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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 devices running Junos OS and with significantly greater throughput than when committing data to the candidate configuration database. Devices running Junos OS 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. Junos OS 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 OS 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 OS processes must check and evaluate their complete configuration, which might cause a spike in CPU utilization, potentially impacting other critical software processes.


If the ephemeral configuration database is present on a device running Junos OS, 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. Synchronous commit operations are slower than asynchronous commit operations but enable 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 OS 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 to the other Routing Engine when you commit an ephemeral instance on the primary Routing Engine in a dual Routing Engine device or an MX Series Virtual Chassis.

Synchronous commit operations are slower than asynchronous commit operations but provide better assurance that the ephemeral configuration is synchronized between Routing Engines. Although asynchronous commit operations are faster, the device could fail to synchronize the ephemeral configuration to the other Routing Engine under certain circumstances.

  • Default: asynchronous


Disable the default instance of the ephemeral configuration database.

The remaining statements are explained separately. See CLI Explorer.

Required Privilege Level

maintenance—To view this statement in the configuration.

maintenance—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 16.2R2.

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