Rework sysconfig file/startup environment

[Crunsher]

The sysconifg file now only contains the defaults as comments, changes
made there are given to the init.d script, prepare-dirs, safe-reload and
Icinga 2 itself. If nothing is set in the sysconfig file (as is the
default as all lines are commented out) the defaults are used.

fixes #6255

[Crunsher]

TODO: Windows, as always

Testing:

• Install and run on a init.d system
• Validate changes in the sysconfig file are read and used (user and filelimit are easy to test)
• Test running in foreground
• Install and run on a systemd system
• Validate changes in the sysconfig file are read and used (user and filelimit are easy to test)
• Test running in foreground

[dnsmichi]

getenv() also is available on Windows, needs proper tests though.

[Crunsher]

While windows can use getenv, we never set the environment and the user we store at a different place. So this is a different issue.

[dnsmichi]

True that, still we should keep it in mind when it comes to changes related to environments (where getenv() comes in handy).

[dnsmichi]

It seems that this PR cherry-picked a commit of mine and is not fast forward.

4a6320d

[N-o-X]

I couldn't get the expected result while testing this on Ubuntu 18.04.
It seems like Icinga isn't using the values.

Tested with:
ICINGA2_LOG=@CMAKE_INSTALL_FULL_LOCALSTATEDIR@/log/icinga2/icinga51241322.log
And:
ICINGA2_ERROR_LOG=@CMAKE_INSTALL_FULL_LOCALSTATEDIR@/log/icinga2/erro515125135r.log

Both logs were still written to icinga2.log and error.log

I've also tried removing the file to validate that it is in the correct location:
Sysconfig file '/etc/sysconfig/icinga2' cannot be read. Using default values.

[dnsmichi]

ICINGA2_LOG=@CMAKE_INSTALL_FULL_LOCALSTATEDIR@/log/icinga2/icinga51241322.log

that's from a git source, how does your sysconfig file actually look like on the system you're testing on?

The wrong location for Debian-ized sysconfig files needs to be dealt with in a separate patch, hiding this warning. Maybe you're using the wrong branch to test, which commit are you on?

[N-o-X]

Whoops… didn't see that CMAKE variable there :D
I used the file from git source. The package didn't create it. Might be because the directory /etc/sysconfig doesn't exist on Debian derivatives, like you said.

And you're right I used https://build.icinga.com/job/icinga2-dev/job/deb-ubuntu-bionic-1binary/arch=x86_64/1/, because @Crunsher said that that build is based on branch sysconfig-env but is actually based on master. Sorry for that, will test it again.

[Crunsher]

The dev package was built from the sysconfig-env. If the result is of the wrong branch, our dev pipeline is broken

[N-o-X]

@Crunsher you're right, it build from sysconfig-env and did what it should.
My sysconfig currently looks like this:

ICINGA2_PID_FILE=/var/log/icinga2/icinga218.pid
ICINGA2_ERROR_LOG=/var/log/icinga2/erro515125135r.log
ICINGA2_LOG=/var/log/icinga2/icinga51241322.log

But it still doesn't affect Icinga.

[dnsmichi]

Keep in mind that ICINGA2_ERROR_LOG is taken into account by the Systemd/init script itself, which passes --errorlog as argument. We should discuss whether this is now obsoleted.

Same applies to the other settings above. Looking at the patch I can only see that USER/GROUP and RTSTACK limits are properly read and used.

[dnsmichi]

See my notes above, all environment variables should have an effect on Icinga 2, even without Systemd/init.d.

[dnsmichi]

Review

As discussed offline, this issue is solely to fix USER, GROUP and RLIMIT settings which have been introduced with 2.8.2. No other focus with environment variables here.

Set environment variable

michi@mbmif ~/coding/icinga/icinga2 (sysconfig-env<>) $ sudo ICINGA2_USER=abc icinga2 daemon -C
critical/cli: Invalid user specified: abc

michi@mbmif ~/coding/icinga/icinga2 (sysconfig-env<>) $ sudo ICINGA2_USER=icinga icinga2 daemon -C
[2018-06-05 11:22:52 +0200] information/cli: Icinga application loader (version: v2.8.4-731-g2b5f95060; debug)
...
[2018-06-05 11:22:52 +0200] information/cli: Finished validating the configuration file(s).

RSTACK

Requires Linux, doesn't work on macOS. Updates soon from inside Vagrant.

[dnsmichi]

Manual Stacksize on Linux

[root@icinga2 ~]# ICINGA2_RLIMIT_STACK=16 icinga2 daemon -C
[2018-06-05 14:19:08 +0200] warning/Application: The user-specified value for RLimitStack cannot be smaller than the default value (262144). Using the default value instead.

Systemd

[root@icinga2 ~]# for p in $(pidof icinga2); do cat /proc/$p/limits | grep files; done
Max open files            16384                16384                files
Max open files            16384                16384                files
[root@icinga2 ~]# vim /etc/sysconfig/icinga2
...
ICINGA2_RLIMIT_FILES=50000

[root@icinga2 ~]# systemctl restart icinga2
[root@icinga2 ~]# for p in $(pidof icinga2); do cat /proc/$p/limits | grep files; done
Max open files            50000                50000                files
Max open files            50000                50000                files

[dnsmichi]

Initscripts pass the environment variables as expected, there's not much difference here involved.