week_8_systemd、signal、awk

作者: 人間失格_430b | 来源:发表于2019-03-22 19:59 被阅读0次

week_8_systemd、signal、awk
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Q:

1、systemd查看日志文件有隐藏该如何处理？
2、自己动手写一个systemd的配置文件，让nginx服务可以开机启动
3、SIGHUP、SIGQUIT、SIGTERM、SIGINTERRUPT的区别
4、用awk查看tcp连接处于TIMEOUT的连接个数

A:

1、systemd查看日志文件有隐藏该如何处理？

CentOS 7日志系统由 systemd-journald 和 rsyslog 两个服务组成默认，systemd日志保存于/run/log/journal中，系统重启后会清除，rsyslog会根据一定的规则，将日志写到到/var/log目录中永久保存systemd统一管理所有Unit的启动日志，包含内核日志和应用日志。

查看单个服务的日志

[root@localhost ~]# systemctl status nginxTest -l
● nginxTest.service - This is a nginx test service
   Loaded: loaded (/etc/systemd/system/nginxTest.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2019-03-22 02:23:49 EDT; 10min ago
  Process: 8570 ExecStart=/usr/sbin/nginx (code=exited, status=0/SUCCESS)
  Process: 8554 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=0/SUCCESS)
  Process: 8542 ExecStartPre=/usr/bin/rm -f /run/nginx.pid (code=exited, status=0/SUCCESS)
 Main PID: 8572 (nginx)
   CGroup: /system.slice/nginxTest.service
           ├─8572 nginx: master process /usr/sbin/ngin
           ├─8573 nginx: worker proces
           ├─8574 nginx: worker proces
           ├─8575 nginx: worker proces
           └─8577 nginx: worker proces

Mar 22 02:23:49 localhost.localdomain systemd[1]: Starting This is a nginx test service...
Mar 22 02:23:49 localhost.localdomain nginx[8554]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
Mar 22 02:23:49 localhost.localdomain nginx[8554]: nginx: configuration file /etc/nginx/nginx.conf test is successful
Mar 22 02:23:49 localhost.localdomain systemd[1]: Started This is a nginx test service.
[root@localhost ~]# journalctl -u nginxTest
-- Logs begin at Thu 2019-03-21 23:18:05 EDT, end at Fri 2019-03-22 02:34:14 EDT. --
Mar 22 02:17:09 localhost.localdomain systemd[1]: [/etc/systemd/system/nginxTest.service:7] Unknown lvalue 'PIDfile' in section 'Service'
Mar 22 02:17:09 localhost.localdomain systemd[1]: [/etc/systemd/system/nginxTest.service:7] Unknown lvalue 'PIDfile' in section 'Service'
Mar 22 02:22:39 localhost.localdomain systemd[1]: [/etc/systemd/system/nginxTest.service:7] Unknown lvalue 'PIDfile' in section 'Service'
Mar 22 02:23:49 localhost.localdomain systemd[1]: Starting This is a nginx test service...
Mar 22 02:23:49 localhost.localdomain nginx[8554]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
Mar 22 02:23:49 localhost.localdomain nginx[8554]: nginx: configuration file /etc/nginx/nginx.conf test is successful
Mar 22 02:23:49 localhost.localdomain systemd[1]: Started This is a nginx test service.

尴尬的显示：在我手动添加的unit文件中PIDfile字段无法解析，应该是PIDFile

systemd的日志文件直接cat是乱码(who fucking knows how to check this file)

[root@localhost ~]# ls /run/log/journal/5f47125a1faf4b438a9b7aec3758819e/system.journal -l
-rwxr-x---+ 1 root systemd-journal 6438912 Mar 22 02:25 /run/log/journal/5f47125a1faf4b438a9b7aec3758819e/system.journal

直接使用journalctl查看日志

[root@localhost ~]# journalctl  -n 10 
-- Logs begin at Thu 2019-03-21 23:18:05 EDT, end at Fri 2019-03-22 02:34:14 EDT. --
Mar 22 02:34:14 localhost.localdomain NetworkManager[5877]: <info>  [1553236454.8042] dhcp4 (ens33):   nameserver '192.168.223.2'
Mar 22 02:34:14 localhost.localdomain NetworkManager[5877]: <info>  [1553236454.8042] dhcp4 (ens33):   domain name 'localdomain'
Mar 22 02:34:14 localhost.localdomain NetworkManager[5877]: <info>  [1553236454.8043] dhcp4 (ens33): state changed bound -> bound
Mar 22 02:34:14 localhost.localdomain dbus[5788]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-
Mar 22 02:34:14 localhost.localdomain dhclient[6174]: bound to 192.168.223.131 -- renewal in 843 seconds.
Mar 22 02:34:14 localhost.localdomain systemd[1]: Starting Network Manager Script Dispatcher Service...
Mar 22 02:34:14 localhost.localdomain dbus[5788]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Mar 22 02:34:14 localhost.localdomain systemd[1]: Started Network Manager Script Dispatcher Service.
Mar 22 02:34:14 localhost.localdomain nm-dispatcher[8769]: req:1 'dhcp4-change' [ens33]: new request (3 scripts)
Mar 22 02:34:14 localhost.localdomain nm-dispatcher[8769]: req:1 'dhcp4-change' [ens33]: start running ordered scripts...

2、自己动手写一个systemd的配置文件，让nginx服务可以开机启动

       Table 1.  Load path when running in system mode (--system).
       ┌────────────────────────┬─────────────────────────────┐
       │Path                    │ Description                 │
       ├────────────────────────┼─────────────────────────────┤
       │/etc/systemd/system     │ Local configuration         │
       ├────────────────────────┼─────────────────────────────┤
       │/run/systemd/system     │ Runtime units               │
       ├────────────────────────┼─────────────────────────────┤
       │/usr/lib/systemd/system │ Units of installed packages │
       └────────────────────────┴─────────────────────────────┘

通过查看nginx状态获知nginx.service unit文件路径

[root@localhost ~]# systemctl status nginx
● nginx.service - The nginx HTTP and reverse proxy server
   Loaded: loaded (/usr/lib/systemd/system/nginx.service; disabled; vendor preset: disabled)
   Active: inactive (dead)

Mar 22 00:20:22 localhost.localdomain systemd[1]: Unit nginx.service cannot be reloaded because it is inactive.

[root@localhost ~]# cat /usr/lib/systemd/system/nginx.service 
[Unit]
Description=The nginx HTTP and reverse proxy server
After=network.target remote-fs.target nss-lookup.target

[Service]
Type=forking
PIDFile=/run/nginx.pid
# Nginx will fail to start if /run/nginx.pid already exists but has the wrong
# SELinux context. This might happen when running `nginx -t` from the cmdline.
# https://bugzilla.redhat.com/show_bug.cgi?id=1268621
ExecStartPre=/usr/bin/rm -f /run/nginx.pid
ExecStartPre=/usr/sbin/nginx -t
ExecStart=/usr/sbin/nginx
ExecReload=/bin/kill -s HUP $MAINPID
KillSignal=SIGQUIT
TimeoutStopSec=5
KillMode=process
PrivateTmp=true

[Install]
WantedBy=multi-user.target

手动写一个unit文件并enable

[root@localhost ~]# vim /etc/systemd/system/nginxTest.service
[root@localhost ~]# systemctl enable nginxTest
Created symlink from /etc/systemd/system/multi-user.target.wants/nginxTest.service to /etc/systemd/system/nginxTest.service.
[root@localhost ~]# systemctl daemon-reload
[root@localhost ~]# reboot

[root@localhost ~]# systemctl get-default
multi-user.target

由于在unit文件Install段内注明此服务被多用户目标所弱依赖，所以在开机启动后默认进入多用户模式并启动nginxTest服务

不重启手动启动多用户模式查看nginxTest服务状态

[root@localhost ~]# systemctl status nginxTest
● nginxTest.service - This is a nginx test service
   Loaded: loaded (/etc/systemd/system/nginxTest.service; enabled; vendor preset: disabled)
   Active: inactive (dead)

Mar 22 02:17:09 localhost.localdomain systemd[1]: [/etc/systemd/system/nginxTest.service:7] Unknown lvalue 'PIDfile' in section 'Service'
Mar 22 02:17:09 localhost.localdomain systemd[1]: [/etc/systemd/system/nginxTest.service:7] Unknown lvalue 'PIDfile' in section 'Service'
Mar 22 02:22:39 localhost.localdomain systemd[1]: [/etc/systemd/system/nginxTest.service:7] Unknown lvalue 'PIDfile' in section 'Service'
[root@localhost ~]# systemctl isolate multi-user.target
[root@localhost ~]# systemctl status nginxTest
● nginxTest.service - This is a nginx test service
   Loaded: loaded (/etc/systemd/system/nginxTest.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2019-03-22 02:23:49 EDT; 6s ago
  Process: 8570 ExecStart=/usr/sbin/nginx (code=exited, status=0/SUCCESS)
  Process: 8554 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=0/SUCCESS)
  Process: 8542 ExecStartPre=/usr/bin/rm -f /run/nginx.pid (code=exited, status=0/SUCCESS)
 Main PID: 8572 (nginx)
   CGroup: /system.slice/nginxTest.service
           ├─8572 nginx: master process /usr/sbin/nginx
           ├─8573 nginx: worker process
           ├─8574 nginx: worker process
           ├─8575 nginx: worker process
           └─8577 nginx: worker process

Mar 22 02:23:49 localhost.localdomain systemd[1]: Starting This is a nginx test service...
Mar 22 02:23:49 localhost.localdomain nginx[8554]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
Mar 22 02:23:49 localhost.localdomain nginx[8554]: nginx: configuration file /etc/nginx/nginx.conf test is successful
Mar 22 02:23:49 localhost.localdomain systemd[1]: Started This is a nginx test service.

3、SIGHUP、SIGQUIT、SIGTERM、SIGINTERRUPT的区别

没有signal的manual文件提示及解决方法

[root@localhost ~]# man signal
No manual entry for signal

[root@localhost ~]# yum install man-pages

       Signal     Value     Action   Comment
       ──────────────────────────────────────────────────────────────────────
       SIGHUP        1       Term    Hangup detected on controlling terminal
                                     or death of controlling process
       SIGINT        2       Term    Interrupt from keyboard
       SIGQUIT       3       Core    Quit from keyboard

       SIGTERM      15       Term    Termination signal

4、用awk查看tcp连接处于TIMEOUT的连接个数

[root@localhost ~]# netstat -tan |awk '{$NF~/^TIMEOUT$/?count++:Continue}END{printf "The number of links ,which has TIMEOUT stat : %d\n",count}'
The number of links ,which has TIMEOUT stat : 0

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week_8_systemd、signal、awk

Q:

A:

1、systemd查看日志文件有隐藏该如何处理？

2、自己动手写一个systemd的配置文件，让nginx服务可以开机启动

3、SIGHUP、SIGQUIT、SIGTERM、SIGINTERRUPT的区别

4、用awk查看tcp连接处于TIMEOUT的连接个数

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