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在機器關閉/重新啟動之前等待服務正常退出

tag-icon • tag-icon systemd
在機器關閉/重新啟動之前等待服務正常退出

如何撰寫一個能夠在機器關閉或重新啟動時正常關閉的 systemd 服務？特別是，它應該延遲機器關閉，直到它正常退出。

我有一個需要 10 秒鐘才能關閉的服務：/usr/local/bin/shutdowntest.sh：

#!/bin/bash

SHUTDOWN=0
SHUTDOWN_TIME=10
TRAPPED_SIGNAL=

function onexit() {
  TRAPPED_SIGNAL=$1
  SHUTDOWN=1
}

for SIGNAL in SIGINT SIGTERM SIGHUP SIGPIPE SIGALRM SIGUSR1 SIGUSR2; do
  trap "onexit $SIGNAL" $SIGNAL
done

echo >&2 "shutdowntest running"
while ((!SHUTDOWN || SHUTDOWN_TIME>0)); do
  if [[ -n "$TRAPPED_SIGNAL" ]]; then
    echo >&2 "shutdowntest received signal $TRAPPED_SIGNAL"
    TRAPPED_SIGNAL=
  elif ((SHUTDOWN)); then
    echo >&2 "shutdowntest Shutting down: $SHUTDOWN_TIME more sleeps"
    SHUTDOWN_TIME=$((SHUTDOWN_TIME-1))
    sleep 1
  else
    sleep 10
  fi
done
echo >&2 "shutdowntest Finished shutting down; quitting"

我在 /etc/systemd/system/shutdowntest.service 中將 TimeoutStopSec 設定為 15 秒：

[Service]
ExecStart=/usr/local/bin/shutdowntest.sh
TimeoutStopSec=15

[Install]
WantedBy=multi-user.target

當我運行時sudo systemctl stop shutdowntest.service，服務會根據以下內容正常關閉/var/log/syslog：

00:57:11 shutdowntest.sh[1980]: shutdowntest received signal SIGTERM
00:57:11 shutdowntest.sh[1980]: shutdowntest Shutting down: 10 more sleeps
00:57:11 systemd[1]: Stopping shutdowntest.service...
00:57:11 shutdowntest.sh[1980]: Terminated
00:57:11 shutdowntest.sh[1980]: shutdowntest Shutting down: 9 more sleeps
00:57:12 shutdowntest.sh[1980]: shutdowntest Shutting down: 8 more sleeps
00:57:13 shutdowntest.sh[1980]: shutdowntest Shutting down: 7 more sleeps
00:57:14 shutdowntest.sh[1980]: shutdowntest Shutting down: 6 more sleeps
00:57:15 shutdowntest.sh[1980]: shutdowntest Shutting down: 5 more sleeps
00:57:16 shutdowntest.sh[1980]: shutdowntest Shutting down: 4 more sleeps
00:57:17 shutdowntest.sh[1980]: shutdowntest Shutting down: 3 more sleeps
00:57:18 shutdowntest.sh[1980]: shutdowntest Shutting down: 2 more sleeps
00:57:19 shutdowntest.sh[1980]: shutdowntest Shutting down: 1 more sleeps
00:57:20 shutdowntest.sh[1980]: shutdowntest Finished shutting down; quitting
00:57:20 systemd[1]: Stopped shutdowntest.service.

但當我sudo reboot或sudo shutdown now機器時，服務沒有足夠的時間優雅退出就被殺死，/var/log/syslog 僅在 1s 後結束。

00:59:30 shutdowntest.sh[2014]: Terminated
00:59:30 shutdowntest.sh[2014]: shutdowntest received signal SIGTERM
00:59:30 shutdowntest.sh[2014]: shutdowntest Shutting down: 10 more sleeps
00:59:30 systemd[1]: Stopping shutdowntest.service...

如何確保在機器關閉或重新啟動時給服務有時間（TimeoutSec或）退出？TimeoutStopSec

答案1

這來自比貢的評論是正確的。我正在查看/var/log/syslog，但這是由 編寫的rsyslog.service，systemd 在關閉過程中很早就停止了（如下面的“停止的系統日誌服務”所示）。

在我啟用持久日誌記錄後（Storage=persistent在/etc/systemd/journald.conf和systemctl restart systemd-journald），journalctl -b-1 -u shutdowntest.service顯示我的服務確實有足夠的時間在系統reboot啟動後shutdown或按下電源鍵（ACPI G2 軟關閉）後關閉。

journalctl -b-1 -u shutdowntest.service -u rsyslog.service -u systemd-logind
-- Logs begin at Mon 2018-03-26 18:39:12 UTC, end at Mon 2018-03-26 20:22:34 UTC. --
…
Mar 26 18:46:46 myhost systemd-logind[1202]: Power key pressed.
Mar 26 18:46:46 myhost systemd-logind[1202]: Powering Off...
Mar 26 18:46:46 myhost systemd-logind[1202]: System is powering down.
Mar 26 18:46:46 myhost shutdowntest.sh[1237]: Terminated
Mar 26 18:46:46 myhost shutdowntest.sh[1237]: shutdowntest received signal SIGTERM
Mar 26 18:46:46 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 10 more sleeps
Mar 26 18:46:46 myhost systemd[1]: Stopping shutdowntest.service...
Mar 26 18:46:46 myhost systemd[1]: Stopping Login Service...
Mar 26 18:46:46 myhost systemd[1]: Stopped Login Service.
Mar 26 18:46:46 myhost systemd[1]: Stopping System Logging Service...
Mar 26 18:46:47 myhost systemd[1]: Stopped System Logging Service.
Mar 26 18:46:47 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 9 more sleeps
Mar 26 18:46:48 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 8 more sleeps
Mar 26 18:46:49 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 7 more sleeps
Mar 26 18:46:50 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 6 more sleeps
Mar 26 18:46:51 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 5 more sleeps
Mar 26 18:46:52 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 4 more sleeps
Mar 26 18:46:53 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 3 more sleeps
Mar 26 18:46:54 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 2 more sleeps
Mar 26 18:46:55 myhost shutdowntest.sh[1237]: shutdowntest Shutting down: 1 more sleeps
Mar 26 18:46:56 myhost shutdowntest.sh[1237]: shutdowntest Finished shutting down; quitting
Mar 26 18:46:56 myhost systemd[1]: Stopped shutdowntest.service.

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