LACP in WSL2 post

Author: commitconfirmed

site/content/posts/lacp-in-wsl2/featured.svg

@@ -0,0 +1,182 @@
++++
+title = "LACP 802.3ad bonding for Ubuntu hosts in WSL2"
+date = "2025-07-01"
+description = "A guide to getting LACP functional for Ubuntu hosts on Containerlab in Windows"
+tags = [
+    "bonding",
+    "containerlab",
+    "lacp",
+    "wsl2",
+    "linux",
+    "ubuntu",
+]
+showComments = "true"
+robots = "all"
++++
+
+## Introduction
+
+This article will show you how to get 802.3ad LACP bonding working easily on Linux hosts in Containerlab inside of a WSL2 instance, despite search results an your friendly LLM telling you this is not possible (unless you build your own WSL2 kernel). 
+
+## Issue
+
+If you have tried to enable bonding in the traditional way, you will see the below error message:
+
+```bash
+admin@host1:~$ sudo modprobe bonding mode=802.3ad miimon=100 lacp_rate=fast
+modprobe: FATAL: Module bonding not found in directory /lib/modules/6.6.87.2-microsoft-standard-WSL2
+```
+
+Searching around you will find the below explanation:
+
+> WSL2 does not support loading arbitrary kernel modules, including bonding, using modprobe by default. The WSL2 kernel is a custom kernel with pre-compiled modules and does not include the bonding module or support for loading new modules. To use bonding in WSL2, you would need to build a custom WSL2 kernel with the module included and then configure WSL2 to use that custom kernel. 
+
+## Solution
+
+To fix this, we can simply include the iproute2 package in the Dockerfile builds of your relevant container, i.e.
+
+```Dockerfile
+FROM ubuntu:latest
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Install iproute2
+RUN apt-get update -y && apt-get install -y \
+iproute2 \
+&& apt-get autoremove -y \
+&& apt-get clean -y \
+&& rm -rf /var/lib/apt/lists/*
+```
+
+A full example host Dockerfile is available [here](https://github.com/commitconfirmed/npa-showcases/blob/main/containers/lab-host/Dockerfile)
+
+{{< alert >}}
+**Note**: I also build the iperf3 application from source since in this Dockerfile since the ubuntu package manager has an older version. You can remove this and the gcc / make packages if you don't want to use iperf3
+{{< /alert >}}
+
+From here, you can simply execute the below in a script on the host or via the Containerlab [exec](https://containerlab.dev/cmd/exec/) option in your clab file:
+
+```bash
+ip link add bond0 type bond
+ip link set bond0 type bond mode 802.3ad lacp_active on lacp_rate fast
+ip link set eth1 down
+ip link set eth2 down
+ip link set eth1 master bond0
+ip link set eth2 master bond0
+ip addr add 192.168.100.10/24 dev bond0
+ip link set bond0 up
+```
+
+A full list of options can be seen by executing `ip link help bond`
+
+<details>
+<summary>Expand / Collapse command output</summary>
+
+```bash
+admin@host1:~$ ip link help bond
+Usage: ... bond [ mode BONDMODE ] [ active_slave SLAVE_DEV ]
+                [ clear_active_slave ] [ miimon MIIMON ]
+                [ updelay UPDELAY ] [ downdelay DOWNDELAY ]
+                [ peer_notify_delay DELAY ]
+                [ use_carrier USE_CARRIER ]
+                [ arp_interval ARP_INTERVAL ]
+                [ arp_validate ARP_VALIDATE ]
+                [ arp_all_targets ARP_ALL_TARGETS ]
+                [ arp_ip_target [ ARP_IP_TARGET, ... ] ]
+                [ ns_ip6_target [ NS_IP6_TARGET, ... ] ]
+                [ primary SLAVE_DEV ]
+                [ primary_reselect PRIMARY_RESELECT ]
+                [ fail_over_mac FAIL_OVER_MAC ]
+                [ xmit_hash_policy XMIT_HASH_POLICY ]
+                [ resend_igmp RESEND_IGMP ]
+                [ num_grat_arp|num_unsol_na NUM_GRAT_ARP|NUM_UNSOL_NA ]
+                [ all_slaves_active ALL_SLAVES_ACTIVE ]
+                [ min_links MIN_LINKS ]
+                [ lp_interval LP_INTERVAL ]
+                [ packets_per_slave PACKETS_PER_SLAVE ]
+                [ tlb_dynamic_lb TLB_DYNAMIC_LB ]
+                [ lacp_rate LACP_RATE ]
+                [ lacp_active LACP_ACTIVE]
+                [ ad_select AD_SELECT ]
+                [ ad_user_port_key PORTKEY ]
+                [ ad_actor_sys_prio SYSPRIO ]
+                [ ad_actor_system LLADDR ]
+                [ arp_missed_max MISSED_MAX ]
+
+BONDMODE := balance-rr|active-backup|balance-xor|broadcast|802.3ad|balance-tlb|balance-alb
+ARP_VALIDATE := none|active|backup|all|filter|filter_active|filter_backup
+ARP_ALL_TARGETS := any|all
+PRIMARY_RESELECT := always|better|failure
+FAIL_OVER_MAC := none|active|follow
+XMIT_HASH_POLICY := layer2|layer2+3|layer3+4|encap2+3|encap3+4|vlan+srcmac
+LACP_ACTIVE := off|on
+LACP_RATE := slow|fast
+AD_SELECT := stable|bandwidth|count
+```
+</details>
+
+## Demonstration
+
+See the below output from a host in my [npa-showcases](/npa-showcases) repo in the [basic-ceos-clos](https://github.com/commitconfirmed/npa-showcases/tree/main/examples/basic-ceos-clos) lab.
+
+```bash
+admin@host1:~$ ip addr list bond0.100
+9: bond0.100@bond0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
+    link/ether aa:c1:ab:44:7a:12 brd ff:ff:ff:ff:ff:ff
+    inet 192.168.100.10/24 scope global bond0.100
+       valid_lft forever preferred_lft forever
+    inet6 fe80::a8c1:abff:fe44:7a12/64 scope link
+       valid_lft forever preferred_lft forever
+
+admin@host1:~$ cat /proc/net/bonding/bond0
+Ethernet Channel Bonding Driver: v6.6.87.2-microsoft-standard-WSL2
+
+Bonding Mode: IEEE 802.3ad Dynamic link aggregation
+Transmit Hash Policy: layer2 (0)
+MII Status: up
+MII Polling Interval (ms): 100
+Up Delay (ms): 0
+Down Delay (ms): 0
+Peer Notification Delay (ms): 0
+
+802.3ad info
+LACP active: on
+LACP rate: fast
+Min links: 0
+Aggregator selection policy (ad_select): stable
+
+Slave Interface: eth1
+MII Status: up
+Speed: 10000 Mbps
+Duplex: full
+Link Failure Count: 0
+Permanent HW addr: aa:c1:ab:44:7a:12
+Slave queue ID: 0
+Aggregator ID: 2
+Actor Churn State: monitoring
+Partner Churn State: monitoring
+Actor Churned Count: 0
+Partner Churned Count: 0
+
+Slave Interface: eth2
+MII Status: up
+Speed: 10000 Mbps
+Duplex: full
+Link Failure Count: 0
+Permanent HW addr: aa:c1:ab:9e:04:09
+Slave queue ID: 0
+Aggregator ID: 2
+Actor Churn State: monitoring
+Partner Churn State: monitoring
+Actor Churned Count: 0
+Partner Churned Count: 0
+
+admin@host1:~$ ping 192.168.100.1
+PING 192.168.100.1 (192.168.100.1) 56(84) bytes of data.
+64 bytes from 192.168.100.1: icmp_seq=1 ttl=64 time=1.91 ms
+64 bytes from 192.168.100.1: icmp_seq=2 ttl=64 time=1.24 ms
+^C
+--- 192.168.100.1 ping statistics ---
+2 packets transmitted, 2 received, 0% packet loss, time 1001ms
+rtt min/avg/max/mdev = 1.241/1.577/1.913/0.336 ms
+```