test: Use NFS by default for test VMs

The new K8sVerifier test compiles some Cilium binaries inside the VM,
which can lead to 'interrupted system call' errors. Using NFS should fix
it by speeding up the filesystem accesses.

This commit switches the test VMs to use NFS by default, thereby
enabling NFS in our CI.

NFS remains disabled in the CI's Runtime tests because it leads to
permission errors [1].

1 - https://jenkins.cilium.io/job/Cilium-PR-Runtime-4.9/2739/consoleFull
Signed-off-by: Paul Chaignon <paul@cilium.io>

jenkinsfiles/ginkgo-runtime-kernel.Jenkinsfile

@@ -9,6 +9,7 @@ pipeline {
         PROJ_PATH = "src/github.com/cilium/cilium"
         VM_MEMORY = "8192"
         VM_CPUS = "4"
+        NFS = "0"
         GINKGO_TIMEOUT="150m"
         DEFAULT_KERNEL="""${sh(
             returnStdout: true,

jenkinsfiles/ginkgo.Jenkinsfile

@@ -128,6 +128,7 @@ pipeline {
                         TESTED_SUITE="runtime"
                         GOPATH="${WORKSPACE}/${TESTED_SUITE}-gopath"
                         TESTDIR="${GOPATH}/${PROJ_PATH}/test"
+                        NFS="0"
                     }
                     steps {
                         sh 'mkdir -p ${GOPATH}/src/github.com/cilium'
@@ -227,6 +228,7 @@ pipeline {
                         TESTED_SUITE="runtime"
                         GOPATH="${WORKSPACE}/${TESTED_SUITE}-gopath"
                         TESTDIR="${GOPATH}/${PROJ_PATH}/test"
+                        NFS="0"
                     }
                     steps {
                         sh 'cd ${TESTDIR}; ginkgo --focus="$(echo ${ghprbCommentBody} | sed -r "s/([^ ]* |^[^ ]*$)//" | sed "s/^$/Runtime/" | sed "s/K8s.*/NoTests/")" -v --failFast=${FAILFAST} -- -cilium.provision=false -cilium.timeout=${GINKGO_TIMEOUT}'

test/Vagrantfile

@@ -14,7 +14,7 @@ $BUILD_NUMBER = ENV['BUILD_NUMBER'] || "0"
 $JOB_NAME = ENV['JOB_BASE_NAME'] || "LOCAL"
 $K8S_VERSION = ENV['K8S_VERSION'] || "1.19"
 $K8S_NODES = (ENV['K8S_NODES'] || "2").to_i
-$NFS = ENV['NFS']=="1"? true : false
+$NFS = ENV['NFS']=="0"? false : true
 $IPv6=(ENV['IPv6'] || "0")
 $CONTAINER_RUNTIME=(ENV['CONTAINER_RUNTIME'] || "docker")
 $CNI_INTEGRATION=(ENV['CNI_INTEGRATION'] || "")