Open Sourcerers
Amazon’s Alexa enabled devices, such as the Echo, Dot and most recently Tap provide a hands-free voice controlled environment, to make calls, send and receive messages, provide information and more — instantly. Alexa is the cloud-based voice service that powers this category of devices. All the user has to do is ask Alexa to perform […]
Introduction For mobile users who require tasks, information or status updates asynchronously without requiring to explicitly request it, by for example pressing a refresh button, Red Hat MAP provides a very useful built in MBaaS service for this purpose – the Sync framework. This framework makes it possible to keep a mobile app in sync […]
OpenShift 3.3 and later contain the functionality to route pod traffic to the external world via a well-defined IP address. This is useful for example if your external services are protected using a firewall and you do not want to open the firewall to all cluster nodes. The way it works is that a egress […]
In the OpenShift world, Services take place on the OSI Layer 3 / IP, while Routing is an OSI Layer 7 / HTTP/TLS concept. Once you’ve wrapped your head around this backwards choice of naming, things are fairly easy: An OpenShift Router is a component which listens on a physical host’s HTTP/S ports for incoming […]
To allow stable endpoints in an environment of ever changing starting and stopping Pods (and therefore constantly changing IP addresses), Kubernetes introduces (and OpenShift uses) the concept of services. Services are stable IP addresses (taken per default from the 172.30.0.0/16 subnet) that remain the same as long as the service exists. Connection requests to a […]
So far, this sounds like a lot of effort to achieve a little more than a plain docker host – containers that can talk to each other and to the host network, potentially segregated based on kubernetes namespace. However OpenShift SDN also allows pods on different nodes to communicate with each other. To this end, […]
Abstract Many organisations are now facing a challenge when it comes to choosing and setting up the right messaging infrastructure. It must be able to scale and handle massive parallel connections. This challenge often emerges with IoT & Big Data projects where a massive number of sensors are potentially connected to produce messages that need to […]
In OpenShift, networking is equally simple from a container point of view. Within the container’s namespace there is a eth0 network interface configured and services such as DNS just work. You can still use dedicated NICs on the host to isolate specific types of traffic. What’s the difference? It turns out there is hardly any […]
From a container point of view, networking on a plain Docker Host is simple. A running container is nothing more than a Linux process which is namespaced and constrained with regards to access (SELinux) and resource consumption (cgroups). In each namespace, there is a single (virtual) network interface called eth0 which is assigned an IP […]
If you are debugging IPTables, it is handy to be able to trace the packets while it traverses the various chains. I was trying to find out why port forwarding from the external NIC to a virtual machine attached to a virtual bridge device was not working. You need to perform the following preparations: Load […]