kubectl trace run fails on CoreOS

[miguelbernadi]

Our cluster nodes are running CoreOS and upon trying to test this tool we found the following error:

Error: failed to start container "kubectl-trace-2056455a-4836-11ea-a279-9078419759fa": Error response from daemon: error while creating mount source path '/usr/src': mkdir /usr/src: read-only file system

In CoreOS the main filesystem is read-only. Does the tool need to read/write there? Is it possible to configure it as user to avoid it? I couldn't find mentions in the docs or other issues on how to tackle this.

[alban]

I can reproduce the issue on Flatcar Container Linux too. The issue seems to have been introduced by commit 6be420a (#76).

On CoreOS, there is no /usr/src but it is not needed: the headers are directly available under /lib/modules/$(uname -r)/. The tool does not need to read/write there.

To support both Ubuntu (with /usr/src) and CoreOS/Flatcar (without /usr/src), I would suggest to mount the host /usr under /usr-host in the tracerunner container and have a symlink from /usr-host/src to /usr/src.

I'll give it a try.