怎么修改docker容器中使用的内核参数?

2023-05-30 00:04| 来源: 网络整理| 查看: 265

怎么样修改容器使用的内核参数？

通过下面的实验，你将知道，如何对容器使用的内核参数进行调整

1、背景信息

操作系统的内核参数 net.ipv4.ip_forward = 1

[root@centos7 ~]# sysctl -a | grep ip_forward sysctl: reading key "net.ipv6.conf.all.stable_secret" net.ipv4.ip_forward = 1 net.ipv4.ip_forward_use_pmtu = 0

启动一个容器，查看容器中的内核参数值

发现，容器中的内核参数 net.ipv4.ip_forward 的值 1

[dc68fc884ae9 root:/usr/local/tomcat]# sysctl -a | grep ip_forward sysctl: error reading key 'net.ipv6.conf.all.stable_secret': I/O error net.ipv4.ip_forward = 1 net.ipv4.ip_forward_use_pmtu = 0 sysctl: error reading key 'net.ipv6.conf.default.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.eth0.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.lo.stable_secret': I/O error

2、修改内核参数及验证

在操作系统上，将内核参数修改为 0

[root@centos7 ~]# cat /etc/sysctl.conf # sysctl settings are defined through files in # /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/. # # Vendors settings live in /usr/lib/sysctl.d/. # To override a whole file, create a new file with the same in # /etc/sysctl.d/ and put new settings there. To override # only specific settings, add a file with a lexically later # name in /etc/sysctl.d/ and put new settings there. # # For more information, see sysctl.conf(5) and sysctl.d(5). net.ipv4.ip_forward=0 [root@centos7 ~]# # 让参数生效 sysctl -p

从操作系统上看，内核参数已经生效，值变为了0

[root@centos7 ~]# sysctl -a |grep ip_forward net.ipv4.ip_forward = 0 net.ipv4.ip_forward_use_pmtu = 0

现在，进入到容器中，看参数值是否发生变化

参数值，还是 1

容器中执行sysctl -p重新加载

发现，参数值还是1，没有变化

[dc68fc884ae9 root:/usr/local/tomcat]# sysctl -p [dc68fc884ae9 root:/usr/local/tomcat]# sysctl -a | grep ip_forward sysctl: error reading key 'net.ipv6.conf.all.stable_secret': I/O error net.ipv4.ip_forward = 1 net.ipv4.ip_forward_use_pmtu = 0 sysctl: error reading key 'net.ipv6.conf.default.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.eth0.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.lo.stable_secret': I/O error

OK，那重点来了 ...

重启容器

# 从容器中退出 [dc68fc884ae9 root:/usr/local/tomcat]# exit exit # 重新启动容器 [root@centos7 ~]# docker run -it --rm tomcat:9.0.73-jdk8u202-alpine bash WARNING: IPv4 forwarding is disabled. Networking will not work. using system default DNS server. time="2023-05-26 15:05:44" level=info msg="【配置中心下载器【4.1版本】】日志如下 ==> " time="2023-05-26 15:05:44" level=warning msg="未设置环境变量cf_disconf_conf_server_host，将不会执行下载配置文件的功能，下载器正常运行结束." 当前服务HOSTNAME:9c5e53cf2ed5 截取后的服务名为：9c5e53cf2ed5 识别到当前为标准业务服务，设置容器内下载路径为/usr/local/tomcat/webapps/ROOT/WEB-INF/ dbDriverTool.jar or driver directory is not exist. + gitproject= + test -z + echo 'Patchmangement parameter gitproject is not set!' Patchmangement parameter gitproject is not set!

查看内核参数

内核参数已经修改为0了，已经和操作系统一样了

[9c5e53cf2ed5 root:/usr/local/tomcat]# sysctl -a | grep ip_forward sysctl: error reading key 'net.ipv6.conf.all.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.default.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.eth0.stable_secret': I/O error sysctl: error reading key 'net.ipv6.conf.lo.stable_secret': I/O error net.ipv4.ip_forward = 0 net.ipv4.ip_forward_use_pmtu = 0 [9c5e53cf2ed5 root:/usr/local/tomcat]#

3、结论

操作系统内核参数，docker容器会继承。

如果操作系统内核参数修改了，docker容器要重启，才会生效。

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