73 lines
2.3 KiB
Markdown
73 lines
2.3 KiB
Markdown
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# Capturing VPP core dumps
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In order to debug a crash of VPP, it is required to provide a coredump file, which allows backtracing of the VPP issue. The following items are the requirements for capturing a coredump:
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#### 1. Disable k8s Probes to Prevent k8s from Restarting the POD with a Crashed VPP
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As described in [BUG_REPORTS.md](BUG_REPORTS.html#collecting-the-logs-in-case-of-crash-loop).
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#### 2. Modify VPP Startup config file
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In `/etc/vpp/contiv-vswitch.conf`, add the following lines into the `unix` section:
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```
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unix {
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...
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coredump-size unlimited
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full-coredump
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}
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```
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#### 3. Turn on Coredumps in the Vswitch Container
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After re-deploying Contiv-VPP networking, enter bash shell in the vswitch
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container (use actual name of the vswitch POD - `contiv-vswitch-7whk7` in this case):
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```
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kubectl exec -it contiv-vswitch-7whk7 -n kube-system -c contiv-vswitch bash
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```
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Enable coredumps:
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```
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mkdir -p /tmp/dumps
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sysctl -w debug.exception-trace=1
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sysctl -w kernel.core_pattern="/tmp/dumps/%e-%t"
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ulimit -c unlimited
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echo 2 > /proc/sys/fs/suid_dumpable
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```
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#### 4. Let VPP Crash
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Now repeat the steps that lead to the VPP crash. You can also force VPP to crash at the point where it is
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running (e.g., if it is stuck) by using the SIGQUIT signal:
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```
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kill -3 `pidof vpp`
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```
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#### 5. Locate and Inspect the Core File
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The core file should appear in `/tmp/dumps` in the container:
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```
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cd /tmp/dumps
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ls
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vpp_main-1524124440
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```
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You can try to backtrace, after installing gdb:
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```
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apt-get update && apt-get install gdb
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gdb vpp vpp_main-1524124440
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(gdb) bt
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```
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#### 6. Copy the Core File Out of the Container
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Finally, copy the core file out of the container. First, while still inside the container,
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pack the core file into an archive:
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```
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cd /tmp/dumps
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tar cvzf vppdump.tar.gz vpp_main-1524124440
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```
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Now, on the host, determine the docker ID of the container, and then copy the file out of the host:
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```
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docker ps | grep vswitch_contiv
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d7aceb2e4876 c43a70ac3d01 "/usr/bin/supervisor…" 25 minutes ago Up 25 minutes k8s_contiv-vswitch_contiv-vswitch-zqzn6_kube-system_9923952f-43a6-11e8-be84-080027de08ea_0
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docker cp d7aceb2e4876:/tmp/dumps/vppdump.tar.gz .
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```
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Now you are ready to file a bug in [jira.fd.io](https://jira.fd.io/) and attach the core file.
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