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diff --git a/_drafts/first-release-of-installiso.md b/_drafts/first-release-of-installiso.md deleted file mode 100644 index 7c6537d..0000000 --- a/_drafts/first-release-of-installiso.md +++ /dev/null @@ -1,193 +0,0 @@ ---- -title: "First release of installiso" -description: "A utility to customize OpenBSD installation images for unattended installation." -published: 2021-07-24 ---- - -<!-- TODO: Test all commands --> -<!-- TODO: Reset git history, tag release, build tarball, and man page --> -<!-- TODO: Test all links --> -<!-- TODO: Update date --> - -One year ago I [posted](/posts/autoinstall-openbsd-on-qemu/) how to script an unattended installation of OpenBSD on the QEMU virtual machine monitor on Linux. -The script involved setting up a complicated network boot environment because I treated the installation image as a black box. -Of course, I could have mounted the ISO 9660 image and created a modified image using [`mkisofs(8)`](http://cdrtools.sourceforge.net/private/man/cdrecord/mkisofs.8.html). -But I didn't know how to insert the [`autoinstall(8)`](https://man.openbsd.org/OpenBSD-6.9/autoinstall) response file into the RAMDISK kernel in the ISO 9660 image. -That was no surprise -- why would anyone need to change an OpenBSD kernel on Linux. - -OpenBSD, on the other hand, includes adequate utilities. -Thanks to [`vmctl(8)`](https://man.openbsd.org/OpenBSD-6.9/vmctl), [`rdsetroot(8)`](https://man.openbsd.org/OpenBSD-6.9/rdsetroot), and [`mkhybrid(8)`](https://man.openbsd.org/OpenBSD-6.9/mkhybrid), we can modify the ISO 9660 image _and_ the contained RAMDISK kernel. -The exact process is a bit tedious so I decided to automate it. -The resulting script is more hacky than pretty but it gets the job done and I found it useful enough to give it a name, `installiso`, and release it today. -Currently, it's limited to the _amd64_ architecture, though it should work on other architectures alike. -You can download the very first release [here](/files/installiso-0.1.0.tar.gz). -The man page is also viewable [here](/files/installiso.8-0.1.0.html). -Feedback appreciated! - -In the remainder of this post I'll show how to use `installiso` to create custom OpenBSD installation images for unattended -- and possibly offline -- installation. -As an example, I'll show how to create virtual machines on OpenBSD's own virtual machine monitor, [`vmm(4)`](https://man.openbsd.org/OpenBSD-6.9/vmm). -Finally, I'll list the concrete commands necessary to patch an installation image without `installiso` because I would want to know how it works. - -## Installation - -You can install the `installiso` utility as follows. - - $ ftp https://www.skreutz.com/files/installiso-0.1.0.tar.gz - $ tar -xzf installiso-0.1.0.tar.gz - $ cd installiso-0.1.0/ - $ doas make install - $ man 8 installiso - -Alternatively, you can run `./installiso.ksh` without installation. - -## Usage - -Given a response file `install.conf`, and a file-specific file set `site/`, you can download, verify, and customize an official installation image as follows. - - $ installiso -v fetch -r 6.9 - $ doas installiso -v \ - patch -i install.conf -s site/ install69.iso custom.iso - -You can also specify a mirror, another release or the latest development snapshot, and a [`signify(1)`](https://man.openbsd.org/OpenBSD-6.9/signify) public key if you like. -See the [man page](/files/installiso.8-0.1.0.html). - -## Example - -You can create a virtual machine on OpenBSD's own virtual machine monitor, [`vmm(4)`](https://man.openbsd.org/OpenBSD-6.9/vmm), as follows. - -First, we create an [`autoinstall(8)`](https://man.openbsd.org/OpenBSD-6.9/autoinstall) response file. -Here, we'll setup a regular user and authorize an [`ssh(1)`](https://man.openbsd.org/OpenBSD-6.9/ssh) public key. -Of course, you can skip this step and have the installer mail you the responses recorded during an interactive installation instead. - - $ cat >install.conf <<EOF - Change the default console to com0 = yes - Which speed should com0 use = 115200 - System hostname = openbsd-vm - DNS domain name = example.com - Password for root = ************* - Start sshd(8) by default = yes - Allow root ssh login = no - Setup a user = $USER - Full name for user $USER = $( userinfo "$USER" | sed -n 's/^gecos[[:space:]]*\(.*\)$/\1/p' ) - Password for user = ************* - Public ssh key for user = $( cat "$HOME/.ssh/id_rsa.pub" ) - What timezone are you in = UTC - Location of sets = cd0 - Set name(s) = site*.tgz - Directory does not contain SHA256.sig. Continue without verification = yes - EOF - -Second, we create a site-specific file set. - - $ mkdir site - $ cat >site/install.site <<EOF - #! /bin/ksh - - set -o errexit - - # Set OpenBSD mirror server used by pkg_add(1) and other commands. - echo "https://cdn.openbsd.org/pub/OpenBSD" > /etc/installurl - - # Permit user group wheel to run any command as root - # without entering their password using doas(1). - echo "permit nopass keepenv :wheel" > /etc/doas.conf - - # Install packages on the first boot. - echo "pkg_add sqlite3" >> /etc/rc.firsttime - EOF - -Third, fetch and patch an installation image as above. - - $ installiso -v fetch -r 6.9 - $ doas installiso -v \ - patch -i install.conf -s site/ install69.iso custom.iso - -Forth, we start a virtual machine off a new disk image and the custom installation image. -The OpenBSD FAQ contains a good [introduction](https://www.openbsd.org/faq/faq16.html) to [`vmm(4)`](https://man.openbsd.org/OpenBSD-6.9/vmm). -I assume you've setup the network option 2. - - $ vmctl create -s 10G disk.qcow2 - $ doas vmctl start -c -i 1 -L -m 512M -d disk.qcow2 \ - -r custom.iso tmp - -Finally, we can log into the new virtual machine once the unattended installation has completed. - - $ ssh \ - -o "StrictHostKeyChecking no" \ - -o "UserKnownHostsFile /dev/null" \ - 100.64.1.3 - -## Disklabel template - -In the above example, the OpenBSD installer allocates all disk space automatically, see [`disklabel(8)`](https://man.openbsd.org/OpenBSD-6.9/disklabel). -You can supply a custom disklabel template instead if you need more control. - -First, create a disklabel template. - - $ cat >disklabel_template <<EOF - / 5G - swap 1G - /home 2G - EOF - -Second, add a corresponding URL to the response file. - - $ echo "URL to autopartitioning template for disklabel = http://100.64.1.2:8080/disklabel_template" >> install.conf - -Finally, serve the file during the unattended installation. - - $ printf 'HTTP/1.0 200 OK\n\n' | - cat - disklabel | - nc -lN 8080 - -## Inner workings - -The `installiso patch` command used above - - $ doas installiso -v \ - patch -i install.conf -s site/ install69.iso custom.iso - -boils down to the following commands, excluding error handling, temporary files, options, etc. - -First, we extract the ISO 9660 image. - - # vnconfig vnd0 install69.iso - # mount -t cd9660 /dev/vnd0c /mnt - # mkdir cd - # tar -C /mnt -c -f - . | tar -C cd -x -p -f - - # umount /mnt - # vnconfig -u vnd0 - -Second, we patch the RAMDISK kernel. - - # gzip -d -o bsd.rd cd/6.9/amd64/bsd.rd - # rdsetroot -x bsd.rd disk.fs - # vnconfig vnd0 disk.fs - # mount /dev/vnd0a" /mnt - # install -o root -g wheel -m 0644 -C \ - install.conf /mnt/auto_install.conf - # umount /mnt - # vnconfig -u vnd0 - # rdsetroot bsd.rd disk.fs - # gzip -9fnq bsd.rd - -Third, we insert the patched kernel and the site-specific file set into the extracted ISO 9660 image. - - # install -o root -g 2000 -m 0755 -C \ - bsd.rd.gz cd/6.9/amd64/bsd.rd - # ( cd site/ && tar -c -z -f ../cd/6.9/amd64/site69.tgz . ) - # ( cd cd/6.9/amd64/ && ls -l > index.txt ) - -Finally, we create the bootable ISO 9660 image. - - # mkhybrid -a -R -T -L -l -d -D -N -o custom.iso \ - -A "Custom OpenBSD 6.9 amd64 Install CD" \ - -b 6.9/amd64/cdbr -c 6.9/amd64/boot.catalog \ - cd - -[^tmpdir]: -The `installiso` utility may fail due to not enough space in `/tmp`. -If so, you can set the `TMPDIR` environment variable of [`mktemp(1)`](https://man.openbsd.org/OpenBSD-6.9/mktemp). -Remember that [`doas(1)`](https://man.openbsd.org/OpenBSD-6.9/doas) creates a new environment by default, though. -You can either configure `doas(1)` to keep the `TMPDIR`, or you execute a shell: -`doas sh -c 'TMPDIR=/path/to/tmp installiso patch ...'`. |