Re: [Dnsmasq-discuss] Multiple instances of dnsmasq on Debian with systemd

2018-12-16 Thread Simon Kelley
This is obviously a large amount of work, so thanks very much for that.

To make use of it, I need to be able to see as clearly as possible what
is being changed, and why. To that end, I'd much rather have diff files
ten  replacement files, but it's fairly easy to generate those for
myself. Having done that, I get vast amounts of noise where you've fixed
up indentation and end-of-line spaces, which makes seeing the actual
changes very difficult. However, reading carefully, I can see most of
what you describe, but also the reversion of all the changes that have
happened to the files since the Debian stable release.


Could I ask you to do the following?


1) Start with the latest code for the sysV init script, systemd unit and
defaults file. You can get these from the git repo at

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob_plain;f=debian/init;hb=HEAD

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob_plain;f=debian/systemd.service;hb=HEAD

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob_plain;f=debian/default;hb=HEAD


2) Make just the functional changes you've identified: no formatting or
other extraneous changes.

3) Send me context diffs (diff -u) of the changes you've made



Cheers,

Simon.


On 01/12/2018 12:20, M. Buecher wrote:
> Hello Simon,
> 
> on my first tries to start multiple dnsmasq instances on Debian 9
> "Stretch" with systemd I faced several issues and created Debian bug
> report #914305 [1].
> Yesterday I finally managed to spend several hours on the issue and
> found a clean solution for it.
> While preparing the text for the bug report I recognized that you're the
> maintainer of the Debian packages, so I decided to write to the dnsmasq
> mailing list first.
> 
> [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914305
> 
> 
> 
> systemd unit files [2] allow to be used for multiple instances when the
> service unit file name ends with the at symbol (@).
> Then the service can be enabled with an instance name following the at
> symbol, e.g. `systemctl enable dnsmasq@main.service`.
> The instance name is available in an escaped format in variable %i
> (lower case) when the unit file is processed.
> The attached unit file dnsmasq@.service passes the escaped instance name
> to the init.d script (minor changes to the code plus `mv -v
> /lib/systemd/system/dnsmasq.service /lib/systemd/system/dnsmasq@.service`).
> 
> The 2nd attached file is the updated init.d script for dnsmasq.
> It now recognizes the instance name via the second script paramater and
> uses it wherever needed or possible (default file, pid file, resolvconf
> protocol, log entries).
> 
> Additionally three special cases had to be handled when running multiple
> instances of dnsmasq:
> a) The original systemd unit file wants to check the configuration
> before starting the service but does not honor the settings from the
> default file (conf file and dir).
>    Therefore the option checkconfig was added to the init.d script.
>    I don't know if there's a common SysInit V standard name for such a
> function [3].
> b) `mkdir /run/dnsmasq` in the init.d script can fail as unit files are
> run in parallel, so the directory has to be checked again if mkdir failed.
> c) Only one dnsmasq instance should be the dns resolver for the local
> system and should bind to localhost.
>    Therefore revived DNSMASQ_EXCEPT="lo" in the default file (3rd
> attached file).
> 
> Additional changes to the files are typo corrections.
> 
> [2] https://www.freedesktop.org/software/systemd/man/systemd.unit.html
> [3]
> https://www.debian.org/doc/debian-policy/ch-opersys.html#writing-the-scripts
> 
> 
> 
> 
> For testing I installed openresolv and dnsmasq on latest Debian 9
> "Stretch" and created some virtual network interfaces via systemd [4].
> The main dnsmasq instance shall run on the real NIC while special
> instances shall run on the extra virtual NICs (dnsextra*).
> 
> Stopped and disabled the original service from the Debian dnsmasq package:
> `systemctl stop dnsmasq.service`
> `systemctl disable dnsmasq.service`
> `systemctl status dnsmasq.service`
> 
> Prepared dnsmasq systemd unit file for instances by renaming and
> updating it:
> `mv -v /lib/systemd/system/dnsmasq.service
> /lib/systemd/system/dnsmasq@.service`
> 
> As instance enabled systemd unit files have to be used with an instance
> name I decided to name the default dnsmasq instance simply "main".
> Not to break SysInit V compatibility a symbol link was used for the
> "renaming" of the default file.
> `ln -s -T dnsmasq /etc/default/dnsmasq.main`
> (P.S. Other idea would be to default INSTANCE in init.d to 'main' when
> instance name not given.)
> 
> Updated also init.d script and normal default file.
> 
> Then prepared two dnsmasq instances:
> 1. Default file for main instance (/etc/default/dnsmasq.main)
> Changed to DNSMASQ_OPTS="--bind-dynamic --except-interface=dnsextra*"
> This way it will avoid binding to the extra virtual NICs while still
> 

Re: [Dnsmasq-discuss] Multiple instances of dnsmasq on Debian with systemd

2018-12-03 Thread M. Buecher



On 2018-12-02 01:01, M. Buecher wrote:

I spent some time on how to keep backward compatibility for current
configurations.

The simplest solution would be to provide 2 systemd unit files:
1. An updated dnsmasq.service file for the main/default/standard
"instance", that reflects the fix for checking the configuration (see
attached file).
2. The new dnsmasq@.service file from the previous post for additional
instances.

This way nothing would change for people running just a single dnsmasq
instance. No need to rename or sym-link /etc/default/dnsmasq to
dnsmasq.main (or similar).
Still people could easily create extra instances with the new
dnsmasq@.service file and a corresponding
/etc/default/dnsmasq. file.


Got some time to look at the upstream repo.
Updated init.d script to current state plus renamed files for upstream 
repo.
# This file has six functions:
# 1) to completely disable starting this dnsmasq instance
# 2) to set DOMAIN_SUFFIX by running `dnsdomainname`
# 3) to select an alternative config file
#by setting DNSMASQ_OPTS to --conf-file=
# 4) to tell dnsmasq to read the files in /etc/dnsmasq.d for
#more configuration variables.
# 5) to stop the resolvconf package from controlling dnsmasq's
#idea of which upstream nameservers to use.
# 6) to avoid using this dnsmasq instance as the system's default resolver
#by setting DNSMASQ_EXCEPT="lo"
# For upgraders from very old versions, all the shell variables set
# here in previous versions are still honored by the init script
# so if you just keep your old version of this file nothing will break.

#DOMAIN_SUFFIX=`dnsdomainname`
#DNSMASQ_OPTS="--conf-file=/etc/dnsmasq.alt"

# Whether or not to run the dnsmasq daemon; set to 0 to disable.
ENABLED=1

# By default search this drop directory for configuration options.
# Libvirt leaves a file here to make the system dnsmasq play nice.
# Comment out this line if you don't want this. The dpkg-* are file
# endings which cause dnsmasq to skip that file. This avoids pulling
# in backups made by dpkg.
CONFIG_DIR=/etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new

# If the resolvconf package is installed, dnsmasq will use its output
# rather than the contents of /etc/resolv.conf to find upstream
# nameservers. Uncommenting this line inhibits this behaviour.
# Note that including a "resolv-file=" line in
# /etc/dnsmasq.conf is not enough to override resolvconf if it is
# installed: the line below must be uncommented.
#IGNORE_RESOLVCONF=yes

# If the resolvconf package is installed, dnsmasq will tell resolvconf
# to use dnsmasq under 127.0.0.1 as the system's default resolver.
# Uncommenting this line inhibits this behaviour.
#DNSMASQ_EXCEPT="lo"
#!/bin/sh
### BEGIN INIT INFO
# Provides:   dnsmasq
# Required-Start: $network $remote_fs $syslog
# Required-Stop:  $network $remote_fs $syslog
# Default-Start:  2 3 4 5
# Default-Stop:   0 1 6
# Description:DHCP and DNS server
### END INIT INFO

# Don't exit on error status
set +e

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DAEMON=/usr/sbin/dnsmasq
NAME=dnsmasq
DESC="DNS forwarder and DHCP server"
INSTANCE="${2}"

# Most configuration options in /etc/default/dnsmasq are deprecated
# but still honoured.
ENABLED=1
if [ -r /etc/default/${NAME}${INSTANCE:+.${INSTANCE}} ]; then
. /etc/default/${NAME}${INSTANCE:+.${INSTANCE}}
fi

# Get the system locale, so that messages are in the correct language, and the
# charset for IDN is correct
if [ -r /etc/default/locale ]; then
. /etc/default/locale
export LANG
fi

# The following test ensures the dnsmasq service is not started, when the
# package 'dnsmasq' is removed but not purged, even if the dnsmasq-base
# package is still in place.
test -e /usr/share/dnsmasq/installed-marker || exit 0

test -x ${DAEMON} || exit 0

# Provide skeleton LSB log functions for backports which don't have LSB functions.
if [ -f /lib/lsb/init-functions ]; then
. /lib/lsb/init-functions
else
log_warning_msg () {
echo "${@}."
}

log_success_msg () {
echo "${@}."
}

log_daemon_msg () {
echo -n "${1}: ${2}"
}

log_end_msg () {
if [ "${1}" -eq 0 ]; then
echo "."
elif [ "${1}" -eq 255 ]; then
/bin/echo -e " (warning)."
else
/bin/echo -e " failed!"
fi
}
fi

# RESOLV_CONF:
# If the resolvconf package is installed then use the resolv conf file
# that it provides as the default.  Otherwise use /etc/resolv.conf as
# the default.
#
# If IGNORE_RESOLVCONF is set in /etc/default/dnsmasq or an explicit
# filename is set there then this inhibits the use of the resolvconf-provided
# information.
#
# Note that if the resolvconf package is installed it is not possible to
# override it just by configuration in /etc/dnsmasq.conf, it is necessary
# to set IGNORE_RESOLVCONF=yes in /etc/default/dnsmasq.

if [ ! "${RESOLV_CONF}" ] &&
   [ "${IGNORE_RESOLVCONF}" != "yes" ] &&
   [ -x /sbin/resolvconf 

Re: [Dnsmasq-discuss] Multiple instances of dnsmasq on Debian with systemd

2018-12-01 Thread M. Buecher




On 2018-12-01 16:19, Geert Stappers wrote:

On Sat, Dec 01, 2018 at 01:20:58PM +0100, M. Buecher wrote:


[Unit]
Description=dnsmasq (%i) - A lightweight DHCP and caching DNS server
Requires=network.target
Wants=nss-lookup.target
Before=nss-lookup.target


The "Wants" and the "Before" have the same targets.
That feels odd to me.



Wants= is a weaker version of Requires=, which tries to start those 
additional services but a failure of them doesn't stop the dnsmasq 
service from starting.


Before= just manages the start order of the services.

My changes only added support for instances and didn't change the 
dependencies.


Thanks for checking
Maddes

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Re: [Dnsmasq-discuss] Multiple instances of dnsmasq on Debian with systemd

2018-12-01 Thread Geert Stappers
On Sat, Dec 01, 2018 at 01:20:58PM +0100, M. Buecher wrote:

> [Unit]
> Description=dnsmasq (%i) - A lightweight DHCP and caching DNS server
> Requires=network.target
> Wants=nss-lookup.target
> Before=nss-lookup.target

The "Wants" and the "Before" have the same targets.
That feels odd to me.



Groeten
Geert Stappers
-- 
Leven en laten leven

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Re: [Dnsmasq-discuss] Multiple instances of dnsmasq on Debian with systemd

2018-12-01 Thread M. Buecher

Hello Simon,

on my first tries to start multiple dnsmasq instances on Debian 9 
"Stretch" with systemd I faced several issues and created Debian bug 
report #914305 [1].
Yesterday I finally managed to spend several hours on the issue and 
found a clean solution for it.
While preparing the text for the bug report I recognized that you're the 
maintainer of the Debian packages, so I decided to write to the dnsmasq 
mailing list first.


[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914305



systemd unit files [2] allow to be used for multiple instances when the 
service unit file name ends with the at symbol (@).
Then the service can be enabled with an instance name following the at 
symbol, e.g. `systemctl enable dnsmasq@main.service`.
The instance name is available in an escaped format in variable %i 
(lower case) when the unit file is processed.
The attached unit file dnsmasq@.service passes the escaped instance name 
to the init.d script (minor changes to the code plus `mv -v 
/lib/systemd/system/dnsmasq.service 
/lib/systemd/system/dnsmasq@.service`).


The 2nd attached file is the updated init.d script for dnsmasq.
It now recognizes the instance name via the second script paramater and 
uses it wherever needed or possible (default file, pid file, resolvconf 
protocol, log entries).


Additionally three special cases had to be handled when running multiple 
instances of dnsmasq:
a) The original systemd unit file wants to check the configuration 
before starting the service but does not honor the settings from the 
default file (conf file and dir).

   Therefore the option checkconfig was added to the init.d script.
   I don't know if there's a common SysInit V standard name for such a 
function [3].
b) `mkdir /run/dnsmasq` in the init.d script can fail as unit files are 
run in parallel, so the directory has to be checked again if mkdir 
failed.
c) Only one dnsmasq instance should be the dns resolver for the local 
system and should bind to localhost.
   Therefore revived DNSMASQ_EXCEPT="lo" in the default file (3rd 
attached file).


Additional changes to the files are typo corrections.

[2] https://www.freedesktop.org/software/systemd/man/systemd.unit.html
[3] 
https://www.debian.org/doc/debian-policy/ch-opersys.html#writing-the-scripts




For testing I installed openresolv and dnsmasq on latest Debian 9 
"Stretch" and created some virtual network interfaces via systemd [4].
The main dnsmasq instance shall run on the real NIC while special 
instances shall run on the extra virtual NICs (dnsextra*).


Stopped and disabled the original service from the Debian dnsmasq 
package:

`systemctl stop dnsmasq.service`
`systemctl disable dnsmasq.service`
`systemctl status dnsmasq.service`

Prepared dnsmasq systemd unit file for instances by renaming and 
updating it:
`mv -v /lib/systemd/system/dnsmasq.service 
/lib/systemd/system/dnsmasq@.service`


As instance enabled systemd unit files have to be used with an instance 
name I decided to name the default dnsmasq instance simply "main".
Not to break SysInit V compatibility a symbol link was used for the 
"renaming" of the default file.

`ln -s -T dnsmasq /etc/default/dnsmasq.main`
(P.S. Other idea would be to default INSTANCE in init.d to 'main' when 
instance name not given.)


Updated also init.d script and normal default file.

Then prepared two dnsmasq instances:
1. Default file for main instance (/etc/default/dnsmasq.main)
Changed to DNSMASQ_OPTS="--bind-dynamic --except-interface=dnsextra*"
This way it will avoid binding to the extra virtual NICs while still 
recognizing new addresses and other new NICs, and it will also be the 
DNS resolver for the local system.


2. New default file for first extra instance 
(/etc/default/dnsmasq.extra01)
Copied from default file of main instance via `cp /etc/default/dnsmasq 
/etc/default/dnsmasq.extra01`

Changed the following settings for this extra instance:
* DNSMASQ_OPTS="--bind-dynamic --interface=dnsextra01 
--address=/heise.de/192.168.0.250"

  Binds to one explicit interface while still recognizing new addresses.
  One modified address resolution for testing with dig.
* IGNORE_RESOLVCONF=yes
  Always using /etc/resolv.conf therefore either using the dnsmasq main 
instance (if it is started) as upstream dns server or the upstream 
server from resolvconf (e.g. via DHCP).

* DNSMASQ_EXCEPT="lo"
  Avoid binding to localhost and also not being used as the DNS resolver 
for the local system.


With this setup I could start/stop any dnsmasq instance while keeping a 
working DNS setup.
Additionally I could assign an explicit dnsmasq instance to any dhcp 
client.


[4] https://gist.github.com/maddes-b/e487d1f95f73f5d40805315f0232d5d9



I hope that I explained everything understandably, completely and in 
correct English.
Any feedback is welcome and it would be great to see this in Debian 10 
:)


Kind regards
Maddes

[Unit]
Description=dnsmasq (%i) - A lightweight DHCP and caching DNS server