** DONE Poor Man's Monitoring of a Remote Linux Host via Syncthing      :blog:linux:software:tip:diy:
CLOSED: [2019-07-07 Sun 14:37] SCHEDULED: <2019-07-07 Sun>
:PROPERTIES:
:CREATED: [2019-07-07 Sun 13:39]
:ID: 2019-07-07-simple-linux-monitoring
:END:
:LOGBOOK:
- State "DONE"       from "DONE"       [2019-07-09 Tue 10:08]
- State "DONE"       from "STARTED"    [2019-07-07 Sun 14:37]
:END:

Updates:

- 2019-07-09: Explanation on Git and changed cron job from "@daily" to
  "@reboot". This is because the "@daily" cron job may only be
  executed at a fixed time during the night where the notebook is
  usually not running. This is depending on the specific GNU/Linux
  distribution used.

I'm helping some old lady by administrating her notebook. I set it up
with Xubuntu LTS GNU/Linux which comes with the very easy to use and
fast [[https://en.wikipedia.org/wiki/Xfce][Xfce]] environment: not bloated and offers everything necessary. I
stripped down the "start menu" such that it only shows the ten apps
she's using.

Remote access is done via TeamViewer if necessary.

Today, I set it up with a neat monitoring I'm going to explain in this
post.

--------------

The purpose is to have the possibility to take a quick look at the
most basic status information whenever I want to.

For that, I wrote a small shell script named =autologs.sh=:

#+BEGIN_SRC sh
#!/bin/sh

## This script saves some basic infos about this host and commits them via git

## NOTE: if you add a new file, it has to be added to the Git repo manually.

## directory where the results are written to:
LOGDIR="/home/USER/.vk/share/autologs"

## ----------------------------------------------------------------------- ##

## get list of current cron jobs
crontab -l > "${LOGDIR}"/root-crontab.txt

## get list of installed Debian packages
dpkg --get-selections > "${LOGDIR}"/dpkg--get-selections.txt

## get current log file of Debian packages in order to review updates
cp /var/log/apt/history.log "${LOGDIR}"/var-log-apt-history.log

## how much space is left on the drives?
df -h > "${LOGDIR}"/df-h.txt

## when were the most recent backups?
ls -la /home/USER/.cache/deja-dup > "${LOGDIR}"/deja-dup_files.log

## what hardware is attached?
lspci > "${LOGDIR}"/lspci.txt
lsusb > "${LOGDIR}"/lsusb.txt
hwinfo --short > "${LOGDIR}"/hwinfo--short.txt

## ----------------------------------------------------------------------- ##

## commit everything after being generated
git -C "${LOGDIR}" add "${LOGDIR}"
git -C "${LOGDIR}" commit -a -m "`date '+%Y-%m-%dT%H.%M.%S autocommit by autologs.sh'`"

#end
#+END_SRC

Of course, "USER" is replaced with the account name.

The folder =/home/USER/.vk/= is a hidden one which I shared via
[[https://en.wikipedia.org/wiki/Syncthing][Syncthing]]. Syncthing doesn't need a public IP or a firewall rule in
order to synchronize two folders between two hosts that are online at
the same time. I configured Syncthing to [[https://docs.syncthing.net/users/autostart.html#linux][start as user service via
systemd]] automatically.

My own (receiving) host runs 24/7 and is therefore always available
whenever the other notebook is running.

The =autologs.sh= is invoked two minutes after each boot via [[https://en.wikipedia.org/wiki/Cron][cron]] as
user =root= on the remote notebook:

: @reboot sleep 2m ; /home/USER/.vk/share/autologs/autologs.sh

It then produces the files mentioned in the script, they are
synchronized via Syncthing to my personal host where I can take a look
on some status information any time.

I'm committing to a local Git repository because Git is extremely
efficient in storing a history of linear text files that change
slightly over time. It also provides decent tools to visualize
differences between two given points in time.

Using the described method obove, I do have an up-to-date status
report on remote hosts without having direct access to the remote
host. Nothing fancy, simple to set up, reliable in use and probably a
small trick you haven't thought of yet.