Map Subdomains to Docker Containers with Synology

Posted by in IT, Tutorial

The other day I got fed up with having to insert diskstation.local:12345 to point towards an installed service on my NAS. I also thought that my SO has difficulties remembering all the ports (I do too) and cleaning up the browser cache doesn’t help either. So, I thought: Wouldn’t it be nicer if instead of disksation.local:32400 I could just type plex.laurii.lan? Yes! Yes, it would! :) So I started my quest to make things happen. Use case My se case is the following: As a local user, I want to…read more

Build a Django Docker Image with Cx-Oracle

Posted by in Software, Tutorial

TL;DR: Don’t use alpine images. There’s a glibc issue. We added a cx-oracle dependency to one of our django apps. As the previous image was just an alpine basic (python) image we needed to put in place a process to build the new image. Initially, I’ve tried to use the same alpine image (oh, the slimmed down size is sooo tempting), but then I’ve hit a bunch of “Unknown symbol” messages when I’ve ran the install of cx-oracle in the docker build process. Subsequently, I’ve had to switch to python:3.6-slim-jessie….read more

Monitor Docker Logs with ELK – 1

Posted by in IT, Tutorial

Following my attempts to monitor ethOS data via ElasticSearch and Kibana, I’ve thought it would be a good idea to start monitoring the logs produced by my various docker instances. This first part deals with configuring ELK and logspout. Prerequisites I assume the following: ELK is installed. You can do it either as a set of Docker images (oh, the meta!) or just plain package install. The receiver machine is configured. E.g., if you’re on windows, create a firewall rule opening TCP port 35000 (corresponding to the config). Once this…read more

Docker Exec Path-based Commands

Posted by in IT, Tutorial

TL;DR: Use sh -c “command with arguments” I’ve tried to execute

in order to see the size used by a container’s logs. Unfortunately, this resulted in an error along the lines: du: C:/Program Files/Git: No such file or directory This means that my git bash prompt interpreted the / itself. In order to get around this limitation, you need to run:

HTH, A little experiment: If you find this post and ad below useful, please check the ad out :-)

Fix *standard_init_linux.go:XXX: exec user process caused “no such file or directory”* Error

Posted by in IT, Tutorial

TL;DR: Use dos2unix While switching from Ubuntu to Alpine images, I’ve encountered the fillowing error: standard_init_linux.go:195: exec user process caused “no such file or directory” Quite unfortunate, because the script stayed in the same spot and only the image changed. After reading a bunch, I figured that it’s the fact that I’m editing on Windows and Alpine doesn’t seem to interpret #/bin/sh properly – adding a ^M :). The solution is to either fix the script locally or to format it as part of the docker build process. I chose…read more

HTTP 400 Bad Request with docker-maven-plugin

Posted by in IT

TL;DR: Check your Dockerfile (try to build it manually) before anything else! Today I was struggling with a 400 error: Exception caught: Request error: POST 400: HTTP 400 Bad Request -> [Help 1] when building an image with the docker-maven-plugin. After installing and uninstalling docker, cleaning up certificates etc, I figured out my setup had nothing to do with it. Instead, there was a configuration error or the docker file. More specific, I was using alpine and I forgot the RUN prefix to a command. I’ve tried to dun…read more

Initialise Python with GoCD

Posted by in IT, Tutorial

Following the deployment of a python-aware agent, we can start creating a pipeline. The first stage would be to: Clean up any previous data Create a virtual environment for python Install all dependencies from a requirements.txt file in our project Note: we assume the global pipeline settings and the Materials are properly set up (e.g. out project will be checked out in ./project). Since the above operations must be executed in order, I’ve set up a Setup stage with a job named virtualenv. The job has three tasks: rm virtualenv…read more

Create a Python-friendly GoCD Agent in Docker

Posted by in IT, Tutorial

I’ve got two requirements to make GoCD useful: Run both the server and agent(s) in Docker Make it python-friendly Fortunately, GoCD offers Docker images (and Dockerfiles) for both, so it’s just a matter of extending it:

Unfortunately, pip is not quite adequate, so we re-install it from source. In the Dockerfile we add:

Now we have a fully functional Docker file capable of building python applications and we can actually build the image. In the directory where we have the Dockerfile, execute:

Then, you can run it…read more

Allow Docker Container Access Behind Proxy

Posted by in IT, Tutorial

In the previous post, I’ve described how to build an image when you’re behind a proxy. Now, if your container needs access to the internet for e.g. downloading python dependencies, you’ll need to give it explicitly. The way to do it is via -e parameter (environment) of docker run. You can either make it verbose, or you can build an alias:

Then, you can just execute:

HTH, A little experiment: If you find this post and ad below useful, please check the ad out :-)

Use Docker Behind Proxy on Windows 8

Posted by in Software, Tutorial

The other day I had to install Docker at work, aka behind a corporate proxy (on Windows 8). While the docker installer is stand-alone and all is good, dealing with the VM is a different matter… The problem popped up when I tried to create a Django image and pip install failed miserably. To get around, you need to create a docker machine:

You also need to pass in the proxy as a build argument to build:

You can also pass the build argument to docker-compose but, in…read more