fix: Mount /usr/src in pod template

[joestringer]

Ensure that /usr/src is mounted, since several common distributions link
/lib/modules/$(uname -r)/build to /usr/src/kernels/$(uname -r) or
/usr/src/linux-headers-$(uname -r).

This was required for me to successfully locate kernel headers on Amazon Linux 2.

Fixes: #76

[fntlnz]

Thanks for this @joestringer !
I didn't know about that

[stafot]

@joestringer Because I am facing the same with Amazon Linux 2. Apart from your change is something that we need to do on the node? I am using the binary of second pre-release which should contain your fix. But still getting error as mentioned here.
The trace i am trying to run looks like this.

kubectl trace run --serviceaccount=kubectltrace ip-10-x-x-x.ec2.internal -f udpconnect.bt

[joestringer]

@stafot yes, the kernel headers must be installed on the node. Some others have reported more specific details to get it working on different distros in the issue #76 .