更改 systemd 单元标签发送到 journalctl/syslog

Question

是否可以更改 systemd 托管服务用于日志记录的标签？例如，我的自定义服务report-daemon.service定义为

# ...
[Service]
ExecStart=/usr/bin/php # ...
# ...

显示为php而不是report-daemon（似乎从 推断标签ExecStart）

$ sudo journalctl --unit report-daemon

# ...
May 30 16:26:11 delta php[994]: Found 0 new revisions for Ctytn4a6zjw
May 30 16:26:12 delta php[994]: Found 0 new revisions for efE8xuvUjAo
# ...

手册页没有列出在单元文件中设置它的任何选项。是否可以在某处更改标签？

Answer 1

SyslogIdentifier=将进程名称（“syslog 标记”）设置为发送到日志系统或内核日志缓冲区的日志行的前缀。如果未设置，则默认为已执行进程的进程名称。此选项仅在 StandardOutput= 或 StandardError= 设置为 journal、syslog 或 kmsg（或与 +console 组合设置为相同设置）时才有用，并且仅适用于写入 stdout 或 stderr 的日志消息。

https://www.freedesktop.org/software/systemd/man/systemd.exec.html#SyslogIdentifier=

这会覆盖输出中的SYSLOG_IDENTIFIER字段journalctl。

# cat /etc/systemd/system/prvzn.service | grep prvzn
ExecStart=/opt/infra/prvzn exec --config-dir ${CONFIG_DIR} 
SyslogIdentifier=prvzn-foobar

导致 journalctl 行如下：

# journalctl | grep prvzn | tail -n1
Apr 30 08:29:16 ro01 prvzn-foobar[31787]: prvzn (info)2018/04/30 08:29:16 evaluation successful.

我正在运行不同版本的 Ubuntu (14.04, 16.04, 17.10) 和 CentOS (7) ...我自己的挣扎是 systemd 一直在快速变化，许多配置选项不能一致地工作，或者在某些情况下不是'甚至在版本之间可用。检查您的 systemd 特定版本的手册页。嗯嗯

Answer 2

更新 1：详细选项将以长格式列出，因此包括 UNIT：

[root@localhost]# journalctl --unit newnginx -o verbose
-- Logs begin at Sun 2015-04-05 10:36:30 BST, end at Mon 2015-06-01 08:17:58 BST. --
Sun 2015-05-31 10:27:38.344553 BST [s=4cc44a9cf9344c948fd4716fe024439e;i=3198;b=be3381af5b1d4743a4ccc1e346eab405;m=1548bfaf08;t=5175d51fadf41;x=eb6bb8ee2b2be47e]
    PRIORITY=6
    _UID=0
    _GID=0
    _BOOT_ID=be3381af5b1d4743a4ccc1e346eab405
    _MACHINE_ID=9619293167aa4f76b45b745e9f4e8935
    _HOSTNAME=localhost.localdomain
    _CAP_EFFECTIVE=1fffffffff
    _SYSTEMD_CGROUP=/
    SYSLOG_FACILITY=3
    SYSLOG_IDENTIFIER=systemd
    _TRANSPORT=journal
    _PID=1
    _COMM=systemd
    _EXE=/usr/lib/systemd/systemd
    _CMDLINE=/usr/lib/systemd/systemd --system --deserialize 21
    _SELINUX_CONTEXT=system_u:system_r:init_t:s0
    CODE_FILE=src/core/unit.c
    CODE_LINE=1115
    CODE_FUNCTION=unit_status_log_starting_stopping_reloading
    MESSAGE_ID=7d4958e842da4a758f6c1cdc7b36dcc5
    MESSAGE=Starting nginx - high performance web server...
    UNIT=newnginx.service
    _SOURCE_REALTIME_TIMESTAMP=1433064458344553
Sun 2015-05-31 10:27:38.354983 BST [s=4cc44a9cf9344c948fd4716fe024439e;i=3199;b=be3381af5b1d4743a4ccc1e346eab405;m=1548bfd0ee;t=5175d51fb0127;x=bc50f03db39f8d09]
    PRIORITY=6
    _UID=0
    _GID=0
    _BOOT_ID=be3381af5b1d4743a4ccc1e346eab405
    _MACHINE_ID=9619293167aa4f76b45b745e9f4e8935
    _HOSTNAME=localhost.localdomain
    _CAP_EFFECTIVE=1fffffffff
    _SYSTEMD_CGROUP=/
    SYSLOG_FACILITY=3
    _SELINUX_CONTEXT=system_u:system_r:init_t:s0
    _TRANSPORT=stdout

更新 2：用于打印所需条目的 Python 脚本：

from systemd import journal

j = journal.Reader()
j.this_boot()
j.add_match(_SYSTEMD_UNIT="newnginx.service")
for entry in j:
   print('{} {}'.format(entry['_SYSTEMD_UNIT'], entry['MESSAGE']))

看一下 nginx 的这个例子：

[root@localhost tmp]# journalctl --unit nginx
-- Logs begin at Sun 2015-04-05 10:36:30 BST, end at Sun 2015-05-31 11:12:29 BST. --
May 31 10:20:41 localhost.localdomain systemd[1]: Starting nginx - high performance web server...
May 31 10:20:41 localhost.localdomain nginx[111169]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
May 31 10:20:41 localhost.localdomain nginx[111169]: nginx: configuration file /etc/nginx/nginx.conf test is successful
May 31 10:20:41 localhost.localdomain systemd[1]: Failed to read PID from file /run/nginx.pid: Invalid argument
May 31 10:20:41 localhost.localdomain systemd[1]: Started nginx - high performance web server.
May 31 10:27:05 localhost.localdomain systemd[1]: Stopping nginx - high performance web server...
May 31 10:27:05 localhost.localdomain systemd[1]: Stopped nginx - high performance web server.
May 31 10:58:36 localhost.localdomain systemd[1]: Stopped nginx - high performance web server.
May 31 11:12:29 localhost.localdomain systemd[1]: Starting nginx - high performance web server...
May 31 11:12:29 localhost.localdomain nginx[112202]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
May 31 11:12:29 localhost.localdomain nginx[112202]: nginx: configuration file /etc/nginx/nginx.conf test is successful
May 31 11:12:29 localhost.localdomain systemd[1]: Failed to read PID from file /run/nginx.pid: Invalid argument
May 31 11:12:29 localhost.localdomain systemd[1]: Started nginx - high performance web server.

有人出现并执行 ps 来查找并杀死 nginx：

[root@localhost tmp]# ps -ef | grep nginx
root     112205      1  0 11:12 ?        00:00:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
nginx    112207 112205  0 11:12 ?        00:00:00 nginx: worker process
root     112212 111775  0 11:12 pts/4    00:00:00 grep --color=auto nginx
[root@localhost tmp]# kill -9 112205

该期刊现在包含：

[root@localhost tmp]# journalctl --unit nginx
-- Logs begin at Sun 2015-04-05 10:36:30 BST, end at Sun 2015-05-31 11:12:57 BST. --
May 31 10:20:41 localhost.localdomain systemd[1]: Starting nginx - high performance web server...
May 31 10:20:41 localhost.localdomain nginx[111169]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
May 31 10:20:41 localhost.localdomain nginx[111169]: nginx: configuration file /etc/nginx/nginx.conf test is successful
May 31 10:20:41 localhost.localdomain systemd[1]: Failed to read PID from file /run/nginx.pid: Invalid argument
May 31 10:20:41 localhost.localdomain systemd[1]: Started nginx - high performance web server.
May 31 10:27:05 localhost.localdomain systemd[1]: Stopping nginx - high performance web server...
May 31 10:27:05 localhost.localdomain systemd[1]: Stopped nginx - high performance web server.
May 31 10:58:36 localhost.localdomain systemd[1]: Stopped nginx - high performance web server.
May 31 11:12:29 localhost.localdomain systemd[1]: Starting nginx - high performance web server...
May 31 11:12:29 localhost.localdomain nginx[112202]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
May 31 11:12:29 localhost.localdomain nginx[112202]: nginx: configuration file /etc/nginx/nginx.conf test is successful
May 31 11:12:29 localhost.localdomain systemd[1]: Failed to read PID from file /run/nginx.pid: Invalid argument
May 31 11:12:29 localhost.localdomain systemd[1]: Started nginx - high performance web server.
May 31 11:12:57 localhost.localdomain systemd[1]: nginx.service: main process exited, code=killed, status=9/KILL
May 31 11:12:57 localhost.localdomain kill[112215]: Usage:
May 31 11:12:57 localhost.localdomain kill[112215]: kill [options] <pid|name> [...]
May 31 11:12:57 localhost.localdomain kill[112215]: Options:
May 31 11:12:57 localhost.localdomain kill[112215]: -a, --all              do not restrict the name-to-pid conversion to processes
May 31 11:12:57 localhost.localdomain kill[112215]: with the same uid as the present process
May 31 11:12:57 localhost.localdomain kill[112215]: -s, --signal <sig>     send specified signal
May 31 11:12:57 localhost.localdomain kill[112215]: -q, --queue <sig>      use sigqueue(2) rather than kill(2)
May 31 11:12:57 localhost.localdomain kill[112215]: -p, --pid              print pids without signaling them
May 31 11:12:57 localhost.localdomain kill[112215]: -l, --list [=<signal>] list signal names, or convert one to a name
May 31 11:12:57 localhost.localdomain kill[112215]: -L, --table            list signal names and numbers
May 31 11:12:57 localhost.localdomain kill[112215]: -h, --help     display this help and exit
May 31 11:12:57 localhost.localdomain kill[112215]: -V, --version  output version information and exit
May 31 11:12:57 localhost.localdomain kill[112215]: For more details see kill(1).
May 31 11:12:57 localhost.localdomain systemd[1]: nginx.service: control process exited, code=exited status=1
May 31 11:12:57 localhost.localdomain systemd[1]: Unit nginx.service entered failed state.

观察您只看到php 的列如何包含作用于 nginx systemd 单元的进程的名称，systemd、nginx、kill 都列在那里。这有助于解释吗？

单元名称由文件名指定。在 Centos 7 上我做了：

(cfs)[root@localhost system]# pwd
/usr/lib/systemd/system

^?(cfs)[root@localhost system]# cp nginx.service newnginx.service

停止原来的nxginx：

(cfs)[root@localhost system]# service nginx stop
Redirecting to /bin/systemctl stop  nginx.service
(cfs)[root@localhost system]# service h^Cinx stop

查看并启动“newnginx”：

(cfs)[root@localhost system]# service newnginx status
Redirecting to /bin/systemctl status  newnginx.service
newnginx.service - nginx - high performance web server
   Loaded: loaded (/usr/lib/systemd/system/newnginx.service; disabled)
   Active: inactive (dead)
     Docs: http://nginx.org/en/docs/

(cfs)[root@localhost system]# service newnginx start
Redirecting to /bin/systemctl start  newnginx.service

Journalctl 现在列出newnginx单位：

(cfs)[root@localhost system]# journalctl --unit newnginx
-- Logs begin at Sun 2015-04-05 10:36:30 BST, end at Sun 2015-05-31 10:27:38 BST. --
May 31 10:27:38 localhost.localdomain systemd[1]: Starting nginx - high performance web server...
May 31 10:27:38 localhost.localdomain nginx[111311]: nginx: the configuration file /etc/nginx/nginx.conf syntax is o
May 31 10:27:38 localhost.localdomain nginx[111311]: nginx: configuration file /etc/nginx/nginx.conf test is success
May 31 10:27:38 localhost.localdomain systemd[1]: Failed to read PID from file /run/nginx.pid: Invalid argument
May 31 10:27:38 localhost.localdomain systemd[1]: Started nginx - high performance web server.

现在有两个 nginx systemd 单元：

# systemctl list-unit-files --all | grep nginx
newnginx.service                            disabled
nginx.service                               disabled