This post is a guide on how to convert any VM into a template that can be used to clone new servers.
Control panel config
- Hardware > CD/DVD Drive (ide2) > edit and select “do not use any media”
- Hardware > Add > CloudInit Drive (needed for cloning to work)
- Options > QEMU Guest Agent. Click on Edit and check “Use QENU Guest Agent”.
- Options > Start at boot. Click on Edit and check box.
- Cloud-Init and change user and password options.
Update system and set-up QEMU agent
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| sudo apt update && sudo apt dist-upgrade
sudo apt install qemu-guest-agent
sudo systemctl start qemu-guest-agent.service
systemctl status qemu-guest-agent.service
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Make sure cloud-init is installed
Clear out host keys
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| ls -l /etc/ssh
sudo rm /etc/ssh/ssh_host_*
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Automate creation of SSH host keys
Copy and paste these contents into regenerate_ssh_host_keys.service
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| [Unit]
Description=Regenerate SSH host keys
Before=ssh.service
ConditionFileIsExecutable=/usr/bin/ssh-keygen
[Service]
Type=oneshot
ExecStartPre=-/bin/dd if=/dev/hwrng of=/dev/urandom count=1 bs=4096
ExecStartPre=-/bin/sh -c "/bin/rm -f -v /etc/ssh/ssh_host_*_key*"
ExecStart=/usr/bin/ssh-keygen -A -v
ExecStartPost=/bin/systemctl disable regenerate_ssh_host_keys
[Install]
WantedBy=multi-user.target
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| nano regenerate_ssh_host_keys.service
sudo chown root:root regenerate_ssh_host_keys.service
sudo mv regenerate_ssh_host_keys.service /etc/systemd/system
sudo systemctl daemon-reload
sudo systemctl enable regenerate_ssh_host_keys.service
sudo systemctl status regenerate_ssh_host_keys.service # verify it is enabled
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Make sure machine-id is empty
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cat /etc/machine-id # needs to be unique
sudo truncate -s 0 /etc/machine-id # empty it out
# check to ensure symlink exists (if it doesn't create it - sudo ln -s /var/lib/dbus/machine-id /etc/machine-id)
ls -l /var/lib/dbus/machine-id
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Run the following to make sure your image is as clean as possible
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| sudo apt clean
sudo apt autoremove
sudo poweroff
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Post Set-up commands to run
You should change the hostname for your new VM’s created form the clone so they are easy to identify
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sudo nano /etc/hostname # change it to whatever you want
sudo nano /etc/hosts # find the old hostname an dupdate it
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