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BuildTroubleshooting.md

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Summary

Building images for embedded devices can be sometimes tricky. It may involve cross-compiling, kernel and package management, chroot(), and other system devices that individually are not that complicated but come together to be a lot of sharp edges. Part of the value of ONL is the scripts that automate these steps for you. That said, with any automation, someone eventually needs to understand what the steps are to fix it when things break. This document tries to address some of the most common sources of build problems.

chws and isolate

The mkws, chws, and isolate commands all come together to build a dedicated and isolated workspace to build the various switch images.

This 'isolate' environment actually does a number of things including:

With a workspace, you can have multiple builds running in parallel and any ports that get bound actually get bound inside the name space so that they do not conflict.

When properly setup, inside the name space you should see:

    robs@ubuntu:~/work.onl/ONL$ cd ..
    robs@ubuntu:~/work.onl$ mkws -a amd65 ws.amd64
    # lots of output
    robs@ubuntu:~/work.onl$ cd ws.amd64
    robs@ubuntu:~/work.onl/ws.amd64$ chws
    (iso1:ws.amd64)robs@ubuntu:~/work.onl/ws.amd64$ ifconfig
    iso1      Link encap:Ethernet  HWaddr 5a:d3:21:66:13:21  
              inet addr:10.198.0.1  Bcast:0.0.0.0  Mask:255.255.255.254     <=== IP inside workspace
              inet6 addr: fe80::58d3:21ff:fe66:1321/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:29 errors:0 dropped:0 overruns:0 frame:0
              TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:8101 (7.9 KiB)  TX bytes:328 (328.0 B)
    [snip]
    (iso1:ws.amd64)robs@ubuntu:~/work.onl/ws.amd64$ route
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    default         10.198.0.0      0.0.0.0         UG    0      0        0 iso1 <=== route out to host machine
    10.198.0.0      *               255.255.255.254 U     0      0        0 iso1

So, it is almost like a virtual machine inside a virtual machine. This VM has IP 10.192.0.1 and has a default route to 10.192.0.0 (yes, 10.192.0.0 is a valid address). If you look outside the network namespace (e.g., on another shell), you should see the iso0 device has IP 10.192.0.0:

    robs@ubuntu:~/work.onl/ONL$ ifconfig
    [snip]
    iso0      Link encap:Ethernet  HWaddr 1a:12:86:31:29:9b  
              inet addr:10.198.0.0  Bcast:0.0.0.0  Mask:255.255.255.254     <=== the "router" for the workspace
              inet6 addr: fe80::1812:86ff:fe31:299b/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:9 errors:0 dropped:0 overruns:0 frame:0
              TX packets:39 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:635 (635.0 B)  TX bytes:9298 (9.2 KB)

So the first thing to check is to make sure that you can ping from inside the workspace to the 10.198.0.0 address:

    (iso1:ws.amd64)robs@ubuntu:~/work.onl/ws.amd64$ ping 10.198.0.0
    PING 10.198.0.0 (10.198.0.0) 56(84) bytes of data.
    64 bytes from 10.198.0.0: icmp_req=1 ttl=64 time=0.182 ms
    64 bytes from 10.198.0.0: icmp_req=2 ttl=64 time=0.059 ms
    # works!

If this step fails, then perhaps you have some kind of IP management daemon (e.g., NetworkManager) turned on. Verify the iso0 IP address on the outside of the workspace and if it does not have an IP assigned or if it is different from 10.192.0.0, this is probably the problem.

The second thing to check is to see if you can ping from inside the workspace to the outside world:

    (iso1:ws.amd64)robs@ubuntu:~/work.onl/ws.amd64$ ping 8.8.8.8
    PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
    64 bytes from 8.8.8.8: icmp_req=1 ttl=127 time=55.3 ms
    64 bytes from 8.8.8.8: icmp_req=2 ttl=127 time=47.2 ms
    # works!

If this does not work, then your Linux machine/VM does not have IP forwarding enabled -- check the top of the QUICKSTART.readme instructions for how to enable IP forwarding.

The third thing to try is to make sure that DNS resolution is working inside the workspace:

    (iso1:ws.amd64)robs@ubuntu:~/work.onl/ws.amd64$ ping google.com
    PING google.com (74.125.239.130) 56(84) bytes of data.
    64 bytes from nuq05s02-in-f2.1e100.net (74.125.239.130): icmp_req=1 ttl=127 time=28.9 ms
    64 bytes from nuq05s02-in-f2.1e100.net (74.125.239.130): icmp_req=2 ttl=127 time=33.8 ms
    # works!

If this does not work, then check the /etc/resolv.conf inside the workspace and make sure you can ping that DNS server. It should match the DNS server from your host Linux machine.