linsomniac / drbdlinks Goto Github PK

Python 2.7 will not be maintained past 2020, so drbdlinks should support Python 3…and if it does, it should be reflected in the documentation.

If my /etc/drbdlinks.conf contains

mountpoint('/drbd')
link('/etc/crontab')

unfortunately drbdlinks status still says

$ drbdlinks status
info: DRBD Links OK (present)
$ 

even if it looks like this

$ ls -l /etc/crontab /drbd/etc/crontab
-rw-r--r--. 1 root root 1699 Apr  9 08:10 /etc/crontab
-rw-r--r--. 1 root root 1751 Apr  9 08:04 /drbd/etc/crontab
$ 

while it should be

$ ls -l /etc/crontab /drbd/etc/crontab
lrwxrwxrwx. 1 root root   24 Apr 17 10:09 /etc/crontab -> /drbd/etc/crontab
-rw-r--r--. 1 root root 1751 Apr  9 08:04 /drbd/etc/crontab
$ 

In this case, something dereferenced /etc/crontab symlink outside of drbdlinks by accident, but drbdlinks does not detect this scenario (unfortunately). Note, this also could happen for a directory, so the check likely should be if managed symlink is really a symlink.

Would it be possible to extend the restart/reload logic present today for syslog/syslog-ng/rsyslog & cron to any arbitrary service?

I am writing Ansible playbook to automate my DRBD setup and I will include multiple roles on a single system. As a result, each role will have to append drbdlinks configuration with its own link directive.

The usual way to ease such modular configuration is to include files available in a .d configuration directory.

Here is a work-around I have implemented directly at the end of drbdlinks.conf because I found out it was passed through execfile

import glob
for conf in glob.iglob('/etc/drbdlinks.d/*.conf'):
    execfile(conf)

It took me a while to figure out that the trailing / at the end of my directive

link('/var/lib/postgresql/')

was the reason why initialize_shared_storage failed to detect lacking target directories and just aborted its copy tentative.

It would be an interesting improvement to discard trailing slash if present in link declaration or else to abort early with dedicated error message.