Tag Archives: Remote Access


In general I try to buy server-class hardware for my home lab, primarily so that I could have IPMI / Remote access console for remote OS installation & troubleshooting. I recently got a new desktop and found myself with a Threadripper 1950x that would make an excellent addition to my server cluster. The one problem being it’s a desktop-class board, so it does not have any IPMI / remote access device.

I solved my problem with pikvm. It works wonderfully! Pikvm uses a raspberry pi with some additional hardware and software to interface with a system to control power & reset capabilities, as well as KVM functions with the ability to upload OS images and do OS installations remotely. The whole project cost me about $150 since I didn’t have some of the essential items for it. It could definitely be cheaper if I didn’t buy large packs of items or already had some electronics components.

The process was straightforward as outlined on their github page. The only snag I ran into was creating the USB Y (split) cable. It did not work the first time, so I had to tear it all down and start again. One cable I used had more than 4 wires (3 red wires, 1 black, 1 green, 1 white, and 1 yellow.) When I re-assembled to include the yellow wire with the red and black, it all worked.

My custom made Y cable (made from two cables I had lying around)
fully assembled and ready to test
Attached to a test motherboard

I scavenged the metal mounting bracket from some old networking adapter cards. With those I was able to mount the pi and the HDMI-in module to two standard PCI express card slots. I accidentally destroyed one of my SD cards while doing this so be careful if you try it! The PI is mounted at a slight angle so as to not damage the SD card. I had to mount it backwards (ethernet in the back) because I couldn’t get power to it otherwise (power port right up against the motherboard.) My workaround for this was to custom make a short length ethernet cord and use an RJ45 coupler on the outside of the chassis to provide an easy to access network port for the pi.

I wired the power & reset switch, as well as HDD and power LEDs in parallel so they would function with the chassis as well as with the KVM. To do this simply get some male-to-male jumper wires. On one end plug into the chassis wire, and on the other plug into the corresponding positive and negative slots right next to the ones going to the pi.

Cable management nightmare. But it works XD
Finished product

Broadboard pinout: https://github.com/pikvm/pikvm/blob/master/img/v2.png

USB split cable diagram: https://github.com/pikvm/pikvm/blob/master/img/v2_splitter.png

Parts list:

Raspberry Pi 4B 2GB edition: https://www.amazon.com/gp/product/B07TD42S27/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Raspberry Pi 4 headsink pack: https://www.amazon.com/gp/product/B07ZLZRDXZ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Raspberry Pi HDMI in Module: https://www.amazon.com/gp/product/B0899L6ZXZ/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

16GB Micro SD card: https://www.amazon.com/gp/product/B073K14CVB/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1

1 foot HDMI cable: https://www.amazon.com/gp/product/B00DI88XEG/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Breadboard 3 pack: https://www.amazon.com/gp/product/B077DN2PS1/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1

Breadboard Jumper Wires: https://www.amazon.com/gp/product/B07GD2BWPY/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Resistor Assortment Kit: https://www.amazon.com/gp/product/B0792M83JH/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

390 OHM resistors: https://www.amazon.com/gp/product/B07QK9NFGT/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1

SSR relays: https://www.digikey.com/product-detail/en/G3VM-61A1/Z2100-ND/673290

Install Guacamole 0.9.8 in CentOS 7

Lately I’ve embarked in installing the latest version of Guacamole, 0.9.8, in a fresh installation of CentOS 7. Kudos go to the excellent guide I found from here. ¬†Derek’s guide is for 0.9.7 but it also works for 0.9.8. I ran into a few hangups but after I figured them out it worked beautifully.

First, fetch the needed binaries:

rpm -Uvh http://mirror.metrocast.net/fedora/epel/7/x86_64/e/epel-release-7-5.noarch.rpm   # EPEL Repo
yum -y install wget   # wget
wget http://download.opensuse.org/repositories/home:/felfert/Fedora_19/home:felfert.repo && mv home\:felfert.repo /etc/yum.repos.d/   # Felfert Repo
yum -y install tomcat libvncserver freerdp libvorbis libguac libguac-client-vnc libguac-client-rdp libguac-client-ssh
yum -y install cairo-devel pango-devel libvorbis-devel openssl-devel gcc pulseaudio-libs-devel libvncserver-devel terminus-fonts \
freerdp-devel uuid-devel libssh2-devel libtelnet libtelnet-devel tomcat-webapps tomcat-admin-webapps java-1.7.0-openjdk.x86_64

Next, install guac server (the latest as of this writing is 0.9.8)

mkdir ~/guacamole && cd ~/
wget http://sourceforge.net/projects/guacamole/files/current/source/guacamole-server-0.9.8.tar.gz
tar -xzf guacamole-server-0.9.8.tar.gz && cd guacamole-server-0.9.8
./configure --with-init-dir=/etc/init.d
make install

I received an error while running ./configure :

checking for jpeg_start_compress in -ljpeg... no
configure: error: "libjpeg is required for writing jpeg messages"

It means I didn’t have libjpeg dev libraries installed. Easily fixed:

yum install libjpeg-turbo-devel

Next, install the guacamole war files

mkdir -p /var/lib/guacamole && cd /var/lib/guacamole/
 wget http://sourceforge.net/projects/guacamole/files/current/binary/guacamole-0.9.8.war -O guacamole.war
 ln -s /var/lib/guacamole/guacamole.war /var/lib/tomcat/webapps/
 rm -rf /usr/lib64/freerdp/guacdr.so
 ln -s /usr/local/lib/freerdp/guacdr.so /usr/lib64/freerdp/

Next comes configuring the database

#Install database and connector
yum -y install mariadb mariadb-server
 mkdir -p ~/guacamole/sqlauth && cd ~/guacamole/sqlauth
 wget http://sourceforge.net/projects/guacamole/files/current/extensions/guacamole-auth-jdbc-0.9.8.tar.gz
 tar -zxf guacamole-auth-jdbc-0.9.8.tar.gz
 wget http://dev.mysql.com/get/Downloads/Connector/j/mysql-connector-java-5.1.32.tar.gz
 tar -zxf mysql-connector-java-5.1.32.tar.gz
 mkdir -p /usr/share/tomcat/.guacamole/{extensions,lib}
 mv guacamole-auth-jdbc-0.9.8/mysql/guacamole-auth-jdbc-mysql-0.9.8.jar /usr/share/tomcat/.guacamole/extensions/
 mv mysql-connector-java-5.1.32/mysql-connector-java-5.1.32-bin.jar /usr/share/tomcat/.guacamole/lib/
 systemctl restart mariadb.service

#Configure database
mysqladmin -u root password MySQLRootPass
mysql -u root -p   # Enter above password
create database guacdb;
create user 'guacuser'@'localhost' identified by 'guacDBpass';
grant select,insert,update,delete on guacdb.* to 'guacuser'@'localhost';
flush privileges;
cd ~/guacamole/sqlauth/guacamole-auth-jdbc-0.9.8/mysql/schema/
cat ./*.sql | mysql -u root -p guacdb   # Enter SQL root password set above

Now we need to configure guacamole to use our new database.

mkdir -p /etc/guacamole/ && vi /etc/guacamole/guacamole.properties
# MySQL properties
mysql-hostname: localhost
mysql-port: 3306
mysql-database: guacdb
mysql-username: guacuser
mysql-password: guacDBpass

# Additional settings
mysql-disallow-duplicate-connections: false

Link the file you just made to the tomcat configuration directory

ln -s /etc/guacamole/guacamole.properties /usr/share/tomcat/.guacamole/

Cleanup temporary files and enable necessary services on boot

cd ~ && rm -rf guacamole*
systemctl enable tomcat.service && systemctl enable mariadb.service && chkconfig guacd on
systemctl reboot

Lastly, open the firewall up for port 8080 (thanks stack overflow)

firewall-cmd --permanent --add-port=8080/tcp
firewall-cmd --reload

Navigate to guacamole in your browser: http://<IP address>/guacamole:8080. You should see the guacamole login screen.

Additional hiccup

This new version of guacamole has a different user interface. It took me longer than I’d like to admit to realize how to get out of a guacamole session once it’s started. Sessions are now full screen with no obvious way to exit.

The way to exit the full screen guacamole session is to press the magic key combination of ctrl, alt, and shift. It will reveal a menu from the side. This is all clearly defined in the user documentation, but my lack of willingness to read it caused me to waste much time. Lesson learned!