Multipass is a lightweight, command-line virtualization tool developed by Canonical that allows you to create and manage Ubuntu virtual machines (VM) on your local machine. It lets you run multiple isolated instances of Ubuntu for development and testing.
Multipass is cross-platform, which means you can run it on macOS, Windows, and Linux. However, on Linux, Multipass uses the Kernel-based Virtual Machine (KVM) for virtualization, which ensures it has an overall minimal overhead.
In this article, we'll discuss in detail the different commands you need to create to manage your Multipass virtual machines on Linux successfully. Our host system is running Ubuntu 23.04
Benefits of Multipass
Multipass offers several benefits, which separate it from other virtualization tools. Some of its key advantages are:
- Quick setup and lightweight: Multipass abstracts the process of downloading, configuring, and launching virtual machines, allowing you to focus on your work.
- Isolated virtual environments: Each virtual machine Multipass creates is self-contained, which allows you to avoid conflicts between different projects and protect your host machine from mishaps.
- Cloud-init support: Multipass supports Cloud-init, which is the standard method of configuring cloud instances.
- Cross-platform: Multipass can be used across different operating systems, including macOS, Windows, and Linux.
Overall, Multipass simplifies the process of working with virtual machines, providing a flexible and efficient virtualization tool.
How to Install Multipass
Multipass is available as a Snap package, which means you can install it on any Linux operating system with Snapd. By default, Snapd comes preinstalled on Ubuntu 18.04 and above.
Nonetheless, you can check whether Snapd is available on your machine, by executing:
snap version
However, if it isn't present on your machine, you can follow these instructions to install it.
After verifying that you have Snapd installed, run the following command to install Multipass:
$ sudo snap install multipass multipass 1.11.0 from Canonical** installed $
You can print the version information like this:
$ multipass version multipass 1.11.0 multipassd 1.11.0 $
After installation, you should verify that Multipass has given your group write access to its socket, so you can interact with Multipass without the need to run sudo commands. To that end, you should execute the following command:
ls -l /var/snap/multipass/common/multipass_socket
$ ls -l /var/snap/multipass/common/multipass_socket srw-rw---- 1 root sudo 0 May 29 15:01 /var/snap/multipass/common/multipass_socket $
The output above indicates that the "root" user and "sudo" group have read and write permissions for the multipass_socket file.
1. List Available Images
To explore the available images that can be used to create instances with Multipass, run the following command:
multipass find
After executing the command above, Multipass obtains the list of available images and displays it as shown below:
$ multipass find Image Aliases Version Description snapcraft:core18 18.04 20201111 Snapcraft builder for Core 18 snapcraft:core20 20.04 20210921 Snapcraft builder for Core 20 snapcraft:core22 22.04 20220426 Snapcraft builder for Core 22 snapcraft:devel 20230528 Snapcraft builder for the devel series core core16 20200818 Ubuntu Core 16 core18 20211124 Ubuntu Core 18 core20 20230119 Ubuntu Core 20 core22 20230119 Ubuntu Core 22 18.04 bionic 20230525 Ubuntu 18.04 LTS 20.04 focal 20230523 Ubuntu 20.04 LTS 22.04 jammy,lts 20230518 Ubuntu 22.04 LTS 22.10 kinetic 20230524 Ubuntu 22.10 23.04 lunar 20230502 Ubuntu 23.04 appliance:adguard-home 20200812 Ubuntu AdGuard Home Appliance appliance:mosquitto 20200812 Ubuntu Mosquitto Appliance appliance:nextcloud 20200812 Ubuntu Nextcloud Appliance appliance:openhab 20200812 Ubuntu openHAB Home Appliance appliance:plexmediaserver 20200812 Ubuntu Plex Media Server Appliance anbox-cloud-appliance latest Anbox Cloud Appliance charm-dev latest A development and testing environment for charmers docker 0.4 A Docker environment with Portainer and related tools jellyfin latest Jellyfin is a Free Software Media System that puts you in control of managing and streaming your media. minikube latest minikube is local Kubernetes ros-noetic 0.1 A development and testing environment for ROS Noetic. ros2-humble 0.1 A development and testing environment for ROS 2 Humble. $
The output above shows that the remote images available include Snapcraft builders, Ubuntu Core, and Ubuntu LTS (Long-Term support).
In addition, you can look up a specific image by including the image name in the "find" command, as shown in the example below.
$ multipass find 18.04 Image Aliases Version Description 18.04 20230525 Ubuntu 18.04 LTS daily:18.04 20230525 Ubuntu 18.04 LTS $
2. Launch a VM Instance
To create a new VM instance, run the following command:
multipass launch
On executing this command, Multipass will download a default image and launch a VM instance, with some basic default configuration, giving it a randomly generated name. Downloading can take some time depending on your internet speed.
Sample output:
Launched: affecting-shark
However, when creating an instance, you also have the option to use a specific image by adding the image's name to the command, as illustrated below:
multipass launch 18.04
Furthermore, you can enable logs, which provide detailed information about the processes going on in the background, as Multipass tries to download and launch an instance. This is particularly useful when troubleshooting.
To enable logging, add the "-v" option to the command. In addition, you can increase the verbosity of the output produced by adding more "v", up to four "v", as shown below:
multipass launch 18.04 -vvvv
Sample output:
[2023-05-20T07:31:59.677] [debug] [qemu-system-x86_64] [3619] started: qemu-system-x86_64 -nographic -dump-vmstate /tmp/multipassd.TkdrsS [2023-05-20T07:31:59.989] [debug] [daemon] Applied AppArmor policy: multipass.executive-sandfish.qemu-system-x86_64 [2023-05-20T07:31:59.989] [info] [executive-sandfish] process state changed to Starting [2023-05-20T07:31:59.996] [info] [executive-sandfish] process state changed to Running [2023-05-20T07:31:59.996] [debug] [qemu-system-x86_64] [3624] started: qemu-system-x86_64 -bios OVMF.fd --enable-kvm -cpu host -nic tap,ifname=tap-2b54b832d18,script=no,downscript=no,model=virtio-net-pci,mac=52:54:00:69:80:02 -device virtio-scsi-pci,id=scsi0 -drive file=/var/snap/multipass/common/data/multipassd/vault/instances/executive-sandfish/ubuntu-18.04-server-cloudimg-amd64.img,if=none,format=qcow2,discard=unmap,id=hda -device scsi-hd,drive=hda,bus=scsi0.0 -smp 1 -m 1024M -qmp stdio -chardev null,id=char0 -serial chardev:char0 -nographic -cdrom /var/snap/multipass/common/data/multipassd/vault/instances/executive-sandfish/cloud-init-config.iso [2023-05-20T07:31:59.997] [info] [executive-sandfish] process started Launched: executive-sandfish [2023-05-20T07:33:11.827] [debug] [daemon] Returning setting local.privileged-mounts=true
Here is another example launching ubuntu 22.10 with verbose messages on the command line
silver@ubuntussd:~$ multipass launch 22.10 -vvv [2023-05-30T12:55:55.306] [debug] [qemu-system-x86_64] [4594] started: qemu-system-x86_64 --version [2023-05-30T12:57:23.956] [debug] [daemon] Applied AppArmor policy: multipass.qemu-img [2023-05-30T12:57:23.960] [debug] [qemu-img] [4814] started: qemu-img info --output=json /var/snap/multipass/common/cache/multipassd/vault/images/kinetic-20230524/ubuntu-22.10-server-cloudimg-amd64.img [2023-05-30T12:57:24.350] [debug] [daemon] Applied AppArmor policy: multipass.qemu-img [2023-05-30T12:57:24.352] [debug] [qemu-img] [4823] started: qemu-img info /var/snap/multipass/common/cache/multipassd/vault/images/kinetic-20230524/ubuntu-22.10-server-cloudimg-amd64.img [2023-05-30T12:57:24.387] [debug] [daemon] Applied AppArmor policy: multipass.qemu-img [2023-05-30T12:57:24.388] [debug] [qemu-img] [4833] started: qemu-img resize /var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/ubuntu-22.10-server-cloudimg-amd64.img 5368709120 [2023-05-30T12:57:27.175] [debug] [qemu-img] [4840] started: qemu-img snapshot -l /var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/ubuntu-22.10-server-cloudimg-amd64.img [2023-05-30T12:57:27.236] [debug] [romantic-rodent] process working dir '/snap/multipass/8465/qemu' [2023-05-30T12:57:27.236] [info] [romantic-rodent] process program 'qemu-system-x86_64' [2023-05-30T12:57:27.236] [info] [romantic-rodent] process arguments '-bios, OVMF.fd, --enable-kvm, -cpu, host, -nic, tap,ifname=tap-cf2818956a7,script=no,downscript=no,model=virtio-net-pci,mac=52:54:00:d4:87:8a, -device, virtio-scsi-pci,id=scsi0, -drive, file=/var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/ubuntu-22.10-server-cloudimg-amd64.img,if=none,format=qcow2,discard=unmap,id=hda, -device, scsi-hd,drive=hda,bus=scsi0.0, -smp, 1, -m, 1024M, -qmp, stdio, -chardev, null,id=char0, -serial, chardev:char0, -nographic, -cdrom, /var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/cloud-init-config.iso' [2023-05-30T12:57:27.238] [debug] [qemu-system-x86_64] [4859] started: qemu-system-x86_64 -nographic -dump-vmstate /tmp/multipassd.iQVqfR [2023-05-30T12:57:27.254] [debug] [daemon] Applied AppArmor policy: multipass.romantic-rodent.qemu-system-x86_64 [2023-05-30T12:57:27.254] [info] [romantic-rodent] process state changed to Starting [2023-05-30T12:57:27.255] [info] [romantic-rodent] process state changed to Running [2023-05-30T12:57:27.256] [debug] [qemu-system-x86_64] [4876] started: qemu-system-x86_64 -bios OVMF.fd --enable-kvm -cpu host -nic tap,ifname=tap-cf2818956a7,script=no,downscript=no,model=virtio-net-pci,mac=52:54:00:d4:87:8a -device virtio-scsi-pci,id=scsi0 -drive file=/var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/ubuntu-22.10-server-cloudimg-amd64.img,if=none,format=qcow2,discard=unmap,id=hda -device scsi-hd,drive=hda,bus=scsi0.0 -smp 1 -m 1024M -qmp stdio -chardev null,id=char0 -serial chardev:char0 -nographic -cdrom /var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/cloud-init-config.iso [2023-05-30T12:57:27.256] [info] [romantic-rodent] process started Launched: romantic-rodent [2023-05-30T12:57:51.563] [debug] [daemon] Returning setting local.privileged-mounts=true silver@ubuntussd:~$
If you read the verbose message carefully you will note that multipass is using qemu/kvm in the background to actually create and launch ubuntu virtual machines. The specific command in the above case looks something like this:
qemu-system-x86_64 -bios OVMF.fd --enable-kvm -cpu host -nic tap,ifname=tap-cf2818956a7,script=no,downscript=no,model=virtio-net-pci,mac=52:54:00:d4:87:8a -device virtio-scsi-pci,id=scsi0 -drive file=/var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/ubuntu-22.10-server-cloudimg-amd64.img,if=none,format=qcow2,discard=unmap,id=hda -device scsi-hd,drive=hda,bus=scsi0.0 -smp 1 -m 1024M -qmp stdio -chardev null,id=char0 -serial chardev:char0 -nographic -cdrom /var/snap/multipass/common/data/multipassd/vault/instances/romantic-rodent/cloud-init-config.iso
We can directly use Qemu to launch ubuntu virtual machines ourselves, but multipass makes it easier, so that we do not have to worry about lots of command line options and pass them correctly. Check out our previous posts on Qemu:
How to Boot Ubuntu 23.04 Live ISO with Qemu/KVM on Ubuntu Host
How to install Ubuntu 23.04 in Qemu/KVM on Ubuntu Host
2. Open a shell to the virtual machine
After you have launched a virtual machine running ubuntu, its time to connect to it via some kind of shell. Just like you would connect to a remote server via ssh.
The "multipass shell" command is used to launch the shell prompt of a specific instance, which allows you to execute commands directly on the instance. As noted previously, this command will open the shell prompt of the primary instance if an instance's name isn't indicated.
To open the shell prompt of an instance named "romantic-rodent" from the previous step, run the following command:
multipass shell romantic-rodent
Sample output:
silver@ubuntussd:~$ multipass shell romantic-rodent Welcome to Ubuntu 22.10 (GNU/Linux 5.19.0-42-generic x86_64) * Documentation: https://help.ubuntu.com * Management: https://landscape.canonical.com * Support: https://ubuntu.com/advantage System information as of Tue May 30 13:04:22 IST 2023 System load: 0.0 Processes: 91 Usage of /: 32.8% of 4.67GB Users logged in: 0 Memory usage: 21% IPv4 address for ens3: 10.73.220.25 Swap usage: 0% 1 update can be applied immediately. 1 of these updates is a standard security update. To see these additional updates run: apt list --upgradable New release '23.04' available. Run 'do-release-upgrade' to upgrade to it. To run a command as administrator (user "root"), use "sudo <command>". See "man sudo_root" for details. ubuntu@romantic-rodent:~$ uname -a Linux romantic-rodent 5.19.0-42-generic #43-Ubuntu SMP PREEMPT_DYNAMIC Tue Apr 18 18:21:28 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux ubuntu@romantic-rodent:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 22.10 Release: 22.10 Codename: kinetic ubuntu@romantic-rodent:~$
Note that we were able to run the commands uname -a and lsb_release -a. Its a complete ubuntu command line where you can run any command like you would run on a normal ubuntu installation.
After the shell prompt is launched, you can execute any Linux command as you normally would on the instance. Conversely, enter "exit" in the shell prompt to return to your host machine.
Run commands without shell: With the exec command, Multipass also allows you to execute a command on a VM without having to launch the VM's shell. The example below demonstrates how to use the "exec" command to view the memory usage of an instance by telling Multipass to execute the "free" command on the instance.
multipass exec romantic-rodent -- free
In the command above, the instance's name is passed as the first argument to the "exec" command, while the two hyphens (--) separate the "exec" command from the actual instance's command, which in this case is "free".
Sample output:
$ multipass exec romantic-rodent -- free
total used free shared buff/cache available
Mem: 988520 177268 467176 956 344076 663960
Swap: 0 0 0
silver@ubuntussd:~$
3. Create Instance with custom parameters
So far, we've used the default Multipass configuration when launching new instances. However, Multipass grants the flexibility of customizing resources allocated to a VM, including the name assigned to the VM.
Multipass allows the customization of different resources, including:
- CPU: Multipass provides the "--cpu" or "-c" options, which allow you to set the number of CPUs for an instance. This value defaults to 1 if not specified.
- Disk space: The "--disk" or "-d" options are used when allocating disk space to an instance. Generally, the value for the disk space is a positive integer expressed in bytes or with a K (kilobytes), M (megabytes), or G (gigabytes) suffix. However, the minimum value acceptable is 512M and will default to 5G if a value is not specified.
- Memory: Multipass offers the "--memory" or "-m" options to set the amount of memory available for an instance. These options accept a positive integer or decimal number expressed either in bytes or with a K, M, or, G suffix. In any case, the minimum acceptable value is 128M and will default to 1G if this option is omitted.
- Name: The "--name" or "-n" options are used to give an instance a name.
To tailor an instance to your desired configuration, add the appropriate options to the "multipass launch" command and specify your desired values. For example, to create a VM with 4 cores, 8G of memory, and 10G disk space, named "foo", the following command can be executed:
multipass launch 18.04 -c 4 -m 8G -d 10G -n "foo" -vvv
Sample output:
[2023-05-20T08:52:39.709] [info] [foo] process state changed to Starting [2023-05-20T08:52:39.716] [info] [foo] process state changed to Running [2023-05-20T08:52:39.938] [debug] [qemu-system-x86_64] [4795] started: qemu-system-x86_64 -bios OVMF.fd --enable-kvm -cpu host -nic tap,ifname=tap-85a8e535edf,script=no,downscript=no,model=virtio-net-pci,mac=52:54:00:79:1e:e7 -device virtio-scsi-pci,id=scsi0 -drive file=/var/snap/multipass/common/data/multipassd/vault/instances/foo/ubuntu-18.04-server-cloudimg-amd64.img,if=none,format=qcow2,discard=unmap,id=hda -device scsi-hd,drive=hda,bus=scsi0.0 -smp 4 -m 8192M -qmp stdio -chardev null,id=char0 -serial chardev:char0 -nographic -cdrom /var/snap/multipass/common/data/multipassd/vault/instances/foo/cloud-init-config.iso [2023-05-20T08:52:39.939] [info] [foo] process started Launched: foo [2023-05-20T08:53:45.399] [debug] [daemon] Returning setting local.privileged-mounts=true
4. List Available Instances
To keep track of your VM instances and their current state, run the "multipass list" command. This command will display a list of all the instances you've previously created.
multipass list
Sample output:
Name State IPv4 Image affecting-shark Running 10.118.249.167 Ubuntu 22.04 LTS correct-longspur Running 10.118.249.215 Ubuntu 22.04 LTS executive-sandfish Running 10.118.249.97 Ubuntu 18.04 LTS primary-pipit Stopped -- Ubuntu 22.04 LTS
From the output produced, you can observe that the output provides information on the available instances, including their names, current state, IP address, and associated image.
List Image data in Json format
Additionally, Multipass supports displaying the list in other formats, including JSON, CSV, and YAML. This is achieved by adding the "--format" option to the "list" command and specifying the appropriate value. For example, to show the list in JSON format, run:
multipass list --format JSON
Sample output:
{
"list": [
{
"ipv4": [
"10.118.249.97"
],
"name": "executive-sandfish",
"release": "Ubuntu 18.04 LTS",
"state": "Running"
},
{
"ipv4": [
"10.118.249.167"
],
"name": "affecting-shark",
"release": "Ubuntu 22.04 LTS",
"state": "Running"
},
{
"ipv4": [
"10.118.249.215"
],
"name": "correct-longspur",
"release": "Ubuntu 22.04 LTS",
"state": "Running"
},
{
"ipv4": [
],
"name": "primary-pipit",
"release": "Ubuntu 22.04 LTS",
"state": "Stopped"
}
]
}
The above kind of output is useful if you need to manage the instances programatically through automation of some kind.
5. View Instance Information
The "multipass info" command offers detailed information about a specific instance, including disk usage, memory usage, current state, IP address, and load. This is particularly useful for monitoring the resources used by individual VMs.
To obtain information about an instance, add the instance name as an argument to the "multipass info" command as shown in the example below:
multipass info foo
Sample output:
Name: foo State: Running IPv4: 10.118.249.30 Release: Ubuntu 18.04.6 LTS Image hash: 1975f68897bb (Ubuntu 18.04 LTS) CPU(s): 4 Load: 0.10 0.15 0.07 Disk usage: 1.2GiB out of 9.5GiB Memory usage: 110.4MiB out of 7.8GiB Mounts: --
Alternatively, use the "--all" option to view detailed information for all the available instances.
multipass info --all
Additionally, similar to the list command, you have the option of presenting this information in other formats, using the "--format" option, as shown in the example below:
multipass info --all --format json
Here is another example:
$ multipass info romantic-rodent Name: romantic-rodent State: Running IPv4: 10.73.220.25 Release: Ubuntu 22.10 Image hash: 784c67d61181 (Ubuntu 22.10) CPU(s): 1 Load: 0.00 0.02 0.00 Disk usage: 1.5GiB out of 4.7GiB Memory usage: 174.4MiB out of 965.4MiB Mounts: -- silver@ubuntussd:~$
6. Modify an Instance
If after creating an instance, you realize that some of the properties you defined do not fit your needs, you can alter these properties using the "multipass set" command. However, properties that you can modify are limited to the CPU, memory, and disk size.
Before modifying an instance, you first need to stop the instance. The "stop" command is used to stop an instance by passing it in the instance's name as shown in the following example:
multipass stop foo
After stopping the instance, invoke the "set" command together with the name and new value of the property that you want to update using the following syntax: "local.instance-name.property=value". For example, to change the disk size of the "foo" instance to 200G, run:
multipass set local.foo.disk=200G
Similarly, to change the number of CPUs and memory to 3 and 16G respectively, run:
multipass set local.foo.cpus=3 multipass set local.foo.memory=16G
7. Set a Primary Instance
In Multipass, a primary instance refers to the default VM instance that is triggered when the commands — shell, start, stop, restart, and suspend are executed without specifying an instance name. In addition, the home directory of the host computer is usually mounted under the "Home" directory of the primary instance, which allows you to seamlessly share files between your host machine and the VM.
Generally, the primary instance is created automatically when you invoke the aforementioned commands if one doesn't exist. However, Multipass provides a way to set previously created instances as the primary instance.
To configure a specific instance as the primary instance, run the following command, replacing "foo" with the name of the instance to be set as the primary:
multipass set client.primary-name=foo
After executing the command, subsequent calls to the commands mentioned above will be performed on the configured primary instance.
8. Start, Stop, and Suspend an Instance
A VM instance can be in a running, stopped, suspended, or deleted state. The "start", "stop', and "suspend" commands can be used to change the state of a VM.
A VM in the suspended or stopped state can be started by running the following command, where "foo" is the VM name:
multipass start foo
Alternatively, you can launch multiple instances at the same time by passing two or more instance names to the start command.
multipass start foo affecting-shark correct-longspur
Additionally, you can start all the available instances by adding the "--all" option to the start command, as shown below:
multipass start --all
In the suspended state, Multipass preserves the state of the VM, which is then restored when the VM is started again.
To suspend an instance, invoke the "suspend" command, specifying the instance's name as shown below:
multipass suspend foo
Similar to the "start" command, you can suspend multiple instances at once by specifying two or more instance names.
multipass suspend foo affecting-shark correct-longspur
In the same way, you can suspend all running instances by adding the "--all" option to the suspend command.
multipass suspend --all
The "stop" command is used to terminate a running instance. For example, to stop an instance named "foo", run:
multipass stop foo
Similarly, to stop multiple instances at once, add two or more instance names as shown below:
multipass stop foo affecting-shark correct-longspur
In addition, the "--all" option can be used to stop all running instances.
multipass stop --all
9. How to Use a Command Alias
Multipass supports the use of aliases, which are shortcuts for commands that can be executed in an instance. Multipass provides the "alias" command for creating aliases.
The following syntax is used when creating an alias:
multipass alias instance-name:command alias-name
For example, the following command creates an alias of the "df" command named "fstore" for the "foo" instance:
multipass alias foo:df fstore
After creating the alias, the alias can be invoked by running:
multipass fstore
Executing the alias will produce a similar output to the one below, which displays information about available disks and filesystems.
Filesystem 1K-blocks Used Available Use% Mounted on udev 3036832 0 3036832 0% /dev tmpfs 609952 632 609320 1% /run /dev/sda1 203056560 1431280 201608896 1% / tmpfs 3049752 0 3049752 0% /dev/shm tmpfs 5120 0 5120 0% /run/lock tmpfs 3049752 0 3049752 0% /sys/fs/cgroup /dev/sda15 106858 5336 101522 5% /boot/efi tmpfs 609948 0 609948 0% /run/user/1000
In addition, Multipass provides a way to add options for aliases. To achieve this, two hyphens (--) are used to separate the alias part of the command from the options as shown below:
multipass fstore -- -h
In the command above, the "-h" option is added to the "fstore" alias, which displays the storage metrics of the underlying "df" command in a human-readable format.
To view all the aliases that you have created, run:
multipass aliases
Sample output:
Alias Instance Command Working directory aflist affecting-shark ls map clfree correct-longspur free map cllist correct-longspur ls map ffe foo free map fstore foo df map
The output produced shows information about the available aliases, their corresponding commands, the instance they run on, and their working directory mapping.
Conversely, the "unalias" command is used to remove previously defined alias. The "unalias" command takes a name argument of the alias to be removed.
For example, running the following command will remove the "ffe" alias:
multipass unalias ffe
Alternatively, you can remove multiple aliases at once by passing two or more aliases to the "unalias" command, as shown below:
multipass unalias aflist clfree cllist
In addition, the "--all" option can be added to the "unalias" command to remove all defined aliases.
multipass unalias --all
10. Share Data with an Instance
Data can be shared between the host machine and the VM instance in two ways — via mount and transfer.
The Mount Method
The mount method, which is the recommended way of sharing data involves mounting a directory of the host machine into a specific directory within the VM with the help of the "mount" command.
In general, the "mount" command uses the following syntax:
multipass mount /host/directory instance-name:/instance/destination/directory
For instance, let's say we have a directory "/home/foo/bar" on the host machine, and we want to mount it in a VM named "my-vm" at the path "/home/ubuntu/example". The following command can be used to achieve this:
multipass mount /home/foo/bar my-vm:/home/ubuntu/example
After executing the command above, the directory "/home/foo/bar" will be accessible within the "my-vm" instance at the path "/home/ubuntu/example". Hence, any changes made to files and directories at this mount point will reflect on the host machine and vice versa.
Moreover, you can create as many mount points as needed for a VM. You can also view the mount points on a VM by executing the "multipass info" command on that instance.
multipass info my-vm
Sample output:
Name: my-vm
State: Running
IPv4: 10.118.249.31
Release: Ubuntu 22.04.2 LTS
Image hash: afb820a92602 (Ubuntu 22.04 LTS)
CPU(s): 1
Load: 0.00 0.15 0.13
Disk usage: 1.4GiB out of 4.7GiB
Memory usage: 173.6MiB out of 965.9MiB
Mounts: /home/foo/bar => /home/ubuntu/example
UID map: 1000:default
GID map: 1000:default
On the other hand, the "umount" command is used to unmount a directory by specifying either the directory to be unmounted or only the instance's name, which ensures that all mount points on that instance are removed.
The following command shows how to unmount a specific directory:
multipass umount my-vm:/home/ubuntu/example
Alternatively, use the command below to remove all mount points on a VM.
multipass umount my-vm
The Transfer Method
Multipass provides the "transfer" command, which allows seamless copying of files between the host machine and the VM without the need to configure a mount point.
To copy a file from the host machine to the VM, run the following command:
multipass transfer example.txt my-vm:.
In the command above, the file "example.txt" is copied from the host machine to the home directory of the "my-vm" instance.
Alternatively, you can copy a file from a VM to the host machine as shown in the command below:
multipass transfer my-vm:hello.txt .
In addition, starting from Multipass version 1.11.0, you can also copy an entire directory by including the "--recursive" option in the "transfer" command.
To copy a directory named "foo" to a VM, run:
multipass transfer --recursive foo my-vm:.
11. Remove an Instance
The "multipass delete" command can be used to get rid of unneeded VMs. However, this command does not remove the VM completely, as the deleted VM can be restored using the "recover" command. As a result, the "--purge" or "-p" options are usually included when you want to totally remove a VM.
To delete a VM that can be restored, run:
multipass delete vm-name
To permanently delete a VM, run the following command instead:
multipass delete --purge vm-name
In addition, you can delete all available instances by adding the "--all" option as shown below:
multipass delete --all
multipass delete --all --purge
Conclusion
Multipass is a robust virtualization tool that simplifies the management and deployment of Ubuntu virtual machines. It offers several convenient commands, allowing you to configure and spin up VMs with ease.
Using Multipass, you can set up self-contained development environments for experimentation, testing, and deploying applications. However bear in mind that multipass is not the only tool to launch virtual machines. There are other solutions like qemu/kvm, vmware, xen etc. And if you do not need a full operating system for your use case you can run just the application inside a container like docker.
