[Dnsmasq-discuss] dnsmasq command to add dhcp-host record?

Geert Stappers stappers at stappers.nl
Sat Jan 9 16:08:25 GMT 2021


On Sat, Jan 09, 2021 at 04:06:41PM +0100, Jelle de Jong wrote:
> On 1/7/21 11:44 AM, Dominik wrote:
> > On 06.01.21 21:00, Jelle de Jong wrote:
> > > dnsmasq inotify is trigger happy and it would be nice to have a second
> > > or so delay in the actual re-scanning, that would help a lot...
> > > 
> > > currently when ansible places the file dnsmasq tries to read the
> > > config file, but the content is not always there yet and then it is
> > > messed up.
> > 
> > dnsmasq configured the inotify watchers to trigger on either
> > file-close-after-write or file-moved-into-directory. There should be no
> > way to write to the file without dnsmasq noticing this, EXCEPT, if the
> > file is not closed after having done the writing. I just tried the
> > following:
> > 
> > 1. Created an empty file in my hostsdir (hostsdir=/etc/hostsdir) directory:
> > 
> > The dnsmasq log said:
> > 
> > Jan  7 11:36:03 dnsmasq[494780]: inotify, new or changed file /etc/hostsdir/something
> > Jan  7 11:36:03 dnsmasq[494780]: read /etc/hostsdir/something - 0 addresses
> > 
> > 2. Wrote some content into the file (echo "127.1.2.3 somebody" | sudo
> > tee /etc/hostsdir/something):
> > 
> > The dnsmasq log said:
> > 
> > Jan  7 11:37:49 dnsmasq[494780]: inotify, new or changed file /etc/hostsdir/something
> > Jan  7 11:37:49 dnsmasq[494780]: read /etc/hostsdir/something - 1 addresses
> > 
> > 
> > On 06.01.21 21:00, Jelle de Jong wrote:
> > > currently when ansible places the file dnsmasq tries to read the
> > > config file, but the content is not always there yet and then it is
> > > messed up.
> > 
> > Can you be a bit more specific about this messing up?
> > 
> > 
> > On 06.01.21 21:00, Jelle de Jong wrote:
> > > I need to rewrite the scripts to work in some notification bus
> > 
> > dnsmasq's dbus option may be something for you if you want to go down
> > this road.
> > 
> > 
> > Overall, I'd first check if Ansible closes the file correctly. dnsmasq
> > doesn't really have any other way to detect reliably when writing is
> > done. As you can see in my example above, everything works as expected
> > when doing things manually. Maybe there is another option specifically
> > for committing (writing + closing) the file in Ansible?
> 
> not an inotify issue here, just the flow of dnsmasq that keeps throwing me
> off..
> 
> How can I force a new macaddr to an excising IP lease....
> 
> Jan  9 15:50:27 firewall01 dnsmasq[3180]: inotify, new or changed file /etc/dnsmasq.d/dhcp/samba01.powercraft.lan.conf
> Jan  9 15:50:27 firewall01 dnsmasq-dhcp[3180]: read /etc/dnsmasq.d/dhcp/samba01.powercraft.lan.conf
> Jan  9 15:50:27 firewall01 dnsmasq[3180]: duplicate dhcp-host IP address 192.168.25.23 at line 1 of /etc/dnsmasq.d/dhcp/samba01.powercraft.lan.conf
> 
> There is no duplicated dhcp-host IP address , just a replaced file with a
> different macaddr with the same ip...
> 
> systemctl stop dnsmasq
> vim /var/lib/misc/dnsmasq.leases
> # remove all old ip leases releated to the old mac and ip
> systemctl start dnsmasq
> 
> 

I wonder how
> > first check if Ansible closes the file correctly
did happen.
Mostly because I like to learn how to perform that check.   :-)
Other reason is that the advice of long term dnsmasq community member
Dominik makes sense and Jelle still is stuck.


Regards
Geert Stappers
-- 
Silence is hard to parse



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