About #docker

What happens when you only limit the maximum heap size?

#java / Nov 15, 2022 / 13 min
The JVM has spoiled us with its cleverness. It makes so many decisions behind the scenes, that lots of us gave up on looking at what’s inside. Memory-related discussions are probably more likely to appear at a conference or during a job interview than at “real” work. Of course, depending on what you work on. Java apps are often run in containers these days. Built-in container awareness makes the JVM respect various container-specific limits (e.
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DYI security audits - half a year later

#security / Jun 2, 2019 / 2 min
At the end of 2018, I had a pleasure to give a talk at Testwarez - the oldest testing-oriented conference organized in Poland. The recording recently appeared on YouTube, so I decided to take this opportunity to figure out what has changed through the past few months in terms of tools that I presented. The goal of my talk was to present some practices and open source tools for improving the overall security of Java-based projects.
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Build docker images with Jenkins running in docker

#jenkins / Jan 21, 2018 / 3 min
Building docker images within the CI pipeline isn’t something new or unusual these days. Normally it’s super easy - you just have to install Docker in your Jenkins CI environment and add jenkins user to the docker group. Problems appear when your Jenkins instance is a docker container itself. Inception begins How to make docker available inside your container? Here is a three steps solution: Install docker in your container. Expose docker socket (/var/run/docker.
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How micro should a microservice be?

#docker / Oct 20, 2016 / 3 min
Two days ago I’ve participated in a JUG meeting in Poznań which special guest was famous Java rock star Adam Bien with his presentation called Microservices in 2016 — What Worked Well. The session was focused on the typical Bien’s stack: JEE microservices & Docker and overlapped with his presentation on Devoxx Poland 2016. But don’t get me wrong - it was totally worth it! The Bien’s way One of the most controversial topics during the session was the preffered size and the granularity of microservices.
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Docker shared storage file permission problems

#docker / Sep 11, 2016 / 2 min
Case Imagine the following scenario: your world-famous web application is hosted with two Docker containers (eg. with application server). Both containers have access to same host’s directories (passed with Docker’s -v parameter) mounted as: /configuration - containing few configuration files, /logs - storing log files outside containers. Arguably, there are lots of better solutions (including databases, log indexing systems etc.) but that’s the issue we need to face now. The following user accounts are involved:
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Solving locale issues with docker containers

#docker / May 16, 2016 / 3 min
When docker kicked in to the enterprise market many things started changing. Along with microservice-based architectures it became a must-have technology for any “modern” project (the containers idea itself isn’t new - docker has just made things much simplier). In analogy to Java related slogan from 1995 “Write once, run anywhere” almost 20 years later docker enthusiasts say: “Build once, run everywhere”. In fact both ideas can coexist easily and that’s probably one of the reason they really do in practice nowadays.
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