feat: add zfs-service to zfs extension (unmount, encryption)

This patch adds a new service to the zfs extension (`zfs-service`) that
handles pool import and unmount. These operations are tied to the
service lifecycle: the service imports all pools when it starts, waits
for an exit signal, then unmounts all pools before exiting.

As a subtle additional benefit, the service passes the `-l` flag to
`zpool-import`[^1], which instructs it to request encryption keys for
all encrypted datasets. Using the zfs `keylocation`[^2] property and
Talos secure boot and TPM disk encryption, a ZFS encryption key file can
be safely stored on the EPHEMERAL partition to import encrypted datasets
at boot. Alternatively, a key can be stored on an https server.

[^1]: https://openzfs.github.io/openzfs-docs/man/master/8/zpool-import.8.html
[^2]: https://openzfs.github.io/openzfs-docs/man/master/7/zfsprops.7.html#keylocation

Signed-off-by: Jean-Francois Roy <[email protected]>
Signed-off-by: Noel Georgi <[email protected]>

Author: jfroy

Diff for: storage/zfs/manifest.yaml

@@ -4,7 +4,7 @@ metadata:
   version: "$VERSION"
   author: Andrei Kvapil, Aenix
   description: |
-    This system extension provides kernel module driver for ZFS built against a specific Talos version.
+    This system extension provides the ZFS kernel module, the ZFS utilities, and a service to import all ZFS pools on start and unmount all pools on stop.
   compatibility:
     talos:
       version: ">= v1.6.0"

Diff for: storage/zfs/pkg.yaml

@@ -9,19 +9,18 @@ dependencies:
   - stage: libtirpc-zfs
   - stage: zlib-zfs
   - stage: zfs-tools
+  - stage: zfs-service
 steps:
   - prepare:
       - |
         sed -i 's#$VERSION#{{ .VERSION }}#' /pkg/manifest.yaml
   - install:
       - |
-        mkdir -p /rootfs/lib/modules /rootfs/usr/local/lib/containers/zpool-importer
-
-        cp -R /lib/modules/* /rootfs/lib/modules
+        mkdir -p /rootfs/lib/modules
+        cp -R /lib/modules/* /rootfs/lib/modules/
       - |
         mkdir -p /rootfs/usr/local/etc/containers
-
-        cp /pkg/zpool-importer.yaml /rootfs/usr/local/etc/containers/zpool-importer.yaml
+        cp /pkg/zfs-service.yaml /rootfs/usr/local/etc/containers/
     test:
       - |
         mkdir -p /extensions-validator-rootfs

Diff for: storage/zfs/zpool-importer.yaml renamed to storage/zfs/zfs-service.yaml

@@ -1,15 +1,10 @@
-name: zpool-importer
+name: zfs-service
 depends:
   - service: udevd
   - service: cri
   - path: /dev/zfs
 container:
-  security:
-    rootfsPropagation: shared
-  entrypoint: /usr/local/sbin/zpool
-  args:
-    - import
-    - -fa
+  entrypoint: /zfs-service
   mounts:
     # ld-musl-x86_64.so.1
     - source: /lib
@@ -44,11 +39,20 @@ container:
         - rshared
         - rbind
         - rw
+    - source: /run
+      destination: /run
+      type: bind
+      options:
+        - rshared
+        - rbind
+        - rw
     - source: /var
       destination: /var
       type: bind
       options:
         - rshared
         - rbind
         - rw
+  security:
+    rootfsPropagation: shared
 restart: untilSuccess

Diff for: storage/zfs/zfs-service/go.mod

@@ -0,0 +1,5 @@
+module zfs-service
+
+go 1.22
+
+require golang.org/x/sys v0.24.0

Diff for: storage/zfs/zfs-service/go.sum

@@ -0,0 +1,2 @@
+golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
+golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

Diff for: storage/zfs/zfs-service/main.go

@@ -0,0 +1,34 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"os/signal"
+
+	"golang.org/x/sys/unix"
+)
+
+func main() {
+	cmd := exec.Command("/usr/local/sbin/zpool", "import", "-fal")
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		log.Fatalf("zfs-service: zpool import error: %v\n", err)
+	}
+
+	ch := make(chan os.Signal, 1)
+	signal.Notify(ch, unix.SIGINT, unix.SIGTERM)
+	<-ch
+
+	cmd = exec.Command("/usr/local/sbin/zfs", "unmount", "-au")
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		log.Fatalf("zfs-service: zfs unmount error: %v\n", err)
+	}
+}

Diff for: storage/zfs/zfs-service/pkg.yaml

@@ -0,0 +1,21 @@
+name: zfs-service
+variant: scratch
+shell: /toolchain/bin/bash
+dependencies:
+  - stage: base
+steps:
+  - cachePaths:
+      - /.cache/go-build
+      - /go/pkg
+    build:
+      - |
+        export PATH=${PATH}:${TOOLCHAIN}/go/bin
+        cp -r /pkg/* .
+        CGO_ENABLED=0 go build -ldflags "-s -w" -trimpath -o zfs-service main.go
+    install:
+      - |
+        mkdir -p /rootfs/usr/local/lib/containers/zfs-service
+        cp zfs-service /rootfs/usr/local/lib/containers/zfs-service/
+finalize:
+  - from: /rootfs
+    to: /rootfs