> -----Original Message----- > From: Dan Williams [mailto:dan.j.willi...@intel.com] > Sent: Thursday, March 15, 2018 3:20 AM > To: Qi, Fuli/斉 福利 <qi.f...@jp.fujitsu.com> > Cc: linux-nvdimm <linux-nvdimm@lists.01.org> > Subject: Re: [RFC PATCH v4] ndctl: monitor: add ndctl monitor daemon > > On Tue, Mar 13, 2018 at 4:33 AM, QI Fuli <qi.f...@jp.fujitsu.com> wrote: > > This is the v4 patch for ndctl monitor daemon, a tiny daemon to monitor the > > smart events of nvdimm DIMMs. Users can run a monitor as a one-shot > command > > or a daemon in background by using the [--daemon] option. DIMMs to monitor > > can be selected by [--dimm] [--bus] [--region] [--namespace] options. > > When a smart event fires, monitor daemon will log the notification which > > including dimm health status to syslog or a logfile by setting [--log] > > option. > > The notification follows json format and can be consumed by log collectors > > like Fluented. > > > > For example, a monitor daemon can be started by the following command: > > # ndctl monitor --dimm nmem1 --log /var/log/monitor.log --daemon > daemon-name > > > > Then check the monitor daemon status by using systemd: > > # systemctl status ndctl-monitor@daemon-name.service > > > > To stop the monitor daemon by: > > # systemctl stop ndctl-monitor@daemon-name.service > > > > Also, a monitor daemon can be started by systemd: > > # systemctl start ndctl-monitor.service > > Which monitors all dimms. > > > > In this implemention, when a ndctl monitor starts with [--daemon] option, > > all > > the arguments will be saved into a temp file named as daemon-name and placed > > under /etc/sysconfig/ndctl/ directory. The temp file would be used as an > > EnvironmentFile by systemd, and it would be deleted automatically when the > > systemd service is stopped. > > The monitors started by hand should be kept separate from the monitors > started by systemd. The default monitor started by systemd should get > its configuration from /etc/ndctl.conf, and we should otherwise have a > --conf-file option to the monitor to override the default > configuration. Any other monitors started outside of the systemd > should remain independent. >
I prefer to add an EnvironmentFile like /etc/sysconfig/ndctl/monitor to systemd rather than add a configuration file. According to [1], environment variable substitution is supported in systemd.service, so we can define the variables through "EnvironmentFile=/etc/sysconfig/ndctl/monitor". In this fashion, we do not need to add any extra codes to parse the configuration file. In this case, [--conf-file] option is not necessary either. According to [2], sytemd units can be instantiated from a template file, thus we only need to add a template unit file in advance. If user wants to run multiple monitors with different configurations, they can differentiate them by adding multiple EnvironmentFiles, like /etc/sysconfig/ndctl/<monitor1...n>. Then the monitors can be started by command like "# systemctl start ndctl-monitor@<monitor1...n>.service". When the monitors started by hand, it will do not need any configuration files, because we can add options and parameters directly. [1]https://www.freedesktop.org/software/systemd/man/systemd.service.html [2]https://www.freedesktop.org/software/systemd/man/systemd.unit.html _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
