bento: add auto reboot mode

README.md

@@ -84,6 +84,7 @@ Here is the typical directory layout for using **bento** for the non-flakes syst
 `bento` is using the following environment variables as configuration:
 - `BENTO_DIR`: contains the path of a bento directory, so you can run `bento` commands from anywhere
 - `NAME`: contains machine names (flake config or directory in `hosts/`) to restrict commands `deploy` and `build` to this machine only
+- `VERBOSE`: if defined to anything, display `nixos-rebuild` output for local builds done with `bento build` or `bento deploy`
 
 # Workflow
 
@@ -109,6 +110,10 @@ Systems will be reported as "auto upgraded" in the `bento status` command if the
 
 This adds at least 8 kB of inbound bandwidth for each input when checking for changes.
 
+# Auto reboot
+
+You can create a file named `REBOOT` in a host directory. When that host will rebuild the system, it will look at the new kernel, kernel modules and initrd, if they changed, a reboot will occur immediately after reporting a successful upgrade.  A kexec is used for UEFI systems for a faster reboot (this avoids BIOS and bootloader steps).
+
 # Examples
 
 ## Get started with bento
@@ -199,6 +204,8 @@ A parameter can be added to only update a given source with, i.e to update all n
 - DONE ~~upgrades could be triggered by the user by accessing a local socket, like opening a web page in a web browser to trigger it, if it returns output that'd be better~~
 - a way to tell a client (when using flakes) to try to update flakes every time even if no configuration changed, to keep them up to date
 - DONE ~~being able to use a single flakes with multiple hosts that **bento** will automatically assign to the nixosConfiguration names as hosts~~
+- DONE ~~handle automatic reboot if the kernel changed~~
+- automatic reboot should be scheduled if desired, this may require making bento a NixOS module to set a timer in it, if no timer then it would reboot immediately
 
 ## Minor
 

bento

@@ -334,6 +334,18 @@ then
     else
         echo "put \${LOGFILE}.gz /logs/\$(date +%Y%m%d-%H%M)_\${OSVERSION}_success.log.gz" | sftp ${dest}@${REMOTE_IP}:
     fi
+
+    # handle auto reboot if kernel changed
+    if [ -f "REBOOT" ]
+    then
+        booted="\$(readlink /run/booted-system/{initrd,kernel,kernel-modules})"
+        built="\$(readlink /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
+
+        if [ ! "\${booted}" = "\${built}" ]
+        then
+            systemctl kexec || systemctl reboot
+        fi
+    fi
 else
     # check if we did a rollback
     if [ "\$SUCCESS" -eq 255 ]
@@ -374,6 +386,13 @@ build_config()
     TMPLOG="$(mktemp /tmp/bento-build-log.XXXXXXXXXXXX)"
     rsync -rltgoDL  "$SOURCES/" "$TMP/"
 
+    if [ -z "VERBOSE" ]
+    then
+        output="/dev/null"
+    else
+        output="/dev/stderr"
+    fi
+
     SECONDS=0
     cd "$TMP" || exit 5
 
@@ -385,9 +404,9 @@ build_config()
         test -d .git || git init >/dev/null 2>/dev/null
         git add . >/dev/null
 
-        $SUDO nixos-rebuild "${COMMAND}" --flake ".#${NAME}" 2>"${TMPLOG}" >"${TMPLOG}"
+        $SUDO nixos-rebuild "${COMMAND}" --flake ".#${NAME}" | tee "${output}" 2>"${TMPLOG}" >"${TMPLOG}"
     else
-        $SUDO nixos-rebuild "${COMMAND}" --no-flake -I nixos-config="$TMP/configuration.nix" 2>"${TMPLOG}" >"${TMPLOG}"
+        $SUDO nixos-rebuild "${COMMAND}" --no-flake -I nixos-config="$TMP/configuration.nix" | tee "${output}" 2>"${TMPLOG}" >"${TMPLOG}"
     fi
     if [ $? -eq 0 ]; then printf "success " ; else printf "failure " ; BAD_HOSTS="${NAME} ${BAD_HOSTS}" ; SUCCESS=$(( SUCCESS + 1 )) ; cat "${TMPLOG}" ; fi
     ELAPSED=$(elapsed_time $SECONDS)