On Friday, March 06, 2015 04:05:55 AM richard lucassen wrote: > On Thu, 5 Mar 2015 21:05:09 -0500 > > Neal Murphy <neal.p.murphy@xxxxxxxxxxxx> wrote: > > I was under the impression that a special tool is needed to set the > > kernel TZ. What I did for Smoothwall 3.1 is set the hardware clock to > > localtime and ensure that the system time is correctly pulled from > > it. Then ensure that features that use '-m time' include the > > --kerneltz option. > > I read that as well, but AFAIUI this program is deprecated and a > "hwclock --systz" will do the job: > > man hwclock: > > --systz Set the kernel's timezone and reset the System Time based > on the current timezone. By gorry, I do sometimes learn new things on certain days! That looks to be just what we need. I'll set it to run on 8 March and 1 November this year. (Our switch to DST happens in less than two days.) N > > > The bit I haven't done yet is implement a way to detect the local > > time zone, determine the DST changeovers from the TZDATA package, > > then schedule an at job for the two specific times when the kernel TZ > > must be updated. Thus, if the system is running at that time, the > > kernel TZ will be updated. If the system is not running at that time, > > the kernel TZ will be correctly set the next time the system boots. > > (This means that a system reboot will ensure the kernel TZ is > > correct.) > > For the moment I simply put a "/sbin/hwclock --systz" in /etc/rc.local > and rebooted the machine to see what happens and the rules using > --kerneltz indeed worked as expected at locatime. I need to reboot > during summertime to see what happens. > > > The program to set the kerneltz is 'setknltz' by David Madore. A cron > > job runs at 0159 on 3/8 and 11/1 (for US/Eastern zone). The script > > that is run sleeps for 1.02 seconds, then runs setknltz. Next, I > > believe the rules that use '-m time' need to be reset so they have > > the correct offset from UTC. > > We'll see what will happen on next March 29 at 3:00 AM. I have no idea > if the xt_time module needs to be reloaded. I'll let you know within a > few weeks. > > > I wrote some of this up on the smoothwall forum: > > http://community.smoothwall.org/forum/viewtopic.php?p=332138#p332138 > > > > and the fourth post below it. I might not be completely correct in my > > assumptions, but I'm fairly sure the method will be sound. > > I have no idea how American DST changes are regulated, but in Europe DST > changes take place om the last Sunday of March and October, which will > be translated in a simple crontab entry: > > 0 3 25-31 3,10 0 /sbin/hwclock --systz > > (mind: wrong DST during 1 hour per year) > > R. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
