Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

 
 

Performing a Unified ISSU

SUMMARY Follow the steps below to perform a unified ISSU.

Best Practices for Performing a Unified ISSU

When you are planning to perform a unified in-service software upgrade (ISSU), choose a time when your network is as stable as possible. As with a normal upgrade, Telnet sessions, SNMP, and CLI access are briefly interrupted. In addition, the following restrictions apply:

  • The primary Routing Engine and backup Routing Engine must be running the same software version before you can perform a unified ISSU.

  • Verify that your platform supports the unified ISSU feature.

  • Read the “Unified ISSU Considerations” topic in the chapter Unified ISSU System Requirements to anticipate any special circumstances that might affect your upgrade.

Example: Performing a Unified ISSU

This example shows how to perform a unified in-service software upgrade (ISSU).

Requirements

This example uses the following hardware and software components:

  • MX480 router with dual Routing Engines

  • Junos OS Release 13.3R6 as the starting release

  • Junos OS Release 14.1R4 as the ending release

Before You Begin

Before you perform a unified ISSU, be sure you:

  • Perform a compatibility check to ensure that the software and hardware components and the configuration on the device support unified ISSU by using the request system software validate in-service-upgrade command

  • Read the chapter Unified ISSU System Requirements to anticipate any special circumstances that might affect your upgrade.

    • Verify that your platform supports the unified ISSU feature.

    • Verify that the field-replaceable units (FRUs) installed in your platform support the unified ISSU feature or that you can accept the results of performing the upgrade with some FRUs that do not support unified ISSU.

    • Verify that the protocols and features configured on your platform support the unified ISSU feature or that you can accept the results of performing the upgrade with some protocols and features that do not support unified ISSU.

  • Download the software package from the Juniper Networks Support website at https://www.juniper.net/support/ and place the package on your local server.

    Best Practice:

    When you access the Download Software web page for your device, record the md5 checksum. After downloading the software package to your device, confirm that it is not modified in any way by using the file checksum md5 command. For more information about verifying the md5 checksum, see https://kb.juniper.net/InfoCenter/index?page=content&id=KB17665 .

    Note:

    Starting with Junos OS Release 16.1R1, while performing a unified ISSU from a FreeBSD 6.1 based Junos OS to an upgraded FreeBSD 10.x based Junos OS, the configuration must be validated on a remote host or on a routing engine. The remote host or the routing engine must be running a Junos OS with an upgraded FreeBSD. In addition, only a few selected directories and files will be preserved while upgrading from FreeBSD 6.1 based Junos OS to FreeBSD 10.x based Junos OS. See Upgrading Junos OS with Upgraded FreeBSD and request system software valdiate on (Junos OS with Upgraded FreeBSD)

Overview

This procedure can be used to upgrade M Series, T Series, MX Series, EX Series, and PTX Series devices that have dual Routing Engines installed and support unified ISSU.

In the example, the hostnames, filenames, and FRUs are representational. When you perform the procedure on your device, the hostnames, filenames, and FRUs are different. The command output is truncated to only show the text of interest in this procedure.

Topology

Figure 1 shows the topology used in this example.

Figure 1: Unified ISSU Example TopologyUnified ISSU Example Topology

Configuration

There are variations of the procedure depending on if you want to install the new software on one or both Routing Engines and if you want to automatically reboot both Routing Engines or manually reboot one of the Routing Engines.

In all cases, you must verify that dual Routing Engines are installed and that graceful Routing Engine switchover (GRES) and nonstop active routing (NSR) are enabled. We recommend that you back up the device software before the upgrade.

To perform a unified ISSU, select the appropriate tasks from the following list:

Verifying Dual Routing Engines and Enabling GRES and NSR

Procedure

Step-by-Step Procedure

Enabling GRES and NSR is required regardless of which variation of the unified ISSU procedure you use.

To verify that your device has dual Routing Engines and to enable GRES and NSR:

  1. Log in to your device.

  2. Verify that dual Routing Engines are installed in your device by using the show chassis hardware command.

    The command output contains lines listing Routing Engine 0 and Routing Engine 1.

  3. By default, GRES is disabled; if you have not already done so, enable GRES by including the graceful-switchover statement at the [edit chassis redundancy] hierarchy level on the primary Routing Engine.

  4. By default, NSR is disabled; if you have not already done so, enable NSR by including the nonstop-routing statement at the [edit routing-options] hierarchy level.

  5. When you configure NSR, you must also include the commit synchronize statement at the [edit system] hierarchy level so that configuration changes are synchronized on both Routing Engines.

  6. After you have verified your configuration and are satisfied with it, commit the changes by using the commit command.

    When you enable GRES and commit the configuration, the CLI prompt changes to indicate which Routing Engine you are using. For example:

  7. Exit configuration mode by using the exit command.

  8. Verify that NSR is configured on the primary Routing Engine (re0) by using the show task replication command.

    In the output, verify that the Synchronization Status field displays Complete.

  9. Verify that GRES is enabled on the backup Routing Engine (re1) by using the show system switchover command.

    In the output, verify that the Graceful switchover field state displays On. For more information about the show system switchover command, see show system switchover.

Verifying the Software Versions and Backing Up the Device Software

Procedure

Step-by-Step Procedure

Unified ISSU requires that both Routing Engines are running the same version of Junos OS before the upgrade. As a preventive measure in case any problems occur during an upgrade, it is a best practice to back up the system software to the device hard disk.

To verify the software versions and back up the device software:

  1. Verify that the same version of Junos OS is installed and running on both Routing Engines by using the show version command.

  2. Back up the system software to the device hard disk by using the request system snapshot command on each Routing Engine.

    Note:

    The root file system is backed up to /altroot, and /config is backed up to /altconfig. After you issue the request system snapshot command, the device flash and hard disks are identical. You can return to the previous version of the software only by booting the device from removable media.

Adjusting Timers and Changing Feature-Specific Configuration

Procedure

Step-by-Step Procedure

If you have any of the following feature-specific configuration on your device, perform the appropriate steps.

To adjust timers and change feature-specific configuration:

  1. Bidirectional Forwarding Detection (BFD) sessions temporarily increase their detection and transmission timers during unified ISSU procedures. After the upgrade, these timers revert to the values in use before the unified ISSU started.

    If BFD is enabled on your device and you want to disable the BFD timer negotiation during the unified ISSU, include the no-issu-timer-negotiation statement at the [edit protocols bfd] hierarchy level.

    Note:

    If you include this statement, the BFD timers maintain their original values during the unified ISSU, and the BFD sessions might flap during the unified ISSU or Routing Engine switchover, depending on the detection intervals.

  2. If proxy ARP is enabled on your M Series, MX Series, or EX 9200 Series device, remove the unconditional-src-learn statement from the [edit interfaces interface-name unit 0 family inet] hierarchy level.

    By default the statement is not included. This example shows the ge-0/0/1 interface only.

  3. If LACP is enabled on your PTX Series device, remove the lacp statement from the [edit interfaces interface-name aggregated-ether-options] hierarchy level.

  4. If ATM Point-to-Point Protocol (PPP) is enabled on your M Series or T Series device, set the keepalive interval to 10 seconds or greater.

    PPP requires three keepalives to fail before it brings down the session. Thirty seconds (10 seconds x three) provides a safe margin to maintain PPP sessions in case of any traffic loss during the unified ISSU operation.

    This example shows the at-0/0/1 interface only.

  5. If ATM OAM is enabled on your M Series or T Series device, set the OAM F5 loopback cell period to 20 seconds or greater to maintain ATM connectivity across the unified ISSU.

    Include the oam-period statement at the [edit interfaces interface-name unit logical-unit-number] hierarchy level and specify 20 seconds. This example shows the at-0/0/1 interface only.

  6. After you have verified your configuration and are satisfied with it, commit the changes by using the commit command.

  7. Exit configuration mode by using the exit command.

Upgrading and Rebooting Both Routing Engines Automatically

Procedure

Step-by-Step Procedure

In this procedure, both Routing Engines automatically reboot. Rebooting both Routing Engines automatically is the most common scenario. Variations to this procedure are described in other sections.

Table 1 shows the Routing Engine status prior to starting the unified ISSU.

Table 1: Routing Engine Status Before Upgrading

RE0

RE1

Primary

Backup

Old software version installed

Old software version installed

Old software version running

Old software version running

To upgrade and reboot both Routing Engines automatically:

  1. Copy the Junos OS software package to the device by using the file copy ftp://username@hostname.net/filename /var/tmp/filename command.

    We recommend that you copy the package to the /var/tmp directory, which is a large file system on the hard disk.

    Best Practice:

    When you access the Download Software web page for your device, record the md5 checksum. After downloading the software package to your device, confirm that it is not modified in any way by using the file checksum md5 command. For more information about verifying the md5 checksum, see https://kb.juniper.net/InfoCenter/index?page=content&id=KB17665 .

  2. On the primary Routing Engine, start the upgrade by using the request system software in-service-upgrade package-name reboot command.

    Note:

    Do not try running any additional commands until after the Connection closed message is displayed and your session is disconnected.

    When the Routing Engine that was previously the primary is rebooted, you are logged out of the device.

  3. Wait a few minutes and then log in to the device again.

    Table 2 shows the Routing Engine status after the unified ISSU.

    Table 2: Routing Engine Status After Upgrading and Rebooting Both Routing Engines

    RE0

    RE1

    Backup

    Primary

    New software version installed

    New software version installed

    New software version running

    New software version running

    You are logged in to the new backup Routing Engine (re0).

  4. Verify that both Routing Engines have been upgraded by using the show version command.

  5. If you want to, you can optionally display the unified ISSU log messages by using the show log messages command.

  6. If you want to, you can optionally make re0 the primary Routing Engine by using the request chassis routing-engine master acquire command.

    Table 3 shows the Routing Engine status after Step 5 is completed.

    Table 3: Routing Engine Status After Upgrading, Rebooting, and Switching Primary Role

    RE0

    RE1

    Primary

    Backup

    New software version installed

    New software version installed

    New software version running

    New software version running

  7. Perform the applicable steps in Restoring Feature-Specific Configuration.

  8. If you are satisfied with the results of your testing, you can optionally back up the system software to the device’s hard disk by using the request system snapshot command on each Routing Engine.

    Note:

    The root file system is backed up to /altroot, and /config is backed up to /altconfig. After you issue the request system snapshot command, you cannot easily return to the previous version of the software, because the device flash and hard disks are identical. To return to the previous version of the software, you must boot the device from removable media.

Restoring Feature-Specific Configuration

Procedure

Step-by-Step Procedure

If you have any of the following feature-specific configuration on your device, perform the appropriate steps.

To restore feature-specific configuration:

  1. If BFD is enabled on your device and you previously disabled the BFD timer negotiation, delete the no-issu-timer-negotiation statement at the [edit protocols bfd] hierarchy level.

  2. If proxy ARP is enabled on your M Series, MX Series, or EX9200 device and you previously removed the unconditional-src-learn statement, include the statement again.

    This example shows the ge-0/0/1 interface only.

  3. If LACP is enabled on your PTX Series device and you previously removed the lacp statement, include the statement again.

  4. If ATM PPP is enabled on your M Series or T Series device and you previously set the keepalive interval to 10 seconds or greater, restore the original value.

    This example shows the at-0/0/1 interface only and shows the interval being set to the default 3 seconds.

  5. If ATM OAM is enabled on your M Series or T Series device and you previously set the OAM F5 loopback cell period to 20 seconds or greater, change the configuration back to the original value.

    This example shows the at-0/0/1 interface only and shows the period being set to 10 seconds.

  6. After you have verified your configuration and are satisfied with it, commit the changes by using the commit command.

  7. Exit configuration mode by using the exit command.

Upgrading Both Routing Engines and Rebooting the New Backup Routing Engine Manually

Procedure

Step-by-Step Procedure

In certain circumstances, you might want to install the new software on only one Routing Engine and reboot only the primary until after you can test the new software. A Routing Engine does not start running the new software until after it is rebooted.

The advantage is if the results of your testing requires you to downgrade the software, you can switch Routing Engines to run the old software on one Routing Engine and then install the old software on the other Routing Engine. This is not the typical scenario.

To upgrade both Routing Engines and to reboot the new backup Routing Engine manually:

  1. Perform the steps in Verifying Dual Routing Engines and Enabling GRES and NSR.

  2. Perform the steps in Verifying the Software Versions and Backing Up the Device Software.

  3. Perform the steps in Adjusting Timers and Changing Feature-Specific Configuration.

  4. Copy the Junos OS software package to the device using the file copy ftp://username@hostname.net/filename /var/tmp/filename command.

    We recommend that you copy the package to the /var/tmp directory, which is a large file system on the hard disk.

    Best Practice:

    When you access the Download Software web page for your device, record the md5 checksum. After downloading the software package to your device, confirm that it is not modified in any way by using the file checksum md5 command. For more information about verifying the md5 checksum, see https://kb.juniper.net/InfoCenter/index?page=content&id=KB17665 .

    Table 4 shows the Routing Engine status prior to starting the unified ISSU.

    Table 4: Routing Engine Status Before Upgrading and Manually Rebooting the Backup Routing Engine

    RE0

    RE1

    Primary

    Backup

    Old software version installed

    Old software version installed

    Old software version running

    Old software version running

  5. On the primary Routing Engine, start the upgrade by using the request system software in-service-upgrade package-name command without the reboot option.

    Table 5 shows the Routing Engine status after the unified ISSU and before manually rebooting the backup Routing Engine.

    Table 5: Routing Engine Status After Upgrading and Before Manually Rebooting the Backup Routing Engine

    RE0

    RE1

    Backup

    Primary

    New software version installed

    New software version installed

    Old software version running

    New software version running

  6. Verify that the new backup, (old primary) Routing Engine (re0), is still running the previous software image and that the new primary Routing Engine (re1) is running the new software image, by using the show version command.

  7. At this point, if you do not want to install the newer software version on the new backup Routing Engine (re0), issue the request system software delete package-name command on it.

    Otherwise, to complete the upgrade, go to the next step.

  8. Reboot the new backup Routing Engine (re0) by issuing the request system reboot command.

    If you are not on the console port, you are disconnected from the device session.

    Table 6 shows the Routing Engine status after the unified ISSU, after rebooting the backup Routing Engine, but before switching primary role.

    Table 6: Routing Engine Status After Upgrading, Manually Rebooting, and Before Switching Primary Role

    RE0

    RE1

    Backup

    Primary

    New software version installed

    New software version installed

    New software version running

    New software version running

  9. Wait a few minutes, then log in to the device again.

    You are logged in to the new backup Routing Engine (re0).

  10. Verify that both Routing Engines have been upgraded by using the show version command.

  11. If you want to, you can optionally display the unified ISSU log messages by using the show log messages command.

  12. If you want to, you can optionally make re0 the primary Routing Engine by using the request chassis routing-engine master acquire command:

    Table 7 shows the Routing Engine status after the unified ISSU, after rebooting the backup Routing Engine, and after switching primary role.

    Table 7: Routing Engine Status After Upgrading, Manually Rebooting, and Switching Primary Role

    RE0

    RE1

    Primary

    Backup

    New software version installed

    New software version installed

    New software version running

    New software version running

  13. Perform the applicable steps in Restoring Feature-Specific Configuration.

  14. If you are satisfied with the results of your testing, you can optionally back up the system software to the device’s hard disk by using the request system snapshot command on each Routing Engine.

    Note:

    The root file system is backed up to /altroot, and /config is backed up to /altconfig. After you issue the request system snapshot command, you cannot easily return to the previous version of the software, because the device flash and hard disks are identical. To return to the previous version of the software, you must boot the device from removable media.

Upgrading and Rebooting Only One Routing Engine

Procedure

Step-by-Step Procedure

In certain circumstances you might want to install the new software on only one Routing Engine.

The advantage is if the results of your testing requires you to downgrade the software, you can switch Routing Engines to run the old software on one Routing Engine and then install the old software on the other Routing Engine. This is not the typical scenario.

Table 8 shows the Routing Engine status prior to starting the unified ISSU.

Table 8: Routing Engine Status Before Upgrading and Rebooting One Routing Engine

RE0

RE1

Primary

Backup

Old software version installed

Old software version installed

Old software version running

Old software version running

To upgrade and rebooting only one Routing Engine:

  1. Perform the steps in Verifying Dual Routing Engines and Enabling GRES and NSR.

  2. Perform the steps in Verifying the Software Versions and Backing Up the Device Software.

  3. Perform the applicable steps in Adjusting Timers and Changing Feature-Specific Configuration.

  4. Copy the Junos OS software package to the device by using the file copy ftp://username@hostname.net/filename /var/tmp/filename command.

    We recommend that you copy the package to the /var/tmp directory, which is a large file system on the hard disk.

    Best Practice:

    When you access the Download Software web page for your device, record the md5 checksum. After downloading the software package to your device, confirm that it is not modified in any way by using the file checksum md5 command. For more information about verifying the md5 checksum, see https://kb.juniper.net/InfoCenter/index?page=content&id=KB17665 .

  5. On the primary Routing Engine, start the upgrade by using the request system software in-service-upgrade package-name no-old-master-upgrade command.

    Table 9 shows the Routing Engine status after the unified ISSU upgrades the primary Routing Engine but before the backup Routing Engine is upgraded.

    Table 9: Routing Engine Status After Upgrading One Routing Engine and Before Upgrading the Other Routing Engine

    RE0

    RE1

    Backup

    Primary

    Old software version installed

    New software version installed

    Old software version running

    New software version running

  6. Verify that the new backup, (old primary) Routing Engine (re0), is still running the previous software image and that the new primary Routing Engine (re1) is running the new software image, by using the show version command.

  7. If your testing is complete and you want to install the new software on the backup Routing Engine, you must first disable GRES and NSR on both Routing Engines and commit the configuration.

  8. Install the new software on the backup Routing Engine (re0) by using the request system software add /var/tmp/jinstall64-14.1R4.10-domestic-signed.tgz command.

  9. Reboot re0 by using the request system reboot command.

    If you are not on the console port, you are disconnected from the router session.

  10. After waiting a few minutes, log in to the device again.

    You are logged in to the backup Routing Engine (re0).

  11. Verify that both Routing Engines are running the new software image by using the show version command.

  12. If you want to, you can optionally display the unified ISSU log messages by using the show log messages command.

  13. If you want to, make re0 the primary Routing Engine by using the request chassis routing-engine master acquire command.

    Table 10 shows the Routing Engine status after the unified ISSU, after rebooting the backup Routing Engine, and after switching primary role.

    Table 10: Routing Engine Status After Upgrading, Manually Rebooting, and Switching Primary Role

    RE0

    RE1

    Primary

    Backup

    New software version installed

    New software version installed

    New software version running

    New software version running

  14. Enable GRES and NSR again by performing the steps in Verifying Dual Routing Engines and Enabling GRES and NSR.

  15. Perform the applicable steps in Restoring Feature-Specific Configuration.

  16. If you are satisfied with the results of your testing, you can optionally back up the system software to the device’s hard disk by using the request system snapshot command on each Routing Engine.

    Note:

    The root file system is backed up to /altroot, and /config is backed up to /altconfig. After you issue the request system snapshot command, you cannot easily return to the previous version of the software, because the device flash and hard disks are identical. To return to the previous version of the software, you must boot the device from removable media.

Performing an In-Service Software Upgrade (ISSU) with Non-Stop Routing

You can use an in-service software upgrade with non-stop routing to upgrade the software running on the switch with minimal traffic disruption during the upgrade.

Note:

Starting with Junos OS Release 18.2R1 on the QFX5200 switch, we recommend that you wait at least five minutes between in-service software upgrades.

Note:

Starting with Junos OS Release 17.1R1, on QFX5100 and EX4600 switches, you cannot perform an ISSU from a Junos OS Release earlier than 17.1R1 to Junos OS Release 17.1R1.

This topic covers:

Preparing the Switch for Software Installation

Before you begin software installation using ISSU:

Note:

Before you perform an in-service software upgrade, if applicable, remove the set system internet-options no-tcp-reset drop-all-tcp command from the configuration, otherwise the upgrade will fail and an error message will be displayed.

NSB and non-stop routing enable NSB-supported Layer 2 protocols to synchronize protocol information between the primary and backup Routing Engines.

Upgrading the Software Using ISSU

This procedure describes how to upgrade the software running on a standalone switch:

Note:

If the Host OS software needs to be updated, you cannot perform an ISSU. Instead, perform a standard software upgrade.

To upgrade the switch using ISSU:

  1. Download the software package by following the procedure in the Downloading Software Files with a Browser section in Installing Software Packages on QFX Series Devices.

  2. Copy the software package or packages to the switch. We recommend that you copy the file to the /var/tmp directory.

  3. Log in to the console connection. Using a console connection allows you to monitor the progress of the upgrade.

  4. Start the ISSU:

    • On the switch, enter:

      where package-name.tgz is, for example, jinstall-host-qfx-5e-18.1R1-secured-signed.tgz.

    Note:

    During the upgrade, you will not be able to access the Junos OS CLI.

    The switch displays status messages similar to the following messages as the upgrade executes:

    Note:

    If the ISSU process stops, you can look at the CLI output when you issue the request system software in-service-upgrade command to diagnose the problem. You can also look at syslog files for more information.

  5. Log in after the reboot of the switch completes. To verify that the software has been upgraded, enter the following command:

Performing an In-Service Software Upgrade (ISSU) in ACX5000 Series Routers

You can use an in-service software upgrade to upgrade the software running on the router with minimal traffic disruption during the upgrade.

Note:

ISSU is supported in Junos OS Release 15.1X54–D60 and later on ACX5000 Series routers.

This topic covers:

Preparing the Router for Software Installation

Before you begin software installation using ISSU:

Note:

Before you perform an in-service software upgrade, if applicable, remove the set system internet-options no-tcp-reset drop-all-tcp command from the configuration, otherwise the upgrade will fail and an error message will be displayed.

  • Ensure that nonstop active routing (NSR) and nonstop bridging (NSB) are enabled. If enabled, disable graceful restart (GR), because NSR and GR cannot be enabled simultaneously. NSB and GR enable NSB-supported Layer 2 protocols to synchronize protocol information between the primary and backup Routing Engines.

  • If NSR is not enabled (Stateful Replication is Disabled), then enable NSR. NSR requires you to configure graceful Routing Engine switchover (GRES). By default, NSR is disabled.

    • To enable graceful Routing Engine switchover, include the graceful-switchover statement at the [edit chassis redundancy] hierarchy level as user@host#set chassis redundancy graceful-switchover.

    • To enable NSR, include the nonstop-routing statement at the [edit routing-options] hierarchy level as user@host#set routing-options nonstop-routing.

  • Enable nonstop bridging (NSB). Nonstop bridging requires you to configure graceful Routing Engine switchover (GRES). By default, NSB is disabled.

    • To enable graceful Routing Engine switchover, include the graceful-switchover statement at the [edit chassis redundancy] hierarchy level as user@host#set chassis redundancy graceful-switchover.

    • To enable NSB, include the nonstop-bridging statement at the [edit protocols layer2-control] hierarchy level as user@host#set protocols layer2-control nonstop-bridging.

  • (Optional) Back up the system software—Junos OS, the active configuration, and log files—on the router to an external storage device with the request system snapshot command.

On ACX5000 line of routers, you need to consider the following feature before performing ISSU:

  • ISSU supports link fault management (LFM) timeout sessions of 1 second interval. During ISSU, you may notice LFM flaps for sessions having timeout interval of less than 1 second.

  • Bidirectional Forwarding Detection (BFD) sessions having timeout interval of less than 1 second need to be reconfigured to 1 second before starting the ISSU process. You can restore the timeout interval to its original value after completing the ISSU process.

  • ISSU supports interval slow (every 30 seconds) for periodic transmission of Link Aggregation Control Protocol (LACP) packets.

  • ISSU supports Virtual Router Redundancy Protocol (VRRP) version 3.

ISSU do not support the following ACX5000 features:.

  • Downgrade to an earlier version of Junos OS software. If you want to install an earlier version of Junos OS software, use the request system software add CLI command.

  • Upgrade of Host OS software.

  • Connectivity fault management (CFM).

  • TWAMP, RPF, RFC2544, and clocksyncd daemon (timing functionality).

  • Mirroring and pseudowire cross connect.

  • IPv6 firewall, IPv6 COS (classification and rewrite), IPv6 VPN, and VPLS mesh group.

  • Virtual Router Redundancy Protocol (VRRP) version 1 and 2.

  • Interval fast (every second) for periodic transmission of Link Aggregation Control Protocol (LACP) packets. If the periodic interval fast is configured, then you may notice traffic drops because of LACP links going down during ISSU. ACX5000 line of routers can support LACP with fast hello by configuring the fast-hello-issu option (user@host# set protocols lacp fast-hello-issu) on the main router and peer routers before starting ISSU.

    Note:

    The peer router must have Junos OS software to support this functionality.

Upgrading the Software Using ISSU

This procedure describes how to upgrade the software running on a standalone router:

Note:

If the Host OS software needs to be updated, you cannot perform an ISSU. Instead, perform a standard software upgrade.

It is recommended to cleanup any unwanted data from the /var directory (/var/log, /var/tmp) before initiating the ISSU process.

To upgrade the router using ISSU:

  1. Download the software package from the Juniper Networks Support website https://www.juniper.net/support/downloads/junos.html .

    Note:

    To access the download site, you must have a service contract with Juniper Networks and an access account. If you need help obtaining an account, complete the registration form at the Juniper Networks website https://www.juniper.net/registration/Register.jsp .

  2. Go to ACX Series section and select the ACX5000 Series platform software you want to download.

  3. Copy the software package or packages to the router. We recommend that you copy the file to the /var/tmp directory.

  4. Log in to the console connection. Using a console connection allows you to monitor the progress of the upgrade.

  5. Start the ISSU:

    • On the router, enter:

      where package-name.tgz is, for example, jinstall-acx5k-15.1X54-D60.9-domestic-signed.tgz.

    Note:

    During the upgrade, you will not be able to access the Junos OS CLI.

    The router displays status messages similar to the following messages as the upgrade executes:

    Note:

    An ISSU might stop instead of terminate if the FPC is at the warm boot stage. Also, any links that go down and up will not be detected during a warm boot of the Packet Forwarding Engine (PFE).

    Note:

    If the ISSU process stops, you can look at the log files to diagnose the problem. The log files are located at /var/log/vjunos-log.tgz.

  6. Log in after the router reboots. To verify that the software has been upgraded, enter the following command:

  7. Disable or delete the configuration done to enable the ISSU. This includes disabling nonstop active routing (NSR), nonstop bridging (NBR) and graceful Routing Engine (GRES).

Verifying a Unified ISSU

Verify the status of FPCs and their corresponding PICs after the most recent unified ISSU.

Issue the show chassis in-service-upgrade command on the primary Routing Engine.

Display the unified ISSU process messages by using the show log messages command.

How to Use Unified ISSU with Enhanced Mode

Unified ISSU with Enhanced Mode Overview

Enhanced mode is an in-service software upgrade (ISSU) option available on MPC8E, MPC9E, and MPC11E line cards that eliminates packet loss during the unified ISSU process. This is achieved by taking advantage of new line card architecture improvements that make it possible to have a second copy of the Junos OS software running on the line card in standby mode ready to take over while software moves from an old image to a new one during unified ISSU. You can enable enhanced mode by adding the enhanced-mode option to the request system software in-service-upgrade CLI command.

SUMMARY Use this document to learn about unified ISSU with enhanced mode and how to use it.

Benefits of Unified ISSU with Enhanced Mode

Unified ISSU with enhanced mode provides the following benefits:

  • Upgrades to a new software version with no loss of transit or host bound traffic

  • Reduces packet loss to zero or several milliseconds depending on configuration and network conditions

  • Allows software upgrades to be performed without the need for maintenance windows

  • Uses the existing unified ISSU process and doesn’t require any special configuration

Prerequisites for Performing Unified ISSU with Enhanced Mode

Before you begin a unified ISSU with enhanced mode, there are several prerequisites to keep in mind:

  • The device running unified ISSU with enhanced mode must use an MPC8E, MPC9E, or MPC11E line card.

    Note:

    If you are performing unified ISSU with enhanced mode on a device that has a mix of supported and unsupported line cards, there will be sub-second traffic loss for traffic passing through the unsupported line cards.

    Note:

    If you are performing unified ISSU with enhanced mode on guest network functions (GNFs), then all GNFs should be using MPC8E, MPC9E, or MPC11E line cards to avoid traffic loss.

  • The Linux version running on your Flexible PIC Concentrator (FPC) and the line card Linux version in the target release need to be compatible.

  • Enhanced mode won’t work if the target release carries changes that require the ASIC blocks to be reset.

  • Forwarding memory usage should be below 75 percent to ensure no packet loss during the unified ISSU process

    Note:

    Unified ISSU with enhanced mode will still work if forwarding memory usage is above 75 percent, but it might introduce several milliseconds of packet loss.

  • All prerequisites for unified ISSU also apply to enhanced mode. See Unified ISSU System Requirements for more information.

You can check to see if your device can use unified ISSU with enhanced mode to upgrade to a specific release by using the request system software validate in-service-upgrade package-name.tgz enhanced-mode command. If your device and the target release are not compatible with enhanced mode, you can still use regular unified ISSU to upgrade with minimal disruption of traffic.

Performing Unified ISSU with Enhanced Mode

To perform a unified ISSU with enhanced mode, follow these steps:

  1. Download the software package by following the procedure in Downloading Software.

  2. Copy the software package or packages to the device. We recommend that you copy the file to the /var/tmp directory.

  3. Log in to the console connection. Using a console connection allows you to monitor the progress of the upgrade.

  4. Verify that you can use unified ISSU with enhanced mode for your desired release.

    1. On the device, enter:

      where package-name.tgz is the name of the software package you downloaded in Step 1.

  5. Start the unified ISSU with enhanced mode:

    1. On the device, enter:

      where package-name.tgz is the name of the software package you downloaded in Step 1.

    Note:

    During the upgrade, you will not be able to access the Junos OS CLI.

    The device displays status messages similar to the following messages as the upgrade executes:

    Note:

    If the unified ISSU process stops, you can look at the CLI output by using the request system software in-service-upgrade command to diagnose the problem. You can also look at syslog files for more information.

  6. Log in after the reboot of the device is completed. To verify that the software has been upgraded, enter the following command:

Note:

When using unified ISSU with enhanced mode, the base Linux OS on your FPC cannot be upgraded as part of the ISSU process. Linux can be updated with an upgrade done through regular unified ISSU or a reboot of the FPC.

Verifying a Unified ISSU

Purpose

Verify the status of FPCs and their corresponding PICs after the most recent unified ISSU.

Action

Issue the show chassis in-service-upgrade command on the primary Routing Engine.

Display the unified ISSU process messages by using the show log messages command.

Meaning

See show chassis in-service-upgrade for more information.

Troubleshooting Unified ISSU Problems

If the unified ISSU procedure stops progressing:

  1. Open a new session on the primary Routing Engine and issue the request system software abort in-service-upgrade command.

  2. Check the existing router session to verify that the upgrade has been terminated.

    An “ISSU: terminated!” message is provided. Additional system messages provide you with information about where the upgrade stopped and recommendations for the next step to take.

See request chassis cluster in-service-upgrade abort (ISSU) for more information.

Managing and Tracing BFD Sessions During Unified ISSU Procedures

Bidirectional Forwarding Detection (BFD) sessions temporarily increase their detection and transmission timers during unified ISSU procedures. After the upgrade, these timers revert to the values in use before the unified ISSU started. The BFD process replicates the unified ISSU state and timer values to the backup Routing Engine for each session.

No additional configuration is necessary to enable unified ISSU for BFD. However, you can disable the BFD timer negotiation during the unified ISSU by including the no-issu-timer-negotiation statement at the [edit protocols bfd] hierarchy level.

If you include this statement, the BFD timers maintain their original values during unified ISSU.

CAUTION:

The BFD sessions might flap during unified ISSU or Routing Engine switchover, depending on the detection intervals.

For more information about BFD, see the Junos OS Routing Protocols Library.

To configure unified ISSU trace options for BFD sessions, include the issu statement at the [edit protocols bfd traceoptions flag] hierarchy level.

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release
Description
18.1R1
Starting with Junos OS Release 18.2R1 on the QFX5200 switch, we recommend that you wait at least five minutes between in-service software upgrades.
17.1R1
Starting with Junos OS Release 17.1R1, on QFX5100 and EX4600 switches, you cannot perform an ISSU from a Junos OS Release earlier than 17.1R1 to Junos OS Release 17.1R1.