From Fedora Project Wiki

(add instructions to connect via ssh (also, I forgot to describe the previous commit: "instead of having root account auto-enabled, enable the default 'fedora' user instead, to be consistent with other Fedora Cloud set-up instructions"))
m (reorder command arguments to make it look better)
 
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<ol>
 
<ol>
 
<li>Create the VM using the following command:
 
<li>Create the VM using the following command:
<pre>virt-install --name localcloud1 --memory 2000 --disk=size=10,backing_store="/path/to/Cloud.qcow2" --cloud-init user-data="/path/to/cloudinit-user-data.yaml" --noreboot --os-variant detect=on,name=fedora-unknown</pre>
+
<pre>virt-install --name localcloud1 --memory 2000 --noreboot --os-variant detect=on,name=fedora-unknown --cloud-init user-data="/path/to/cloudinit-user-data.yaml" --disk=size=10,backing_store="/path/to/Cloud.qcow2"</pre>
 
You can of course adjust all the values. Be sure to replace `/path/to/Cloud.qcow2` with an ''absolute'' path to your downloaded Fedora Cloud image, and `/path/to/cloudinit-user-data.yaml` with a path to the config file you created in the [[#Setup|Setup]] section.
 
You can of course adjust all the values. Be sure to replace `/path/to/Cloud.qcow2` with an ''absolute'' path to your downloaded Fedora Cloud image, and `/path/to/cloudinit-user-data.yaml` with a path to the config file you created in the [[#Setup|Setup]] section.
 
{{admon/tip|The original image is unchanged|Thanks to using the `backing_store{{=}}` option, a new ''overlay'' image is created (with the maximum size specified in `size{{=}}`) in a default libvirt image location, called `localcloud1.qcow2`, which only contains the changes you'd made on disk against the original Cloud image (`Cloud.qcow2`). The original Cloud image is kept untouched, and so you can reuse it repeatedly in future VMs.}}
 
{{admon/tip|The original image is unchanged|Thanks to using the `backing_store{{=}}` option, a new ''overlay'' image is created (with the maximum size specified in `size{{=}}`) in a default libvirt image location, called `localcloud1.qcow2`, which only contains the changes you'd made on disk against the original Cloud image (`Cloud.qcow2`). The original Cloud image is kept untouched, and so you can reuse it repeatedly in future VMs.}}

Latest revision as of 07:37, 1 December 2020

This guide shows how to test Fedora Cloud images using virt-install (which is a part of virt-manager).

Setup

  1. Install virt-install:
    sudo dnf install virt-install
    Important.png
    Minimum package version
    You need to have virt-install at at least version 3.2.0 for this guide to work.
    • If you just installed the whole libvirt virtualization stack with this command (you didn't have it before), it's recommended that you reboot your machine.
  2. Download the preferred Fedora Cloud image that you want to test. It's recommended to pick the qcow2 image (raw.xz works too, if you prefer it, just make sure you don't forget to decompress it).
  3. Create a file named cloudinit-user-data.yaml and populate it with the following content:
    #cloud-config
    password: 'CLOUDPASSWORD'
    chpasswd: { expire: False }

    Replace CLOUDPASSWORD with the password you want to authenticate with into the Cloud VM.

Create the virtual machine

  1. Create the VM using the following command:
    virt-install --name localcloud1 --memory 2000 --noreboot --os-variant detect=on,name=fedora-unknown --cloud-init user-data="/path/to/cloudinit-user-data.yaml" --disk=size=10,backing_store="/path/to/Cloud.qcow2"

    You can of course adjust all the values. Be sure to replace /path/to/Cloud.qcow2 with an absolute path to your downloaded Fedora Cloud image, and /path/to/cloudinit-user-data.yaml with a path to the config file you created in the Setup section.

    Idea.png
    The original image is unchanged
    Thanks to using the backing_store= option, a new overlay image is created (with the maximum size specified in size=) in a default libvirt image location, called localcloud1.qcow2, which only contains the changes you'd made on disk against the original Cloud image (Cloud.qcow2). The original Cloud image is kept untouched, and so you can reuse it repeatedly in future VMs.
  2. When a login prompt appears, log in as user fedora and the password you specified in the config file.
  3. Do whatever is needed in the VM (your current user can invoke sudo if you need to perform some administrative commands).
  4. You can either power the machine down using sudo poweroff, or just disconnect from the serial console using Ctrl+].

Connect to the virtual machine later

  • If you want to connect to an existing localcloud1 VM later, first make sure it is started:
    virsh start localcloud1

    and then connect to the serial console:

    virsh console localcloud1

    (hit Enter to see the command/login prompt)

  • You can also control and connect to the VM from virt-manager.

Connecting through the network

If you want to SSH into the VM (connect through the network), then the VM must be created in qemu:///system scope (the default is qemu:///session).

  1. Delete the existing VM and create it again, but this time append --connect qemu:///system argument to all virt-install and virsh commands.
    • Alternatively, you can run
      export LIBVIRT_DEFAULT_URI=qemu:///system
      in your terminal and then all future commands in that terminal will use the system scope by default.
  2. Once you have your VM running in the system scope, connect to it via the serial console as usual:
    virsh --connect qemu:///system console localcloud1
    and figure out its IP address from within the VM using:
    ip address
    • Alternatively, you can figure out the VM's IP address from the host using:
      virsh --connect qemu:///system domifaddr localcloud1
  3. SSH to the VM as usual:
    ssh fedora@IP_ADDRESS

Clean up the virtual machine

  • You can easily remove your VM together with the overlay disk drive. Fist make sure the VM is shut down:
    virsh destroy localcloud1

    and then remove the VM and its disk:

    virsh undefine --remove-all-storage localcloud1
  • You can also remove your VM from virt-manager.