Containerization

ASAB is designed for deployment into containers such as LXC/LXD or Docker. ASAB allows you to build microservices that provide REST APIs or consume MQ messages while being deployed into a container for the sake of the infrastructure flexibility.

Running ASAB in a LXC/LXD container

1. Prepare LXC/LXD container based on Alpine Linux

   lxc launch images:alpine/3.10 asab
   

2. Swich into a container

   lxc exec asab -- /bin/ash
   

3. Prepare Python3 environment

   apk update
   apk upgrade
   apk add --no-cache python3
   
   python3 -m ensurepip
   

4. Deploy ASAB

   apk add --virtual .buildenv python3-dev gcc musl-dev git
   pip3 install git+https://github.com/TeskaLabs/asab
   apk del .buildenv
   

5. Deploy dependencies

   pip3 install python-daemon
   

6. Use OpenRC to automatically start/stop ASAB application

   vi /etc/init.d/asab-app
   

   Adjust the example of OpenRC init file.

   chmod a+x /etc/init.d/asab-app
   rc-update add asab-app
   

   Note

   If you need to install Python packages that require compilation using C compiler, you have to add following dependencies:

   apk add --virtual .buildenv python3-dev
   apk add --virtual .buildenv gcc
   apk add --virtual .buildenv musl-dev
   

   And removal of the build tools after pip install:

   apk del .buildenv
   

Docker Remote API

In order for ASAB applications to read the Docker container name as well as other information related to the container to be used in logs, metrics, and other analysis, the Docker Remote API must be enabled. To enable the Docker Remote API:

1. Open the Docker service file:

   vi /lib/systemd/system/docker.service
   

2. Find the line which starts with ExecStart and add -H=tcp://0.0.0.0:2375.

3. Save the file.

4. Reload the Docker daemon and restart the Docker service:

   sudo systemctl daemon-reload && sudo service docker restart
   

   Then in the ASAB application's configuration, provide the Docker Socket path in docker_socket configuration option:

   [general]
   docker_socket=<YOUR_DOCKER_SOCKET_FILE>
   

Thus, the metric service as well as log manager can use the container name as hostname instead of container ID, which provides better readability when analyzing the logs and metrics, typically when using InfluxDB and Grafana.