にゅーステレオ天国 (linuxについての記事)

systemd: enabling a user-unit service

Shimoda — Tue, 14 Oct 2025 23:00:00 GMT

In my experience, setting up a systemd service as a user unit can be trickier than setting it up as a system unit.

You need to pay attention to a few key points to get it working correctly.

TL;DR

At first, here is my service file.

[Unit]
Description=voice from pushbullet
#Wants=default.target
After=network.target

[Service]
Type=simple
WorkingDirectory=%h/src/pb-va
ExecStart=%h/bin/pb_va some options...
ExecStop=pkill pb-va
Restart=always

[Install]
WantedBy=default.target

Copy this file to the systemd directory and enable it::

$ mkdir -p ~/.config/systemd/user
$ cp pb-va.service ~/.config/systemd/user
$ systemctl --user daemon-reload
$ systemctl --user enable pb-va.service
$ systemctl --user start pb-va.service
$ loginctl enable-linger $USER

Do not specify the `User=` and `Group=` options

In the [Service] section, system units can use the User= and Group= options.

However, user units run under your own user account by default, so adding these options will cause the service to fail on startup.

Use User-Specific Targets like default.target

You might be used to seeing targets like multi-user.target in system-wide services.

Those targets are for system units and won't work for user units. For user services, you should almost always use WantedBy=default.target.

This is the user's equivalent and ensures your service starts after you log in.

Remember to re-enable the service and reload the daemon after changing the serfice file to apply your changes:

$ systemctl --user daemon-reload
$ systemctl --user disable pb-va.service
$ systemctl --user enable pb-va.service

By default, user services stop when you log out.

If you want your service to start at boot and keep running, you must enable linger for your user.

$ loginctl enable-linger your-username

# then confirm the linger status.

$ loginctl list-users
 UID USER   LINGER
1001 your-username yes

systemd.mount with disk label

Shimoda — Thu, 07 Aug 2025 10:00:00 GMT

here are some points

e2label will not work with the mounted partitions.
the service file name is correspond with the Where option.
check the systemctl status results for the unit file.

here is my procedure and the unit file example.

# label the partition
e2label /dev/sd?? hdd-label1

# create the unit file.
cat > /etc/systemd/system/mnt-aaa.mount <<EOF
[Unit]
Description = mount WesternDigital 1T to /mnt/aaa
After = local-fs.target

[Mount]
#What = /dev/disk/by-label/ts1t-deg
What = LABEL=wd1t-deg
Where = /mnt/aaa
Type = ext4
Options = nofail

[Install]
WantedBy = default.target
EOF

# reload and mount...
systemctl daemon-reload
systemctl status mnt-aaa.mount  # check the errors
systemctl start mnt-aaa.mount

Chromebook: Input Method 2 - qterminal不調

Shimoda — Thu, 07 Aug 2025 04:00:00 GMT

qterminalですが、入力はできるのですが、 BSで入力中の文字を消すと最後の一文字が残ってしまいます。

文字が残ったら一回入力すればいいだけ、とはいえ不便...

![remain character][こんな感じ]

1年半ほどqterminalで快適に過ごしてましたが、
Input Methodが動かなくなりました。

terminal	.	24/2/20	25/8/7	25/10/12
標準terminal	？	？	◯	◯
st	x	x	x	x
terminator	o	x	?	?
terminus	?	?	o	?
qterminal	?	o	x	△

crostiniのupgradeが原因と思う。

他にもOpenSCADなどグラフィック系でChromebookが
落ちるようになった。うーん...

apply overlayfs several directories.

Shimoda — Thu, 31 Jul 2025 00:00:00 GMT

how to reduce the access to SD card in Raspberry-Pi OS.

the one method for it, use the overlay filesystem to several paths in SD card.

here is the script sample to mount the overlayfs onto SD card root file system::

mount-overlay-usr-src: /usr/src/f_overlay
mount-overlay-var-log: /var/log/f_overlay

/usr/src/f_overlay: d:=/mnt/storage1/usr-src
/usr/src/f_overlay: l:=lowerdir=/usr/src
/usr/src/f_overlay: u:=$d/usr-src-upper
/usr/src/f_overlay: w:=$d/usr-src-temp
/usr/src/f_overlay:
    mkdir -p $u $w
    mount -t overlay overlay -o $l,upperdir=$u,workdir=$w $(dir $@)
    touch $@

/var/log/f_overlay: d:=/mnt/storage1/var-log
/var/log/f_overlay: l:=lowerdir=/var/log
/var/log/f_overlay: u:=$d/var-log-upper
/var/log/f_overlay: w:=$d/var-log-temp
/var/log/f_overlay:
    mkdir -p $t $w
    mount -t overlay overlay -o $l,upperdir=$u,workdir=$w $(dir $@)
    touch $@

write down above text to Makefile then run them by::

$ make mount-overlay-usr-src
$ make mount-overlay-var-log

make it to the systemd unit file for persistence mount.

create /etc/systemd/system/mount-overlay.service::

$ cat > /etc/systemd/system/mount-overlay.service <<EOF
[Unit]
Description = mount overlay filesystem to reduce SD card access.
After = mnt-storage1.mount

[Mount]
ExecStart = make -C /path/to/script mount-overlay-var-log
ExecStop = umount -f /var/log

[Install]
WantedBy = default.target
EOF

$ systemctl daemon-reload
$ systemctl start mount-overlay
$ systemctl enable mount-overlay

ARM SBC: install mqtt server with rootless podman

Shimoda — Sun, 22 Jun 2025 23:00:00 GMT

install MQTT server to SBC.

at this time, this MQTT server does not encrypt the communications. we need the TLS encryption for it.

make the configuration file::

cat >> mqtt.conf <<EOF
allow_anonymous false
listener 1883
listener 9001
protocol websockets
persistence true
password_file        /srv/mqtt/mqtt.pwfile
persistence_file     mqtt.db
persistence_location /srv/mqtt/data/

user root  # for podman rootless
EOF

points:
- persistence_file is the relative path from `persistence_location`
- a rootless podman needs `root user` as the running user,
    containers `mqtt` user does not have any permissions to mounted points.

create the container file::

```bash
mkdir app.mqtt; cd app.mqtt
cat > Containerfile <<EOF
FROM debian:12.11-slim

RUN apt update -y
RUN apt install -y mosquitte

RUN mkdir -p /srv/mqtt
RUN mosquitte_passwd -c -b /root/mqtt.pwfile admin ??????
RUN mosquitte_passwd    -b /root/mqtt.pwfile sensor1 ?????
RUN mosquitte_passwd    -b /root/mqtt.pwfile sensor2 ?????
RUN mosquitte_passwd    -b /root/mqtt.pwfile viewer  ?????

COPY mqtt.conf /srv/mqtt/mqtt.conf
CMD ["mosquitte", "-c", "/srv/mqtt/mqtt.conf"]
EOF

build the container::

podman build -t mqtt-server

up the container::

ext=/mnt/external/mqtt
podman run -v /srv/mqtt/data:$ext/data \
           -v /srv/mqtt/log:$ext/log \
           -p 1883 -p 9001 \
           -d mqtt-server

ARM SBC: podman install

Shimoda — Sun, 15 Jun 2025 23:00:00 GMT

My experience in the debian armhf. To install podman, according to https://wiki.debian.org/Podman.

it is need to enable the registory at search::

sudo apt install podman
echo 'unqualified-search-registries=["quay.io"]' > /tmp/registries.conf
CONTAINERS_REGISTRIES_CONF=/tmp/registries.conf podman search podman

move cache directory to an external drive,

sudo mkdir -o /nmt/external/containers.$USER
sudo chown $USER:$USER /nmt/external/containers.$USER
sudo mount -o bind /mnt/external/containers.$USER ~/.local/share/containers

thanks podman github .

I want to build the application from a debian image.

podman pull debian:12.11-slim

build the application.

mkdir app; cd app
echo "FROM debian:12.11-slim" > Containerfile
podman build

install the network program:

sudo apt install uidmap
sudo apt install slirp4netns

thanks github issue .

then run the container:

podman run

ARM SBC: overlayfs error -2

Shimoda — Sat, 14 Jun 2025 23:00:00 GMT

overlayfs errors had began from 2025/05/25, since the SBC was launched at 2024/09/23::

zram-config stop 2025-02-25-08:00:44-JST
ztab remove log /zram1 /var/log /opt/zram/log.bind
serviceConfiguration: Stopping services that interfere with zram device configuration.
removeZdir: Beginning removal of device /dev/zram1.
umount: /var/log (overlay1) unmounted
mergeOverlay: Beginning merge of /opt/zram/opt/zram/log.bind.
ls: /opt/zram/zram1/upper: Input/output error
/opt/zram:
ls: /opt/zram/zram1: Input/output error

I think, it is worth to use overlayfs and zram-config at the sametime, then the overlayfs cannot mount at boot::

kernel: overlayfs: "xino" feature enabled using 2 upper inode
kernel: overlayfs: failed to verify origin (/, ino=12,
kernel: overlayfs: failed to verify upper root origin

to fix it, disable the features of overlayfs at mount. by::

index=off,metacopy=off

here is my fstab.

overlay /var/log overlay noauto,index=off,metacopy=off,workdir=/mnt/external/var-log.tmp,lowerdir=/var/log,upperdir=/mnt/external/var-log 0 0

thanks for arch linux BBS

overlayfsにエラー発生して、以後書き込みができなくなっていた。

その後、再起動してもマウントできなくなった。

あまり起こらないエラーのようで
対処法がなかった。

上のようにすると回避はできた。

何の機能でどういうメリットがあるのかは
調べていないが...

Chromebook Linux terminal(6): podmanでGitHub actionする

Shimoda — Mon, 25 Nov 2024 10:00:00 GMT

GitHub actionではいろいろなことが自動化できて、
私のように自宅に良いPCを持ってない場合は随分助かります。

ただ、GitHub actionのデバッグを
ブラウザで実行するのは待ち時間が長かったり、大変です。

Localでデバッグができるactを使用します。

actをdownloadする

$ git clone https://github.com/nektos/act

downloadしたREADMEを確認すると
go 1.20+とあるので、インストールします。

Goをinstallする

$ apt install golang-1.23

/usr/lib/go1.23/bin にgoがinstallされます

actをbuild/installする

まずはpodmanを実行

$ apt install podman
$ systemctl --user start --now podman.socket

こんな内容のファイルを作成しておきます。

$ sudo sh -c "echo '$USER-desuyo:100000:65536' > /etc/subuid"
$ sudo sh -c "echo '$USER-desuyo:100000:65536' > /etc/subgid"

次にactをbuildします

$ cd act
$ export DOCKER_HOST=unix:///run/user/1000/podman/podman.sock
$ make build

最後にinstall...なんですが
/usr/localに書き込み権限が必要なんで
適当に対処します。

$ sudo -E make install

あとはprojectに移動して act を実行します。

$ cd path/to/project
$ act

何回もデバッグします。
ローカルとはいっても作るものの性格上
ネットへの接続は必要です。

非力なChromebookでもなんとか動きそう...

ARM SBC: セットアップ

Shimoda — Wed, 06 Nov 2024 00:00:00 GMT

整備していく

[x] hardware: new USB-hub
[x] hardware: new MCU Board to USB
[x] hardware: MCU Board - センサ等を接続
[x] hardware: mSATA SSD - USB
[x] hardware: MCU Board - USB
[x] hardware: 電源ケーブルの整理 - USB-HubとSBC電源を分岐
[x] hardware: SSD thermal pad, heat sink
5Vの電源を細工するのは多いですね。
ACアダプタ増やすより分岐ケーブル作る方がスッキリするので
mSATAのアダプタがなかったので購入。
動かしたけどすごく熱を持つ...
MCUとセンサの接続は、本数が多くて大変だった。
外れないようにケーブルにホットボンドとかした。(久々...)

ソフト面も整備していく

[x] setup nim
[x] setup dnsmasq - 自宅内のDNS(サブ)
[x] setup ntp - systemd-timesyncd はじめて
[x] config custom - register to systemctl
[x] program: loop / daemon
[ ] program:

確認もいろいろ

[x] watt ... Normal+WiFi 4.5-5.0W
[x] watt ... WiFi+Ether 5.5W
[x] watt ... WiFi+Ether+MCU+Fan 5.9W
[ ] watt ... Normal ?
[ ] SD speed ...
[x] SSD speed ... 30MB/sec

SSD speed

hdparm で確認したSSD読込み速度。
前回とほとんど同じ。
ほとんどUSBの速度で決まってそう。

$ sudo hdparm -Tt /dev/sda1

/dev/sda1:
 Timing cached reads:   684 MB in  2.00 seconds = 341.64 MB/sec
 Timing buffered disk reads:  92 MB in  3.02 seconds =  30.45 MB/sec
shinji@tvbox:/home/root$ sudo hdparm -Tt /dev/sda1

/dev/sda1:
 Timing cached reads:   690 MB in  2.00 seconds = 344.97 MB/sec
 Timing buffered disk reads:  92 MB in  3.01 seconds =  30.53 MB/sec
shinji@tvbox:/home/root$ sudo hdparm -Tt /dev/sda1

/dev/sda1:
 Timing cached reads:   662 MB in  2.01 seconds = 330.05 MB/sec
 Timing buffered disk reads:  92 MB in  3.01 seconds =  30.59 MB/sec

ARM SBC: 再始動

Shimoda — Fri, 06 Sep 2024 09:00:00 GMT

家にまだ稼働していないSBCがあるので
常時稼働のNASを復活させる計画をする。

残念ながらGPIOがないタイプ ... 小型のマイコンボードでカバーする
SSDがつけられない ... USB接続で我慢する(基板だったけど接続は同じだし...)

やることは下のような感じ

筐体を作成する
- SSDがぶらぶらするのを固定
- マイコンボードがぶらぶらのを固定
- Fanありにする
マイコンボードでいろいろ作成する
- 温度センサと接続(工作)
- USB-SerialでSBCに結果を送信
- USB-SerialでSBCからFanスピードを受診してFanを回す
SBCの調整
- USB-Serialで温度を取得・保存
- Fan制御
- LED制御
- SW状態の取得、電源終了などの動作
- これらをserverプログラムにする
  - 制御温度→Fanは、定期的に実行する
  - swの取得→イベント発生
  - LED制御も定期的に実行する
  - LED制御の変更をsocket等で受け付ける