Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?




Hierarchy Level


Configure settings for the ephemeral configuration database.

The ephemeral database is an alternate configuration database that enables Juniper Extension Toolkit (JET) applications and NETCONF and Junos XML protocol client applications to simultaneously load and commit configuration changes on Junos devices and with significantly greater throughput than when committing data to the candidate configuration database. Junos devices provide a default ephemeral database instance as well as the ability to configure multiple user-defined instances of the ephemeral configuration database.

The ephemeral database is not subject to the same verification required in the static configuration database. As a result, the ephemeral configuration database does not support configuration groups or interface ranges, or macros, commit scripts, or translation scripts. Additionally, certain configuration statements cannot be configured through the ephemeral database as described in Unsupported Configuration Statements in the Ephemeral Configuration Database. A Junos device validates the syntax but does not validate the semantics of configuration data committed to the ephemeral database. Therefore, all configuration data must be validated before loading it into the ephemeral database and committing it on the device. If you commit invalid configuration data to the database, it can cause Junos processes to restart or even crash and result in disruption to the system or network.


When you configure statements at the [edit system configuration-database ephemeral] hierarchy level and commit the configuration, all Junos processes must check and evaluate their complete configuration, which might cause a spike in CPU utilization, potentially impacting other critical software processes.


When you use the ephemeral configuration database, commit operations on the static configuration database might take longer, because additional operations must be performed to merge the static and ephemeral configuration data.

By default, the ephemeral database performs commit synchronize operations asynchronously. We do not recommend using the ephemeral database with the asynchronous commit model on devices that have graceful Routing Engine switchover (GRES) enabled. If you elect to use the ephemeral database when GRES is enabled, you must explicitly configure the allow-commit-synchronize-with-gres statement to enable the device to synchronize ephemeral configuration data to the backup Routing Engine when you request a commit synchronize operation on an ephemeral instance. The ephemeral database also supports a synchronous commit model for commit synchronize operations. The synchronous commit model enables you to use the ephemeral database with greater reliability on devices that have high availability features enabled.

Ephemeral configuration data does not persist across reboots. In addition, when you install a package that requires rebuilding the Junos schema, such as an OpenConfig or YANG package, the device deletes all ephemeral configuration data in the process of rebuilding the schema.



Enable a device that has GRES enabled and that uses the asynchronous commit synchronize model for the ephemeral database to synchronize an ephemeral instance to the backup Routing Engine when you request a commit synchronize operation on the instance.

commit-synchronize-model (asynchronous | synchronous)

Specify how the device synchronizes ephemeral configuration data in a dual Routing Engine or Virtual Chassis environment.

Synchronous commit operations are slower than asynchronous commit operations but provide better assurance that the ephemeral configuration is synchronized across Routing Engines and Virtual Chassis members.

  • Default: asynchronous

cyclic-version-for-ephemeral-default version

Number of versions of the default ephemeral database for which the system stores deleted configuration objects. After each commit, the device reclaims the space occupied by objects deleted in the previous database version relative to the current database version as determined by the cyclic version value. You can disable cyclic versioning by setting the value to 0.

Thus, starting with the 11th commit operation, the device, by default, reclaims the space occupied by objects deleted in version 1 of the database. The process continues with each subsequent commit operation.

  • Default: 10

  • Range: 0 through 4,294,967,295


Delete the configuration data and files for the default instance of the ephemeral configuration database. When you configure this statement, you must also configure the ignore-ephemeral-default statement.


Disable the default instance of the ephemeral configuration database.

The remaining statements are explained separately. Search for a statement in CLI Explorer or click a linked statement in the Syntax section for details.

Required Privilege Level

maintenance—To view or add this statement in the configuration.

Release Information

Statement introduced in Junos OS Release 16.2R2 and Junos OS Evolved Release 22.1R1.

commit-synchronize-model option added in Junos OS Release 21.1R1.

delete-ephemeral-default statement added in Junos OS Release 22.1R1.

cyclic-version-for-ephemeral-default statement added in Junos OS Release 23.2R1 and Junos OS Evolved Release 23.2R1.