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XRd-Sandbox

XRd is a containerized IOS-XR operating system that you can deploy on any kind of on-premises or public cloud infrastructure.

XRd inherits all the programmability aspects, including NETCONF and YANG models, from IOS-XR.

The XRd Sandbox provides an environment where developers and network engineers can explore the programmability options available.

Important

On this repository, you can find the files used to create the XRd Sandbox for reference.

Find the XRd Sandbox at developer.cisco.com/sandbox click on "Launch Sandbox" look for the XRd Sandbox and create a reservation.

On the XRd Sandbox, you find:

At the end of the Sandbox, you learn how to work with XRd in a containerized environment with a working segment routing topology.

Lab

We have prepared one Lab to run a segment routing topology that consists of seven (7) XRd routers.

One of the XRd routers functions as a PCE, and another XRd router serves as a vRR. Also, we use two alpine containers as the source and destination hosts.

               xrd-7(PCE)
               /        \
            xrd-3 --- xrd-4
             / |        | \
src --- xrd-1  |        |  xrd-2 --- dst
             \ |        | /
            xrd-5 --- xrd-6
               \        /
               xrd-8(vRR)

The Lab is a copy of the segment-routing sample topology from xrd-tools with additional modifications to work on the Sandbox management network.

Docker Driver

Docker macvlan represents one modification that allows the XRd containers to be on the same management network as the host.

networks:
  mgmt:
    ipam:
      config:
        - subnet: 10.10.20.0/24
          gateway: 10.10.20.254
    driver: macvlan
    driver_opts:
      parent: ens160

See the docker-compose.xr.yml file to see the full configuration.

Management Addresses in XRd

For assigning the management address in XRd, we used the flag snoop_v4 to ensure XRd picks the address that is defined under networks/mgmt/ipv4_address.

The flag snoop_v4_default_route was also used to create a default route for this interface, to ensure that management traffic is able to return.

xrd-3:
  xr_startup_cfg: xrd-3-startup.cfg
  xr_interfaces:
    - Gi0/0/0/0
    - Gi0/0/0/1
    - Gi0/0/0/2
    - Gi0/0/0/3
    - Mg0/RP0/CPU0/0:
        snoop_v4: True
        snoop_v4_default_route: True
  networks:
    mgmt:
      ipv4_address: 10.10.20.103

To learn more about these and other flags, see User Interface and Knobs for XRd.

Host-check

When working on your own environment, ensure you run host-check to verify your host is ready for XRd. Make sure you pick the right choices for your image (control plane or vrouter). The host in the Sandbox is already prepared.

Note

You won't be able to run the command in the Sandbox since it requires sudo privileges. Look at the output to become familiar with it.

sudo ~/xrd-tools/scripts/host-check --platform xrd-control-plane --extra-checks docker --extra-checks xr-compose
OUTPUT 
developer@ubuntu:~$ sudo ~/xrd-tools/scripts/host-check --platform xrd-control-plane --extra-checks docker --extra-checks xr-compose
==============================
Platform checks - xrd-control-plane
==============================
 PASS -- CPU architecture (x86_64)
 PASS -- CPU cores (10)
 PASS -- Kernel version (5.15)
 PASS -- Base kernel modules
         Installed module(s): dummy, nf_tables
 INFO -- Cgroups
         Cgroups v2 is in use - this is not supported for production environments.
 PASS -- Inotify max user instances
         64000 - this is expected to be sufficient for 16 XRd instance(s).
 PASS -- Inotify max user watches
         249493 - this is expected to be sufficient for 62 XRd instance(s).
 PASS -- Socket kernel parameters (valid settings)
 PASS -- UDP kernel parameters (valid settings)
 INFO -- Core pattern (core files managed by the host)
 PASS -- ASLR (full randomization)
 WARN -- Linux Security Modules
         AppArmor is enabled. XRd is currently unable to run with the
         default docker profile, but can be run with
         '--security-opt apparmor=unconfined' or equivalent.
         However, some features might not work, such as ZTP.
 PASS -- Kernel module parameters
         Kernel modules loaded with expected parameters.
 PASS -- RAM
         Available RAM is 30.6 GiB.
         This is estimated to be sufficient for 15 XRd instance(s), although memory
         usage depends on the running configuration.
         Note that any swap that may be available is not included.

==============================
Extra checks
==============================

xr-compose checks
-----------------------
 PASS -- docker-compose (version 2.24.0)
 PASS -- PyYAML (installed)
 FAIL -- Bridge iptables
         For xr-compose to be able to use Docker bridges, bridge IP tables must
         be disabled. Note that there may be security considerations associated
         with doing so.
         Bridge IP tables can be disabled by setting the kernel parameters
         net.bridge.bridge-nf-call-iptables and net.bridge.bridge-nf-call-ip6tables
         to 0. These can be modified by adding 'net.bridge.bridge-nf-call-iptables=0'
         and 'net.bridge.bridge-nf-call-ip6tables=0' to /etc/sysctl.conf or in a
         dedicated conf file under /etc/sysctl.d/.
         For a temporary fix, run:
           sysctl -w net.bridge.bridge-nf-call-iptables=0
           sysctl -w net.bridge.bridge-nf-call-ip6tables=0

============================================================================
!! One or more platform checks resulted in a warning, see warnings above !!
----------------------------------------------------------------------------
Extra checks failed: xr-compose
============================================================================
developer@ubuntu:~$

Start the Lab

To practice, go to developer.cisco.com/sandbox click on "Launch Sandbox" look for the XRd Sandbox and create a reservation.

Learn more

Look at the xrdocs tutorials which explain in detail all the in-and-outs of XRd.

You can find additional Labs on the xrd-tools samples GitHub repository.

Check out our IOS-XR Dev Center on DevNet to find more material around IOS-XR programmability.

Help

For questions about XRd itself go to the Network Devices community.

For issues with the Sandbox, first, release your current reservation and initiate a new one. If the issues persist, contact the Sandbox team on the Sandbox community space.

Appendix - Changes done on the VM

Docker Pools

We set up default address pools to avoid overlapping with networks used by the Sandbox infrastructure, which caused traffic blackholes. The bridge networks that are created between XRd containers that are used as links, overlapped with IP segments used by the Sandbox, routing traffic incorrectly as a result.

The fix was to define a default network pool to be used by the Docker bridge driver.

developer@ubuntu:~$ cat /etc/docker/daemon.json
{
  "default-address-pools": [
    {
      "base": "172.80.0.0/16",
      "size": 24
    }
  ]
}
developer@ubuntu:~$

How the Sandbox was built

A Ubuntu server LTS was used as OS.

We installed Docker from the official Docker documentation to ensure using the latest version available.

The following settings were applied to the VM. These settings were requested by the host-check script.

echo -e "fs.inotify.max_user_instances=64000\n\
net.core.netdev_max_backlog=300000\n\
net.core.optmem_max=67108864\n\
net.core.rmem_default=67108864\n\
net.core.rmem_max=67108864\n\
net.core.wmem_default=67108864\n\
net.core.wmem_max=67108864\n\
net.bridge.bridge-nf-call-iptables=0\n\
net.bridge.bridge-nf-call-ip6tables=0\n\
net.ipv4.udp_mem=1124736 10000000 67108864" | sudo tee /etc/sysctl.d/local.conf \
&& sudo service procps force-reload
OUTPUT 
developer@ubuntu:~/xrd-tools/scripts$ cat /etc/sysctl.d/local.conf
fs.inotify.max_user_instances=64000
net.core.netdev_max_backlog=300000
net.core.optmem_max=67108864
net.core.rmem_default=67108864
net.core.rmem_max=67108864
net.core.wmem_default=67108864
net.core.wmem_max=67108864
net.bridge.bridge-nf-call-iptables=0
net.bridge.bridge-nf-call-ip6tables=0
net.ipv4.udp_mem=1124736 10000000 67108864