Standard Upgrades and Downgrades

Standard software upgrades and downgrades on Arista switches are accomplished by installing a different EOS image and reloading the switch. On switches with redundant supervisors, you must install the EOS image on both supervisors. Using the following procedures will minimize packet loss during a standard upgrade or downgrade.

These sections describe standard switch upgrade and downgrade procedures:

Upgrading or Downgrading the EOS on a Single-Supervisor Switch

Modifying the active EOS image is a five-step process:
  1. Prepare the switch for upgrade (Prepare the Switch for SSU).
  2. Transfer the image file to the switch (Transfer the Image File). (This is not required if the desired file is on the switch).
  3. Modify the boot-config file to point to the desired image file (Modify boot-config for Single-Supervisor Switch).
  4. Reload the switch (Reload).
  5. Verify the switch is running the new image (Verify the New Image for Single-Supervisor Switch).

Preparing the Switch for SSU

To prepare the switch for SSU, use the following steps:
Note: Configuring BGP graceful restart resets BGP sessions. If configuring BGP graceful restart as part of the SSU process, ensure you have stable BGP sessions and all BGP routing information has been learned and advertised before proceeding with SSU.

Backing Up Critical Software

Before upgrading the EOS image, be sure you have copies of the currently running EOS version and the running-config file available in case of corruption during the upgrade process. To copy the running-config file, use the copy running-config command. In this example, the system copies the running-config contents to a file on the switch flash drive.
switch# copy running-config flash:/cfg_06162014
Copy completed successfully.
switch#

Making Room on the Flash Drive

Determine the size of the new EOS image. Verify enough space exists on the flash drive for two copies of this image, plus a recommended 240MB (if available) for diagnostic information in case of a fatal error. Use the dir command to check the bytes free figure.
switch# dir flash:
Directory of flash:/
-rwx   293168526      Nov 4    22:17   EOS4.11.0.swi
-rwx          36      Nov 8    10:24   boot-config
-rwx       37339      Jun 16   14:18   cfg_06162014

606638080 bytes total (602841088 bytes free)

Verifying Connectivity

Ensure the switch has a management interface configured with an IP address and default gateway. See Assigning a Virtual IP Address to Access the Active Ethernet Management Port and .Configuring a Default Route to the Gateway. Confirm network connectivity to the switch using the show interfaces status command and pinging the default gateway.
switch# show interfaces status
Port    Name     Status     Vlan       Duplex   Speed      Type
Et3/1            notconnect   1         auto    auto     1000BASE-T

<-------OUTPUT OMITTED FROM EXAMPLE-------->
Ma1/1            connected   routed     unconf   unconf    Unknown 

switch# ping 1.1.1.10
PING 172.22.26.1 (172.22.26.1) 72(100) bytes of data.
80 bytes from 1.1.1.10: icmp_seq=1 ttl=64 time=0.180 ms
80 bytes from 1.1.1.10: icmp_seq=2 ttl=64 time=0.076 ms
80 bytes from 1.1.1.10: icmp_seq=3 ttl=64 time=0.084 ms
80 bytes from 1.1.1.10: icmp_seq=4 ttl=64 time=0.073 ms
80 bytes from 1.1.1.10: icmp_seq=5 ttl=64 time=0.071 ms

Verifying Configuration

Verify the switch has a valid configuration for SSU using the show reload fast-boot command. If parts of the configuration block SSU execution, an error message displays explaining the issues. For SSU to proceed, correct the configuration conflicts before issuing the reload fast-boot command.
switch# show reload fast-boot
switch#'reload fast-boot' cannot proceed due to the following:
  Spanning-tree portfast is not enabled for one or more ports
  Spanning-tree BPDU guard is not enabled for one or more ports
switch#
Note: You can still use the show reload hitless and reload hitless commands, but they have the same effect as the commands shown earlier.

Configuring BGP

For hitless restart of BGP and MP-BGP, BGP graceful restart must first be enabled using the graceful-restart command. The default restart time value (300 seconds) is appropriate for most configurations.

The BGP configuration mode issuing the graceful-restart command determines which BGP connections will restart gracefully.

Note: Configuring BGP graceful restart resets BGP sessions. If configuring BGP graceful restart as part of the SSU process, be sure you have stable BGP sessions and all BGP routing information has been learned and advertised before proceeding with SSU.
For all BGP connections, use the graceful-restart command in BGP configuration mode:
switch# config
switch(config)# router bgp 64496
switch(config-router-bgp)# graceful-restart
switch(config-router-bgp)#
For all BGP connections in a specific VRF, use the graceful-restart command in BGP VRF configuration mode:
switch# config
switch(config)# router bgp 64496
switch(config-router-bgp)# vrf purple
switch(config-router-bgp-vrf-purple)# graceful-restart
switch(config-router-bgp-vrf-purple)# exit
switch(config-router-bgp)#
For all BGP connections in a specific BGP address family, use the graceful-restart command in BGP address-family configuration mode:
switch# config
switch(config)# router bgp 64496
switch(config-router-bgp)# address-family ipv6
switch(config-router-bgp-af)# graceful-restart
switch(config-router-bgp-af)# exit
switch(config-router-bgp)#

Configuring MLAG

Note: For EOS versions earlier than 4.31.2, configure the reload-delay parameter. For versions 4.31.2 and later, no configuration required.
Before performing a hitless upgrade on switches configured with MLAG, configure the reload-delay parameter to 0 using the following commands:
switch(config)# mlag
switch(config-mlag)# reload-delay 0
Note: To minimize the traffic disruption during MLAG SSU, all links remain up to let traffic flow during the upgrade process.

If performing the upgrade on the primary MLAG switch, the switch first transitions to the secondary MLAG switch and becomes the primary switch.

All MLAG port channel interfaces with STP enabled shutdown locally on the MLAG peer undergoing the upgrade.

Transfer the Image File

The target image must be copied to the file system on the switch, typically onto the flash drive. After verifying that there is space for the image, use the CLI copy command to copy the image to the flash drive, then confirm that the system transferred the new image file correctly.

The following command examples illustrate transferring an image file from various locations to the flash drive.

USB Memory

Command

copy usb1:/sourcefile flash:/destfile

Example
switch# copy usb1:/EOS-4.13.2.swi flash:/EOS-4.13.2.swi

FTP Server

Command

copy ftp:/ftp-source/sourcefile flash:/destfile

Example
switch# copy ftp:/user:password@10.0.0.3/EOS-4.13.2.swi flash:/EOS-4.13.2.swi

SCP

Command

copy scp://scp-source/sourcefile flash:/destfile

Example
switch# copy scp://user@10.1.1.8/user/EOS-4.13.2.swi flash:/EOS-4.13.2.swi

HTTP

Command

copy http://http-source/sourcefile flash:/destfile

Example
switch# copy http://10.0.0.10/EOS-4.13.2.swi flash:/EOS-4.13.2.swi
After transferring the file, verify that it is present in the directory, then confirm the MD5 checksum using the verify command. The MD5 checksum is available from the EOS download page of the Arista website.
switch# dir flash:
Directory of flash:/
-rwx     293168526   Nov 4     22:17     EOS4.11.0.swi
-rwx            36   Nov 8     10:24     boot-config
-rwx         37339   Jun 16    14:18     cfg_06162014
-rwx     394559902   May 30    02:57     EOS-4.12.2.swi

606638080 bytes total (208281186 bytes free)
switch#53# verify /md5 flash:EOS-4.13.2.swi 
verify /md5 (flash:EOS-4.13.2.swi) =c277a965d0ed48534de6647b12a86991

Modify boot-config for Single-Supervisor Switch

After transferring and confirming the desired image file, use the boot system command to update the boot-config file to point to the new EOS image.

This command changes the boot-config file to point to the image file located in flash memory at EOS-4.12.2.swi.
switch# configure terminal
switch(config)# boot system flash:/EOS-4.13.2.swi
Use the show boot-config command to verify that the boot-config file is correct:
switch(config)# show boot-config
Software image: flash:/EOS-4.13.2.swi
Console speed: (not set)
Aboot password (encrypted): $1$ap1QMbmz$DTqsFYeauuMSa7/Qxbi2l1
Save the configuration to the startup-config file with the write command.
switch# write

Reload

After updating the boot-config file, reset the switch to activate the new image. The reload command resets the switch, resulting in temporary downtime and packet loss on single supervisor switches.

The terminal displays all rebooting messages when reloading from the console port. From any port except the console, the CLI displays this text:
switch# reload
The system is going down for reboot NOW!
Note: The EOS boot process makes a copy of the .swi image file in the internal flash while booting, so sufficient space for two copies must be present when loading the new EOS image. If the switch reloads without adequate space on the flash drive, it boots to the Aboot prompt from which you can delete files from /mnt/flash to free up additional space. Exiting Aboot begins the boot process again.

Verify the New Image for Single-Supervisor Switch

After the switch finishes reloading, log into the switch and use the show version command to confirm the correct image is loaded. The Software image version line displays the version of the active image file.
switch# show version
Arista DCS-7150S-64-CL-F
Hardware version:    01.01
Serial number:       JPE13120819
System MAC address:  001c.7326.fd0c

Software image version: 4.13.2F
Architecture:           i386
Internal build version: 4.13.2F-1649184.4132F.2
Internal build ID:      eeb3c212-b4bd-4c19-ba34-1b0aa36e43f1

Uptime:                 14 hours and 48 minutes
Total memory:           4017088 kB
Free memory:            1569760 kB

Upgrading or Downgrading the EOS on a Dual-Supervisor Switch

Modifying the active EOS image is a four-step process:
  1. Prepare the switch for upgrade (Prepare the Switch for Dual-Supervisor Switch).
  2. Transfer the image file to the primary supervisor (Transfer the Image File to the Primary Supervisor). (This is not required if the desired file is on the switch).
  3. Use the install command to install the new EOS image and update boot-config ( Install the New EOS Image).
  4. Verify the switch is running the new image ( Verify the New Image).
    Note: Due to a change in the supervisor heartbeat timeout, booting one supervisor with a post-SSO image (version 4.10.0-SSO, 4.11.X and later) while the other supervisor is running a pre-SSO image will cause the supervisor running the pre-SSO image to reload. This causes a disruption as both supervisors are inactive for a short time. To minimize downtime, upgrade the images on both supervisors and reload the entire chassis using the install command.

Prepare the Switch for Dual-Supervisor Switch

To prepare the switch for an EOS upgrade, take the following steps:

  • Back up all essential files.
  • Address and ensure the following:
    • Logged into the primary supervisor.
    • Confirm that the primary supervisor is reachable and that the management interfaces are configured.
    • Enough room on both supervisors for the new image file.
    • Any extensions running on the active supervisor also available on the standby.
Before upgrading the EOS image, ensure that you have available backup copies of the currently running EOS version and the running-config file in case of corruption during the upgrade process. To copy the running-config file, use the copy running-config command. In the following example, the running-config file copies to a file called backup2 on the flash drive.
switch# copy running-config backup2
Copy completed successfully.
switch#
Be sure you log into the primary supervisor, not the standby. Use the show redundancy status command, and verify that my status reads ACTIVE and not STANDBY.
switch# show redundancy status
my status = Active
peer state = STANDBY HOT
Unit = Secondary
Unit ID = 1
Redundancy Protocol (Operational) = Stateful Switchover
Redundancy Protocol (Configured) = Stateful Switchover
Communications = Up
Ready for switchover
Last switchover time = 25 days, 19:51:34 ago
Last switchover reason = Other supervisor stopped sending heartbeats
Be sure the switch has a management interface configured with an IP address and default gateway. Refer to the sections Assigning a Virtual IP Address to Access the Active Ethernet Management Port and Configuring a Default Route to the Gateway, and confirm that both management interfaces have an Up state and can ping the default gateway by using the show interfaces status command and ping command.
Note: If configuring the management VRF interface, use the virtual management interface (management 0) instead of the IP address on the physical management interface.
switch# show interfaces status
Port    Name     Status     Vlan       Duplex   Speed      Type
Et3/1            notconnect   1         auto    auto     1000BASE-T

<-------OUTPUT OMITTED FROM EXAMPLE-------->
Ma1/1            connected   routed     unconf   unconf    Unknown 

switch# ping 1.1.1.10
PING 172.22.26.1 (172.22.26.1) 72(100) bytes of data.
80 bytes from 1.1.1.10: icmp_seq=1 ttl=64 time=0.180 ms
80 bytes from 1.1.1.10: icmp_seq=2 ttl=64 time=0.076 ms
80 bytes from 1.1.1.10: icmp_seq=3 ttl=64 time=0.084 ms
80 bytes from 1.1.1.10: icmp_seq=4 ttl=64 time=0.073 ms
80 bytes from 1.1.1.10: icmp_seq=5 ttl=64 time=0.071 ms
Determine the size of the new EOS image. Then verify the flash drive has enough space available for two copies of this image (use the dir command to check the bytes free figure).
switch# dir flash:
Directory of flash:/
-rwx   293168526      Nov 4    22:17   EOS4.11.0.swi
-rwx          36      Nov 8    10:24   boot-config
-rwx       37339      Jun 16   14:18   cfg_06162014

<-------OUTPUT OMITTED FROM EXAMPLE-------->
606638080 bytes total (602841088 bytes free)
Standby supervisor:
switch# dir supervisor-peer:mnt/flash/
Directory of flash:/
-rwx 293168526 Nov 4 22:17 EOS4.11.0.swi
-rwx 36 Nov 8 10:24 boot-config
-rwx 37339 Jun 16 14:18 cfg_06162014
<-------OUTPUT OMITTED FROM EXAMPLE-------->
606638080 bytes total (602841088 bytes free)

Finally, ensure that any extensions running on the primary supervisor are also available on the secondary supervisor.

Transfer the Image File to the Primary Supervisor

Load the desired image to the file system on the primary supervisor, typically into the flash. Use the CLI copy command to load files to the flash on the primary supervisor, then confirm that the system transferred the new image file correctly.

The following command examples illustrate transferring an image file from various locations to the flash drive.

USB Memory

Command

copy usb1:/sourcefile flash:/destfile

Example
switch# copy usb1:/EOS-4.13.2.swi flash:/EOS-4.13.2.swi

FTP Server

Command

copy ftp:/ftp-source/sourcefile flash:/destfile

Example
switch# copy ftp:/user:password@10.0.0.3/EOS-4.13.2.swi flash:/EOS-4.13.2.swi

SCP

Command

copy scp://scp-source/sourcefile flash:/destfile

Example
switch# copy scp://user@10.1.1.8/user/EOS-4.13.2.swi flash:/EOS-4.13.2.swi

HTTP

Command

copy http://http-source/sourcefile flash:/destfile

Example
switch# copy http://10.0.0.10/EOS-4.13.2.swi flash:/EOS-4.13.2.swi
After transferring the file, verify that it is present in the directory, then confirm the MD5 checksum using the verify command. The MD5 checksum for each available image can be found on the EOS download page of the Arista website.
switch# dir flash:
Directory of flash:/
-rwx      293168526     Nov 4    22:17     EOS4.11.0.swi
-rwx             36     Nov 8    10:24     boot-config
-rwx          37339     Jun 16   14:18     cfg_06162014
-rwx      394559902     May 30   02:57     EOS-4.12.2.swi

<-------OUTPUT OMITTED FROM EXAMPLE-------->

606638080 bytes total (208281186 bytes free)
switch#53# verify /md5 flash:EOS-4.13.2.swi 
verify /md5 (flash:EOS-4.13.2.swi) =c277a965d0ed48534de6647b12a86991

Install the New EOS Image

After the EOS image has been copied to the primary supervisor's flash drive, use the install command to update the boot-config, copy the new image to the secondary supervisor, and reload both supervisors. Both supervisors will briefly be unavailable when upgrading to a new image; using the install command minimizes packet loss during reload.
switch(config)# install source EOS-4.13.2.swi reload
Preparing new boot-config... done.
Copying new software image to standby supervisor... done.
Copying new boot-config to standby supervisor... done.
Committing changes on standby supervisor... done.
Reloading standby supervisor... done.
Committing changes on this supervisor... done.
Reloading this supervisor...

Verify the New Image

After the switch finishes reloading, log in to the switch and use the show version command to confirm the correct image is loaded. The Software image version line displays the version of the active image file.
switch# show version
Arista DCS-7504
Hardware version:    01.01
Serial number:       JPE13120819
System MAC address:  001c.7326.fd0c

Software image version: 4.13.2F
Architecture:           i386
Internal build version: 4.13.2F-1649184.4132F.2
Internal build ID:      eeb3c212-b4bd-4c19-ba34-1b0aa36e43f1

Uptime:                 1 hour and 36 minutes
Total memory:           4017088 kB
Free memory:            1473280 kB

switch#