kubectl get pods -A -o wide | grep dns
kube-system kube-dns-5bfd847c64-bkkhf 4/4 Running 0 80m 10.108.0.5 gke-vanilla-default-pool-ddebe65c-pkzw <none> <none>
kubectl debug -n kube-system -it kube-dns-5bfd847c64-bkkhf --image=busybox:1.28 --target=dnsmasq
Targeting container "dnsmasq". If you don't see processes from this container it may be because the container runtime doesn't support this feature.
Defaulting debug container name to debugger-qz6cb.
If you don't see a command prompt, try pressing enter.
/ #
/ # ps axf
PID USER TIME COMMAND
1 root 0:00 /dnsmasq-nanny -v=2 -logtostderr -configDir=/etc/k8s/dns/dnsmasq-nanny -restartDnsmasq=true -- -k --cache-size=1000 --no-negcache --dns-forward-max=1500 --log-facility=- --server=/cluster.local/127.0.0.1#10053 --server=/in-addr.arpa/127.0.0.1#10053 --server=/ip6.arpa/127.0.0.1#10053 --max-ttl=30 --max-cache-ttl=30
10 root 0:00 /usr/sbin/dnsmasq -k --cache-size=1000 --no-negcache --dns-forward-max=1500 --log-facility=- --server=/cluster.local/127.0.0.1#10053 --server=/in-addr.arpa/127.0.0.1#10053 --server=/ip6.arpa/127.0.0.1#10053 --max-ttl=30 --max-cache-ttl=30
12 root 0:00 sh
18 root 0:00 ps axf
/ #
# ulimit -c
unlimited
mkdir /dumps
on the host
echo "/dumps/core.%e.%p" > /proc/sys/kernel/core_pattern