Initramfs init

2021-08-24T16:40:11Z

Enckse: There was a typo "cryptokey" should be "cryptkey"

{{draft}}
==Usage==
Under a running alpine machine, the following command can be used if for some reason the initramfs has not been created properly for a new kernel.
mkinitfs -c /etc/mkinitfs/mkinitfs.conf -b / <kernelvers>
The script is located in /sbin/ and is created with ash. It expects /lib/modules to be populated with the <kernelvers> listed. For variations on this command (e.g. for chroot) Search "mkinitfs".

== initramfs init cmdline options (work in progress) ==

In addition to the [https://www.kernel.org/doc/html/v4.14/admin-guide/kernel-parameters.html kernel boot parameters] are a number of parameters that the init script understands.

Although you may specify your own init script when building an initramfs, these parameters allow for extensive control over the initial startup of an Alpine Linux system.

<code>quiet</code> : less verbose init script execution

<code>debug_init</code> : sets '-x' in the init script and -d for mdev

<code>chart</code> : Enables bootchartd for measuring system startup speed.

<code>ip=dhcp</code> : use DHCP for network configuration.

<code>ip=client-ip:server-ip:gw-ip:netmask:hostname:device:autoconf:dns1:dns2</code> : use static IP configuration, each field is separated by a colon <code>:</code>
* <code>client-ip</code> ip address of the guest VM where we are going to run the installer
* <code>server-ip</code> not used, leave blank or fill with <code>none</code>
* <code>gw-ip</code> the gateway ip address
* <code>netmask</code> the netmask
* <code>hostname</code> not used, leave blank or fill with <code>none</code>
* <code>device</code> the network interface of the guest VM, default is <code>eth0</code> if left blank
* <code>autoconf</code> not used, leave blank or fill with <code>none</code> or <code>off</code>
* <code>dns1</code> address of the DNS server
* <code>dns2</code> address of the 2nd DNS server

<code>modloop=URL</code> : the remote location of the image containing kernel's modules, required for LVM and raid setup.

:The remote location of the <code>modloop</code> image is the same as the kernel and initramfs (see below).

<code>blacklist=MODULE{,MODULE}</code> : This comma-separated list names kernel modules that modprobe will reject to load.

<code>alpine_repo=URL</code> : the location of the Alpine repository from which packages are downloaded.

:For stable release, use <code>http://dl-cdn.alpinelinux.org/alpine/v3.9/main</code>

:For rolling release, use <code>http://dl-cdn.alpinelinux.org/alpine/edge/main</code>

<code>ssh_key=URL</code> : the remote location of your SSH public key. It will be added to root's authorized_keys. Also triggers OpenSSH-server to be installed and started.

<code>apkovl=URL</code> : Unpack the APK Overlay file from this URL. Happens immediately after network is up . This option will set the default for service install and setup to false. (see .default_boot_services).

(work in progress)

* init=
* init_args=

* dasd=
* s390x_net=
* rootfstype=
* modules=
* crytptroot=
* cryptdm=
* cryptheader=
* cryptoffset=
* cryptkey=
* nbd=
* root=
* resume
* rootflags
* usbdelay
* pkgs=
* ssh_key=
* keep_apk_new
* splash=
* ...

[[category:Kernel]]

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Initramfs init