mingbo's tech tips

Graphite will align timestamp based on the retention defined in storage-schemas.conf,  whenever you send a metric to Graphite, Graphite will align timestamp like this: timestamp  - (timestamp % interval) so for example, let's say you have 1 minute interval (time per point), or  60  seconds for one of your metrics, then you send: my.useful.metric 2022 1414516239 Graphite will save (timestamp aligned): my.useful.metric 2022 1414516200 because 1414516239 - 1414516239 % 60 = 1414516200 and if you send multiple values with same timestamp, or you send multiple values then all of them  are within defined interval ----- that is: (timestamp  - (timestamp % interval)) has same value. the last one wins . Graphite will only save last value ( with exceptions, see detail in last part of this post ). So back to previous example, if you send in below order (doesn't matter when you actually send them, with  exceptions ): my.useful.metric 322   1414516229  my.useful.metric 52

It's difficult to find out who's using the security group if you looked at wrong place. Here's how to find out dependent objects: 1. Search group name or group ID at "Network Interfaces" under EC2 Management Console. This will give you all direct usage from instances including EC2, RDS, RedShift .... 2. find out dependencies between/among security groups by using this small program:   https://github.com/mingbowan/sgdeps you will get something like: python sgdeps.py --region us-east-1 mingbotest-A sg-b4566ad1 (mingbotest-A) |-- sg-9b566afe (mingbotest-C2) |-- sg-9f566afa (mingbotest-C1) |  |-- sg-69576b0c (mingbotest-D2) |  |  `-- sg-b4566ad1 (mingbotest-A) ** loop |  `-- sg-64576b01 (mingbotest-D1) |     `-- sg-9b566afe (mingbotest-C2) |-- sg-8b566aee (mingbotest-B2) `-- sg-86566ae3 (mingbotest-B1) then delete dependent rules/groups.