Virtualization with libvirt - Historial de revisiones

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‎Step 3: Configuring the Ubuntu image with virt-customize

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For the realization of this practice you will need an Ubuntu Cloud image that we will download from https://cloud-images.ubuntu.com/ and we will need a
host system with Ubuntu 18.04.

In this practice we will use the image downloaded from the Ubuntu Cloud website and we will use the '''cloud-init''' tool to configure it.

Next, we will use the Ubuntu image already configured to be imported to the virtualization software '''libvirt''''.

= Step 1: Downloading the Ubuntu Cloud image

We enter https://cloud-images.ubuntu.com/ and download the Ubuntu 18.04 LTS (Long Time Support) image.

You can download it directly with the command ''wget'':

<syntaxhighlight lang="bash">
wget https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img
</syntaxhighlight>

if it started downloading you will see output similar to this:

<syntaxhighlight lang="bash">
-2019-08-06 12:26:26-- https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img
Resolving cloud-images.ubuntu.com (cloud-images.ubuntu.com).... 91.189.88.89, 2001:67c:1560:8001::8001
Connecting to cloud-images.ubuntu.com (cloud-images.ubuntu.com)[91.189.88.89]:443... connected.
HTTP request sent, waiting for response... 200 OK
Length: 343474176 (328M) [application/octet-stream] [application/octet-stream] [application/octet-stream]...
Saving to: "bionic-server-cloudimg-amd64.img"

bionic-server-cloudimg-amd64.img. 0%[ ] 2.21M 472KB/s eta 14m 6s
</syntaxhighlight>

Wait until the image is 100% downloaded.

The Ubuntu cloud image comes with 2 GBytes of space by default, you can expand the size with the following command before using it in the virtual machine:

<syntaxhighlight lang="bash">
qemu-img resize bionic-server-cloudimg-amd64.img +8G
</syntaxhighlight>

This increases the image by 8 Gbytes, so you are left with a 10 GByte Ubuntu cloud image.

= Step 3: Installing the libguestfs package =

Next, you have to install the [[packages]] that provide the ''virt-customize'' tool to configure the Ubuntu image you downloaded.

We can install these packages with the '''apt'''' tool from the shell.

For Ubuntu 18.04:

<syntaxhighlight lang="bash">
sudo apt install libguestfs
</syntaxhighlight>

For Ubuntu 20.04:

<syntaxhighlight lang="bash">
sudo apt install libguestfs-tools
</syntaxhighlight>

''On the practice classroom computers these packages will already be pre-installed, so you can skip this step.''

= Step 3: Configuring the Ubuntu image with virt-customize =

The ''virt-customize'' command allows you to set the password of the administrator user of the image we have downloaded.

<syntaxhighlight lang="bash">
virt-customize -a bionic-server-cloudimg-amd64.img --root-password password:coolpass
</syntaxhighlight>

The above example shows how to configure the downloaded image to have the user ''root'', and in this case, the password is ''coolpass''.

Translated with www.DeepL.com/Translator (free version)

← Revisión anterior		Revisión del 18:14 26 nov 2021
Línea 387:		Línea 387:

	* https://dennisnotes.com/note/20180614-ubuntu-18.04-qemu-setup/		* https://dennisnotes.com/note/20180614-ubuntu-18.04-qemu-setup/
		+
		+	= Exercise 1 (2021-11-26) =
		+	1. Create 2 Virtual Machines with the same image
		+	2. Install the package "netcat" in both
		+	3. Create a netcat server in VM1 using
		+	<syntaxhighlight lang="bash">
		+	nc -l -p8000
		+	</syntaxhighlight>
		+	4. Connect to said server in VM2 using
		+	<syntaxhighlight lang="bash">
		+	nc IP_VM1 8000
		+	</syntaxhighlight>
		+	5. Install openssh-server in VM1 and openssh-client in VM2

@@ Línea 329: / Línea 329: @@
 * From the host machine, we should ping both machines.
-= Step 7: Snapshots of virtual machines
+= Step 7: Snapshots of virtual machines =
 Snapshots allow us to store a snapshot of the running state of a virtual machine at a certain point in time that we can restore when necessary. The snapshots will be useful if you have work half done in the virtual machine, so that you want to save what you have done to restore it later.
@@ Línea 358: / Línea 358: @@
 After this we have a hard disk with a capacity of 5 GBytes to use in a virtual machine.

← Revisión anterior		Revisión del 17:08 26 nov 2021
Línea 308:		Línea 308:

	More information about [[network configuration in libvirt]] is available.		More information about [[network configuration in libvirt]] is available.
		+
		+	= Step 6: Cloning of virtual machines =
		+
		+	We are going to reuse the configuration and the created virtual machine, to create several identical ones. Let's start:
		+
		+	# We turn off the virtual machine if we have it on, to allow us to make a clone. Virtual machine --> Shutdown --> Shutdown''.
		+	# In the main window, right click on the virtual machine that we want to clone, and click ''Clone ...'''
		+	# In the window that appears, by default it will select the same network and create a different MAC for the new machine and clone the ubuntu image that we use for storage. We give a new name to our machine, and click on ''Clone''.
		+	# We repeat this step until we have all the desired virtual machines, in our case, we will only create one to test the network details.
		+
		+	Now we will start the original machine and the cloned one, and we will verify that both are in the same network and that they can see each other. As we commented in the previous step, we will check the IP of the original virtual machine and the cloned one, and we will ping from inside the machines to check that they can see each other.
		+
		+	Example:
		+
		+	* Original machine has IP 192.168.100.168.
		+	* Cloned machine has IP 192.168.100.169
		+	* From the original machine we will do a ping 192.168.100.169
		+	* From the cloned machine we will ping 192.168.100.168
		+	* From both machines, we will check that the gateway is the same, doing an ''ip route''.
		+	* From the host machine, we should ping both machines.
		+
		+	= Step 7: Snapshots of virtual machines
		+
		+	Snapshots allow us to store a snapshot of the running state of a virtual machine at a certain point in time that we can restore when necessary. The snapshots will be useful if you have work half done in the virtual machine, so that you want to save what you have done to restore it later.
		+
		+	To create a snapshot, we access to the virtual machine in execution and we deploy the menu ''View'' and click on ''Screenshots'' (Snapshot). Then click on the ''+'' button that appears at the bottom left, indicate the name of the snapshot and click on ''Finish''.
		+
		+	The creation of snapshots takes some time, be patient. You can store as many snapshots as you want. The name ''Screenshot'' is an unfortunate translation of ''snapshot'' which refers to the term ''snapshot''.
		+
		+	= Step 8: Manual installation of Linux =
		+
		+	In addition to installing from the Ubuntu Cloud image, it is possible to perform an installation from scratch by making use of the Ubuntu installer. This process is '''slower''' than using the Ubuntu Cloud image.
		+
		+	== Download the Ubuntu minimal CD image ==
		+
		+	The first thing is to download the Ubuntu installer image:
		+
		+	<syntaxhighlight lang="bash">
		+	wget http://archive.ubuntu.com/ubuntu/dists/bionic/main/installer-amd64/current/images/netboot/mini.iso
		+	</syntaxhighlight>
		+
		+	== Creating the virtual hard disk ==
		+
		+	You have to create a virtual hard disk that is initially empty:
		+
		+	<syntaxhighlight lang="bash">
		+	qemu-img create -f qcow2 server-base.qcow 5G
		+	</syntaxhighlight>
		+
		+	After this we have a hard disk with a capacity of 5 GBytes to use in a virtual machine.

← Revisión anterior		Revisión del 14:56 23 nov 2021
Línea 231:		Línea 231:

	We already have our virtual machine created with our configuration. Now we are going to test that everything works correctly. The machine should be booting and the login message should appear. [File:virt-manager-login.png\|thumb\|Login for ubuntu.		We already have our virtual machine created with our configuration. Now we are going to test that everything works correctly. The machine should be booting and the login message should appear. [File:virt-manager-login.png\|thumb\|Login for ubuntu.
		+
		+	We use as user ''ubuntu'', which is the default user and as password we use the one we have chosen in step 3. With this we validate successfully in the system. [[File:virt-manager-logged.png\|thumb\|User already validated, in the shell]]]
		+
		+	We already have a shell in our Ubuntu cloud operating system running on our virtual machine.
		+
		+	''''Note''''': The keyboard of the Ubuntu cloud image running on the virtual machine is in English, you can change it with the following command:
		+
		+	<syntaxhighlight lang="bash">
		+	sudo loadkeys en
		+	</syntaxhighlight>
		+
		+	= Step 5: Configuring the network in libvirt =
		+
		+	Before we look at the network details, let's make a small difference between the two windows we have open, virt-manager main and virt-manager ubuntu machine running. In the first one we will have the general configurations and in the second one we will have the configurations of a specific virtual machine, in our case, the configuration of the ubuntu virtual machine.
		+
		+	With this, we will see two ways to know the IP of our virtual machine:
		+
		+	# In the window of our ubuntu virtual machine, let's change the view and see the details of our machine. ''View --> Details''. Here we have all the configuration of our machine, but we are only going to focus on the Virtual Network Interface, which is where we will be able to see which is the IP address of our machine and which is the network source that is being used. [[File:virt-manager-nic.png\|thumb\|Virtual Network Interface]]]
		+	# The other option is using commands, we can use ''ip address'' in the console of our virtual machine.
		+
		+	<syntaxhighlight lang="bash">
		+	$ sudo ip address
		+	1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
		+	link/loopback 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00 brd 00:00:00:00:00:00:00:00
		+	inet 127.0.0.1.1/8 scope host lo
		+	valid_lft forever preferred_lft forever
		+	inet6 ::1/128 scope host
		+	valid_lft forever preferred_lft forever
		+	2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
		+	link/ether 3d:f0:ee:49:aa:22 brd ff:ff:ff:ff:ff:ff:ff:ff
		+	inet 192.168.100.168/24 brd 192.168.2.255 scope global eth0
		+	valid_lft forever preferred_lft forever
		+	inet6 fe80::3e97:eff:fe39:dd20/64 scope link
		+	valid_lft forever preferred_lft forever
		+	</syntaxhighlight>
		+
		+	Which allows us to check that we are using the IP address 192.168.100.168.
		+
		+	If the interface does not show an IP address, you can force an IP address to be obtained from the virtual machine for the ''ens3'' interface with the command:
		+
		+	<syntaxhighlight lang="bash">
		+	sudo dhclient ens3
		+	</syntaxhighlight>
		+
		+	Let's check now from a terminal on the host that we reach our virtual machine.
		+
		+	<syntaxhighlight lang="bash">
		+	ping 192.168.100.168
		+	</syntaxhighlight>
		+
		+	We should see output similar to the following:
		+
		+	<syntaxhighlight lang="bash">
		+	PING 192.168.100.168 (192.168.100.168) 56(84) bytes of data.
		+	64 bytes from 192.168.100.168: icmp_seq=1 ttl=64 time=0.397 ms
		+	64 bytes from 192.168.100.168: icmp_seq=2 ttl=64 time=0.409 ms
		+	64 bytes from 192.168.100.168: icmp_seq=3 ttl=64 time=0.321 ms
		+	</syntaxhighlight>
		+
		+	If there were any connectivity problems the output would look like this:
		+
		+	<syntaxhighlight lang="bash">
		+	PING 192.168.100.168 (192.168.100.168) 56(84) bytes of data.
		+	From 192.168.100.1 icmp_seq=1 Destination Host Unreachable
		+	From 192.168.100.1 icmp_seq=2 Destination Host Unreachable
		+	From 192.168.100.1 icmp_seq=3 Destination Host Unreachable
		+	</syntaxhighlight>
		+
		+	In such a case, you can force an IP address to be obtained with the command:
		+
		+	<syntaxhighlight lang="bash">
		+	sudo dhclient ens3
		+	</syntaxhighlight>
		+
		+	This means that the network configuration is incorrect, or perhaps that the IP address of your virtual machine is not 192.168.100.168 :-).
		+
		+	More information about [[network configuration in libvirt]] is available.

@@ Línea 69: / Línea 69: @@
 The above example shows how to configure the downloaded image to have the user ''root'', and in this case, the password is ''coolpass''.
 For the realization of this practice you will need an Ubuntu Cloud image that we will download from https://cloud-images.ubuntu.com/ and we will need a
 host system with Ubuntu 18.04.

@@ Línea 6: / Línea 6: @@
 Next, we will use the Ubuntu image already configured to be imported to the virtualization software '''libvirt''''.
-= Step 1: Downloading the Ubuntu Cloud image
+= Step 1: Downloading the Ubuntu Cloud image =
 We enter https://cloud-images.ubuntu.com/ and download the Ubuntu 18.04 LTS (Long Time Support) image.
@@ Línea 139: / Línea 139: @@
 The above example shows how to configure the downloaded image to have the user ''root'', and in this case, the password is ''coolpass''.

← Revisión anterior		Revisión del 14:53 23 nov 2021
Línea 70:		Línea 70:


−	Translated with www.DeepL.com/Translator (free version)	+	Translated with www.DeepL.com/Translator (free version)For the realization of this practice you will need an Ubuntu Cloud image that we will download from https://cloud-images.ubuntu.com/ and we will need a
		+	host system with Ubuntu 18.04.
		+
		+	In this practice we will use the image downloaded from the Ubuntu Cloud website and we will use the '''cloud-init''' tool to configure it.
		+
		+	Next, we will use the Ubuntu image already configured to be imported to the virtualization software '''libvirt''''.
		+
		+	= Step 1: Downloading the Ubuntu Cloud image
		+
		+	We enter https://cloud-images.ubuntu.com/ and download the Ubuntu 18.04 LTS (Long Time Support) image.
		+
		+	You can download it directly with the command ''wget'':
		+
		+	<syntaxhighlight lang="bash">
		+	wget https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img
		+	</syntaxhighlight>
		+
		+	if it started downloading you will see output similar to this:
		+
		+	<syntaxhighlight lang="bash">
		+	-2019-08-06 12:26:26-- https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img
		+	Resolving cloud-images.ubuntu.com (cloud-images.ubuntu.com).... 91.189.88.89, 2001:67c:1560:8001::8001
		+	Connecting to cloud-images.ubuntu.com (cloud-images.ubuntu.com)[91.189.88.89]:443... connected.
		+	HTTP request sent, waiting for response... 200 OK
		+	Length: 343474176 (328M) [application/octet-stream] [application/octet-stream] [application/octet-stream]...
		+	Saving to: "bionic-server-cloudimg-amd64.img"
		+
		+	bionic-server-cloudimg-amd64.img. 0%[ ] 2.21M 472KB/s eta 14m 6s
		+	</syntaxhighlight>
		+
		+	Wait until the image is 100% downloaded.
		+
		+	The Ubuntu cloud image comes with 2 GBytes of space by default, you can expand the size with the following command before using it in the virtual machine:
		+
		+	<syntaxhighlight lang="bash">
		+	qemu-img resize bionic-server-cloudimg-amd64.img +8G
		+	</syntaxhighlight>
		+
		+	This increases the image by 8 Gbytes, so you are left with a 10 GByte Ubuntu cloud image.
		+
		+	= Step 3: Installing the libguestfs package =
		+
		+	Next, you have to install the [[packages]] that provide the ''virt-customize'' tool to configure the Ubuntu image you downloaded.
		+
		+	We can install these packages with the '''apt'''' tool from the shell.
		+
		+	For Ubuntu 18.04:
		+
		+	<syntaxhighlight lang="bash">
		+	sudo apt install libguestfs
		+	</syntaxhighlight>
		+
		+	For Ubuntu 20.04:
		+
		+	<syntaxhighlight lang="bash">
		+	sudo apt install libguestfs-tools
		+	</syntaxhighlight>
		+
		+	''On the practice classroom computers these packages will already be pre-installed, so you can skip this step.''
		+
		+	= Step 3: Configuring the Ubuntu image with virt-customize =
		+
		+	The ''virt-customize'' command allows you to set the password of the administrator user of the image we have downloaded.
		+
		+	<syntaxhighlight lang="bash">
		+	virt-customize -a bionic-server-cloudimg-amd64.img --root-password password:coolpass
		+	</syntaxhighlight>
		+
		+	The above example shows how to configure the downloaded image to have the user ''root'', and in this case, the password is ''coolpass''.