Take AWS ec2 volume instance snapshot

This post is just related to how can you take snapshot/backup of your AWS  ec2 instance's volume using boto.

Two method is their:- (which we can use)

1. Cron Method

2. Check time difference between last snapshot creation time and current time.

1. Cron method:- Two cron method (C1 ,C2 two cron)

                    i)C1 runs every hour, 5th minute

                       Picks up the current hour, say CHOUR

                       Pick up volumes defined with backup in hours(2_hour,4_hour ... etc) 

                       Take 2,4 as frequency accordingly

                       if(CHOUR%freq)==0 Take snapshot

                     ii)C2 runs every day, 12th hour

                       Pick up the current day, say CDAY

                       Pick up volumes defined with backup in days(1_day,7_day ... etc)

                       Take 1,7 as frequency accordingly

                       if(CDAY%freq)==0 Take snapshot

Pseudo Code:-   

       i) Make connection with aws.

       
          connection = boto.ec2.connect_to_region('Region_Name',                                aws_access_key_id='aws_access_key_id',aws_secret_access_key='aws_secret_access_key')

      ii)  a)   Take command line argument which type cron is this (backup_type = "day/hour")

            b)  Get all machine/instance which has same backup type as you passed in command line argument. 

            c)  Take snapshot those instances.  It's simple :)

2.   Check time difference between last snapshot creation time and current time method:-

      One cron can take back up for any type of back up freq.

       

      i) We have to check first that machine has any already any back up/ snapshot or not. If it has not simple take sanpshot that machine.

         other wise get all snapshot of that machine and sort them according to time creation. 

       eg:- 

           snapshots = conn.get_all_snapshots(filters={'volume_id':volume.id})//filter via volume id. or                                                                  //can also check boto documentation 

         
           snap_sort = sorted([(s.id,s.start_time) for s in snapshots] , key =lambda k :k[1])

         
           index = len(snap_sorted) - 1 // get the index of latest create snapshot

         
          snap = snap_sorted[index]   //snapshot value.

          

      Now just check time difference between last create snapshot and current time.

       eg:- 

             snapshotTimeDiff = (datetime.utcnow() - datetime.strptime(snap[1], "%Y-%m-%dT%H:%M:%S.000Z")).total_seconds()

   
      Now compare this with  backup freq for that instance.

             if  snapshotTimeDiff  >=  freqOfCreatingSnapshotInSecond:

                   (Take snapshot of this instance volume.)

Note:- 

       we have a machine config file where we mention every thing about ec2 instance.

       e.g:-  machine_configure.py

                "Instance_Name" : {

                    "backup_freq":"4_hour", "retention": "30_day",

                   "Environment" : "Dev",

                    "monitoring" : "basic",

                   "volume_override" : { // machine can have multiple volume and we want some volume back up freq diff from default so we choose this override 

      "volumne_id" : { "backup_freq":"4_hour", "retention": "7_day"},

      "volume_id" : { "backup_freq":"4_hour", "retention": "2_day"},

      "volume_id" : { "backup_freq":"1_day", "retention": "2_day"},

               }

Happy Coding :) 

Feel free to ask me to anything . It's My first blog.

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