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Configuring switchd

The switchd service enables the switch to communicate with Cumulus Linux and all the applications running on Cumulus Linux.

Configure switchd Settings

You can control certain options associated with the switchd process. For example, you can set polling intervals, optimize ACL hardware resources for better utilization, configure log message levels, set the internal VLAN range, and configure VXLAN encapsulation and decapsulation.

To configure switchd options, you either run NVUE commands or manually edit the /etc/cumulus/switchd.conf file.

NVUE currently only supports a subset of the switchd configuration available in the /etc/cumulus/switchd.conf file.

You can run NVUE commands to set the following switchd options:

  • The statistic polling interval for physical interfaces and for logical interfaces.
    • For physical interfaces, you can specify a value between 1 and 10. The default setting is 2 seconds
    • For logical interfaces, you can specify a value between 1 and 30. The default setting is 5 seconds.

A low setting, such as 1, might affect system performance.

  • The log level to debug the data plane programming related code. You can specify debug, info, notice, warning, or error. The default setting is info. NVIDIA recommends that you do not set the log level to debug in a production environment.
  • The DSCP action and value for encapsulation. You can set the DSCP action to copy (to copy the value from the IP header of the packet), set (to specify a specific value), or derive (to obtain the value from the switch priority). The default action is derive. Only specify a value if the action is set.
  • The DSCP action for decapsulation in VXLAN outer headers. You can specify copy (to copy the value from the IP header of the packet), preserve (to keep the inner DSCP value), or derive (to obtain the value from the switch priority). The default action is derive.
  • The preference between a route and neighbor with the same IP address and mask. You can specify route, neighbor, or route-and-neighbor. The default setting is route.
  • The ACL mode (atomic or non-atomic). The default setting is atomic.
  • The reserved VLAN range. The default setting is 3725-3999.

Certain switchd settings require a switchd restart or reload. Before applying the settings, NVUE indicates if it requires a switchd restart or reload and prompts you for confirmation.

  • When the switchd service restarts, in addition to resetting the switch hardware configuration, all network ports reset.
  • When the switchd service reloads, there is no interruption to network services.

The following command example sets both the statistic polling interval for logical interfaces and physical interfaces to 6 seconds:

cumulus@switch:~$ nv set system counter polling-interval logical-interface 6
cumulus@switch:~$ nv set system counter polling-interval physical-interface 6
cumulus@switch:~$ nv config apply

The following command example sets the log level for debugging the data plane programming related code to warning:

cumulus@switch:~$ nv set system forwarding programming log-level warning
cumulus@switch:~$ nv config apply

The following command example sets the DSCP action for encapsulation in VXLAN outer headers to set and the value to af12:

cumulus@switch:~$ nv set nve vxlan encapsulation dscp action set
cumulus@switch:~$ nv set nve vxlan encapsulation dscp value af12
cumulus@switch:~$ nv config apply

The following command example sets the DSCP action for decapsulation in VXLAN outer headers to preserve:

cumulus@switch:~$ nv set nve vxlan decapsulation dscp action preserve
cumulus@switch:~$ nv config apply

The following command example sets the route or neighbor preference to both route and neighbor:

cumulus@switch:~$ nv set system forwarding host-route-preference route-and-neighbour
cumulus@switch:~$ nv config apply

The following command example sets the ACL mode to non-atomic:

cumulus@switch:~$ nv set system acl mode non-atomic 
cumulus@switch:~$ nv config apply

The following command example sets the reserved VLAN range between 4064 and 4094:

cumulus@switch:~$ nv set system global reserved vlan internal range 4064-4094
cumulus@switch:~$ nv config apply

To configure the switchd parameters, edit the /etc/cumulus/switchd.conf file. Change the setting and uncomment the line if needed. The switchd.conf file contains comments with a description for each setting.

The following example shows the first few lines of the /etc/cumulus/switchd.conf file.

cumulus@switch:~$ sudo nano /etc/cumulus/switchd.conf
#
# /etc/cumulus/switchd.conf - switchd configuration file
#
# Statistic poll interval (in msec)
#stats.poll_interval = 2000

# Buffer utilization poll interval (in msec), 0 means disable
#buf_util.poll_interval = 0

# Buffer utilization measurement interval (in mins)
#buf_util.measure_interval = 0

# Optimize ACL HW resources for better utilization
#acl.optimize_hw = FALSE

# Enable Flow based mirroring.
#acl.flow_based_mirroring = TRUE
...

The following table describes the /etc/cumulus/switchd.conf file parameters and indicates if you need to restart switchd with the sudo systemctl restart switchd.service command or reload switchd with the sudo systemctl reload switchd.service command for changes to take effect when you update the setting.

Restarting the switchd service causes all network ports to reset in addition to resetting the switch hardware configuration.

ParameterDescriptionswitchd reload or restart
stats.poll_intervalThe statistics polling interval in milliseconds.
The default setting is 2000.
restart
buf_util.poll_intervalThe buffer utilization polling interval in milliseconds. 0 disables buffer utilization polling.
The default setting is 0.
restart
buf_util.measure_intervalThe buffer utilization measurement interval in minutes.
The default setting is 0.
restart
acl.optimize_hwOptimizes ACL hardware resources for better utilization.
The default setting is FALSE.
restart
acl.flow_based_mirroringEnables flow-based mirroring.
The default setting is TRUE.
restart
acl.non_atomic_update_modeEnables non atomic ACL updates
The default setting is FALSE.
reload
arp.next_hopsSends ARPs for next hops.
The default setting is TRUE.
restart
route.tableThe kernel routing table ID. The range is between 1 and 2^31.
The default is 254.
restart
route.host_max_percentThe maximum neighbor table occupancy in hardware (a percentage of the hardware table size).
The default setting is 100.
restart
coalescing.reducerThe coalescing reduction factor for accumulating changes to reduce CPU load.
The default setting is 1.
restart
coalescing.timeoutThe coalescing time limit in seconds.
The default setting is 10.
restart
ignore_non_swpsIgnore routes that point to non-swp interfaces.
The default setting is TRUE.
restart
disable_internal_parity_restartDisables restart after a parity error.
The default setting is TRUE.
restart
disable_internal_hw_err_restartDisables restart after an unrecoverable hardware error.
The default setting is FALSE.
restart
nat.static_enableEnables static NAT.
The default setting is TRUE.
restart
nat.dynamic_enableEnables dynamic NAT.
The default setting is TRUE.
restart
nat.age_poll_intervalThe NAT age polling interval in minutes. The minimum is 1 minute and the maximum is 24 hours. You can configure this setting only when nat.dynamic_enable is set to TRUE.
The default setting is 5.
restart
nat.table_sizeThe NAT table size limit in number of entries. You can configure this setting only when nat.dynamic_enable is set to TRUE.
The default setting is 1024.
restart
nat.config_table_sizeThe NAT configuration table size limit in number of entries. You can configure this setting only when nat.dynamic_enable is set to TRUE.
The default setting is 64.
restart
loggingConfigures logging in the format BACKEND=LEVEL. Separate multiple BACKEND=LEVEL pairs with a space. The BACKEND value can be stderr, file:filename, syslog, program:executable. The LEVEL value can be CRIT, ERR, WARN, INFO, DEBUG.
The default value is syslog=INFO
restart
interface.<interface>.storm_control.broadcastEnables broadcast storm control and sets the number of packets per second (pps).
The default setting is 400.
reload
interface.<interface>.storm_control.multicastEnables multicast storm control and sets the number of packets per second (pps).
The default setting is 3000.
reload
interface.<interface>.storm_control.unknown_unicastEnables unicast storm control and sets the number of packets per second (pps).
The default setting is 2000.
reload
stats.vlan.aggregateEnables hardware statistics for VLANs and specifies the type of statistics needed. You can specify NONE, BRIEF, or DETAIL.
The default setting is BRIEF.
restart
stats.vxlan.aggregateEnables hardware statistics for VXLANs and specifies the type of statistics needed. You can specify NONE, BRIEF, or DETAIL.
The default setting is DETAIL.
restart
stats.vxlan.memberEnables hardware statistics for VXLAN members and specifies the type of statistics needed. You can specify NONE, BRIEF, or DETAIL.
The default setting is BRIEF.
restart
stats.vlan.show_internal_vlansShow internal VLANs.
The default setting is FALSE.
restart
stats.vdev_hw_poll_intervalThe polling interval in seconds for virtual device hardware statisitcs.
The default setting is 5.
restart
resv_vlan_rangeThe internal VLAN range.
The default setting is 3725-3999.
restart
netlink.buf_sizeThe netlink socket buffer size in MB.
The default setting is 136314880.
restart
route.delete_dead_routesDelete routes on interfaces when the carrier is down.
The default setting is TRUE.
restart
vxlan.default_ttlThe default TTL to use in VXLAN headers.
The default setting is 64.
restart
bridge.broadcast_frame_to_cpuEnables bridge broadcast frames to the CPU even if the SVI is not enabled.
The default setting is FALSE.
restart
bridge.unreg_mcast_initInitialize the prune module for IGMP snooping unregistered layer 2 multicast flood control.
The default setting is FALSE.
restart
bridge.unreg_v4_mcast_pruneEnables unregistered layer 2 multicast prune to mrouter ports (IPv4).
The default setting is FALSE (flood unregistered layer 2 multicast traffic).
restart
bridge.unreg_v6_mcast_pruneEnables unregistered layer 2 multicast prune to mrouter ports (IPv6).
The default setting is FALSE (flood unregistered layer 2 multicast traffic).
restart
netlink libnl loggerThe default setting is [0-5].restart
netlink.nl_loggerThe default setting is 0.restart
vxlan.def_encap_dscp_actionSets the default VXLAN router DSCP action during encapsulation. You can specify copy if the inner packet is IP, set to set a specific value, or derive to derive the value from the switch priority.
The default setting is derive.
reload
vxlan.def_encap_dscp_valueSets the default VXLAN encapsulation DSCP value if the action is set.
reload
vxlan.def_decap_dscp_actionSets the default VXLAN router DSCP action during decapsulation. You can specify copy if the inner packet is IP, preserve to preserve the inner DSCP value, or derive to derive the value from the switch priority.
The default setting is derive.
reload
ipmulticast.unknown_ipmc_to_cpuEnables sending unknown IPMC to the CPU.
The default setting is FALSE.
restart
vrf_route_leak_enable_dynamicEnables dynamic VRF route leaking.
The default setting is FALSE.
restart
sync_queue_depth_valThe event queue depth.
The default setting is 50000.
restart
route.route_preferred_over_neighSets the preference between a route and neighbor with the same IP address and mask. You can specify TRUE to prefer the route over the neighbor, FALSE to prefer the neighbor over the route, or BOTH to install both the route and neighbor.
The default setting is TRUE.
reload
evpn.multihoming.enableEnables EVPN multihoming.
The default setting is TRUE.
restart
evpn.multihoming.shared_l2_groupsEnables sharing for layer 2 next hop groups.
The default setting is FALSE.
restart
evpn.multihoming.shared_l3_groupsEnables sharing for layer 3 next hop groups.
The default setting is FALSE.
restart
evpn.multihoming.fast_local_protectEnables fast reroute for egress link protection. The default setting is FALSE.restart
evpn.multihoming.bum_sph_filterSets split-horizon filtering for EVPN multihoming. You can specify TRUE to filter only BUM traffic from the Ethernet segment (ES) peer or FALSE to filter all traffic from the ES peer.
The default setting is TRUE.
restart
link_flap_windowThe duration in seconds during which a link must flap the number of times set in the link_flap_threshold before Cumulus Linux sets the link to protodown and specifies linkflap as the reason.
The default setting is 10. A value of 0 disables link flap protection.
restart
link_flap_thresholdThe number of times the link must flap within the link flap window before Cumulus Linux sets the link to protodown and specifies linkflap as the reason.
The default setting is 5. A value of 0 disables link flap protection.
restart
res_usage_warn_thresholdSets the percentage over which forwarding resources (routes, hosts, MAC addresses) must go before Cumulus Linux generates a warning. You can set a value between 50 and 95.
The default setting is 90.
restart
res_warn_msg_intThe time interval in seconds between resource warning messages. Warning messages generate only one time in the specified interval per resource type even if the threshold falls below or goes over the value set in res_usage_warn_threshold multiple times during this interval. You can set a value between 60 and 3600.
The default setting is 300.
restart

Show switchd Settings

You can run the following NVUE commands to show the current switchd configuration settings.

Command
Description
nv show system counter polling-intervalShows the polling interval for physical and logical interface counters in seconds.
nv show system forwarding programmingShows the log level for data plane programming logs.
nv show nve vxlan encapsulation dscpShows the DSCP action and value (if the action is set) for the outer header in VXLAN encapsulation.
nv show nve vxlan decapsulation dscpShows the DSCP action for the outer header in VXLAN decapsulation.
nv show system aclShows the ACL mode (atomic or non-atomic).
nv show system global reserved vlan internalShows the reserved VLAN range.

The following example command shows that the polling interval setting for logical interface counters is 6 seconds:

cumulus@switch:~$ nv show system counter polling-interval
                   applied  description
-----------------  -------  -----------------------------------------------------
logical-interface  0:00:06  Config polling-interval for logical interface(in sec)

The following example command shows that the log level setting for data plane programming logs is warning:

cumulus@switch:~$ nv show system forwarding programming
           applied  description
---------  -------  -------------------
log-level  warning  configure Log-level

The following example command shows that the DSCP action setting for the outer header in VXLAN encapsulation is set and the value is af12.

cumulus@switch:~$ nv show nve vxlan encapsulation dscp
        operational  applied  description
------  -----------  -------  --------------------------------------------------
action  set          set      DSCP encapsulation action
value   af12         af12     Configured DSCP value to put in outer Vxlan packet

The following command example shows that ACL mode is atomic:

cumulus@switch:~$ nv show system acl
      applied  description
----  -------  -----------------------------------------
mode  atomic   configure Atomic or Non-Atomic ACL update

The following command example shows that the reserved VLAN range is between 4064 and 4094:

cumulus@switch:~$ nv show system global reserved vlan internal
       operational  applied    description
-----  -----------  ---------  -------------------
range  4064-4094    4064-4094  Reserved Vlan range

In addition to restarting switchd when you change certain /etc/cumulus/switchd.conf file parameters manually, you also need to restart switchd whenever you modify a switchd hardware configuration file (any *.conf file that requires making a change to the switching hardware, such as /etc/cumulus/datapath/traffic.conf). You do not have to restart the switchd service when you update a network interface configuration (for example, when you edit the /etc/network/interfaces file).