Exam 300-620 topic 1 question 202 discussion

To restore a Cisco ACI configuration after corruption, the administrator needs to overwrite the existing configuration with a previously saved backup. The correct procedure involves importing the backup and using the Atomic import policy to ensure that the entire configuration is replaced in a consistent state. By restoring from an FTP server and using the Atomic import policy, you ensure a complete and consistent restoration of the previous day's configuration across all APIC nodes in the cluster. It is not Roll back the configuration using a local snapshot. Use an import policy set to Atomic Replace. While using "Atomic Replace" is valid, this option assumes that a local snapshot exists. The question specifies restoring from a previous day's backup, which is likely stored externally.

ImportMode: - Best-effort mode: each MO is applied individually, and errors only cause the invalid MOs to be skipped. Note: If the object is not present on the controller, none of the children of the object get configured. Best-effort mode attempts to configure the children of the object. - Atomic mode: configuration is applied by whole shards. A single error causes whole shard to be rolled back to its original state. ImportType: - replace - Current system configuration is replaced with the contents or the archive being imported (only atomic mode is supported) - merge - Nothing is deleted, archive content is applied on top the existing system configuration. https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/kb/b_KB_Using_Import_Export_to_Recover_Config_States.html

Atomic Replace - overwrites existing configuration with imported configuration data. Any objects in the existing configuration that do not exist in the imported configuration are deleted. Objects are deleted from the existing configuration that have children in the existing configuration but do not have children in the incoming imported configuration. For example, if an existing configuration has two tenants, solar and wind, but the imported backed up configuration was saved before the tenant wind was created, tenant soar is restored from the backup but tenant wind is deleted. Rollback is when a previous configuration snapshot is used to replace the current APIC configuration. This can be done on the granularity of a snapshot file. This means that a single tenant can be moved back to a previous configuration while the other tenants keep their current configuration state. This is often referred to as partial rollback. When all of the configuration files for a particular version are used to replace the current APIC configuration, this is referred to as a full rollback.

It is B

B is correct. Atomic Replace—overwrites existing configuration with imported configuration data. Any objects in the existing configuration that do not exist in the imported configuration are deleted. Objects are deleted from the existing configuration that have children in the existing configuration but do not have children in the incoming imported configuration. For example, if an existing configuration has two tenants, solar and wind, but the imported backed up configuration was saved before the tenant wind was created, tenant soar is restored from the backup but tenant wind is deleted.