- Test that pods not matching ingress rules are not able to access
the nettest pods.
- Test upgrading of NPC (from legacy to non-legacy).
- Test new semantics of k8s netpol.
The main difference between new and legacy (pre-1.7) netpol semantics
are the following:
* The DenyDefault ingress isolation annotation is obsoleted.
* Traffic is allowed to a pod if there are no netpol selecting
the pod.
See https://kubernetes.io/docs/api-reference/v1.6/#networkpolicyspec-v1beta1-extensions
vs https://kubernetes.io/docs/api-reference/v1.7/#networkpolicyspec-v1-networking
for more details.
weave-npc can operate either in the legacy or the new mode (default). To
use the legacy, pass "--use-legacy-netpol" arg when starting the npc.
In non-legacy mode we create for each Namespace a default-allow ipset
which stores IP addrs of such Pods which are not selected by any
NetworkPolicy.The ipsets are dst's in rules of the WEAVE-NPC-DEFAULT chain.
Docker 1.13 has changed a default policy of FORWARD chain to DROP
(https://github.com/moby/moby/pull/28257) which makes containers
inaccessible from a remote host when the bridge is exposed.
The change breaks e.g. the AWSVPC mode. To overcome this we install
an explicit rule for accepting forwarded ingress traffic to an
exposed subnet which is appended to the WEAVE-EXPOSE chain.
The chain is a target of the rule "-t filter -A FORWARD -o weave".
The change makes "weave expose" to call the "/expose" HTTP
endpoint implemented in router which exposes the bridge.
Such architectural change required as we need to know whether NPC is
enabled when exposing the bridge and weaver knows this fact the best.
Unfortunately, this change makes impossible to "weave expose"
when weaver is not running.
It's sad because this changes a regular pattern into an irregular one,
which will create spurious diffs if more work is added at the end of
the function. Still, this is easier than fixing the lint runner to
ignore the report.
Mount iptables lock file in weave-kube
iptables uses the file `/run/xtables.lock` so that if changes are
under way, another instance of the iptables command can wait till it
is finished.
We need to mount the lock file from the host to the container in order
for this mechanism to work at all.
Note we rely on kubelet touching the file before running any pods -
see https://github.com/kubernetes/kubernetes/pull/47212
Brice Fernandes