VPP/BugReports

Introduction

Although every situation is different, this page describes data which will help make efficient use of everyone's time when dealing with vpp bugs.

Before you press the Jira button to create a bug report - or email vpp-dev@lists.fd.io - please ask yourself whether there's enough information for someone else to understand / reproduce the issue given a reasonable amount of effort. Unicast emails to maintainers, committers, and the project PTL are strongly discouraged.

A good strategy: file a detailed Jira ticket, and then send a short description of the issue to vpp-dev@lists.fd.io, perhaps from the Jira ticket description.

Image version and operating environment

Please make sure to include the vpp image version:

sudo vppctl show version verbose
vpp v1.0.0-188~geef4d99 built by vagrant on localhost at Wed Feb 24 08:52:13 PST 2016
Built in /home/vagrant/git/vpp
Compiled with GCC 4.8.4
DPDK version is RTE 2.2.0
DPDK EAL init arguments: -c 1 -n 4 --socket-mem 1024 --huge-dir /run/vpp/hugepages --file-prefix vpp 
                         -b 0000:02:00.0 -b 0000:02:01.0 --master-lcore 0 

Please attempt to reproduce issues using unmodified vpp engine images.

With respect to the operating environment: if misbehavior involving a specific VM / container / bare-metal environment is involved, please describe the environment in detail:

• Linux Distro (e.g. Ubuntu 14.04.3 LTS, CentOS-7, etc.)
• NIC type(s) (ixgbe, i40e, enic, etc. etc.), vhost-user, tuntap
• NUMA configuration if applicable

"Show" Command Output

Every situation is different. If the issue involves a sequence of debug CLI command, please enable CLI command logging, and send the sequence involved. Note that the debug CLI is a developer's tool - no warranty express or implied - and that we may choose not to fix debug CLI bugs.

Please include "show error" [error counter] output. It's often helpful to "clear error", send a bit of traffic, then "show error" on noisy networks.

Please include ip4 / ip6 / mpls FIB contents ("show ip fib", "show ip6 fib", "show mpls fib", "show mpls tunnel").

Please include "show hardware", "show interface", and "show interface address" output

Here is a consolidated set of commands that are generally useful before/after sending traffic. Before sending traffic:

sudo vppctl clear hardware
sudo vppctl clear interface
sudo vppctl clear error
sudo vppctl clear run

Send some traffic and then issue the following commands:

sudo vppctl show version verbose
sudo vppctl show hardware
sudo vppctl show hardware address
sudo vppctl show interface
sudo vppctl show run
sudo vppctl show error

Here are some protocol specific show commands that may also make sense. Only include those features which have been configured:

sudo vppctl show l2fib
sudo vppctl show bridge-domain

sudo vppctl show ip fib
sudo vppctl show ip arp

sudo vppctl show ip6 fib
sudo vppctl show ip6 neighbors

sudo vppctl show mpls fib
sudo vppctl show mpls tunnel

Network Topology

Please include a crisp description of the network topology, including L2 / IP / MPLS / segment-routing addressing details. If you expect folks to reproduce and debug issues, this is a must.

At or above a certain level of topological complexity, it becomes problematic to reproduce the original setup.

Packet Tracer Output

If you capture packet tracer output which seems relevant, please include it:

sudo vppctl trace add dpdk-input 100  # or similar

<send-traffic>

sudo vppctl show trace

Binary API Trace

If the issue involves a sequence of control-plane API messages - even a very long sequence - please enable control-plane API tracing. Control-plane API post-mortem traces end up in /tmp/api_post_mortem.<pid>. Please provide a pointer [accessible to the general public!] to the binary API trace. These API traces are especially helpful in cases where the vpp engine is throwing traffic on the floor, e.g. for want of a default route or similar.

Core Files

We would prefer to reproduce issues, rather than trying to debug them by inspection of core files, gdb backtraces, etc. However, production systems as well as long-running pre-production soak-test systems must arrange to collect core images. The Ubuntu "corekeeper" package works well. Vpp core files often appear enormous. Gzip typically compresses them to very manageable sizes. Again, please put core files in public places.

Core files from private, modified images are discouraged. If it's necessary to go that route, access to the unmodified workspace used to build the image in question is required. If we go through the private image + core file setup process only to discover that the image and core files don't match, it will simply delay resolution of the issue. And it will annoy the heck out of the engineer who just wasted their time. Unmodified means unmodified, not "oh, I added a few lines of debug scaffolding since then..."