When you update applications on ECS clusters, choosing the right deployment strategy minimizes downtime and reduces risk. Enterprise Distributed Application Service (EDAS) supports three update strategies -- at-a-time release, phased release, and canary release -- each with different tradeoffs between speed and safety. If an update introduces errors, roll back to the previous version.
Choose an update strategy
| Update strategy | When to use | How it works | Capacity during update | If something goes wrong | Available methods |
|---|---|---|---|---|---|
| At-a-time release | Few instances or simple service architecture | Deploys the new version to all instances simultaneously | All instances update in a single batch | Roll back the application to its previous version | Console, API, plug-ins or tools |
| Phased release | Many instances or complex service architecture | Deploys the new version in batches. Only a few instances update per phase until all instances run the new version | Partially reduced -- only the current batch is updating | Stop the release process and roll back the application. Fix the error, then release again | Console, API, plug-ins or tools |
| Canary release | New version requires validation before full rollout | Deploys the new version to a small number of instances first. After verification succeeds, updates all remaining instances | Mostly unaffected -- only canary instances update initially | Roll back the application to its previous version | Console |
Update an application
Select a strategy and follow the corresponding guide:
At-a-time release
Create and deploy an application on an ECS cluster (console)
Use Alibaba Cloud CLI to deploy an application in an ECS cluster (CLI)
Phased release
Canary release
Roll back an application
If an error occurs during or after an update, roll back the application to its previous version. Fix the error before you update again.
| Scenario | Action |
|---|---|
| Error occurs during the update | Stop the update process and roll back immediately |
| Error occurs after the update completes | Roll back the completed deployment to the previous version |
For step-by-step instructions, see Use the EDAS console to roll back applications in ECS clusters.