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diff --git a/content/post/install-arch-linux-in-virtual-machine.md b/content/post/install-arch-linux-in-virtual-machine.md index b444660..0670bd2 100644 --- a/content/post/install-arch-linux-in-virtual-machine.md +++ b/content/post/install-arch-linux-in-virtual-machine.md @@ -41,3 +41,256 @@ sequenceDiagrams: --- <!--more--> + +Installing Arch Linux on a KVM/QEMU virtual macin eis a fairly startightforward process. We will use command line approach in this post. + +## Create a virtual machine +Here we use `virt-install` to create a virtual machine. Run the following as root: +```bash +virt-install -n arch \ +--os-type=linux \ +--os-variant=archlinux \ +--ram=2048 \ +--vcpus=4 \ +--disk path=/var/lib/libvirt/images/arch.qcow2,bus=virtio,size=32 \ +--graphics=spice \ +--cdrom /path/to/image.iso \ +--network default +``` + +### What is happening here? +- Here we specify name for the virtual machine, which is *arch*. +- Next we specify type and variant. +- The amount of RAM is specified in megabytes. +- We assign four virtual CPUs to the VM. +- In `disk path` we have given the default location where the virtual machine image is stored. +- Size is in gigabyes. +- We have used *spice* for graphics. Alternatively, VNC can be used. +- In `cdrom` we have provided the location of the boot media. +- Finally we asked `virt-install` to use the default network profile. + +Pressing Enter will start the creation of the virtual machine. When done, it will start *virt-viewer* with live media running. + +## Install Arch Linux +This part is the same as any Arch Linux installation. We partition disks, run bootstrap script, generate locales, set timezone, hostname, install bootloader and optionally a desktop environment. + +### Partition disks +The virtual storage goes by `/dev/sda`. We partition disks using `cfdisk`. Select **dos** partition tabke since we are not using UEFI. Create just one partition and use it as root. Write then quit the program. + +Now we format the partition. +```bash +mkfs.ext4 /dev/vda1 +``` + +### Mount root partition and install +Now we are ready to install Arch Linux. Mount root partition on `/mnt` with `mount /dev/vda1 /mnt`. Then we run the bootstrap script that will create the necessary files and install the specified packages. +```bash +pacstrap /mnt base base-devel linux vim dhcpcd +``` + +#### What is happening here? +- Here we asked `pacstrap` to install Arch Linux on `/mnt`. +- Then we specified the packages to be installed. +- The meta package `base` contains a minimal package set that defines a basic Arch Linux installation. It includes basic utilities like glibc, bash, coreutils, networking tools, systemd, etc. +- Next is the `base-devel` group. It contains tools to build many packages like gcc, make, binutils, etc. +- `linux` is the kernel. +- We require `vim` to configure various things. Any text editor will do. +- `dhcpcd` will allow us to connect to the internet. Alternatively, `networkmanager` can be used. + +### Generate fstab +This file tells which partitions to mount during boot. Instead of writing by hand, we use a tool to simplify things for us. Running the following +```bash +genfstab -U /mnt >> /mnt/etc/fstab +``` +will generate a fstab file. We asked it to use `/mnt` partition. Any partition under `/mnt` will also be included, so if you created separate `/home` and `/var` partitions, they will also be included. The `-U` parameter tells `genfstab` to use UUID. + +## Configuration +In this section we set timezones, locale and hostname. + +Chroot into new root +```bash +arch-chroot /mnt +``` + +### Set timezone +List timezones by running `timedatectl list-timezones`. Set timezone with +```bash +timedatectl set-timezone Asia/Kolkata +``` +Replace **Asia/Kolkata** with your timezone. + +### Set locale +Uncomment the desired locales in `locale.gen` +```bash +vim /etc/locale.gen +``` +Save and exit then generate them by running +```bash +locale-gen +``` +And set locale config +```bash +echo LANG=en_US.UTF-8 > /etc/locale.conf +export LANG=en_US.UTF-8 +``` +Replace **en_US.UTF-8** with your locale. + +### Configure network +#### Set hostname +Your virtual machine will be identified by this name on the network +```bash +echo arch-vm > /etc/hostname +``` + +#### Create /etc/hosts +Your computer will look here for resolving domain names before looking out on the internet. Put the following information in `/etc/hosts`: +```bash +127.0.0.1 localhost +::1 localhost +127.0.1.1 arch-vm +``` + +#### Enable dhcpcd +This will enable the virtual machine to connect to the internet +```bash +systemctl enable dhcpcd.service +``` + +### Create a user +Before we create a regular user, it becomes necessary to set a root password. Set it by running +```bash +passwd +``` +Create a new user with +```bash +useradd -m -G wheel,storage,power -s /bin/bash <username> +``` + +#### What is happening here? +- `-m` tells `useradd` ro create a home directory for this user. +- `-G` tells which groups this user will belong to. +- `-s` specifies the login shell for this user. +- Replace <username> with a username of your choice. + +Set a password for this user with +```bash +passwd <username> +``` + +### Install ssh server +If working on command line is all you have to do, then working via SSH is more convenient than using Spice client (or VNC if you chose that). Install it +```bash +pacman -S openssh +``` +and enable it +```bash +systemctl enable sshd.service +``` + +### Install bootloader +The instructions thus far will provide us a working bare minimum Arch Linux environment. Now it is time to install a bootloadet and finish the installation. We will go with grub. +```bash +pacman -S grub +grub-install /dev/vda +grub-mkconfig -p /boot/grub/grub.cfg +``` +#### What is happening here? +- First we install grub package. +- Then we install it on the device `/dev/vda`. +- Next we create a configuration file. It can be modified at `/etc/default/grub`. Every time we modify the configuration, it must be generated with the last command for the changes to take place. + +### Reboot +The installation is complete. Next time we boot, we will be dropped into a working Ach Linux environment. + +Exit chroot. +```bash +exit +``` +Unmount partition +```bash +umoount /mnt +``` +And reboot +```bash +reboot +``` + +## Connecting to the virtual machine +Wait for a minute and the virtual machine will be up. FInd the virtual machine's IP address on host machine (assuming **arch** is the name of your virtual machine) +```bash +virsh domifaddr arch +``` + +Save the IP address in your host's `/etc/hosts` +```bash +printf "<ip-address>\t<guest hostname>\n" | sudo tee -a /etc/hosts +``` +Replace `<ip-address>` with the IP address of the virtual machine and `<guest hostname>` with the hostname you set while installing the virtual machine. It wuold be something like +```bash +printf "192.168.122.43\tarch-vm\n" | sudo tee -a /etc/hosts +``` + +### Create SSH key pair +While not necessary on a local network, it is generally a good habit to use key pair instead of password authentication. + +Go to `~/.ssh` and create a key pair. +```bash +cd ~/.ssh +ssh-keygen -t ed25519 -f arch-vm -C "arch linux virtual machine" +``` + +#### What is happening here? +- `ssh-keygen` generates keys. +- `-t` specifies the type of the key. We chose Ed25519. Other popular types are EdDSA, RSA, DSA, etc. +- `-f` specifies the filename of this key pair. +- `-C` is used to put comment in the key. + +This process will ask for a passphrase and generates a private key and a public key. The public key will have extension `.pub`. + +Create a config file. This will tell SSH which key to use with respect to host. The file is named `config`. Put the following in the file +``` +Host arch-vm + IdentityFile ~/.ssh/arch-vm +``` + +The private key is used to identify you. Anybody with your private key will be impersonate you so keep it safe. + +Now copy the public key over to your virtual machine. It can be achieved by programs like `scp` or `rsync`. However, we will use `ssh-copy-id` to conveniently put our key while abstracting most parts. +```bash +ssh-copy-id -f -i ~/.ssh/arch arch@arch-vm +``` +It is assuming **arch** is the username of the normal user of the virtual machine. + +Now log in by running +```bash +ssh arch@arch-vm +``` + +Modify `/etc/ssh/sshd_config` to only use public key for authentication. +- Change `PubkeyAuthentication` to `yes` +- Change `PasswordAuthentication` to `no` +- Change `X11Forwarding` to `yes` + +Now restart `sshd` for changes to take place. +```bash +systemctl restart sshd.config +``` +Exit and try logging in again. This time it should ask for passphrase. + +## Install a desktop environment +This part is entirely optional if you wish to use GUI. In this post, we will install MATE desktop environment. +```bash +pacman -S mate mate-extra +``` +The desktop environment can be started by running `exec mate-session`. If you want to use xinit then put the command in `~/.xinitrc`. Then install `xorg-xinit` package. Start it with `startx`. + + Alternatively you can use a display manager like GDM, LightDM, SDDM. etc. Install `sddm`, enable and start it + ```bash + systemctl enable sddm.service + systemctl start sddm.service + ``` + + If you wish to run GUI programs over X11 forwarding, a desktop environment might be overkill. In that case just install `xorg`, `xorg-server`. To use X11 forwarding, log in via ssh with + ```bash + ssh -Y arch@arch-vm + ``` |