Add multiarch Debian 9

18 08 2017

dpkg --add-architecture i386
apt-get update
apt-get install libc6:i386


Convert RAID superblock from 0.9 to 1.0

1 08 2017

The kernel wiki have a section with some documentation about this process, but it’s a bit outdated. If you have mdadm-3.3 or newer (usually yes), is it possible to change the superblock in two steps. First get the devices information:

mdadm --detail /dev/md0

And do it:

mdadm --stop /dev/md0
mdadm --assemble /dev/md0 --update=metadata ...list.of.devices...

Install Prometheus and Grafana

31 07 2017

These are the steps to install Prometheus and Grafana in a standalone Linux Debian box for monitor their system with a nice dashboard.

Install the package server and exporter from the repo:

apt-get install prometheus prometheus-node-exporter

Change Prometheus to listen only in localhost and the sync strategy (if you want to save battery) /etc/default/prometheus:

ARGS="-web.listen-address=localhost:9090 -storage.local.series-sync-strategy 'never'"

Assure that there is a target in /etc/prometheus/prometheus.yml:

- job_name: node
# If prometheus-node-exporter is installed, grab stats about the local
# machine by default.
- targets: ['localhost:9100']

Restart it and enable in systemd:

systemctl restart prometheus
systemctl enable prometheus

Change the listen address too in the node exporter /etc/default/prometheus-node-exporter:

ARGS="-collector.diskstats.ignored-devices=^(ram|loop|fd)\d+$ \
-collector.filesystem.ignored-mount-points=^/(sys|proc|dev|run)($|/) \ -web.listen-address="

Restart it and enable in systemd:

systemctl restart prometheus-node-exporter
systemctl enable prometheus-node-exporter

Download Grafana from their website and install it:

mkdir /opt/grafana
cd /opt/grafana
dpkg -i grafana_4.4.1_amd64.deb

Enable and start it in systemd:

systemctl daemon-reload
systemctl enable grafana-server
systemctl start grafana-server

Use the browser and enter this address (user/password: admin/admin):


Add the Prometheus datasource as in the image:

Add a new dashboard following this path in the menu:

Type the id “1860” inside “ Dashboard”. It automatically get it:

Confirm the import fetching the values from localhost:


Change tab size in xfce 4

8 07 2017

If you use Debian 9 in a small screen with xfce 4, maybe you suffer the big tab size of some desktop elements.

For fix that, create a file under ~/.config/gtk-3.0/gtk.css with the following content:

/* reduce padding of tabs */
notebook tab {
min-height: 0;
padding-top: 1px;
padding-bottom: 2px;
/* reduce padding of buttons */
notebook tab button {
min-height: 0;
min-width: 0;
padding: 1px;
margin-top: 1px;
margin-bottom: 2px;

Debian Stretch 9 issue with vim: copy and paste

20 06 2017

In Debian Stetch 9 there is a new behaviour in vim, the copy and paste with the mouse is unusual and don’t work as the previous versions did.

For fix that, in the file /usr/share/vim/vim80/defaults.vim comment the lines:

" if has('mouse')
" set mouse=a
" endif

Force syn date and time

21 05 2017

apt-get install tlsdate
tlsdate -H

Enable autologin in Debian with Systemd

19 05 2017

For allow autologin in a Debian system with systemd (very usefull with testing virtual machines):

Create dir:
mkdir /etc/systemd/system/getty@tty1.service.d/

Create file /etc/systemd/system/getty@tty1.service.d/override.conf with the following content:
ExecStart=-/sbin/agetty --autologin root --noclear %I $TERM

More info: