Debugging `confinement: strict` issues

Jamie Strandboge jamie at
Tue Jun 7 17:22:27 UTC 2016

On Tue, 2016-06-07 at 22:56 +0800, Reinhard Pointner wrote:
> Hi all,
> Does anyone have any hints on how to debug issues that only happen in
> non-devmode? Like logging when certain "interfaces" are used?
> I'm working on snapping a Java application, and I've got `plugs: [home,
> network]` in my snapcraft.yaml but the app can't write any files in the
> user home (home plug should give the app write access right? also, what
> about network shares mounted by the user?). Also, when making http requests
> that thread will just deadlock (no exceptions or and timeouts not
> respected, so i suspect lower level network api issues).

In addition to what Zygmunt said elsewhere in the thread, there is a snap in the
store called 'snappy-debug' that will get better over time but is already

$ sudo snap install snappy-debug --devmode # after 2.0.7 lands, drop --devmode
$ sudo snap connect snappy-debug:log-observe ubuntu-core:log-observe
$ sudo /snap/bin/ scanlog

This scanlog command will tail the syslog, resolving seccomp syscall numbers and
make suggestions on what interfaces to use, changes to make to your snap to work
within the sandbox, etc. Can filter by snap with:

$ sudo /snap/bin/ scanlog <snapname>

Jamie Strandboge             |

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