Use S3 Lifecycle to delete and retain the two recent versions

#aws

🧩 How it works

When S3 versioning is enabled, each update to an object creates a new version:

The latest version = current version
Older ones = noncurrent versions

Lifecycle rules can:

Delete noncurrent versions older than X days (NoncurrentDays), and
Retain only the N most recent noncurrent versions (NewerNoncurrentVersions).

So to keep two versions total, we’ll tell S3 to keep:

1 current version
1 noncurrent version (delete anything older)

⚙️ Lifecycle configuration example (JSON)

{
  "Rules": [
    {
      "ID": "Keep two latest versions",
      "Status": "Enabled",
      "Filter": {},
      "NoncurrentVersionExpiration": {
        "NoncurrentDays": 1,
        "NewerNoncurrentVersions": 1
      }
    }
  ]
}

💡 Meaning

Field	Description
`NoncurrentDays: 1`	Wait one day after a version becomes noncurrent before evaluating it for deletion.
`NewerNoncurrentVersions: 1`	Retain only one noncurrent version (so total of two versions: current + 1 previous).

🧾 Apply it to your bucket

Save the JSON above to a file, e.g. lifecycle.json, then apply with AWS CLI:

aws s3api put-bucket-lifecycle-configuration \
  --bucket my-versioned-bucket \
  --lifecycle-configuration file://lifecycle.json

Confirm:

aws s3api get-bucket-lifecycle-configuration \
  --bucket my-versioned-bucket

⏱ What happens next

Example: you upload photo.jpg several times.

Version	Status	Age	Action
v5	current	—	kept
v4	noncurrent	< 1 day	kept (still too new)
v3	noncurrent	> 1 day	deleted (more than 1 newer noncurrent version)
v2, v1	noncurrent	old	deleted

Result → only v5 and v4 remain.

⚠️ Notes / Caveats

The rule only affects noncurrent versions, never the current one.
Deletion isn’t instant; S3 processes lifecycle actions daily.
You must have versioning enabled on the bucket.
The combination of NoncurrentDays + NewerNoncurrentVersions determines exactly when deletions occur.

✅ Summary