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Update debugging.md

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Fabricio Voznika 2019-04-04 22:31:51 -07:00 committed by Fabricio Voznika
parent e9504bfdf2
commit cd5ded7e06
1 changed files with 15 additions and 17 deletions
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content/docs/user_guide/debugging.md
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@ -32,14 +32,12 @@ Run your container again, and inspect the files under `/tmp/runsc`. The log file
with name `boot` will contain the strace logs from your application, which can
be useful for identifying missing or broken system calls in gVisor.
## Stack Trace
## Stack traces
`runsc debug --stacks` command allows stack traces to be collected while the
sandbox is running which can be useful to troubleshoot issues or just to learn
more about gVisor. It connects to the sandbox process, collects a stack dump,
and writes it to the console.
Here is an example:
The command `runsc debug --stacks` collects stack traces while the sandbox is
running which can be useful to troubleshoot issues or just to learn more about
gVisor. It connects to the sandbox process, collects a stack dump, and writes
it to the console. For example:
```bash
docker run --runtime=runsc --rm -d alpine sh -c "while true; do echo running; sleep .1; done"
@ -52,10 +50,9 @@ sudo runsc --root /var/run/docker/runtime-runsc/moby debug --stacks 63254c6ab3a6
> `/var/run/docker/runtime-[runtime-name]/moby`. If in doubt, `--root` is logged to
> `runsc` logs.
## Profiling
`runsc` integrates with Go profilling tools and gives you easy commands to profile
`runsc` integrates with Go profiling tools and gives you easy commands to profile
CPU and heap usage. First you need to enable `--profile` in the command line options
before starting the container:
@ -72,18 +69,18 @@ before starting the container:
}
```
> Note: Enabling profiler loosens the seccomp protection added to the sandbox,
> Note: Enabling profiling loosens the seccomp protection added to the sandbox,
> and should not be run in production under normal circumstances.
Then restart docker to refresh the runtime options. While the container is running,
execute `runsc debug` to collect profile information and save to a file. Here are
the options available:
* **--profile-heap:** It generates heap profile to the speficied file.
* **--profile-cpu:** It enables CPU profiler, waits for `--profile-delay` seconds
* **--profile-heap:** Generates heap profile to the speficied file.
* **--profile-cpu:** Enables CPU profiler, waits for `--profile-delay` seconds
and generates CPU profile to the speficied file.
Here is an example::
For example:
```bash
docker run --runtime=runsc-prof --rm -d alpine sleep 1000
@ -93,12 +90,13 @@ sudo runsc --root /var/run/docker/runtime-runsc-prof/moby debug --profile-heap=/
sudo runsc --root /var/run/docker/runtime-runsc-prof/moby debug --profile-cpu=/tmp/cpu.prof --profile-delay=30 63254c6ab3a6989623fa1fb53616951eed31ac605a2637bb9ddba5d8d404b35b
```
The resulting files can be opened using `go tool pprof` or [pprof]
(https://github.com/google/pprof/blob/master/doc/README.md). The examples below
create image file (`.svg`) with the heap profile and writes the top functions
using CPU to the console:
The resulting files can be opened using `go tool pprof` or [pprof]. The examples
below create image file (`.svg`) with the heap profile and writes the top
functions using CPU to the console:
```bash
go tool pprof -svg /usr/local/bin/runsc /tmp/heap.prof
go tool pprof -top /usr/local/bin/runsc /tmp/cpu.prof
```
[pprof]: https://github.com/google/pprof/blob/master/doc/README.md