A towel, it says, is about the most massively useful thing an interstellar hitchhiker can have.
-- Douglas Adams
If you are new to linux tracing I highly recommend you read our Getting Started Tutorial. It will walk you through step-by-step how to get started tracing your programs running in a GKE cluster.
go get github.com/jasonkeene/towel/...
# apply the towel daemonset
kubectl towel apply
# exec onto the towel for a given pod
kubectl towel exec nginx
kubectl towel exec -l app=nginx --field-selector spec.nodeName=node-1
# delete the towel daemonset
kubectl towel delete
bpftrace -l
bpftrace -e 'BEGIN { printf("Hello, World!\n"); }'
opensnoop
tcpaccept
tcpconnect
python -c '
from bcc import BPF
BPF(text=r"""
int kprobe__sys_clone(void *ctx)
{
bpf_trace_printk("Hello, World!\n");
return 0;
}
""").trace_print()
'
docker ps
You might run into situations where you need the kernel source. If you are running the chromium OS image on GKE you can use the following:
download-chromium-os-kernel-source
It will print out the environment variables you need to export to allow BCC and bpftrace to know where to look for the sources.