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[Upgrade EX Switch] Stage 2 - Backup configuration



Article ID: KB20350 KB Last Updated: 28 Feb 2020Version: 5.0

This article documents Stage 2 – Proactively Planning a Juniper EX Switch Upgrade. This involves the foresight to prevent losing current configuration on the switch while performing a Junos Software Upgrade. The discussion here centers on multiple methods of backing up the configuration on Juniper EX Switches.

To go directly to other stages of the Junos upgrade on an EX switch, consult the Resolution Guide -- Upgrading EX Series.


  • Best practices for backing up EX Switch configuration(s)

  • Methods for backing-up configuration(s) on Junos devices



The second stage of a Junos Software Upgrade is to back up the configuration. 

Perform the following steps:                          

step1   Confirm if there are any uncommitted changes.

This step is performed to see if there are any uncommitted changes on the Junos device before a configuration backup is done. We recommend that our customers should confirm that there are no uncommitted changes before an upgrade because candidate changes are usually lost on a reboot. Perform this step via JWeb or the CLI:


Select Commit Options > Commit.

Changes are committed after the system validates your configuration and the commit will be acknowledged. For more information, refer to Using the J-Web Interface.


root@ex# top
root@ex# show | compare

If the above command contains configuration information that you want to keep, then perform a commit:

root@ex# commit

step2 Confirm that the ‘active’ configuration is the configuration that you want to backup.

The current committed configuration on the Junos device is called the 'active' configuration.  This is the configuration recommended for backup. If the current running configuration is what you want to backup (which is usually the case since it's the most updated version of the configuration), then continue to Step 3

If you are not sure, refer to the common questions and answers below:

  • If you want more information on the Junos configuration filenames and config directories, refer to Managing Configurations. The current 'active' configuration is named juniper.conf.gz in /var/config, and Candidates Configuration from 4 till 49 can be found the /var/db/config/ directory.

  • If you prefer to back up a different configuration other than the ‘active’ configuration, use the rollback command to load the desired configuration, or note the configuration name using any of the given methods in step 3 to back up the desired configuration.

  • If you want to compare the existing configuration with the previous configuration, refer to Comparing Configuration files with the J-Web Interface.

  • If you are new to Junos, you can refer to the SRX Jumpstation article, KB16693 - Junos CLI Basics, because the SRX and EX CLI basics are the same.

step3 Backup the configuration using any of the following methods:

  • CLI

  • FTP

  • J-Web

  • USB


Perform the following:

  1. Log in to the Junos device or switch via the console. The console port is the data terminal equipment (DTE) interface, providing a direct and continuous interface with the switch. It is important to connect to the console during installation / configuration backup procedures so that we can capture and see any errors during the upgrade. For more information on making a console connection, refer to Connecting an EX Series Switch to a Management Console

  2. Log the console session before performing the following steps in order to capture the command line output. You could also perform a simple Copy – Paste function.

  3. Display the 'active' configuration on the Junos device or switch:

    root@ex> show configuration | no-more


    root@ex> show configuration | display set | no-more

    By default, if the output is longer than the length of the terminal screen, you are provided with a --- (more) --- message to display the remaining output. To display the remaining output, press the Spacebar. To prevent the output from being paginated, enter no-more after the pipe symbol ( | ). For more information on the pipe symbol, refer to Pipe ( | ) Filter Functions in the Junos OS command-line interface.


Download the current/active configuration (juniper.conf.gz) on the Junos device or switch by performing the following:

  1. Prerequisite:  FTP services must be enabled on the Junos device or switch.  These services are not enabled by default. 

    root@ex# set system service ftp
    root@ex# commit 
  2. From the FTP client, log in to the switch (user: root).

  3. On FTP Client, change directory from "/root" to  "/config".

  4. Select the juniper.conf.gz file.  (Note that a list of current and previous 0 to 3 configurations will be displayed, and the 4 to 49 configurations will be stored in /var/db/config . )

  5. Copy the juniper.conf.gz file to the desired location by clicking transfer.


Perform the following:

  1. Click the “Maintain”  tab.

  2. Click “Config Management”.

  3. Click “History”.

  4. Select “Current” Configuration & Download.

    A list of current and previous 49 configurations is displayed as Configuration History in the main pane.

    Refer to the attached screenshot for clarification:


Refer to KB12022 - How to mount a USB disk for configuration file backup or restore for the EX-series Ethernet switch.

step4   [Optional] Capture System Snapshot.

The System Snapshot feature is NOT typically captured before doing a upgrade. For more information on this command, refer to the following:

Understanding System Snapshot
Capture Snapshot instructions
Verify Snapshot

Note: The System Snapshot feature is supported from Junos OS release 10.0R1 on EX3200, EX4200, and EX8200.

step5   After backing up the configuration, continue onto KB20536 - Stage 3 - Upgrade.


Modification History:

2020-02-28: Article checked for accuracy; article found to be relevant and accurate; no changes made.


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