Packer installation

2021-03-17T17:15:36Z

G4li: change /dev/vg0/lv_root to /dev/sda3

== Basic understanding ==

Alpine Linux installer is just a bunch of shell scripts, see [https://git.alpinelinux.org/alpine-conf/tree/setup-alpine.in setup-alpine.in] in [https://git.alpinelinux.org/alpine-conf/tree alpine-conf] repository. Understanding this is key to success.

== packer example boot_command ==

This is a part of 'boot_command' from [https://www.packer.io/docs/builders/qemu.html QEMU] builder:

"boot_command": [
"root<enter><wait>",
"ifconfig eth0 up && udhcpc -i eth0<enter><wait5>",
"wget http://<nowiki>{{ .HTTPIP }}:{{ .HTTPPort }}</nowiki>/answers<enter><wait>",
"setup-alpine -f answers<enter><wait5>",
"<nowiki>{{user `ssh_password`}}</nowiki><enter><wait>",
"<nowiki>{{user `ssh_password`}}</nowiki><enter><wait5>",
"<wait>y<enter><wait10>",
"rc-service sshd stop<enter>",
"mount /dev/sda3 /mnt<enter>",
"echo 'PermitRootLogin yes' >> /mnt/etc/ssh/sshd_config<enter>",
"umount /mnt<enter>",
"reboot<enter>"
],

What it does is to mimic a human typing in "console" (VNC). Before running Alpine Linux installer (ie. 'setup-alpine') it does:

* logins in as 'root' (installation media doesn't require password)
* configures first network interfaces via DHCP
* gets 'answers' file from 'packer' built-in HTTP server to be able to start automated installation
* runs Alpine Linux 'setup-alpine' installer script with 'answers' file
* as 'setup-alpine' script asks to configure root password, it just does that
* after that, you can run whatever commands you want, but keep in mind that it is still installer media; you can 'reboot' into installed system and run 'provisioners'

The 'answer' file can be something like this:

KEYMAPOPTS="us us"
HOSTNAMEOPTS="-n alpine"
INTERFACESOPTS="auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp
"
DNSOPTS="-n 8.8.8.8"
TIMEZONEOPTS="-z UTC"
PROXYOPTS="none"
APKREPOSOPTS="-1"
SSHDOPTS="-c openssh"
NTPOPTS="-c openntpd"
DISKOPTS="-L -m sys /dev/vda"

== packer example provisioners ==

"provisioners": [
{
"type": "shell",
"scripts": [
"<nowiki>{{ template_dir }}</nowiki>/../scripts/00_alpinelinux_base.sh",
"<nowiki>{{ template_dir }}</nowiki>/../scripts/99_alpinelinux_base.sh"
]
}
],

[[Category:Installation]]

Alpine Linux - User contributions [en]

Packer installation