Howto install InfluxDB and Grafana on a Raspberry Pi 3

Inspired by a friend I’ve decided to install InfluxDB and Grafana on my Raspberry Pi 3. InfluxDB is a database optimized for storing time related data like measurements of my recently installed particle sensor. Grafana is used to create beautiful graphs to display the stored data.

The InfluxDB installation can be done in a few simple steps:

This will install the InfluxDB without a user and any rights. You can read up further on that topic. Ideally you should setup an user for authentication but since some IoT devices do not support this I’m not going to explain it here.

The Grafana installation is similar simple:

Please make sure that you’ll get the most current version from github and replace it in the wget command:

First login to Grafana:

Now you’re ready to configure Grafana. Go to http://<ip-of-grafana-machine>:3000 and setup a new username and password for the webinterface. The default is admin/admin

Configure InfluxDB as datasource in Grafana:

You need to configure a datasource under http://<ip-of-grafana-machine>:3000/datasources

Enter as name the name of the database you’ve created earlier. In this case it was topic.

The type of the database is InfluxDB.

The HTTP connection URL is http://localhost:8086

Hit Save & Test, once you’ve configured everything to your liking. The connection to the database should work now.

Howto setup local DNS domains and adresses in pihole

If you use the AVM FritzBox you’ll now about this dreaded DNS suffix „fritz.box“ which every device will get in your network, if you decide to use the DNS server of the FritzBox. I wanted to have something different which doesn’t collide with domains on the internet, e.g. „stuff.local“. As I already use pihole as adblocker on DNS level I needed a solution to configure it in pihole. The following info is based on the pihole forum.

Create a file called lan.list in /etc/pihole and fill it with content in the following format:

<ip-address> <hostname>.stuff.local <hostname>

Create a second dnsmasq config file which references the file we’ve just created:

echo "addn-hosts=/etc/pihole/lan.list" | sudo tee /etc/dnsmasq.d/02-lan.conf

Restart the dns services in pihole:

sudo pihole restartdns

You should now be able to lookup your stuff.local hostnames on your pi with e.g.

nslookup box.stuff.local
Server:		127.0.0.1
Address:	127.0.0.1#53

Name:	box.stuff.local
Address: 192.168.100.1

Howto ensure automatically mounted NFS volume on Raspbian Stretch

I’ve tried to setup NFS on my old Raspberry Pi 1 with Raspbian Stretch. I assumed that I just need to add an entry to the /etc/fstab file and the NFS volume on my Synology NAS would be mounted automatically.

So I’ve added this

mynas:/volume1/databases /mnt/databases nfs defaults 0 0

and thought I would be done. I’ve created the /mnt/databases folder with

mkdir /mnt/databases

and tried to mount everything with

mount -a

and my volume showed up as mounted. After reboot the volume wasn’t mounted anymore and the service couldn’t find its data. So what shall we do? After some research I’ve found these options, which fixed the problem:

mynas:/volume1/databases /mnt/databases nfs defaults,noauto,x-systemd.automount 0 0

The NFS volume now shows up even after a reboot. I’ve also tried to change the configuration of Raspbian so that it waits for the network before any services start but that didn’t fix the problem. Interestingly the entry with only defaults seems to be working on a Raspberry Pi 3 B.

Prepare your Mac for macOS Mojave 10.14

So Apple release the final version of macOS Mojave aka. 10.14. Before you start your update, you should check, if your important tools are 64bit compatible.

This version of macOS will annoy you with warnings about your apps being 32bit each time you start them. While you will still be able to execute 32bit apps in Mojave, I used the opportunity to get rid of a few 32bit apps.

How do you check, which apps are still 32bit? You can verify this from the system information app. Click on your Apple symbol in the menu line and select „About this Mac“. Click on „System Report“. Check now Software/Applications. You can filter the list by „64-bit (Intel)“. Each app marked with „No“ should produce the popup.

In my case I had these apps replaced by either updates or different tools:

  • AudioBookBuilder – version 2.0 will be made public or maybe not  – replaced with AudioBook Binder 
  • Caffeine – no Update and no longer being developed – replaced with KeepingYouAwake
  • iMovie 9 – no Update for this version possible – export all projects and delete, replace with never iMovie version
  • ViMediaManager v0.7α14 – replaced with MediaElch
  • DVD player – will get an update later

Be sure to update all your other 64bit apps as well before you start the update. 

Howto fix Deutsche Telekom slow Mac App Store download speeds

macOS Mojave was released to the public on Monday. As I’m still suffering under terrible problems with macOS High Sierra Updates, I’ve decided to give my Mac a chance and to download Mojave.

macOS Mojave installer start screen

I’ve started the download from the Mac App Store and the download speed was really slow. I’m using a 50MBit VDSL connection provided by the Deutsche Telekom. All other Downloads are fast and saturate the connection at about 5,5MB/s.

Really slow downloads from the App Store. This one should download for 5 and a half hour

The Download from the Mac App Store is terribly slow at around 200kB/s. After searching for problems with Deutsche Telekom and slow App Store speeds, I’ve stumbled over this page.

The solution to my slow download rates seem to be the used DNS server. Even if you use the DNS from Quad9 or the one from Google, you will have slow downloads.

A fast download from the App Store with 5,5MB/s. It finishes in 22 minutes

The recommended IPv4 DNS server are quite fast. I’ve setup a new Network Profile with these DNS server and I have now the full download speed again.

You can switch your network profile afterwards to your local DNS server.