[bug#45692] [PATCH v5 3/3] gnu: Add ZFS service type.

[raid5atemyhomework via Guix-patches via <guix-patches@gnu.org>]

***BUMP***

> Sorry for the lateness everyone.
>
> Hope this one gets reviewed and merged.
>
> --------------------------------------------------------------------------
>
> From 3803e046566278fe12d64f6e39564e9602bf434d Mon Sep 17 00:00:00 2001
> From: raid5atemyhomework raid5atemyhomework@protonmail.com
> Date: Thu, 30 Sep 2021 16:58:46 +0800
> Subject: [PATCH] gnu: Add ZFS service type.
>
> -   gnu/services/file-systems.scm: New file.
>
> -   gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
>
> -   gnu/services/base.scm: Export dependency->shepherd-service-name.
>
> -   doc/guix.texi (ZFS File System): New subsection.
>
>
> doc/guix.texi | 351 ++++++++++++++++++++++++++++++++
> gnu/local.mk | 2 +
> gnu/services/base.scm | 4 +-
> gnu/services/file-systems.scm | 363 ++++++++++++++++++++++++++++++++++
> 4 files changed, 719 insertions(+), 1 deletion(-)
> create mode 100644 gnu/services/file-systems.scm
>
> diff --git a/doc/guix.texi b/doc/guix.texi
> index a72a726b54..dd38103953 100644
> --- a/doc/guix.texi
> +++ b/doc/guix.texi
> @@ -97,6 +97,7 @@ Copyright @copyright{} 2021 Hui Lu@*
> Copyright @copyright{} 2021 pukkamustard@*
> Copyright @copyright{} 2021 Alice Brenon@*
> Copyright @copyright{} 2021 Andrew Tropin@*
> +Copyright @copyright{} 2021 raid5atemyhomework@*
>
> Permission is granted to copy, distribute and/or modify this document
> under the terms of the GNU Free Documentation License, Version 1.3 or
> @@ -14435,6 +14436,356 @@ a file system declaration such as:
> compress-force=zstd,space_cache=v2"))
> @end lisp
>
> +
> +@node ZFS File System
> +@subsection ZFS File System
> +
> +Support for ZFS file systems in Guix is based on the OpenZFS project.
> +OpenZFS currently only supports Linux-Libre and is not available on the
> +Hurd.
> +
> +OpenZFS is free software; unfortunately its license is incompatible with
> +the GNU General Public License (GPL), the license of the Linux kernel,
> +which means they cannot be distributed together. However, as a user,
> +you can choose to build ZFS and use it together with Linux; you can
> +even rely on Guix to automate this task. See
> +@uref{https://www.fsf.org/licensing/zfs-and-linux, this analysis by
> +the Free Software Foundation} for more information.
> +
> +As a large and complex kernel module, OpenZFS has to be compiled for a
> +specific version of Linux-Libre. At times, the latest OpenZFS package
> +available in Guix is not compatible with the latest Linux-Libre version.
> +Thus, directly installing the @code{zfs} package can fail.
> +
> +Instead, you are recommended to select a specific older long-term-support
> +Linux-Libre kernel. Do not use @code{linux-libre-lts}, as even the
> +latest long-term-support kernel may be too new for @code{zfs}. Instead,
> +explicitly select a specific older version, such as @code{linux-libre-5.10},
> +and upgrade it manually later as new long-term-support kernels become
> +available that you have confirmed is compatible with the latest available
> +OpenZFS version on Guix.
> +
> +For example, you can modify your system configuration file to a specific
> +Linux-Libre version and add the @code{zfs-service-type} service.
> +
> +@lisp
> +(use-modules (gnu))
> +(use-package-modules
>
> -   #;@dots{}
> -   linux)
>     +(use-service-modules
>
> -   #;@dots{}
> -   file-systems)
> -
>
> +(define my-kernel linux-libre-5.10)
> +
> +(operating-system
>
> -   (kernel my-kernel)
> -   #;@dots{}
> -   (services
> -   (cons* (service zfs-service-type
> -                      (zfs-configuration
>
>
> -                        (kernel my-kernel)))
>
>
> -             #;@dots{}
>
>
> -             %desktop-services))
>
>
> -   #;@dots{})
>     +@end lisp
>
> -
>
> +@defvr {Scheme Variable} zfs-service-type
> +This is the type for a service that adds ZFS support to your operating
> +system. The service is configured using a @code{zfs-configuration}
> +record.
> +
> +Here is an example use:
> +
> +@lisp
> +(service zfs-service-type
>
> -   (zfs-configuration
> -   (kernel linux-libre-5.4)))
>     +@end lisp
>     +@end defvr
>
> -
>
> +@deftp {Data Type} zfs-configuration
> +This data type represents the configuration of the ZFS support in Guix
> +System. Its fields are:
> +
> +@table @asis
> +@item @code{kernel}
> +The package of the Linux-Libre kernel to compile OpenZFS for. This field
> +is always required. It @emph{must} be the same kernel you use in your
> +@code{operating-system} form.
> +
> +@item @code{base-zfs} (default: @code{zfs})
> +The OpenZFS package that will be compiled for the given Linux-Libre kernel.
> +
> +@item @code{base-zfs-auto-snapshot} (default: @code{zfs-auto-snapshot})
> +The @code{zfs-auto-snapshot} package to use. It will be modified to
> +specifically use the OpenZFS compiled for your kernel.
> +
> +@item @code{dependencies} (default: @code{'()})
> +A list of @code{<file-system>} or @code{<mapped-device>} records that must
> +be mounted or opened before OpenZFS scans for pools to import. For example,
> +if you have set up LUKS containers as leaf VDEVs in a pool, you have to
> +include their corresponding @code{<mapped-ddevice>} records so that OpenZFS
> +can import the pool correctly at bootup.
> +
> +@item @code{auto-mount?} (default: @code{#t})
> +Whether to mount datasets with the ZFS @code{mountpoint} property automatically
> +at startup. This is the behavior that ZFS users usually expect. You might
> +set this to @code{#f} for an operating system intended as a `rescue'' system +that is intended to help debug problems with the disks rather than actually +work in production. + +@item @code{auto-scrub} (default: @code{'weekly}) +Specifies how often to scrub all pools. Can be the symbols @code{'weekly} or +@code{'monthly}, or a schedule specification understood by +@xref{mcron, mcron job specifications,, mcron, GNU@tie{}mcron}, such as +@code{"0 3 * * 6"} for`every 3AM on Saturday''.
> +It can also be @code{#f} to disable auto-scrubbing (@strong{not recommended}).
> +
> +The general guideline is to scrub weekly when using consumer-quality drives, and
> +to scrub monthly when using enterprise-quality drives.
> +
> +@code{'weekly} scrubs are done on Sunday midnight, while @code{monthly} scrubs
> +are done on midnight on the first day of each month.
> +
> +@item @code{auto-snapshot?} (default: @code{#t})
> +Specifies whether to auto-snapshot by default. If @code{#t}, then snapshots
> +are automatically created except for ZFS datasets with the
> +@code{com.sun:auto-snapshot} ZFS vendor property set to @code{false}.
> +
> +If @code{#f}, snapshots will not be automatically created, unless the ZFS
> +dataset has the @code{com.sun:auto-snapshot} ZFS vendor property set to
> +@code{true}.
> +
> +@item @code{auto-snapshot-keep} (default: @code{'()})
> +Specifies an association list of symbol-number pairs, indicating the number
> +of automatically-created snapshots to retain for each frequency type.
> +
> +If not specified via this field, by default there are 4 @code{frequent}, 24
> +@code{hourly}, 31 @code{daily}, 8 @code{weekly}, and 12 @code{monthly} snapshots.
> +
> +For example:
> +
> +@lisp
> +(zfs-configuration
>
> -   (kernel my-kernel)
> -   (auto-snapshot-keep
> -   '((frequent . 8)
> -        (hourly . 12))))
>
>
>
> +@end lisp
> +
> +The above will keep 8 @code{frequent} snapshots and 12 @code{hourly} snapshots.
> +@code{daily}, @code{weekly}, and @code{monthly} snapshots will keep their
> +defaults (31 @code{daily}, 8 @code{weekly}, and 12 @code{monthly}).
> +
> +@end table
> +@end deftp
> +
> +@subsubsection ZFS Auto-Snapshot
> +
> +The ZFS service on Guix System supports auto-snapshots as implemented in the
> +Solaris operating system.
> +
> +@code{frequent} (every 15 minutes), @code{hourly}, @code{daily}, @code{weekly},
> +and @code{monthly} snapshots are created automatically for ZFS datasets that
> +have auto-snapshot enabled. They will be named, for example,
> +@code{zfs-auto-snap_frequent-2021-03-22-1415}. You can continue to use
> +manually-created snapshots as long as they do not conflict with the naming
> +convention used by auto-snapshot. You can also safely manually destroy
> +automatically-created snapshots, for example to free up space.
> +
> +The @code{com.sun:auto-snapshot} ZFS property controls auto-snapshot on a
> +per-dataset level. Sub-datasets will inherit this property from their parent
> +dataset, but can have their own property.
> +
> +You @emph{must} set this property to @code{true} or @code{false} exactly,
> +otherwise it will be treated as if the property is unset.
> +
> +For example:
> +
> +@example
> +# zfs list -o name
> +NAME
> +tank
> +tank/important-data
> +tank/tmp
> +# zfs set com.sun:auto-snapshot=true tank
> +# zfs set com.sun:auto-snapshot=false tank/tmp
> +@end example
> +
> +The above will set @code{tank} and @code{tank/important-data} to be
> +auto-snapshot, while @code{tank/tmp} will not be auto-snapshot.
> +
> +If the @code{com.sun:auto-snapshot} property is not set for a dataset
> +(the default when pools and datasets are created), then whether
> +auto-snapshot is done or not will depend on the @code{auto-snapshot?}
> +field of the @code{zfs-configuration} record.
> +
> +There are also @code{com.sun:auto-snapshot:frequent},
> +@code{com.sun:auto-snapshot:hourly}, @code{com.sun:auto-snapshot:daily},
> +@code{com.sun:auto-snapshot:weekly}, and @code{com.sun:auto-snapshot:monthly}
> +properties that give finer-grained control of whether to auto-snapshot a
> +dataset at a particular schedule.
> +
> +The number of snapshots kept for all datasets can be overridden via the
> +@code{auto-snapshot-keep} field of the @code{zfs-configuration} record.
> +There is currently no support to have different numbers of snapshots to
> +keep for different datasets.
> +
> +@subsubsection ZVOLs
> +
> +ZFS supports ZVOLs, block devices that ZFS exposes to the operating
> +system in the @code{/dev/zvol/} directory. The ZVOL will have the same
> +resilience and self-healing properties as other datasets on your ZFS pool.
> +ZVOLs can also be snapshotted (and will be included in auto-snapshotting
> +if enabled), which snapshots the state of the block device, effectively
> +snapshotting the hosted file system.
> +
> +You can put any file system inside the ZVOL. However, in order to mount this
> +file system at system start, you need to add @code{%zfs-zvol-dependency} as a
> +dependency of each file system inside a ZVOL.
> +
> +@defvr {Scheme Variable} %zfs-zvol-dependency
> +An artificial @code{<mapped-device>} which tells the file system mounting
> +service to wait for ZFS to provide ZVOLs before mounting the
> +@code{<file-system>} dependent on it.
> +@end defvr
> +
> +For example, suppose you create a ZVOL and put an ext4 filesystem
> +inside it:
> +
> +@example
> +# zfs create -V 100G tank/ext4-on-zfs
> +# mkfs.ext4 /dev/zvol/tank/ext4-on-zfs
> +# mkdir /ext4-on-zfs
> +# mount /dev/zvol/tank/ext4-on-zfs /ext4-on-zfs
> +@end example
> +
> +You can then set this up to be mounted at boot by adding this to the
> +@code{file-systems} field of your @code{operating-system} record:
> +
> +@lisp
> +(file-system
>
> -   (device "/dev/zvol/tank/ext4-on-zfs")
> -   (mount-point "/ext4-on-zfs")
> -   (type "ext4")
> -   (dependencies (list %zfs-zvol-dependency)))
>     +@end lisp
>
> -
>
> +You @emph{must not} add @code{%zfs-zvol-dependency} to your
> +@code{operating-system}'s @code{mapped-devices} field, and you @emph{must
> +not} add it (or any @code{<file-system>}s dependent on it) to the
> +@code{dependencies} field of @code{zfs-configuration}. Finally, you
> +@emph{must not} use @code{%zfs-zvol-dependency} unless you actually
> +instantiate @code{zfs-service-type} on your system.
> +
> +@subsubsection Unsupported Features
> +
> +Some common features and uses of ZFS are currently not supported, or not
> +fully supported, on Guix.
> +
> +@enumerate
> +@item
> +Shepherd-managed daemons that are configured to read from or write to ZFS
> +mountpoints need to include @code{user-processes} in their @code{requirement}
> +field. This is the earliest that ZFS file systems are assured of being
> +mounted.
> +
> +Generally, most daemons will, directly or indirectly, require
> +@code{networking}, or @code{user-processes}, or both. Most implementations
> +of @code{networking} will also require @code{user-processes} so daemons that
> +require only @code{networking} will also generally start up after
> +@code{user-processes}. A notable exception, however, is
> +@code{static-networking-service-type}. You will need to explicitly add
> +@code{user-processes} as a @code{requirement} of your @code{static-networking}
> +record.
> +
> +@item
> +@code{mountpoint=legacy} ZFS file systems. The handlers for the Guix mounting
> +system have not yet been modified to support ZFS, and will expect @code{/dev}
> +paths in the @code{<file-system>}'s @code{device} field, but ZFS file systems
> +are referred to via non-path @code{pool/file/system} names. Such file systems
> +also need to be mounted @emph{after} OpenZFS has scanned for pools.
> +
> +You can still manually mount these file systems after system boot; what is
> +only unsupported is mounting them automatically at system boot by specifying
> +them in @code{<file-system>} records of your @code{operating-system}.
>
> -
>
> +@item
> +@code{/home} on ZFS. Guix will create home directories for users, but this
> +process currently cannot be scheduled after ZFS file systems are mounted.
> +Thus, the ZFS file system might be mounted @emph{after} Guix has created
> +home directories at boot, at which point OpenZFS will refuse to mount since
> +the mountpoint is not empty. However, you @emph{can} create an ext4, xfs,
> +btrfs, or other supported file system inside a ZVOL, have that depend on
> +@code{%zfs-zvol-dependency}, and set it to mount on the @code{/home}
> +directory; they will be scheduled to mount before the @code{user-homes}
> +process.
> +
> +Similarly, other locations like @code{/var}, @code{/gnu/store} and so
> +on cannot be reliably put in a ZFS file system, though they may be
> +possible to create as other file systems inside ZVOL containers.
> +
> +@item
> +@code{/} and @code{/boot} on ZFS. These require Guix to expose more of
> +the @code{initrd} very early boot process to services. It also requires
> +Guix to have the ability to explicitly load modules while still in
> +@code{initrd} (currently kernel modules loaded by
> +@code{kernel-module-loader-service-type} are loaded after @code{/} is
> +mounted). Further, since one of ZFS's main advantages is that it can
> +continue working despite the loss of one or more devices, it makes sense
> +to also support installing the bootloader on all devices of the pool that
> +contains the @code{/} and @code{/boot}; after all, if ZFS can survive the
> +loss of one device, the bootloader should also be able to survive the loss
> +of one device.
> +
> +@item
> +ZVOL swap devices. Mapped swap devices need to be listed in
> +@code{mapped-devices} to ensure they are opened before the system attempts
> +to use them, but you cannot currently add @code{%zfs-zvol-dependency} to
> +@code{mapped-devices}.
> +
> +This will also require significant amounts of testing, as various kernel
> +build options and patches may affect how swapping works, which are possibly
> +different on Guix System compared to other distributions that this feature is
> +known to work on.
> +
> +@item
> +ZFS Event Daemon. Support for this has not been written yet, patches are
> +welcome. The main issue is how to design this in a Guix style while
> +supporting legacy shell-script styles as well. In particular, OpenZFS itself
> +comes with a number of shell scripts intended for ZFS Event Daemon, and we
> +need to figure out how the user can choose to use or not use the provided
> +scripts (and configure any settings they have) or override with their own
> +custom code (which could be shell scripts they have written and trusted from
> +previous ZFS installations).
> +
> +As-is, you can create your own service that activates the ZFS Event Daemon
> +by creating the @file{/etc/zfs/zed} directory and filling it appropriately,
> +then launching @code{zed}.
> +
> +@item
> +@file{/etc/zfs/zpool.cache}. Currently the ZFS support on Guix always forces
> +scanning of all devices at bootup to look for ZFS pools. For systems with
> +dozens or hundreds of storage devices, this can lead to slow bootup. One issue
> +is that tools should really not write to @code{/etc} which is supposed to be for
> +configuration; possibly it could be moved to @code{/var} instead. Another issue
> +is that if Guix ever supports @code{/} on ZFS, we would need to somehow keep the
> +@code{zpool.cache} file inside the @code{initrd} up-to-date with what is in the
> +@code{/} mount point.
> +
> +@item
> +@code{zfs share}. This will require some (unknown amount of) work to integrate
> +into the Samba and NFS services of Guix. You @emph{can} manually set up Samba
> +and NFS to share any mounted ZFS datasets by setting up their configurations
> +properly; it just can't be done for you by @code{zfs share} and the
> +@code{sharesmb} and @code{sharenfs} properties.
> +@end enumerate
> +
> +Hopefully, support for the above only requires code to be written, and users
> +are encouraged to hack on Guix to implement the above features.
> +
> @node Mapped Devices
> @section Mapped Devices
>
> diff --git a/gnu/local.mk b/gnu/local.mk
> index d415b892e9..4147badd49 100644
> --- a/gnu/local.mk
> +++ b/gnu/local.mk
> @@ -45,6 +45,7 @@
>
> Copyright © 2021 Sharlatan Hellseher sharlatanus@gmail.com
>
> ===========================================================
>
> Copyright © 2021 Dmitry Polyakov polyakov@liltechdude.xyz
>
> ==========================================================
>
> Copyright © 2021 Andrew Tropin andrew@trop.in
>
> ==============================================
>
> +# Copyright © 2021 raid5atemyhomework raid5atemyhomework@protonmail.com
>
> ==
>
> This file is part of GNU Guix.
>
> ===============================
>
> ==
>
> @@ -633,6 +634,7 @@ GNU_SYSTEM_MODULES = \
> %D%/services/docker.scm \
> %D%/services/authentication.scm \
> %D%/services/file-sharing.scm \
>
> -   %D%/services/file-systems.scm \
>     %D%/services/games.scm \
>     %D%/services/ganeti.scm \
>     %D%/services/getmail.scm \
>     diff --git a/gnu/services/base.scm b/gnu/services/base.scm
>     index 50865055fe..d5d33aeada 100644
>     --- a/gnu/services/base.scm
>     +++ b/gnu/services/base.scm
>     @@ -186,7 +186,9 @@
>
>     references-file
>
>
> -              %base-services))
>
>
>
> -              %base-services
>
>
> -
> -              dependency->shepherd-service-name))
>
>
>
> ;;; Commentary:
> ;;;
> diff --git a/gnu/services/file-systems.scm b/gnu/services/file-systems.scm
> new file mode 100644
> index 0000000000..867349c3a5
> --- /dev/null
> +++ b/gnu/services/file-systems.scm
> @@ -0,0 +1,363 @@
> +;;; GNU Guix --- Functional package management for GNU
> +;;; Copyright © 2021 raid5atemyhomework raid5atemyhomework@protonmail.com
> +;;;
> +;;; This file is part of GNU Guix.
> +;;;
> +;;; GNU Guix is free software; you can redistribute it and/or modify it
> +;;; under the terms of the GNU General Public License as published by
> +;;; the Free Software Foundation; either version 3 of the License, or (at
> +;;; your option) any later version.
> +;;;
> +;;; GNU Guix is distributed in the hope that it will be useful, but
> +;;; WITHOUT ANY WARRANTY; without even the implied warranty of
> +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +;;; GNU General Public License for more details.
> +;;;
> +;;; You should have received a copy of the GNU General Public License
> +;;; along with GNU Guix. If not, see http://www.gnu.org/licenses/.
>
> -
>
> +(define-module (gnu services file-systems)
>
> -   #:use-module (gnu packages file-systems)
> -   #:use-module (gnu services)
> -   #:use-module (gnu services base)
> -   #:use-module (gnu services linux)
> -   #:use-module (gnu services mcron)
> -   #:use-module (gnu services shepherd)
> -   #:use-module (gnu system mapped-devices)
> -   #:use-module (guix gexp)
> -   #:use-module (guix modules)
> -   #:use-module (guix packages)
> -   #:use-module (guix records)
> -   #:use-module (srfi srfi-1)
> -   #:export (zfs-service-type
> -
> -              zfs-configuration
>
>
> -              zfs-configuration?
>
>
> -              zfs-configuration-kernel
>
>
> -              zfs-configuration-base-zfs
>
>
> -              zfs-configuration-base-zfs-auto-snapshot
>
>
> -              zfs-configuration-dependencies
>
>
> -              zfs-configuration-auto-mount?
>
>
> -              zfs-configuration-auto-scrub
>
>
> -              zfs-configuration-auto-snapshot?
>
>
> -              zfs-configuration-auto-snapshot-keep
>
>
> -
> -              %zfs-zvol-dependency))
>
>
> -
>
> +(define-record-type* <zfs-configuration>
>
> -   zfs-configuration
>
> -   make-zfs-configuration
>
> -   zfs-configuration?
>
> -
> -   ;; linux-libre kernel you want to compile the base-zfs module for.
>
> -   (kernel zfs-configuration-kernel)
>
> -
> -   ;; the OpenZFS package that will be modified to compile for the
>
> -   ;; given kernel.
>
> -   ;; Because it is modified and not the actual package that is used,
>
> -   ;; we prepend the name 'base-'.
>
> -   (base-zfs zfs-configuration-base-zfs
>
> -                                (default zfs))
>
>
> -
> -   ;; the zfs-auto-snapshot package that will be modified to compile
>
> -   ;; for the given kernel.
>
> -   ;; Because it is modified and not the actual package that is used,
>
> -   ;; we prepend the name 'base-'.
>
> -   (base-zfs-auto-snapshot zfs-configuration-base-zfs-auto-snapshot
>
> -                                (default zfs-auto-snapshot))
>
>
> -
> -   ;; list of <mapped-device> or <file-system> objects that must be
>
> -   ;; opened/mounted before we import any ZFS pools.
>
> -   (dependencies zfs-configuration-dependencies
>
> -                                (default '()))
>
>
> -
> -   ;; #t to mount all mountable datasets by default.
>
> -   ;; #f if not mounting.
>
> -   ;; #t is the expected behavior on other operating systems, the
>
> -   ;; #f is only supported for "rescue" operating systems where
>
> -   ;; the user wants lower-level control of when to mount.
>
> -   (auto-mount? zfs-configuration-auto-mount?
>
> -                                (default #t))
>
>
> -
> -   ;; 'weekly for weekly scrubbing, 'monthly for monthly scrubbing, an
>
> -   ;; mcron time specification that can be given to `job`, or #f to
>
> -   ;; disable.
>
> -   (auto-scrub zfs-configuration-auto-scrub
>
> -                                (default 'weekly))
>
>
> -
> -   ;; #t to auto-snapshot by default (and `com.sun:auto-snapshot=false`
>
> -   ;; disables auto-snapshot per dataset), #f to not auto-snapshot
>
> -   ;; by default (and `com.sun:auto-snapshot=true` enables auto-snapshot
>
> -   ;; per dataset).
>
> -   (auto-snapshot? zfs-configuration-auto-snapshot?
>
> -                                (default #t))
>
>
> -
> -   ;; association list of symbol-number pairs to indicate the number
>
> -   ;; of automatic snapshots to keep for each of 'frequent, 'hourly,
>
> -   ;; 'daily, 'weekly, and 'monthly.
>
> -   ;; e.g. '((frequent . 8) (hourly . 12))
>
> -   (auto-snapshot-keep zfs-configuration-auto-snapshot-keep
>
> -                                (default '())))
>
>
> -
>
> +(define %default-auto-snapshot-keep
>
> -   '((frequent . 4)
> -   (hourly . 24)
> -   (daily . 31)
> -   (weekly . 8)
> -   (monthly . 12)))
> -
>
> +(define %auto-snapshot-mcron-schedule
>
> -   '((frequent . "0,15,30,45 * * * *")
> -   (hourly . "0 * * * *")
> -   (daily . "0 0 * * *")
> -   (weekly . "0 0 * * 7")
> -   (monthly . "0 0 1 * *")))
> -
>
> +;; A synthetic and unusable MAPPED-DEVICE intended for use when
> +;; the user has created a mountable filesystem inside a ZFS
> +;; zvol and wants it mounted inside the configuration.scm.
> +(define %zfs-zvol-dependency
>
> -   (mapped-device
> -   (source '())
> -   (targets '("zvol/*"))
> -   (type #f)))
> -
>
> +(define (make-zfs-package conf)
>
> -   "Creates a zfs package based on the given zfs-configuration.
> -
> -   OpenZFS is a kernel package and to ensure best compatibility
> -   it should be compiled with the specific Linux-Libre kernel
> -   used on the system. This simply overrides the kernel used
> -   in compilation with that given in the configuration, which
> -   the user has to ensure is the same as in the operating-system."
> -   (let ((kernel (zfs-configuration-kernel conf))
> -          (base-zfs  (zfs-configuration-base-zfs conf)))
>
>
> -   (package
> -        (inherit base-zfs)
>
>
> -        (arguments (cons* #:linux kernel
>
>
> -                          (package-arguments base-zfs))))))
>
>
> -
>
> +(define (make-zfs-auto-snapshot-package conf)
>
> -   "Creates a zfs-auto-snapshot package based on the given
> -   zfs-configuration.
> -
> -   Since the OpenZFS tools above are compiled to a specific
> -   kernel version, zfs-auto-snapshot --- which calls into the
> -   OpenZFS tools --- has to be compiled with the specific
> -   modified OpenZFS package created in the make-zfs-package
> -   procedure."
> -   (let ((zfs (make-zfs-package conf))
> -          (base-zfs-auto-snapshot (zfs-configuration-base-zfs-auto-snapshot conf)))
>
>
> -   (package
> -        (inherit base-zfs-auto-snapshot)
>
>
> -        (inputs `(("zfs" ,zfs))))))
>
>
> -
>
> +(define (zfs-loadable-modules conf)
>
> -   "Specifies that the specific 'module' output of the OpenZFS
> -   package is to be used; for use in indicating it as a
> -   loadable kernel module."
> -   (list (list (make-zfs-package conf) "module")))
> -
>
> +(define (zfs-shepherd-services conf)
>
> -   "Constructs a list of Shepherd services that is installed
>
> -   by the ZFS Guix service.
>
> -
> -   'zfs-scan' scans all devices for ZFS pools, and makes them
>
> -   available to 'zpool' commands.
>
> -   'device-mapping-zvol/' waits for /dev/zvol/ to be
>
> -   populated by 'udev', and runs after 'zfs-scan'.
>
> -   'zfs-auto-mount' mounts all ZFS datasets with a 'mount'
>
> -   property, which defaults to '/' followed by the name of
>
> -   the dataset.
>
> -
> -   All the above behavior is expected by ZFS users from
>
> -   typical ZFS installations. A mild difference is that
>
> -   scanning is usually based on '/etc/zfs/zpool.cache'
>
> -   instead of the 'scan all devices' used below, but that
>
> -   file is questionable in Guix since ideally '/etc/'
>
> -   files are modified by the sysad directly;
>
> -   '/etc/zfs/zpool.cache' is modified by ZFS tools."
>
> -   (let* ((zfs-package (make-zfs-package conf))
>
> -           (zpool           (file-append zfs-package "/sbin/zpool"))
>
>
> -           (zfs             (file-append zfs-package "/sbin/zfs"))
>
>
> -           (zvol_wait       (file-append zfs-package "/bin/zvol_wait"))
>
>
> -           (scheme-modules  `((srfi srfi-1)
>
>
> -                              (srfi srfi-34)
>
>
> -                              (srfi srfi-35)
>
>
> -                              (rnrs io ports)
>
>
> -                              ,@%default-modules)))
>
>
> -   (define zfs-scan
>
> -        (shepherd-service
>
>
> -          (provision '(zfs-scan))
>
>
> -          (requirement `(root-file-system
>
>
> -                         kernel-module-loader
>
>
> -                         udev
>
>
> -                         ,@(map dependency->shepherd-service-name
>
>
> -                                (zfs-configuration-dependencies conf))))
>
>
> -          (documentation "Scans for and imports ZFS pools.")
>
>
> -          (modules scheme-modules)
>
>
> -          (start #~(lambda _
>
>
> -                     (guard (c ((message-condition? c)
>
>
> -                                (format (current-error-port)
>
>
> -                                        "zfs: error importing pools: ~s~%"
>
>
> -                                        (condition-message c))
>
>
> -                                #f))
>
>
> -                       ;; TODO: optionally use a cachefile.
>
>
> -                       (invoke #$zpool "import" "-a" "-N"))))
>
>
> -          ;; Why not one-shot?  Because we don't really want to rescan
>
>
> -          ;; this each time a requiring process is restarted, as scanning
>
>
> -          ;; can take a long time and a lot of I/O.
>
>
> -          (stop #~(const #f))))
>
>
> -
> -   (define device-mapping-zvol/*
>
> -        (shepherd-service
>
>
> -          (provision '(device-mapping-zvol/*))
>
>
> -          (requirement '(zfs-scan))
>
>
> -          (documentation "Waits for all ZFS ZVOLs to be opened.")
>
>
> -          (modules scheme-modules)
>
>
> -          (start #~(lambda _
>
>
> -                     (guard (c ((message-condition? c)
>
>
> -                                (format (current-error-port)
>
>
> -                                        "zfs: error opening zvols: ~s~%"
>
>
> -                                        (condition-message c))
>
>
> -                                #f))
>
>
> -                       (invoke #$zvol_wait))))
>
>
> -          (stop #~(const #f))))
>
>
> -
> -   (define zfs-auto-mount
>
> -        (shepherd-service
>
>
> -          (provision '(zfs-auto-mount))
>
>
> -          (requirement '(zfs-scan))
>
>
> -          (documentation "Mounts all non-legacy mounted ZFS filesystems.")
>
>
> -          (modules scheme-modules)
>
>
> -          (start #~(lambda _
>
>
> -                     (guard (c ((message-condition? c)
>
>
> -                                (format (current-error-port)
>
>
> -                                        "zfs: error mounting file systems: ~s~%"
>
>
> -                                        (condition-message c))
>
>
> -                                #f))
>
>
> -                       ;; Output to current-error-port, otherwise the
>
>
> -                       ;; user will not see any prompts for passwords
>
>
> -                       ;; of encrypted datasets.
>
>
> -                       ;; XXX Maybe better to explicitly open /dev/console ?
>
>
> -                       (with-output-to-port (current-error-port)
>
>
> -                         (lambda ()
>
>
> -                           (invoke #$zfs "mount" "-a" "-l"))))))
>
>
> -          (stop #~(lambda _
>
>
> -                    ;; Make sure that Shepherd does not have a CWD that
>
>
> -                    ;; is a mounted ZFS filesystem, which would prevent
>
>
> -                    ;; unmounting.
>
>
> -                    (chdir "/")
>
>
> -                    (invoke #$zfs "unmount" "-a" "-f")))))
>
>
> -
> -   `(,zfs-scan
>
> -        ,device-mapping-zvol/*
>
>
> -        ,@(if (zfs-configuration-auto-mount? conf)
>
>
> -              `(,zfs-auto-mount)
>
>
> -              '()))))
>
>
> -
>
> +(define (zfs-user-processes conf)
>
> -   "Provides the last Shepherd service that 'user-processes' has to
> -   wait for.
> -
> -   If not auto-mounting, then user-processes should only wait for
> -   the device scan."
> -   (if (zfs-configuration-auto-mount? conf)
> -        '(zfs-auto-mount)
>
>
> -        '(zfs-scan)))
>
>
> -
>
> +(define (zfs-mcron-auto-snapshot-jobs conf)
>
> -   "Creates a list of mcron jobs for auto-snapshotting, one for each
>
> -   of the standard durations."
>
> -   (let* ((user-auto-snapshot-keep (zfs-configuration-auto-snapshot-keep conf))
>
> -           ;; assoc-ref has earlier entries overriding later ones.
>
>
> -           (auto-snapshot-keep           (append user-auto-snapshot-keep
>
>
> -                                                 %default-auto-snapshot-keep))
>
>
> -           (auto-snapshot?               (zfs-configuration-auto-snapshot? conf))
>
>
> -           (zfs-auto-snapshot-package    (make-zfs-auto-snapshot-package conf))
>
>
> -           (zfs-auto-snapshot            (file-append zfs-auto-snapshot-package
>
>
> -                                                      "/sbin/zfs-auto-snapshot")))
>
>
> -   (map
>
> -        (lambda (label)
>
>
> -          (let ((keep   (assoc-ref auto-snapshot-keep label))
>
>
> -                (sched  (assoc-ref %auto-snapshot-mcron-schedule label)))
>
>
> -            #~(job '#$sched
>
>
> -                   (lambda ()
>
>
> -                     (system* #$zfs-auto-snapshot
>
>
> -                              "--quiet"
>
>
> -                              "--syslog"
>
>
> -                              #$(string-append "--label="
>
>
> -                                               (symbol->string label))
>
>
> -                              #$(string-append "--keep="
>
>
> -                                               (number->string keep))
>
>
> -                              "//")))))
>
>
> -        (map first %auto-snapshot-mcron-schedule))))
>
>
> -
>
> +(define (zfs-mcron-auto-scrub-jobs conf)
>
> -   "Creates a list of mcron jobs for auto-scrubbing."
> -   (let* ((zfs-package (make-zfs-package conf))
> -           (zpool          (file-append zfs-package "/sbin/zpool"))
>
>
> -           (auto-scrub     (zfs-configuration-auto-scrub conf))
>
>
> -           (sched          (cond
>
>
> -                             ((eq? auto-scrub 'weekly)  "0 0 * * 7")
>
>
> -                             ((eq? auto-scrub 'monthly) "0 0 1 * *")
>
>
> -                             (else                      auto-scrub))))
>
>
> -   (define code
> -        ;; We need to get access to (guix build utils) for the
>
>
> -        ;; invoke procedures.
>
>
> -        (with-imported-modules (source-module-closure '((guix build utils)))
>
>
> -          #~(begin
>
>
> -              (use-modules (guix build utils)
>
>
> -                           (ice-9 ports))
>
>
> -              ;; The ZFS pools in the system.
>
>
> -              (define pools
>
>
> -                (invoke/quiet #$zpool "list" "-o" "name" "-H"))
>
>
> -              ;; Only scrub if there are actual ZFS pools, as the
>
>
> -              ;; zpool scrub command errors out if given an empty
>
>
> -              ;; argument list.
>
>
> -              (unless (null? pools)
>
>
> -                ;; zpool scrub only initiates the scrub and otherwise
>
>
> -                ;; prints nothing.  Results are always seen on the
>
>
> -                ;; zpool status command.
>
>
> -                (apply invoke #$zpool "scrub" pools)))))
>
>
> -   (list
> -        #~(job '#$sched
>
>
> -               #$(program-file "mcron-zfs-scrub.scm" code)))))
>
>
> -
>
> +(define (zfs-mcron-jobs conf)
>
> -   "Creates a list of mcron jobs for ZFS management."
> -   (append (zfs-mcron-auto-snapshot-jobs conf)
> -            (if (zfs-configuration-auto-scrub conf)
>
>
> -                (zfs-mcron-auto-scrub-jobs conf)
>
>
> -                '())))
>
>
> -
>
> +(define zfs-service-type
>
> -   (service-type
> -   (name 'zfs)
> -   (extensions
> -        (list ;; Install OpenZFS kernel module into kernel profile.
>
>
> -              (service-extension linux-loadable-module-service-type
>
>
> -                                 zfs-loadable-modules)
>
>
> -              ;; And load it.
>
>
> -              (service-extension kernel-module-loader-service-type
>
>
> -                                 (const '("zfs")))
>
>
> -              ;; Make sure ZFS pools and datasets are mounted at
>
>
> -              ;; boot.
>
>
> -              (service-extension shepherd-root-service-type
>
>
> -                                 zfs-shepherd-services)
>
>
> -              ;; Make sure user-processes don't start until
>
>
> -              ;; after ZFS does.
>
>
> -              (service-extension user-processes-service-type
>
>
> -                                 zfs-user-processes)
>
>
> -              ;; Install automated scrubbing and snapshotting.
>
>
> -              (service-extension mcron-service-type
>
>
> -                                 zfs-mcron-jobs)
>
>
> -
> -              ;; Install ZFS management commands in the system
>
>
> -              ;; profile.
>
>
> -              (service-extension profile-service-type
>
>
> -                                 (compose list make-zfs-package))
>
>
> -              ;; Install ZFS udev rules.
>
>
> -              (service-extension udev-service-type
>
>
> -                                 (compose list make-zfs-package))))
>
>
> -   (description "Installs ZFS, an advanced filesystem and volume manager.")))
>
>     base-commit: a939011b58c65f4192a10cde9e925e85702bacf4
>     --
>     2.33.0
>