macOS and the X Window System If you want to use the X Window System on macOS, you need XQuartz. Install XQuartz brew cask install xquartz After a Reboot you will get the $DISPLAY set correctly. If you want to set it without a reboot see Start XQuartz temprorary Test with xeyes /opt/X11/bin/xeyes SSH X11Forwarding You can now use ssh -X or ssh -Y Uninstall brew cask uninstall xquartz Start XQuartz temprorary This is only necessary if you want to start XQuartz without a reboot. Read more

Fatal Error My Docker on macOS doesn’t start anymore. It shows the following At the very last line, you can see the following Error Message: no space left on device Disk full? Of course there is enough space on my local drive available, but the Docker disk image see FAQ is full. The disk image is located here ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2 With the qcow-tool you can check it: $ /Applications/Docker.app/Contents/MacOS/qcow-tool info Docker.qcow2 ((version Three) (backing_file_offset 0) (backing_file_size 0) (cluster_bits 16) (size 68719476736) (crypt_method None) (l1_size 128) (l1_table_offset ((bytes 131072) (is_mutable false) (is_compressed false))) (refcount_table_offset ((bytes 65536) (is_mutable false) (is_compressed false))) (refcount_table_clusters 1) (nb_snapshots 0) (snapshots_offset 0) (additional (((dirty true) (corrupt false) (lazy_refcounts true) (autoclear_features 0) (refcount_order 4)))) (extensions ((Feature_name_table (((ty Incompatible) (bit 0) (feature Dirty)) ((ty Incompatible) (bit 1) (feature Corrupt)) ((ty Compatible) (bit 0) (feature Lazy_refcounts))))))) Okay, looks good so far! Read more

TL;DR NetApp provides a plugin for docker for x86 platforms. With a small modification it works perfectly well on a Raspberry Pi (ARM). Intro A year ago I’ve written some articles about running docker on a cluster of Raspberry Pi. NetApp published a plugin for docker to integrate NetApp’s SolidFire, ONTAP, and E-series storage platforms. Of course this plugin is available for x86 (AMD64), but not for any other platform. Therefore I thought if it is possible to build this plugin for a Raspi (ARM). Read more

What is Caddy? From the website Caddy is an alternative web server that is easy to configure and use. and A web server that serves you Other web servers were designed for the Web, but Caddy was designed for humans, with today’s Web in mind. This wonderful piece of software is a perfect fit for my 6-Node Cluster of Raspberries! Here is an example: Caddy is super easy to install and to configure. Read more

What is Docker Swarm Mode? A swarm is a cluster of Docker engines, or nodes, where you deploy services. What is a node? A node is an instance of the Docker engine participating in the swarm. You can also think of this as a Docker node. You can run one or more nodes on a single physical computer or cloud server, but production swarm deployments typically include Docker nodes distributed across multiple physical and cloud machines. Read more