On 9/4/19 3:39 AM, Alexei Starovoitov wrote:
On 8/30/19 8:19 AM, Nicolas Dichtel wrote:
Le 29/08/2019 à 19:30, Alexei Starovoitov a écrit :
[snip]
These are the links that showing that k8 can delegates caps.
Are you saying that you know of folks who specifically
delegate cap_sys_admin and cap_net_admin _only_ to a container to run bpf in there?
Yes, we need cap_sys_admin only to load bpf:
tc filter add dev eth0 ingress matchall action bpf obj ./tc_test_kern.o sec test
I'm not sure to understand why cap_net_admin is not enough to run the previous
command (ie why load is forbidden).
because bpf syscall prog_load command requires cap_sys_admin in
the current implementation.
I want to avoid sys_admin, thus cap_bpf will be ok. But we need to manage the
backward compatibility.
re: backward compatibility...
do you know of any case where task is running under userid=nobody
with cap_sys_admin and cap_net_admin in order to do bpf ?
If not then what is the concern about compatibility?
Finally managed to find some cycles to pull up a k8s cluster. Looks like it would
break deployments with the patches as-is right away; meaning, any constellation
where BPF is used inside the pod.
With CAP_BPF patches applied on bpf-next:
# kubectl apply -f ./cilium.yaml
[...]
# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
kube-system cilium-cz9qs 0/1 CrashLoopBackOff 4 2m36s 192.168.1.125 apoc <none> <none>
kube-system cilium-operator-6c7c6c788b-xcm9d 0/1 Pending 0 2m36s <none> <none> <none> <none>
kube-system coredns-5c98db65d4-6nhpg 0/1 ContainerCreating 0 4m12s <none> apoc <none> <none>
kube-system coredns-5c98db65d4-l5b94 0/1 ContainerCreating 0 4m12s <none> apoc <none> <none>
kube-system etcd-apoc 1/1 Running 0 3m26s 192.168.1.125 apoc <none> <none>
kube-system kube-apiserver-apoc 1/1 Running 0 3m32s 192.168.1.125 apoc <none> <none>
kube-system kube-controller-manager-apoc 1/1 Running 0 3m18s 192.168.1.125 apoc <none> <none>
kube-system kube-proxy-jj9kz 1/1 Running 0 4m12s 192.168.1.125 apoc <none> <none>
kube-system kube-scheduler-apoc 1/1 Running 0 3m26s 192.168.1.125 apoc <none> <none>
# kubectl -n kube-system logs --timestamps cilium-cz9qs
[...]
2019-09-04T14:11:46.399478585Z level=info msg="Cilium 1.6.90 ba0ed147b 2019-09-03T21:20:30+02:00 go version go1.12.8 linux/amd64" subsys=daemon
2019-09-04T14:11:46.410564471Z level=info msg="cilium-envoy version: b7a919ebdca3d3bbc6aae51357e78e9c603450ae/1.11.1/Modified/RELEASE/BoringSSL" subsys=daemon
2019-09-04T14:11:46.446983926Z level=info msg="clang (7.0.0) and kernel (5.3.0) versions: OK!" subsys=daemon
[...]
2019-09-04T14:11:47.27988188Z level=info msg="Mounting BPF filesystem at /run/cilium/bpffs" subsys=bpf
2019-09-04T14:11:47.279904256Z level=info msg="Detected mounted BPF filesystem at /run/cilium/bpffs" subsys=bpf
2019-09-04T14:11:47.280205098Z level=info msg="Valid label prefix configuration:" subsys=labels-filter
2019-09-04T14:11:47.280214528Z level=info msg=" - :io.kubernetes.pod.namespace" subsys=labels-filter
2019-09-04T14:11:47.28021738Z level=info msg=" - :io.cilium.k8s.namespace.labels" subsys=labels-filter
2019-09-04T14:11:47.280220836Z level=info msg=" - :app.kubernetes.io" subsys=labels-filter
2019-09-04T14:11:47.280223355Z level=info msg=" - !:io.kubernetes" subsys=labels-filter
2019-09-04T14:11:47.280225723Z level=info msg=" - !:kubernetes.io" subsys=labels-filter
2019-09-04T14:11:47.280228095Z level=info msg=" - !:.*beta.kubernetes.io" subsys=labels-filter
2019-09-04T14:11:47.280230409Z level=info msg=" - !:k8s.io" subsys=labels-filter
2019-09-04T14:11:47.280232699Z level=info msg=" - !:pod-template-generation" subsys=labels-filter
2019-09-04T14:11:47.280235569Z level=info msg=" - !:pod-template-hash" subsys=labels-filter
2019-09-04T14:11:47.28023792Z level=info msg=" - !:controller-revision-hash" subsys=labels-filter
2019-09-04T14:11:47.280240253Z level=info msg=" - !:annotation.*" subsys=labels-filter
2019-09-04T14:11:47.280242566Z level=info msg=" - !:etcd_node" subsys=labels-filter
2019-09-04T14:11:47.28026585Z level=info msg="Initializing daemon" subsys=daemon
2019-09-04T14:11:47.281344002Z level=info msg="Detected MTU 1500" subsys=mtu
2019-09-04T14:11:47.281771889Z level=error msg="Error while opening/creating BPF maps" error="Unable to create map /run/cilium/bpffs/tc/globals/cilium_lxc: operation not permitted" subsys=daemon
2019-09-04T14:11:47.28178666Z level=fatal msg="Error while creating daemon" error="Unable to create map /run/cilium/bpffs/tc/globals/cilium_lxc: operation not permitted" subsys=daemon
And /same/ deployment with reverted patches, hence no CAP_BPF gets it up and running again:
# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
kube-system cilium-cz9qs 1/1 Running 13 50m 192.168.1.125 apoc <none> <none>
kube-system cilium-operator-6c7c6c788b-xcm9d 0/1 Pending 0 50m <none> <none> <none> <none>
kube-system coredns-5c98db65d4-6nhpg 1/1 Running 0 52m 10.217.0.91 apoc <none> <none>
kube-system coredns-5c98db65d4-l5b94 1/1 Running 0 52m 10.217.0.225 apoc <none> <none>
kube-system etcd-apoc 1/1 Running 1 51m 192.168.1.125 apoc <none> <none>
kube-system kube-apiserver-apoc 1/1 Running 1 51m 192.168.1.125 apoc <none> <none>
kube-system kube-controller-manager-apoc 1/1 Running 1 51m 192.168.1.125 apoc <none> <none>
kube-system kube-proxy-jj9kz 1/1 Running 1 52m 192.168.1.125 apoc <none> <none>
kube-system kube-scheduler-apoc 1/1 Running 1 51m 192.168.1.125 apoc <none> <none>
Thanks,
Daniel
