centos7 如何在用户级对资源进行限制

- 日理万妓 2022-05-14 04:34 302阅读 0赞

我们已经知道，centos7上建议使用sytemd进行资源限制。

本文主要介绍如何使用systemd进行用户级资源限制。  
以orange用户为例。

## 方案一 临时有效 ##

配置如下：

# systemctl set-property user-1000.slice MemoryLimit=200M
    # systemctl daemon-reload

一般情况下，以上设置就可以了。  
但有时还是会遇到以下问题：

# systemctl set-property user-1000.slice MemoryLimit=200M Failed to set unit properties on user-1000.slice: Unit user-1000.slice is not loaded. User with id 1007 not logged in. First login as that user then set limits

**解决办法**  
首先使用

# systemctl start user-1000.slice

再进行设置

# systemctl set-property user-1000.slice MemoryLimit=200M
    # systemctl daemon-reload

## 方案二 永久生效 ##

首先，编写slice文件user-1000.slice

其中1000是orange用户的uid，可用命令查看

# id -u username

文件内容如下

[Unit]
    Description=orange user.slice
    
    [Slice]
    MemoryAccounting=true
    MemoryLimit=200M

其次，拷贝到指定位置

# cp user-1000.slice /usr/lib/systemd/system

启用

# systemctl start user-1000.slice

重新加载配置

# systemctl daemon-reload

查看系统中的slice

# systemctl -t slice
    UNIT                                                          LOAD ACTIVE SUB DESCRIPTION -.slice loaded active active Root Slice system-getty.slice loaded active active system-getty.slice system-selinux\x2dpolicy\x2dmigrate\x2dlocal\x2dchanges.slice loaded active active system-selinux\x2dpolicy\x2dmigrate\x2dlocal\x2dchanges.slice system.slice loaded active active System Slice user-0.slice loaded active active User Slice of root user-1000.slice loaded active active orange user.slice user.slice loaded active active User and Session Slice LOAD = Reflects whether the unit definition was properly loaded. ACTIVE = The high-level unit activation state, i.e. generalization of SUB. SUB = The low-level unit activation state, values depend on unit type. 7 loaded units listed. Pass --all to see loaded but inactive units, too. To show all installed unit files use 'systemctl list-unit-files'.

查看某个具体的slice

# systemctl status user-1000.slice -l
    ● user-1000.slice - orange user.slice
       Loaded: loaded (/usr/lib/systemd/system/user-1000.slice; static; vendor preset: disabled)
      Drop-In: /etc/systemd/system/user-1000.slice.d
               └─50-MemoryLimit.conf
       Active: active since 四 2018-08-02 15:17:01 CST; 1min 40s ago
       Memory: 1.5M (limit: 200.0M)
       CGroup: /user.slice/user-1000.slice
               └─session-14973.scope
                 └─56361 /export/servers/orange-agent/orange-guard/orange-guard -c cfg.json
    
    8月 02 15:17:01 A02-R05-I79-201-3V98WK2.ORANGE.LOCAL systemd[1]: Created slice orange user.slice.
    8月 02 15:17:01 A02-R05-I79-201-3V98WK2.ORANGE.LOCAL systemd[1]: Starting orange user.slice.
    8月 02 15:17:01 A02-R05-I79-201-3V98WK2.ORANGE.LOCAL CROND[56324]: (orange) CMD (`which taskset` -c `source /export/servers/orange-agent/run_cpus.sh && cpus` /export/servers/orange-agent/super_guard.sh >> /export/servers/orange-agent/orange-agent/var/app.log 2>&1 &)
    8月 02 15:18:01 A02-R05-I79-201-3V98WK2.ORANGE.LOCAL CROND[56925]: (orange) CMD (`which taskset` -c `source /export/servers/orange-agent/run_cpus.sh && cpus` /export/servers/orange-agent/super_guard.sh >> /export/servers/orange-agent/orange-agent/var/app.log 2>&1 &)

经过以上设置后，orange用户启动的所有进程占用的物理内存之和不能超过200M，如果超过，进程机会被kill。

如果进程因为OOM被kill，会在/var/log/message中发现记录。

**如何查看某个进程受哪些资源限制条件**

# cat /proc/PID/cgroup
    11:memory:/user-1000.slice
    10:perf_event:/
    9:devices:/user.slice
    8:hugetlb:/
    7:blkio:/user.slice
    6:cpuset:/
    5:freezer:/
    4:pids:/
    3:cpuacct,cpu:/user.slice
    2:net_prio,net_cls:/
    1:name=systemd:/user.slice/user-1000.slice/session-8569.scope

## 参考 ##

centos7 user.slice  
[https://stackoverflow.com/questions/47367886/cgroup-configuration-in-centos-7][https_stackoverflow.com_questions_47367886_cgroup-configuration-in-centos-7]

centos 7 systemd资源限制举例  
[https://www.certdepot.net/rhel7-get-started-cgroups/][https_www.certdepot.net_rhel7-get-started-cgroups]

Table 10.1. Available systemd Unit Types  
Table 10.2. Systemd Unit Files Locations  
[https://access.redhat.com/documentation/en-us/red\_hat\_enterprise\_linux/7/html/system\_administrators\_guide/chap-managing\_services\_with\_systemd][https_access.redhat.com_documentation_en-us_red_hat_enterprise_linux_7_html_system_administrators_guide_chap-managing_services_with_systemd]

service文件参考  
/usr/lib/systemd/system/ssh.service

[https_stackoverflow.com_questions_47367886_cgroup-configuration-in-centos-7]: https://stackoverflow.com/questions/47367886/cgroup-configuration-in-centos-7
[https_www.certdepot.net_rhel7-get-started-cgroups]: https://www.certdepot.net/rhel7-get-started-cgroups/
[https_access.redhat.com_documentation_en-us_red_hat_enterprise_linux_7_html_system_administrators_guide_chap-managing_services_with_systemd]: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/chap-managing_services_with_systemd