We can enable and suspend versioning from the CLI using the put-bucket-versioning sub-command providing that bucket and versioning-configuration. versioning-configuration contain two parameters: MFADelete, which denotes the required state of MFA Delete (Enabled or Disabled), and Status, which denotes the required state of versioning (Enabled or Suspended). For versioning configuration, we can either use the shorthand form, --versioning-configuration MFADelete=Disabled,Status=Enabled, or we can specify a JSON file with the configuration as --versioning-configuration file://resources/versioning-configuration.json; the JSON file will look as follows:

{
  "MFADelete": "Disabled",
  "Status": "Enabled"
}

Complete CLI commands for enabling and suspending versioning are available with the code files.

Let's quickly go through some important concepts related to S3 versioning:

• Versioning is a sub-resource of an S3 object. 

• A delete request on a suspended bucket will work as follows:

  • If there is a version with the NULL version ID(this is present only if the object was modified after suspending versions), it is deleted and then a delete marker with the NULL version ID is inserted.
  • If there is no version with the NULL version ID, a delete marker with the NULL version ID is inserted.
• We can use life cycle management rules to transition older versions to other S3 storage tiers (archives) or even delete them.
• We can protect versions by enabling MFA Delete. With MFA Delete for versioning, an extra level of authentication is required to delete versions. The MFA Delete configuration is stored within the versioning sub-resource. 

Let's also quickly go through some scenario-based questions to understand versioning better:

• We enabled versioning and PUT the same object twice (with modifications). We then disabled versioning and PUT the same object twice (with modifications). How many versions of the object will now be available if you check? 3.
• We enabled versioning and PUT the same object twice, creating two versions as version 1 and version 2. We then disabled versioning and PUT the same object again, creating version 3. Later, we deleted the object. Can we restore this object? If yes, which version will be the latest? We can restore the object and the latest one following the restoration will be version 2.