1. Auto scale DynamoDB
with
Dynamic DynamoDB
Sebastian Dahlgren!
@sebdah

2. Project overview
Throughput metrics via CloudWatch
Supports auto scaling of
tables & global secondary indexes
Live for about a year
>10.000 monthly downloads
Open source

3. Background
Auto scaling is important!
- Saves money
- Saves your skin
No auto scaling in DynamoDB

4. Basic config example

5. Configuration
• [global]
o AWS credentials
o Check interval
o Circuit breaker
• [logging]
o Logging settings
o Supports external logging config
• [table:
my_table]
o Rules for scaling a certain table
o Maintenance windows
• [gsi:
my_gsi
table:
my_table]
o Rules for scaling Global Secondary Indexes

6. Handling many tables or
dynamic table names
• Table list refreshed for every iteration
o Addition of new tables
o Removal of old tables
• Use regular expressions in your configuration
[table:
^daily_data.*$]

7. Scaling down
• DynamoDB limits down scaling to 4 times per UTC
day
• Optimize downscaling by using
o reads-­‐lower-­‐threshold
o writes-­‐lower-­‐threshold
o always-­‐decrease-­‐rw-­‐together
o maintenance-­‐windows

8. SNS notifications
• Get an email when your
provisioning is updated
• Currently supports:
o scale-up
o scale-down

9. Circuit breaker
• Dynamic DynamoDB
can poll an URL to
check system health
• All scaling is paused if
the URL does not
return HTTP 200
OK

10. CloudFormation template
• Launches a t1.micro
instance
(<$15/mo)
• Auto Scaling Group
min: 1, max: 1
• Running Dynamic
DynamoDB in daemon
mode
• Configuration on S3

11. Tadaa
Image publishing service

12. Thank you!
sebdah / dynamic-dynamodb