Setting memory limit for whole container requires cgroups support and can be used only with Docker Compose services mode. Usually we run just only single process in each container, so limiting memory on single process should be equivalent to limiting whole containers usage.

If you want to run docker-compose up you have only ulimits available to you. Other options like ‘mem_limit’ or ‘deploy’ options are not supported in that mode.

Fortunately, Docker does not limit option names you can put in ulimits section in docker-compose.yaml file (see here basically any option will be translated into corresponding setrlimit call)

This allows usage of RLIMIT_AS option.

Putting following in your docker-compose.yaml file will effectively limit memory usage of each process in container.

  ulimits:
    as:
      soft: 1300000000
      hard: 1300000000

Size is specified in bytes. Other settigns (RSS, DATA, STACK) do not let you effectively limit process memory usage.

Bad part is that this is not visible through normal Linux kernel procfs and you cannot check it in run-time.

What causes most pain for me, that this is NOT DOCUMENTED anywhere in Docker documentation at all.

Additional info on checking resource usage on processes/groups.

/proc/NNN/status shows single process’es status and memory usage
/proc/NNN/limits shows single process limits (but does not show Address space )

to get PID from docker you can run:
docker ps and note container ID, then run docker top ID8a718a717 and note process ID from there.

You can look up current cgroup settings under /sys/fs/cgroup/*/docker/containerID/

Memory settings, for example, are located under /sys/fs/cgroup/memory/docker/containerID/memory.stat .

• Code not running in production is not ‘production quality’ code. Even if you tested it thoroughly, it does mean nothing until it runs in production.
• Commit to releasing small pieces of code – a few dozen lines at once, not a huge commits.
• Monitor system behavior after each release – you’ll notice problems occurring fast and correlate it to specific release. The small is the release – the easier is reviewing it.

Read here.  (5 minute read)

How to improve performance in the teams. If your work depends on your colleague input there are good chances that you will spend time waiting for it. Choosing prices of work so that they will be loosely dependent on each other is important to keep development at full speed. Read here. (3 min)

Below is also research about Google’s code base in a single repository. It sounds as a strange idea until you realize it has advantages of letting people be less dependent on each others’ input. Everything is visible, re-usable and you can make changes for any code and it’s dependencies by yourself.

Main take-aways:

• Simplified organization
• Simplified dependency management
• Tooling is more simple
• Cross-project changes are easier

Read deeper overview  (2 min) and the original article (10 min).

Turns our it happens only when your host machine hibernated or suspended while Vagrant VM was running. And that also should co-oncide with Ubuntu’s systemd missing some dbus event.

You can notice that after such failed restore your network is also missing and you need to restart it manually.

The solution?

Easy – suspend and wake up your host once again and VMs will be in a running state automatically.

Here is more discussion.

This work around worked for me

1. disable monitor which you do NOT want to be used
2. start game in full screen mode and let window manager/wine/whatever remember it’s position
3. enable second monitor back
4. fix display positions

Visual way

On Ubuntu just go to ‘System configuration’/’Displays’, display your monitor you do not want game to use and then run game. After it remembers settings, turn monitor on back again.

Command line way

Some people like it hard way, so here is how to do it from command line.

Step 1

To find our which monitors do you have just run xrandr command

Screen 0: minimum 320 x 200, current 3520 x 1080, maximum 8192 x 8192
LVDS connected primary 1600×900+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1600×900 60.1*+
….
HDMI-0 disconnected (normal left inverted right x axis y axis)
VGA-0 connected 1920×1080+1600+0 (normal left inverted right x axis y axis) 510mm x 290mm
1920×1080 60.0*+
….

You are interested to find display names – they are in bold.

Then issue following command to turn off the monitor

xrandr –output VGA-0 –off

Step 2

Run game as usual in fullscreen mode.

Step 3

Turn monitors back and assign primary/secondary roles

xrandr –output VGA-0 –noprimary –auto
xrandr –output LVDS –primary

–auto argument tells xrandr to fidn mode suitable for monitor best and turn it on.

Step 4

You may need to run ‘System configuration’/’Display’ control panel to fix display mirroring/position.

Afterwards the game should start on correct display.

Docker get integrated with Google Cloud and allows you to push and pull images to private repositories. But there is no easily found, documented way to list images that you have in a project in Google Cloud and what tags you have for each image.

You can see that information from Google Console, but there is no build-in docker command to do that.

Fetching image information from Google Container Registry

You need to have gcloud installed and authenticated.

Replace

• ZONE – with zone where your images are hosted (eu, us, asia)
• PROJECT_NAME – name of your project
• IMAGE_NAME – name of the docker image you want to explore

Getting list of images from GCR

curl -u “oauth2accesstoken:`gcloud auth print-access-token`” https://ZONE.gcr.io/v2/PROJECT_NAME/tags/list | json child | json -a

Getting list of tags for specific image from GCR

curl -u “oauth2accesstoken:`gcloud auth print-access-token`” https://ZONE.gcr.io/v2/PROJECT_NAME/IMAGE_NAME/tags/list | json tags | json -a

You will need to install utility json beforehand

npm install -g json

I finally feel free to say that I’m interested and involved in so much different domains. It includes programming and IT, which I love and continue my involvment in. It includes design and art – I was painting for some time and now I’m more into product design – we launched leather goods ‘Smiles Bags‘ company  with my wife and I design products and also doing a lot of designs for our brand. It includes psychology and people communication – which I will cover in this blog more deeply. This list is anywhere far from complete, so it will grow over the time

Sometimes 32-bit windows programs (under wine) which use OpenGL stop working giving criptic error messages.

The problem is that they lost correct 32-bit Mesa driver. Following commands fix the problem:

rm /usr/lib/i386-linux-gnu/mesa/libGL.so.1
ln -s /usr/lib32/fglrx/libGL.so.1 /usr/lib/i386-linux-gnu/mesa/libGL.so.1

it’s may be because Dropbox or DejaDup (called ‘Backup’ in Ubuntu) are doing a lot of raeding from a drive.

This two commands solve all the issues, making both programs run with as low priority as possible.

Making Dropbox friendly (especially if you have over million files in your Dropbox folder):

ionice -c 3 -p `pgrep dropbox`
renice 20 `pgrep dropbox`

Making DejaDup/duplicity  friendly

renice 20 `pgrep duplicity` `pgrep deja-dup`
ionice -c idle -p `pgrep duplicity`
ionice -c idle -p `pgrep deja-dup`

Have fun! and fast working computer