In-Service Software Upgrade
This topic briefly describes the in-service software upgrade (ISSU) feature and its configuration on the QFX5220 (except the QFX5220-128C switch), QFX5230, QFX5240, and QFX5241 Switches.
Overview
The QFX Series Switches (except QFX5220-128C) support the in-service software upgrade (ISSU) feature. You can use ISSU to upgrade the network devices to a new software version without disrupting the network service. For more information about ISSU on QFX Series Switches, see In-service Software Upgrade.
The upgrade time for an ISSU on the QFX Series Switches depends on the platform and network conditions. The procedure minimizes traffic disruption and downtime. The ISSU process restarts applications instead of performing full system reboot, reducing upgrade time.
Prerequisites to Perform ISSU
You must make sure that the following prerequisites are met before upgrading Junos OS Evolved on your switch:
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You have sufficient disk space for the upgrade and a backup of the system is available.
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Download the software package from the Juniper Networks Support website at https://www.juniper.net/support/ and place the package on your local server.
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If the BGP protocol is configured on the main routing instance or a specific routing instance, then configure BGP graceful restart and set the
restart-timevalue to greater than or equal to 300 seconds.set routing-instances vrf-name protocols bgp graceful-restart set routing-instances vrf-name protocols bgp graceful-restart restart-time 300
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If OSPF runs on the main or specific routing instance, set the graceful
restart-timevalue. The default is 180s, but you can configure it from 300s to 3600s.set routing-instances vrf-name protocols ospf graceful-restart set routing-instances vrf-name protocols ospf graceful-restart restart-duration 300 300
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If the IS-IS protocol is configured on the main routing instance or a specific routing instance, then configure IS-IS graceful restart and set the
restart-timevalue to greater than or equal to 300 seconds. IS-ISrestart-durationrange is 30–300 seconds (default 30 seconds), with a maximum of 300 seconds.set routing-instances instance-name protocols isis graceful-restart set routing-instances instance-name protocols isis graceful-restart restart-duration 300
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To configure BGP graceful restart and the
restart-timevalue on the main routing instance:set protocols bgp graceful-restart set protocols bgp graceful-restart restart-time seconds
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To ensure that graceful restart works reliably, set the IS-IS
hold-timeto 41 seconds or greater (default is 27 seconds).set protocols isis interface interface-name hold-time 41
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If the PIM protocol is configured on the main routing instance or a specific routing instance, then configure PIM graceful restart and set the
restart-timevalue to greater than or equal to 300 seconds.set routing-instances instance-name protocols pim graceful-restart set routing-instances instance-name protocols pim graceful-restart restart-time 300
Note: QFX5230 does not support graceful restart for the PIM protocol. -
To verify any protocol (IS-IS, PIM, BGP, OSPF) configuration:
show configuration protocols protocol-name | display set | match graceful-restart show protocol-name neighbor neighbor-address show protocol-name summary
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If a spanning tree protocol (STP) is configured, then configure the STP-enabled ports as edge ports and enable bridge protocol data unit (BPDU) protection.
set protocols (mstp | rstp | vstp) bpdu-block-on-edge set protocols (mstp | rstp | vstp) interface (interface-name | all) edge
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Configure the value of the Address Resolution Protocol (ARP) aging timer to 240 minutes.
set routing-options arp aging-timer 240
If you want to configure ARP under a specific routing-instance, use the following command:
set routing-instances VRF routing-options arp aging-timer 240
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Validate the existing configuration against the new software image to check whether it supports ISSU.
request system software validate-restart package-name
Upgrade a QFX Series Switch OS Using ISSU
To upgrade the QFX Series Switch operating system (OS) using ISSU:
Run the following command on the switch whose OS you want to upgrade:
request system software add package-path restart
Log in at the login prompt and run the following command to verify the release of the installed software:
show system software list
Verify that the system is running properly and correctly handling traffic following prerequisites listed in Prerequisites to Perform ISSU.
If you want to make any changes to the configuration after the upgrade, remember to back up the software and configuration:
request system snapshot
Effects of ISSU
The packet or data loss that happens during the upgrade process varies from switch to switch.
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The QFX5220-32CD switch has a minimal packet loss of up to 50 ms during upgrade, whereas the QFX5230, QFX5240, and QFX5241 switches have a packet loss of up to 200 ms.
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There is more data loss in the QFX5230, QFX5240, and QFX5241 switches as compared to the QFX5220-32CD switch. This is because the new switches offer more scalability, flexibility, improved architecture, and support for new features such as EVPN-VXLAN.