0-downtime with Blue-Green Deployment

Info

Solution: Choose for temporary Blue and Green deployment. More detail can be found in this Custom Blue Green Deployment With Nginx And Gitlab Ci

Blue and Green deployment strategy

Nginx with bash scripting

• With the bash script is registered via cronjob, we need to consider about two things

  1. Nginx need to be setup for reverse proxy and route traffic when downtime occur
  2. Docker will have strategy about scale up and down the service for reducing down time

• With nginx configuration, it will be possible to reload a new configuration Nginx and except downtime when updating service with nginx (Service will have retries but not return 5xx Error)

• On the script, it will flexibly re-change between 2 configurations via Blue Green Deployment Docker for Zero Downtime

• Have sleep command between them, so it will change to default when the service becomes stable

Docker

With Docker strategy, it will perform some this task like

1. When have new image on container registry, it will perform pull new image on that time. Update the .env file from S3
2. After that, it will scale up the service with 2 new containers, first once for routing traffic from old to new and rename new to original version. Proxy will be return to original version for process a new job
3. This strategy will be occur quickly and carefully by having the health checking of container on each progress.
4. It will reduce downtime when applied new service into. After deploy and recreate success, that will remove both container and image of old one for reclaim resource and update new tags into location for extract for next time.

How to running this script manually

Required tools to perform this script

• This script is created for only Debian distro (Ubuntu, Kali, Raspian, Debian, …) not support for (RedHat, Centos, …). Need to consideration when installing

• Bash Script will need into some tools on below list

  • Docker: docker-compose, docker.io
  • Download Tools: curl, wget
  • JSON processing: jq

Manually run this script

• Parameter is obligated to pass for your command (Please input with right position with numeric):

  1. Name of the gitlab account (This account needs to be work with Token Generated - Token need put into ~/.credentials/gitlab) (E.x: Xeus-DevOps)
  2. Path to env file for whole container (This .env file is same as .env file provide for docker-compose) (E.x: /some_platform/.env)
  3. Path to Nginx configuration file (Nginx configuration file for reverse proxy) (E.x: /some_platform/nginx/nginx_default.conf)
  4. Optional with 2 - 3 containers (This will help optimize the resource for initialization containers, Require huge ram above 3 opt) (E.x: 2 or 3)

• Executable command (Before running this command, make sure it have rule execution enabled)

• For rule execution enabled, run command: chmod +x <your_bash_file> or chmod 0700 <your_bash_file>

• For running the command: using bash or ./<your_script>

#!/bin/bash
bash -c "<your_script> <username_gitlab> <path_env> <path_nginx_config> <containers_numberic>" # Opt 1 
./<your_script> <username_gitlab> <path_env> <path_nginx_config> <containers_numberic> # Opt 2

The contents of script can find out ▶️ ▶️ Blue Green Deployment Docker for Zero Downtime