• Docker ENTRYPOINT vs CMD

  3 min read

  
  

  Docker is a popular tool for deploying and running applications in a containerized environment. One of the important features of Docker is the ability to define a command to be executed when a container is started. This command can be specified in the Dockerfile using two keyword: ENTRYPOINT and CMD.

  02/05/2023

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• AWS CLI in alpine

  1 min read

  
  

  The AWS CLI is a command line interface for interacting with AWS services. To install it in an Alpine-based container we can use pip instead of going thru all the trouble of downloading a zip and install it by running some script.

  09/02/2023

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• Container with alpine failing to execute a file with not found

  3 min read

  
  

  While building a container using alpine as a base image we can get a not found error while trying to execute a file that doesn't make much sense:

  $ docker run -it test /usr/local/bin/example-app
  exec /usr/local/bin/example-app: no such file or directory
  

  14/11/2022

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• How docker generates container's names

  2 min read

  
  

  Everytime you create a container using docker, if not already set using --name, docker chooses a name for you: you can expect two words with a underscore:

  $ docker run --rm -d alpine sleep 24h
  38c4cc4e87762fc113ef174e9a4989e13d21037678abd3fe73840b825f14c7bf
  $ docker ps
  CONTAINER ID   IMAGE                          COMMAND                  CREATED         STATUS                PORTS                    NAMES
  38c4cc4e8776   alpine                         "sleep 24h"              5 seconds ago   Up 3 seconds                                   romantic_shtern
  

  For this example it was chosen romantic_shtern, but it can use a great variety of words:

  $ docker ps --all | grep -v "Up" | awk '{ print $NF }'
  NAMES
  mystifying_poitras
  suspicious_shtern
  focused_chatelet
  keen_mendel
  happy_jackson
  xenodochial_margulis
  kind_blackburn
  gallant_pascal
  trusting_thompson
  (...)
  

  So, how does Docker generate names for it's containers?

  01/08/2022

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• Docker: Using the host's network

  2 min read

  If we use the --net=host option with docker to create a new container, it will share it's network namespace with the host machine. It's main advantage is that it will provide higher performance (it will be close to bare metal speed); however, we might get port conflicts.

  24/02/2022

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