Run ubuntu installer from linux

Run ubuntu installer from linux

This section explains how to install Ubuntu from an existing Unix or Linux system, without using the menu-driven installer as explained in the rest of the manual. This “ cross-install ” HOWTO has been requested by users switching to Ubuntu from Debian, Red Hat, Mandriva, and SUSE. In this section some familiarity with entering *nix commands and navigating the file system is assumed. In this section, $ symbolizes a command to be entered in the user’s current system, while # refers to a command entered in the Ubuntu chroot.

Once you’ve got the new Ubuntu system configured to your preference, you can migrate your existing user data (if any) to it, and keep on rolling. This is therefore a “ zero downtime ” Ubuntu install. It’s also a clever way for dealing with hardware that otherwise doesn’t play friendly with various boot or installation media.

As this is a mostly manual procedure, you should bear in mind that you will need to do a lot of basic configuration of the system yourself, which will also require more knowledge of Ubuntu and of Linux in general than performing a regular installation. You cannot expect this procedure to result in a system that is identical to a system from a regular installation. You should also keep in mind that this procedure only gives the basic steps to set up a system. Additional installation and/or configuration steps may be needed. In general, this method of installation is not recommended for casual or first time users.

D.4.1.В Getting Started

With your current *nix partitioning tools, repartition the hard drive as needed, creating at least one filesystem plus swap. You need around 506MB of space available for a console only install , or about 1536MB if you plan to install X (more if you intend to install desktop environments such as GNOME or KDE) .

Next, create file systems on the partitions. For example, to create an ext3 file system on partition /dev/sda6 (that’s our example root partition):

To create an ext2 file system instead, omit -j .

Initialize and activate swap (substitute the partition number for your intended Ubuntu swap partition):

Instead of using a dedicated swap partition, you may omit the swap partition setup here and later just use a swap file instead.

Mount one partition as /mnt/ubuntu (the installation point, to be the root ( / ) filesystem on your new system). The mount point name is strictly arbitrary, it is referenced later below.

If you want to have parts of the filesystem (e.g. /usr) mounted on separate partitions, you will need to create and mount these directories manually before proceding with the next stage.

D.4.2.В Install debootstrap

The utility used by the Ubuntu installer, and recognized as the official way to install an Ubuntu base system, is debootstrap . It uses wget and ar , but otherwise depends only on /bin/sh and basic Unix/Linux tools [22] . Install wget and ar if they aren’t already on your current system, then download and install debootstrap . If these steps are executed under Ubuntu you can simply do this by apt install debootstrap .

If you have an RPM (Red Hat Package Manager) based system, you can use alien, which is available in the Debian repositories, to convert the .deb file to a useable .rpm file.

Or, you can use the following procedure to install it manually. Make a work folder for extracting the .deb into:

The debootstrap binary is located in the Ubuntu archive (be sure to select the proper file for your architecture). Download the debootstrap .deb from the pool, copy the package to the work folder, and extract the files from it. You will need to have root privileges to install the files.

D.4.3.В Run debootstrap

debootstrap can download the needed files directly from the archive when you run it. You can substitute any Ubuntu archive mirror for ports.ubuntu.com/ubuntu-ports in the command example below, preferably a mirror close to you network-wise. Mirrors are listed at http://wiki.ubuntu.com/Archive.

If you have an Ubuntu focal CD mounted at /cdrom , you could substitute a file URL instead of the http URL: file:/cdrom/ubuntu/

Substitute one of the following for ARCH in the debootstrap command: amd64 , arm64 , armhf , i386 , powerpc , ppc64el , or s390x .

D.4.4.В Configure The Base System

Now you’ve got a real Ubuntu system, though rather lean, on disk. chroot into it:

After chrooting you may need to set the terminal definition to be compatible with the Ubuntu base system, for example:

Depending on the value of TERM, you may have to install the ncurses-term package to get support for it.

If warnings occur like:

The required localization files need to be generated:

D.4.4.1.В Configure Apt

Debootstrap will have created a very basic /etc/apt/sources.list that will allow installing additional packages. However, it is suggested that you add some additional sources, for example for source packages and security updates:

Make sure to run apt update after you have made changes to the sources list.

D.4.4.2.В Install additional packages

Now it’s required to install some additionally required packages, like makedev (needed for the next section): apt install makedev

D.4.4.3.В Create device files

At this point /dev/ only contains very basic device files. For the next steps of the installation additional device files may be needed. There are different ways to go about this and which method you should use depends on the host system you are using for the installation, on whether you intend to use a modular kernel or not, and on whether you intend to use dynamic (e.g. using udev ) or static device files for the new system.

A few of the available options are:

create a default set of static device files using (after chrooting)

manually create only specific device files using MAKEDEV

bind mount /dev from your host system on top of /dev in the target system, like:

Note that the postinst scripts of some packages may try to create device files, so this option should only be used with care.

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Ubuntu Documentation

If you already have Ubuntu installed, it is easy to upgrade using the Update Manager. However, this is not always safe, and it will overwrite your old system.

If upgrading is not an option (you are running a different Linux distro than Ubuntu, or your system is several versions old), or you wish to keep your old system, you should use the live Ubuntu Desktop installer or Debootstrap.

The Ubuntu Desktop installer is usually run on a DVD or a bootable USB stick. However, if you already run Linux, using a DVD or USB is not necessary. You may run the Ubuntu Desktop installer directly from your hard drive, or use Debootstrap.

Note: These are advanced installation techniques and are not recommended for new users. If you are uncomfortable with the command line terminal, you should create a live Ubuntu Desktop DVD or USB.

Running the Ubuntu Desktop installer from your hard drive requires an extra partition. Debootstrap installs Ubuntu directly, without using the guiding Ubuntu Desktop installer. Debootstrap does not require a DVD, USB, Ubuntu Desktop ISO, or an extra installer partition.

Live Ubuntu Desktop from Hard Drive

The Ubuntu Desktop installer is distributed as a .iso file — get it here. If you don’t want to download an ISO, use Debootstrap. If your ISO has «alternate» in its name, you are using an alternate installation image and should see the next section.

Note: You will need blank hard drive space to create new partitions. If your current system partition(s) take up all available space, you must create a live DVD or live USB.

Step 1, Partition

Create a new ext4 partition for the installer, using gparted. The partition must be a little larger than the install image (for example, if du -h disk-image.iso returns 1.1GB, make the partition 1.2GB). Remember the name of the new partition (for example, /dev/sda3).

Step 2, Copy

Copy Ubuntu Desktop installer contents over to the new partition using the commands

Replace disk-image.iso with the path to your disk image and /dev/sda3 with the new partition.

Step 3, Grub

Configure grub2. Edit the file /etc/grub.d/40_custom and add the lines

Replace Ver. with the version number and (hd0,3) with the new partition (for example, /dev/sda3 becomes (hd0,3) because Grub 2 counts drives from 0, but partitions from 1).

Then run update-grub to rebuild the grub configuration.

Step 4, Reboot

Reboot, and choose «installer» from the grub boot menu, and continue as if you were installing from CD. Be sure to set the root partition to another new partition, different from the installer; do not overwrite the whole drive.

Step 5, Grub (again)

The installer may not add an entry in Grub for the new version of Ubuntu. You will have to do this manually.

Older Versions of Ubuntu

Older verions of Ubuntu may use /casper/vmlinuz instead of /casper/vmlinuz.efi

For even older versions of Ubuntu with grub1, change the grub configuration file (typically /etc/grub.conf or /boot/grub/menu.lst) to boot from the new partition by adding the lines

The first line after the title tells grub which partition contains the installer. hd0 stands for «first hard disk,» and the 0 following it standards for first partition. You will need to change this if your installer partition is different from /dev/sda1. sdaN becomes (hd0, N-1), sdbN becomes (hd1,N-1) and so on. As you can see, grub starts counting from 0, which can be confusing.

If you are trying to use Hard Disk installation with Ubuntu 9.10 chances are initrd.gz is renamed as initrd.lz now. So rename accordingly in menu.lst.

Note (old, for grub1) You do not need to modify the grub config of the existing linux system, if you feel uncomfortable modifying an otherwise fine running system. Instead, you may create a new menu.lst file on the new partition, preferably in directory /boot/grub/. Then, reboot, and when the (old) grub menu appears, press ‘c’ to get the grub command line. Then, type: configfile (hd0,1)/boot/grub/menu.lst to switch over to your new grub menu. Tip: use the tab-key halfway typing to have grub help you complete the command, or grub commands such as search or help.

Note: if you unpacked the livecd on the same disk where you want to install Ubuntu, you may run into LP#288675, and be unable to select a partition. The workaround by Nick Spencer («sudo umount -l -r -f /dev/sda3 or sudo umount -l -r -f /cdrom (where sda3 was the device mounted as cdrom)») is a rather terrible hack, but usable as a workaround.

Note2: Instead of using ‘workaround’, an alternative is to modify the file /etc/mtab by erasing the line that specifies the partition where the cdrom is mounted. This way the kernel thinks that the /cdrom is not mounted and will not show the advice when installing ubuntu. I think this procedure is less dangerous than the one in the previous note.

Note3: Instead of the above ‘workarounds’, you may simply use the boot option live-media=/dev/sdb1 or LIVEMEDIA=/dev/sdb1, referring to the USB device holding the ISO. This would be the «bootable usb», even if your pc has a «buggy BIOS» and cannot boot from USB. The running kernel can access the USB device. This boot option is documented in http://manpages.ubuntu.com/manpages/karmic/man7/casper7.html, but unfortunately not supported by Ubuntu 11.10. Use the patch I filed as bug fix in https://bugs.launchpad.net/ubuntu/+source/casper/+bug/423616 while this is not yet put back in the ISO. Warning: this implies building a new initrd.gz which is not very trivial, although this forum has a good manual.

Debootstrap

You can install Ubuntu directly from Linux using debootstrap. Debootstrap installs some essential packages in a directory for use with chroot. Note that the essential packages does not in itself make the system bootable. It just installs what you need to chroot to that directory and use apt-get to install other packages which make Ubuntu usable.

Step 1. First check that you have debootstrap installed.

(NOTE: if you want to install a newer release than your current system, you normally need to install the backported debootstrap version, see: UbuntuBackports)

Step 2. Partition device and make a filesystem.

We will assume /dev/sda is the storage device for your fresh install.

Remove former partitions and create the new one.

Make the filesystem

Step 3. Mount that new partition.

Step 4. Download and install base system packages.

Step 5. Copy files to the new install to keep your repositories

Step 6. Chroot to your new install.

Step 7. Locale and language settings To make dpkg run without warning you need to set this settings first

Step 8. Upgrade the new install. Install your local «language-pack-en-base».

If you are using Software RAID and/or LVM, you should install these packages before installing a kernel:

Step 9. Install Grub and Linux Kernel.

Step 10. Add user and/or set root password.

To add a user and set a password for that user.

You may also want to add your user to the sudo group so that user can run programs as root.

To set a root password:

(NOTE: You must at least set a root password if you aren’t adding a user)

Step 11. Create fstab. A simple example of fstab is

It should now be safe to reboot; you may want the next few things.

Step 12. If you want to access it with ssh after reboot.

Use vi or install nano to edit /etc/hostname.

Remove any text in this file and add the hostname you would like.

Add these lines to /etc/network/interfaces. This will start eth0 at boot and request an IPv4 address with dhclient.

Next you need to install ssh

Your computer should be safe to reboot now. If you want the Ubuntu Gnome desktop, continue with Step 13.

Step 14. Install ubuntu-desktop.

Step 15. Reboot and keep those fingers crossed.

Alternate CD

As of December 29th 2007, the instructions above do not apply to the alternate CD provided for Ubuntu 7.10 (Gutsy Gibbon). Significant changes are required. Procedure 1 below has been used successfully with Gutsy (Ubuntu 7.10) and Procedure 2 with Hardy (Ubuntu 8.04).

Before going any further please note that the alternate CD contains documentation which can help with fixing problems or adapting solutions to your own situation. The documentation is located in doc/install/manual/ on the alternate CD. Please refer to that documentation as needed.

Note that Procedure 2 is potentially less disruptive because it does not call for a new partition.

For a simpler installation method which generally does not require re-partitioning, and downloads the packages at install time rather than requiring an ISO, see Installation/NetbootInstallFromInternet.

Procedure 1

I used the following procedure for Gutsy. It can also be used for Hardy.

Step 1. Use gparted to create a new primary partition and format it to ext3. You need slightly more than 700MB of free space on it. 750MB should be sufficient. Let’s say the name of the partition is /dev/sda1. If your new ubuntu install is going to coexist with your old system, you might find it convenient to create space for your new system as well at this point using gparted.

Step 2. Copy your alternate ISO to the root of the partition you created in step 1. You need to copy the ISO itself rather than the contents of the ISO.

Step 3. Grab the initrd.gz and vmlinuz files found in the following sub-directory of a Ubuntu mirror:

Put these files in your newly created partition. They can be in the root of the partition or in a sub-directory.

Step 4. Edit your grub configuration file (typically /etc/grub.conf or /boot/grub/menu.lst) to boot from the new partition by adding the lines:

If you use LILO, see the official documentation on the alternate CD for how to configure LILO. Or you can adapt the lines above for LILO if you know Grub and LILO well.

The first line after the title tells grub which partition contains the installer. hd0 stands for «first hard disk,» and the 0 following it standards for first partition. You will need to change this if your installer partition is different from /dev/sda1. sdaN becomes (hd0, N-1), sdbN becomes (hd1,N-1) and so on. As you can see, grub starts counting from 0, which can be confusing. The paths for the kernel and the initrd were set to start with /install/ in my setup but you could put those files in the root of the install partition and have them be /vmlinuz and /initrd.gz if you so wish.

As specified in the above, the installer will run without a preseed file. The preseed tells the installer what kind of system you are trying to install and it automatically selects some options for you during installation. For instance, using the ubuntu.seed file tells the installer that you want to install a full «desktop» system, with Gnome and everything. If you do not select a preseed file, it is unclear what the installer thinks. In my (LouisDominiqueDubeau) experience, it installs some sort of CLI or server form of Ubuntu. This is not disastrous but it may not be what you want. In Hardy in particular, running the installer without a seed results in LILO installed as the boot loader rather than Grub. Ugly. So it is better to select a seed. Adding the parameter file=/cdrom/preseed/ubuntu.seed to the kernel line above should take care of the problem. If installing Kubuntu, select kubuntu.seed instead. Adapt to other situations as needed.

Step 5. Reboot, and choose «installer» from the grub boot menu, and continue as normal.

Procedure 2

In this procedure you do not create a new partition to hold the installer. This procedure was used for Hardy. It may be adaptable for Gutsy.

Step 1. Copy your alternate ISO to the root of any partition that the installer can mount. You need to copy the ISO itself rather than the contents of the ISO. The important part here is that you must find a partition that the installer can mount, as it will search during the install procedure. If you use the traditional partitioning system used by DOS since ages immemorial, then any filesystem supported by Ubuntu should work. In particular ext2/ext3/ntfs/fat/vfat should all work. If you use LVM, things are trickier. As of April 26th 2008, the installer is unable to find an ISO stored on a partition managed in LVM. The installer can install Ubuntu in an LVM partition but in the stage at which it looks for the ISO it has not yet loaded the LVM modules so it cannot find the ISO if it is on an LVM partition. An enterprising person should be able to work around that problem but by default the installer won’t find the ISO if it is on an LVM partition. If you have Windows installed, then the Windows partition, which normally is not managed by LVM (because I don’t think Windows supports LVM), can hold the ISO.

Step 2. Grab the initrd.gz and vmlinuz files found in the following subdirectory of a Ubuntu mirror:

You will want to put these files in your normal /boot/ directory. It may be a good idea to create a subdirectory like newinstall, hardy-install, or something similar.

Step 3. Read the information at step 4 of procedure 1 above and then come back here: the information there will tell you what hd0,0 means and will inform you about seeds, etc. Edit your grub configuration file (typically /etc/grub.conf or /boot/grub/menu.lst) to boot from the new partition by adding the lines:

If you want a preseed file, change the kernel line to:

Note that some users report working installs with grub without seeds and/or seeds not working with this method. Adapt as needed to your situation.

Step 4. Reboot, and choose «installer» from the grub boot menu, and continue the installation as normal.

Alternate CD Alternate Method

I have a machine without a CD-ROM drive but with a network connection, and I struggled with these instructions for many days. Finally, I stumbled upon some straightforward solutions which appear to work for me.

1. Obtain Alternate CD. (This method may work for other CDs, I have not tried)

2. Mount at a temporary location, as described previously.

3. Copy vmlinuz and initrd.gz from mounted installation media to normal location on current linux root (the one to be replaced)

4. Unmount CDROM image.

5. Copy image as is to selected partition, i.e. cat "image" > /dev/hdXX

6. Configure grub or LILO as above

8. When choosing CD-ROM drive, choose manually, do not install a driver, for the device enter the partition to which you copied the image.

9. Continue installation as normal.

So far so good! I’ll let you know if it breaks later 😛

Troubleshooting

• If you are having issues installing grub, and dpkg-reconfigure grub-pc does not give you a chance to select the device you want to install grub to, make sure you have mounted /dev in your chroot. Review step 6.

Installation/FromLinux (последним исправлял пользователь jamiesonc 2020-06-23 22:49:53)

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