Sometimes you need to export multiple instances of the same service with a specific IP using same port outside of a docker swarm environment. Using docker swarm environment is easy to have several instances of the same service exporting some API on the same port. The swarm will take care of load balancing the services… Read More »
When running a Websphere Application server instance in a docker container, if the Service Integration Bus (SIB) is defined to store all the messages and data in an external database there is an issue caused by the way the bus is created. When the SIB is initialized the given name depends on the hostname of… Read More »
My setup implies that I have 3 almost identical application nodes (running as containers) that are part of a cluster and they need to be mapped to different external IPs (not part of the docker ingress network) because they are added in a cluster configuration external to docker. The default behavior of port binding is… Read More »
Lately after one of the updates of docker binaries I started to have a strange issue in a Docker Swarm setup configured here. Services were no longer able to see each other if they were running on different nodes. If two services were running on the same swarm node there was no issue. This is… Read More »
CASE 1: If you use multi-stage docker builds you will end up with lots of un-tagged images. The proper way to clean the intermediary leftover images is: docker rmi $(docker images -f “dangling=true” -q) CASE 2: If you want to clean up all the old images for which you no longer have any instantiated container… Read More »
As I discussed in post Portable #Docker #Swarm made of #RaspberryPI – Updated hardware there were several hardware updates done to the swarm. One of the updates was adding a switch and connecting all the Raspberry PIs to the switch. First version of the Docker Swarm was done using the wifi connections of the PIs.… Read More »
I wanted to update my hardware setup for the Docker Swarm cluster from post Portable #Docker #Swarm made of #RaspberryPI. The idea was to make it more portable, more reliable and a bit faster. The following steps were done: Add ethernet support The original setup used a small Edimax router with the Raspberry Pi nodes… Read More »
This is the new cool thing to build at home. A small cluster made of Raspberry PIs. Hardware setup of the cluster ITEM 1: Raspberry Pi 3 Model B I went for a set of 5 PIs because of the greater flexibility when you get more machines. I hope to be able to test several… Read More »
When running complex environments on Docker on Linux again we face the mighty selinux. There are plenty of selinux alerts generated when I start my environment when the host machines have selinux enabled and volumes are used by the containers. Setting selinux permissions is hard and tedious and many people just prefer to disable it.… Read More »
There are some hidden dependencies of running oracle database in a docker container under Fedora/CentOS/RedHat Linux. STEP 1: Kernel parameters Because the Oracle engine from the Docker container uses in fact the kernel of the host machine we cannot escape the need to set up some kernel parameters on the host. On the host machine… Read More »