On Mon, 8 Jul 2019 11:09:38 +0200 Aaron Lauterer <a.laute...@proxmox.com> wrote:
> Some things that I have seen, mostly regarding style and readability. Thanks big time - incorporated and will be included in my v2 > > On 7/5/19 6:31 PM, Stoiko Ivanov wrote: > > With the recently added support for booting ZFS on root on EFI > > systems via `systemd-boot` the documentation needs adapting (mostly > > related to editing the kernel commandline). > > > > This patch adds a short section on Bootloaders to the sysadmin > > chapter describing both `grub` and PVE's use of `systemd-boot` > > > > Signed-off-by: Stoiko Ivanov <s.iva...@proxmox.com> > > --- > > sysadmin.adoc | 2 + > > system-booting.adoc | 144 > > ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 146 > > insertions(+) create mode 100644 system-booting.adoc > > > > diff --git a/sysadmin.adoc b/sysadmin.adoc > > index 21537f1..e045610 100644 > > --- a/sysadmin.adoc > > +++ b/sysadmin.adoc > > @@ -74,6 +74,8 @@ include::local-zfs.adoc[] > > > > include::certificate-management.adoc[] > > > > +include::system-booting.adoc[] > > + > > endif::wiki[] > > > > > > diff --git a/system-booting.adoc b/system-booting.adoc > > new file mode 100644 > > index 0000000..389a0e9 > > --- /dev/null > > +++ b/system-booting.adoc > > @@ -0,0 +1,144 @@ > > +[[system_booting]] > > +Bootloaders > > +----------- > > +ifdef::wiki[] > > +:pve-toplevel: > > +endif::wiki[] > > + > > +Depending on the disk setup chosen in the installer {pve} uses two > > bootloaders +for bootstrapping the system. > > {pve} is using one of two bootloaders, depending on the disk setup > selected in the installer. > > (Putting the most important info at the beginning of the sentence) > > > + > > +For EFI Systems installed with ZFS as the root filesystem > > `systemd-boot` is +used. All other deployments use the standard > > `grub` bootloader (this usually +also applies to systems which are > > installed on top of Debian). + > > +[[installer_partitioning_scheme]] > > +Partitioning scheme used by the installer > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +The {pve} installer creates 3 partitions on disks: > > + > > +* a 1M BIOS Boot Partition (gdisk type EF02) > > + > > +* a 512M EFI System Partition (ESP, gdisk type EF00) > > Besides what Thomas already mentioned; what about using MB (with a > space) instead of M? "512 MB" instead of "512M"? > > + > > +* a third partition spanning the remaining space used for the > > chosen storage > > + type > > + > > +`grub` in BIOS mode (`--target i386-pc`) is installed onto the > > BIOS Boot +Partition of all bootable disks for supporting older > > systems. + > > + > > +Grub > > +~~~~ > > + > > +`grub` has been the de-facto standard for booting Linux systems > > for many years +and is quite well documented > > +footnote:[Grub Manual > > https://www.gnu.org/software/grub/manual/grub/grub.html]. + > > +The kernel and initrd images are taken from `/boot` and its > > configuration file +`/boot/grub/grub.cfg` gets updated by the > > kernel installation process. + > > +Configuration > > +^^^^^^^^^^^^^ > > +Changes to the `grub` configuration are done via the defaults file > > + `/etc/default/grub` or config snippets in `/etc/default/grub.d`. > > +To regenerate the `/boot/grub/grub.cfg` after a change to the > > configuration +run `update-grub`. > > + > > +Systemd-boot > > +~~~~~~~~~~~~ > > + > > +`systemd-boot` is a lightweight EFI bootloader, which reads the > > kernel and > > "...EFI bootloader. It reads the kernel and ...." > Splitting the sentence will produce two shorter sentences that are > easier to grasp. > > > +initrd images directly from the EFI Service Partition (ESP) where > > it is +installed. The main advantage of directly loading the > > +kernel from the ESP is that it does not need to reimplement the > > drivers for +accessing the storage. In the context of ZFS as root > > filesystem this means +that you can use all optional features on > > your root pool instead of the subset +which is also present in the > > ZFS implementation in `grub` or having to create +a separate small > > boot-pool +footnote:[Booting ZFS on root with grub > > https://github.com/zfsonlinux/zfs/wiki/Debian-Stretch-Root-on-ZFS]. > > + +In setups with redundancy (RAID1, RAID10, RAIDZ*) all bootable > > disks (those +being part of the first `vdev`) are partitioned with > > an ESP, ensuring the > > "with an ESP. This ensure that the system can boot even..." > > > +system boots even if the first boot device fails. The ESPs are > > kept in sync by +a kernel postinstall hook script > > `/etc/kernel/postinst.d/zz-pve-efiboot`. The +script copies certain > > kernel versions and the initrd images to `EFI/proxmox/` +on the > > root of each ESP and creates the appropriate config files in > > +`loader/entries/proxmox-*.conf`. + > > +The following kernel versions are configured by default: > > + > > +* the currently booted kernel > > +* the version being installed > > +* the two latest kernels > > +* the latest version of each kernel series (e.g. 4.15, 5.0). > > + > > +The ESPs are not kept mounted during regular operation, in > > contrast to `grub`, +which keeps an ESP mounted on `/boot/efi`. > > This helps preventing filesystem > > "This helps to prevent filesystem..." > > > +corruption to the `vfat` formatted ESPs in case of a system crash, > > and removes +the need to manually adapt `/etc/fstab` in case the > > primary boot device fails. + > > +[[systemd_boot_config]] > > +Configuration > > +^^^^^^^^^^^^^ > > + > > +`systemd-boot` itself is configured via the file > > `loader/loader.conf` in the > > remove the "itself"? > > > +root directory of an ESP. See the `loader.conf(5)` manpage for > > details. + > > +Each bootloader entry is placed in a file of its own in the > > directory +`loader/entries/` > > + > > +An example entry.conf looks like this (`/` refers to the root of > > the ESP): + > > +---- > > +title Proxmox > > +version 5.0.15-1-pve > > +options root=ZFS=rpool/ROOT/pve-1 boot=zfs > > +linux /EFI/proxmox/5.0.15-1-pve/vmlinuz-5.0.15-1-pve > > +initrd /EFI/proxmox/5.0.15-1-pve/initrd.img-5.0.15-1-pve > > +---- > > + > > +.Manually keeping a kernel bootable > > + > > +Should you wish to add a certain kernel and initrd image to the > > list of +bootable kernels you need to: > > + > > +* create a directory on the ESP (e.g. `/EFI/personalkernel`) > > +* copy the kernel and initrd image to that directory > > +* create a entry for this kernel in `/loader/entries/*.conf` > > + > > +NOTE: do not use `/EFI/proxmox` as directory since all entries > > there can be +removed by `/etc/kernel/postinst.d/zz-pve-efiboot` > > + > > +[[systemd-boot-refresh]] > > +.Updating the configuration on all ESPs > > + > > +If you added a new ESP, or made any changes to the available > > kernels you can +sync the kernel and initrd images and their config > > to all ESPs by running the > > "...their config files..." plural > > > +kernel hook script `/etc/kernel/postinst.d/zz-pve-efiboot`. > > +This is equivalent to running `update-grub` on Systems being > > booted with +`grub`. > > + > > + > > +[[edit_kernel_cmdline]] > > +Editing the kernel commandline > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +Depending on the used bootloader you can modify the kernel > > commandline in the +following places: > > "You can modify the kernel commandline in the following places, > depending on the bootloarder used:" > > > + > > +.Grub > > + > > +The kernel commandline needs to be placed in the variable > > +`GRUB_CMDLINE_LINUX_DEFAULT` in the file `/etc/default/grub`. > > Running +`update-grub` appends its content to all `linux` entries in > > +`/boot/grub/grub.cfg`. > > + > > +.Systemd-boot > > + > > +The kernel commandline needs to be placed as line in > > `/etc/kernel/cmdline` +Running > > `/etc/kernel/postinst.d/zz-pve-efiboot` sets it as `option` line > > for +all config files in `loader/entries/proxmox-*.conf`. + > > + > > > > _______________________________________________ > pve-devel mailing list > pve-devel@pve.proxmox.com > https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel _______________________________________________ pve-devel mailing list pve-devel@pve.proxmox.com https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel