test, jenkinsfile: Clean up natnetworks in CI after test run

We currently have a flake in CI that is caused by some incorrect
VirtualBox natnetwork configuration. It is currently unclear why the
natnetworks are sometimes created with an incorrect configuration.

Unfortunately, because we don't delete natnetworks at the end of each CI
job, those incorrect natnetworks remains for subsequent runs and the
tests end up failing with the same flake on every single CI job
executed on that node.

This commit adds a cleanup step for natnetworks in our CI. We still
won't run natnetworks when running tests locally, for the same reason we
don't clean up VMs. This change doesn't fix the flake but it should
limit its impact to a single CI job instead of all jobs running on a
node.

Signed-off-by: Paul Chaignon <paul@cilium.io>

jenkinsfiles/ginkgo-kernel.Jenkinsfile

@@ -246,7 +246,7 @@ pipeline {
                     sh 'cd ${TESTDIR}; ./archive_test_results.sh || true'
                     sh 'cd ${TESTDIR}/..; mv *.zip ${WORKSPACE} || true'
                     sh 'cd ${TESTDIR}; mv *.xml ${WORKSPACE}/${PROJ_PATH}/test || true'
-                    sh 'cd ${TESTDIR}; vagrant destroy -f || true'
+                    sh 'cd ${TESTDIR}; ./vagrant_cleanup.sh || true'
                     archiveArtifacts artifacts: '*.zip'
                     junit testDataPublishers: [[$class: 'AttachmentPublisher']], testResults: 'src/github.com/cilium/cilium/test/*.xml'
                 }

jenkinsfiles/ginkgo-runtime-kernel.Jenkinsfile

@@ -144,7 +144,7 @@ pipeline {
                     sh 'cd ${TESTDIR}; ./archive_test_results_eks.sh || true'
                     sh 'cd ${TESTDIR}/..; mv *.zip ${WORKSPACE} || true'
                     sh 'cd ${TESTDIR}; mv *.xml ${WORKSPACE}/${PROJ_PATH}/test || true'
-                    sh 'cd ${TESTDIR}; vagrant destroy -f || true'
+                    sh 'cd ${TESTDIR}; ./vagrant_cleanup.sh || true'
                     archiveArtifacts artifacts: '*.zip'
                     junit testDataPublishers: [[$class: 'AttachmentPublisher']], testResults: 'src/github.com/cilium/cilium/test/*.xml'
                 }

test/vagrant_cleanup.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+K8S_NODES="${K8S_NODES:-2}"
+
+vagrant destroy -f
+
+i=1
+while [ "$i" -le "$K8S_NODES" ]; do
+    VBoxManage natnetwork remove --netname natnet$i
+    i=$((i+1))
+done
+
+VBoxManage natnetwork list