Influxdb 2.0 lessons learned

I played a bit with influxdb version 2.0.0, telegraf client and two of my raspberry pies.
On my oldest pi  a 1 B+ the telegraf client caused too much performance issues on that light weight single CPU and 480 MB of usable RAM. So I chose a simple bash script with curl to send the CPU temperature to influxdb.

#!/bin/bash
timestamp=$(date +%s)
temp=$(vcgencmd measure_temp)
curl -XPOST \
"https://flux.example.com/api/v2/write?org=none&bucket=pihole&precision=s" \
--header "Authorization: Token asas==" \
--data-raw "cpu-temperature,host=pihole ${temp//\'C/} ${timestamp}"

At first I was running influxdbd by hand. But I didn’t want the usual port of 9999 of the alpha version and I also wanted SSL encryption when I log into the backend. Pretty easy with the already running apache on that server.

<VirtualHost *:443>
	ServerName flux.example.com
	DocumentRoot /var/www/empty

	<Directory /var/www/empty>
		Options Indexes FollowSymLinks
		AllowOverride None
		Require all granted
	</Directory>

	ProxyPass / http://localhost:9999/
	ProxyPassReverse / http://localhost:9999/

	SSLEngine on
	SSLCertificateFile  fullchain.pem
	SSLCertificateKeyFile privkey.pem
</VirtualHost>

so far so good. Starting the influxdb by hand after a reboot or failing isn’t an option.  So I created by on systemd service file

sudo $EDITOR /lib/systemd/system/influxdb2.service

[Unit]
Description=InfluxDB 2.0 service file.
Documentation=https://v2.docs.influxdata.com/v2.0/get-started/
After=network-online.target

[Service]
User=influx
Group=influx
ExecStart=/usr/local/bin/influxd
Restart=on-failure

[Install]
WantedBy=multi-user.target

Do not forget to enable it :D sudo systemctl enable influxdb2

 

So far I made one observation. The telegraf client is doing a lot of DNS requests through the network. If I’m not wrong it does it for every request. If you look at the graphic you see that the bottom a big blue line. That is the DNS requests from telegraf. At some point around 20:00 You see a drop. Well there I change the flush interval to 120 seconds. Later at round 7:30 I wrote the IP and host name into /etc/hosts and the “noise” was gone. That is something you maybe want to do in your devices, too to save some bandwidth and energy.

Compling Apache 2.4 on Ubuntu or Debian

wget http://httpd.apache.org/dev/dist/httpd-2.4.2.tar.gz
wget http://httpd.apache.org/dev/dist/httpd-2.4.2-deps.tar.gz
tar xvfz httpd-2.4.2.tar.gz
tar xvfz httpd-2.4.2-deps.tar.gz
cd httpd-2.4.2/srclib
wget http://mirror.netcologne.de/apache.org//apr/apr-iconv-1.2.1.tar.gz
tar xvfz apr-iconv-1.2.1.tar.gz
mv apr-iconv-1.2.1 apr-iconv
wget http://zlib.net/zlib-1.2.6.tar.gz
tar xvfz zlib-1.2.7.tar.gz
mv zlib-1.2.7 zlib
wget ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-8.21.tar.gz
tar xvfz pcre-8.21.tar.gz
mv pcre-8.21 pcre
wget http://www.openssl.org/source/http://openssl.org/source/openssl-1.0.1.tar.gz
tar xfz openssl-1.0.1.tar.gz
cd openssl-*
./config --prefix=/usr zlib-dynamic --openssldir=/etc/ssl shared
make
make test
sudo make install
cd ../..
./buildconf
./configure --prefix=/opt/apache2 --enable-pie --enable-mods-shared=all --enable-so --disable-include --enable-deflate --enable-headers --enable-expires --enable-ssl=shared --enable-mpms-shared=all --with-mpm=event --enable-rewrite --with-z=/home/mario/apache24/httpd-2.4.2/srclib/zlib --enable-module=ssl --enable-fcgid --with-included-apr
make 
sudo make install
cd ..
wget http://www.trieuvan.com/apache//httpd/mod_fcgid/mod_fcgid-2.3.7.tar.gz
tar xvfz mod_fcgid-2.3.7.tar.gz
cd mod_fcgid-*
APXS=/opt/apache2/bin/apxs ./configure.apxs
make
sudo make install

For using PHP install php-cgi

add httpd.conf

FcgidMaxProcesses 50
FcgidFixPathinfo 1
FcgidProcessLifeTime 0
FcgidTimeScore 3
FcgidZombieScanInterval 20
FcgidMaxRequestsPerProcess 0
FcgidMaxRequestLen 33554432
FcgidIOTimeout 120

in each vhost

Options Indexes ExecCGI
AddHandler fcgid-script .php
FCGIWrapper /usr/lib/cgi-bin/php5 .php

Upgrading OpenSSL on Debian 6 (squeeze) or Ubuntu 8.04 (hardy)

The Problem on the long term ubuntu 8.04 and the current stable debian is that they ship the old OpenSSL 0.9.8o With that I wasn’t able to compile the new apache 2.4.1 with all the SSL features I want. Downloading the OpenSSL source and just configure make make install didn’t help at all.

checking whether to enable mod_ssl... checking dependencies 
 checking for OpenSSL... checking for user-provided OpenSSL base directory... none 
 checking for OpenSSL version >= 0.9.7... FAILED 
 configure: WARNING: OpenSSL version is too old 
 no 
 checking whether to enable mod_ssl... configure: error: mod_ssl has been requested but can not be built due to prerequisite failures 
 mario@h2020668:~/apache24/httpd-2.4.1$ openssl version 
 OpenSSL 0.9.8o 01 Jun 2010

The only thing that helped was to use the unix config script plus the right prefix plus the shared option

wget http://openssl.org/source/openssl-1.0.1.tar.gz 
 tar xfz openssl-1.0.1.tar.gz 
 cd openssl-* 
 ./config --prefix=/usr zlib-dynamic --openssldir=/etc/ssl shared 
 make 
 sudo make install

 

Debian is very fine, but sometimes it sucks because of the lag of new software versions

Posts Tagged debian

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