Machines availability on specific period of time

CliveWatson Could I please get some assistance as I have been trying to get the availability report for our Azure VMs uptime by selecting the data range as from 1st of July to 31st July and using the query below as per your advice but not getting the accurate available number of hours. Some of our VMs have been up 100% of time throughout the month but when running this query, the total available hours and availability rate is coming as incorrect :

let start_time=startofday(datetime("2023-07-01 00:00:00 AM"));
let end_time=endofday(datetime("2023-07-31 11:59:59 PM"));
Heartbeat
| where TimeGenerated > start_time and TimeGenerated < end_time
| summarize heartbeat_per_hour=count() by bin_at(TimeGenerated, 1h, start_time), Computer
| extend available_per_hour=iff(heartbeat_per_hour>0, true, false)
| summarize total_available_hours=countif(available_per_hour==true) by Computer
| extend total_number_of_buckets=round((end_time-start_time)/1h)
| extend availability_rate=total_available_hours*100/total_number_of_buckets

We get the output as below, can I please get some advice if we need to change something to get the correct output:

Hi CliveWatson ,

Amazing, I just adapted to my case and it looks perfectly!

let end_time=(startofmonth(now()) - 1ms);
let start_time=startofmonth(end_time);
Heartbeat
//| where TimeGenerated > start_time and TimeGenerated < end_time
| where TimeGenerated between ( startofmonth(now(),-1).. endofmonth(now(),-1) )
| where Computer contains "TEST"
// find 4th week which is week "3"
| extend maintSaturday_ = endofweek(startofmonth(now(),-1),3) -1d, maintSunday_ = endofweek(startofmonth(now(),-1),3) + 1d
// exclude 4th week from data set
| where  TimeGenerated  !between ( maintSaturday_ .. maintSunday_ )
| summarize heartbeat_per_hour=count() by bin_at(TimeGenerated, 1h, start_time), Computer
| extend available_per_hour=iff(heartbeat_per_hour>0, true, false)
| summarize total_available_hours=countif(available_per_hour==true) by tostring(split(Computer, ".")[0]), bin(TimeGenerated, 1d) 
| extend total_number_of_buckets=round((end_time-start_time)/1h)
| extend availability_rate=total_available_hours*100/total_number_of_buckets
| order by availability_rate desc
| render timechart 

However, could you please just help with the last thing. Why the chart/table starts with December 13 in this case but not December 1st? 

Thank you! 

Hello CliveWatson,

Amazing, Thank you 

I adapted to my case and it looks great!

let end_time=(startofmonth(now()) - 1ms);
let start_time=startofmonth(end_time);
Heartbeat
//| where TimeGenerated > start_time and TimeGenerated < end_time
| where TimeGenerated between ( startofmonth(now(),-1).. endofmonth(now(),-1) )
| where Computer contains "TEST"
// find 4th week which is week "3"
| extend maintSaturday_ = endofweek(startofmonth(now(),-1),3) -1d, maintSunday_ = endofweek(startofmonth(now(),-1),3) + 1d
// exclude 4th week from data set
| where  TimeGenerated  !between ( maintSaturday_ .. maintSunday_ )
| summarize heartbeat_per_hour=count() by bin_at(TimeGenerated, 1h, start_time), Computer
| extend available_per_hour=iff(heartbeat_per_hour>0, true, false)
| summarize total_available_hours=countif(available_per_hour==true) by Computer, bin(TimeGenerated, 1d) 
| extend total_number_of_buckets=round((end_time-start_time)/1h)
| extend availability_rate=total_available_hours*100/total_number_of_buckets
| order by availability_rate desc
| render timechart let end_time=(startofmonth(now()) - 1ms);
let start_time=startofmonth(end_time);
Heartbeat
//| where TimeGenerated > start_time and TimeGenerated < end_time
| where TimeGenerated between ( startofmonth(now(),-1).. endofmonth(now(),-1) )
| where Computer contains "TEST"
// find 4th week which is week "3"
| extend maintSaturday_ = endofweek(startofmonth(now(),-1),3) -1d, maintSunday_ = endofweek(startofmonth(now(),-1),3) + 1d
// exclude 4th week from data set
| where  TimeGenerated  !between ( maintSaturday_ .. maintSunday_ )
| summarize heartbeat_per_hour=count() by bin_at(TimeGenerated, 1h, start_time), Computer
| extend available_per_hour=iff(heartbeat_per_hour>0, true, false)
| summarize total_available_hours=countif(available_per_hour==true) by Computer, bin(TimeGenerated, 1d) 
| extend total_number_of_buckets=round((end_time-start_time)/1h)
| extend availability_rate=total_available_hours*100/total_number_of_buckets
| order by availability_rate desc
| render timechart 

However, could you maybe just help with one thing, why the start date is not the December 1st in this case, but December 13? And is there a way to sum all days instead of having availability rate/row for each day?

Thanks again!