is using a particular port group which doesn’t exist on the destination ESX

ESX / network too busy

• VMotion can’t copy across VMs memory contents/changes quickly enough. An alternative is to use a Low Priory VMotion, which is more likely to succeed, but may result in the VM experiencing temporary freezes (avoids full OS downtime, but not without impact to hosted applications)

ESXs can't communicate'

• ESXs need to be able to communicate via VMotion network. DNS problems and FQDN inaccuracies can also cause problems

VM is connect to CD-ROM/ISO

• VMs CD-ROM is connecting to an ISO file via the host ESX, tying it to that ESX