Every time I look at the Lambda monitoring tab in the AWS Console, one of the charts drives my crazy.
AWS has good intentions behind the charts. These charts show the performance of a Lambda, a tiny split-second function. AWS does a decent job of providing monitoring charts to show you the golden signals of your service performance:
Traffic is displayed in the Invocations chart showing how many times the lambda was called Latency is displayed in the Duration chart showing how long the lambda took to execute Errors are displayed the Error count and success rate chart.
As I hear news stories about COVID-19 trends, I like to look at data to form my own opinion if the narratives are in line with the data. I often want to compare current numbers to the high-water marks for bellweather countries and states. For international COVID data visualizations, my favorite site is Financial Times’ Coronavirus Chart.
I like to see the metrics per 1M people so I can compare countries, regardless of their size.
You can pass a commit hash to checkout to quickly see a previous version of code. I like to commit often as I get new chunks of partial code working. If I advance to the point of breaking everything, it’s an easy way to see what used to work.
git checkout <commit hash>
I created a Python script to create small multiples of key COVID data from The COVID Tracking Project. It allows me to scan the state data to get a comprehensive view of key metrics.
I published the charts on my Covid Small Multiples page.
I was recently struggling with getting a CloudWatch alarm on a log filter metric to work. I was refactoring the creation from a CloudFormation template into just Lambda Python code. I was able to get both the filter metric (looking for errors and exceptions in logs) and alarm created.
But, when I tested the alarm, it never went into an alarm state, even when then metric filter showed active data. It was driving me crazy.
I always struggle trying to convert GMT time to EST or EDT especially in 24 hour format. It’s even harder when I’m staring at a log file trying to find the root cause of an issue.
I wrote this bash alias to output the last 24 hours of time in both local and GMT. I find I’m using it all of the time now. Since it’s an alias, I can easily run it from a Terminal window or within VSCode.
Here is a Cloudformation template snippet to create a CloudTrail that is used to also record data events for Lambda invocations and S3 operations in addition to the typical management events from CloudTrail.
CloudTrail: Type: AWS::CloudTrail::Trail DependsOn: - SNSTopicPolicy - S3BucketPolicy Properties: S3BucketName: Ref: S3Bucket SnsTopicName: Fn::GetAtt: - SNSTopic - TopicName IsLogging: true EnableLogFileValidation: true IncludeGlobalServiceEvents: true IsMultiRegionTrail: true EventSelectors: - DataResources: - Type: AWS::Lambda::Function Values: - arn:aws:lambda - DataResources: - Type: AWS::S3::Object Values: - "arn:aws:s3:::"
I recently tried to schedule an AWS Lambda defined through a SAM template to run every 10 minutes. I used some online cron expression builders but the syntax would not work with Cloudwatch.
Somehow, I missed this reference in the Schedule Expressions for Rules. The online expression builder puts * for both day of the month and day of the week.
You cannot use * in both the Day-of-month and Day-of-week fields.
I attended the 2019 DevOpsDays Raleigh and really enjoyed it. Here are my take-aways and highlights from my favorite talks. The live-stream video of talks are on the DevOpsDays Raleigh YouTube channel and the individual talk videos should be up by mid-November.
1. General Thoughts Don’t forget culture during your transformation Don’t focus on finding a single root cause for an incident. There’s rarely a single event.