Abstract

1. Always backup configuration or data before update it (or use git like tools manage data version)
2. Seperate operations into five steps:
   1. backup
   2. pre-test
   3. update
   4. post-test
   5. rollback or finished

Introduction

Basic

Rules:

1. Every Operation must has RollBack Operation
2. All ops done success or no ops done

Transaction Ops Rule:

1. Stages
   1. Backup Stage
      • backup current system state
      • GoTo Next if Success
      • Exit if it fails
   2. PreTest Stage
      • in order to generate test rule
      • make sure system working before apply operation
      • GoTo Next if Success
      • Exit if it fails
   3. Operate Stage
      • do the operation that we want to do
      • GoTo Next if Success
      • GoTo RollBack Stage if it fails
   4. PostTest Stage
      • apply custom-built test rule
      • apply test rule generate in PreTest Stage
      • GoTo RollBack Stage if it fails
   5. RollBack Stage
      • only exec while Failed PostTest Stage
      • apply Backup Stage to rollback system
2. Use Transaction Ops Framework

Example - Update Network Route

#!/bin/bash

set -u

# notify
notify(){
    # do notify
}

# 1. backup network route
backup_route(){
    # do something
}
# 2. generate test-case
generate_testcase(){
    # do something
    # nameserver in /etc/hosts
    # other connection via "contrack" or "ss" command
}
# 3. update network route
update_route(){
    # do something
}
# 4. apply test-case
apply_testcase(){
    # do something
}
# 5. rollback network route
rollback_route(){
    # do something
}

# main
main(){
    backup_route \
        && generate_testcase \
        && update_route \
        && (apply_testcase || rollback_route)
    if [ $? -ne 0 ]
    then
        notify
    fi
}

main