e2e: GetSafeIPAddress() replaces GetRandomIPAddress

For tests that use '--ip XX', random IP allocation is not
working well. Switch instead to a deterministic algorithm
with CPU affinity and a fudge factor for CNI.

Signed-off-by: Ed Santiago <santiago@redhat.com>

test/e2e/checkpoint_image_test.go

@@ -49,7 +49,7 @@ var _ = Describe("Podman checkpoint", func() {
 		localRunString := []string{
 			"run",
 			"-d",
-			"--ip", GetRandomIPAddress(),
+			"--ip", GetSafeIPAddress(),
 			"--name", containerName,
 			ALPINE,
 			"top",

test/e2e/checkpoint_test.go

@@ -23,7 +23,7 @@ import (
 
 func getRunString(input []string) []string {
 	// CRIU does not work with seccomp correctly on RHEL7 : seccomp=unconfined
-	runString := []string{"run", "--security-opt", "seccomp=unconfined", "-d", "--ip", GetRandomIPAddress()}
+	runString := []string{"run", "--security-opt", "seccomp=unconfined", "-d", "--ip", GetSafeIPAddress()}
 	return append(runString, input...)
 }
 

test/e2e/common_test.go

@@ -103,15 +103,19 @@ func TestLibpod(t *testing.T) {
 }
 
 var (
-	tempdir    string
-	err        error
-	podmanTest *PodmanTestIntegration
+	tempdir      string
+	err          error
+	podmanTest   *PodmanTestIntegration
+	safeIPOctets [2]uint8
 
 	_ = BeforeEach(func() {
 		tempdir, err = CreateTempDirInTempDir()
 		Expect(err).ToNot(HaveOccurred())
 		podmanTest = PodmanTestCreate(tempdir)
 		podmanTest.Setup()
+		// see GetSafeIPAddress() below
+		safeIPOctets[0] = uint8(GinkgoT().ParallelProcess()) + 128
+		safeIPOctets[1] = 2
 	})
 
 	_ = AfterEach(func() {
@@ -479,19 +483,23 @@ func GetPortLock(port string) *lockfile.LockFile {
 	return lock
 }
 
-// GetRandomIPAddress returns a random IP address to avoid IP
-// collisions during parallel tests
-func GetRandomIPAddress() string {
-	// To avoid IP collisions of initialize random seed for random IP addresses
-	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
-
-	nProcs := GinkgoT().ParallelTotal()
-	myProc := GinkgoT().ParallelProcess() - 1
-
-	// 10.88.255 is unlikely to be used by CNI or netavark.
-	// Last octet .0 - .254, and will be unique to this ginkgo process.
-	ip4 := strconv.Itoa(rng.Intn((255-nProcs)/nProcs)*nProcs + myProc)
-	return "10.88.255." + ip4
+// GetSafeIPAddress returns a sequentially allocated IP address that _should_
+// be safe and unique across parallel tasks
+//
+// Used by tests which want to use "--ip SOMETHING-SAFE". Picking at random
+// just doesn't work: we get occasional collisions. Our current approach
+// allocates a /24 subnet for each ginkgo process, starting at .128.x, see
+// BeforeEach() above. Unfortunately, CNI remembers each address assigned
+// and assigns <previous+1> by default -- so other parallel jobs may
+// get IPs in our block. The +10 leaves a gap for that. (Netavark works
+// differently, allocating sequentially from .0.0, hence our .128.x).
+// This heuristic will fail if run in parallel on >127 processors or if
+// one test calls us more than 25 times or if some other test runs more
+// than ten networked containers at the same time as any test that
+// relies on GetSafeIPAddress(). I'm finding it hard to care.
+func GetSafeIPAddress() string {
+	safeIPOctets[1] += 10
+	return fmt.Sprintf("10.88.%d.%d", safeIPOctets[0], safeIPOctets[1])
 }
 
 // RunTopContainer runs a simple container in the background that

test/e2e/create_staticip_test.go

@@ -29,7 +29,7 @@ var _ = Describe("Podman create with --ip flag", func() {
 	})
 
 	It("Podman create with specified static IP has correct IP", func() {
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		result := podmanTest.Podman([]string{"create", "--name", "test", "--ip", ip, ALPINE, "ip", "addr"})
 		result.WaitWithDefaultTimeout()
 		// Rootless static ip assignment without network should error
@@ -47,7 +47,7 @@ var _ = Describe("Podman create with --ip flag", func() {
 
 	It("Podman create two containers with the same IP", func() {
 		SkipIfRootless("--ip not supported without network in rootless mode")
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		result := podmanTest.Podman([]string{"create", "--log-driver", "k8s-file", "--name", "test1", "--ip", ip, ALPINE, "sleep", "999"})
 		result.WaitWithDefaultTimeout()
 		Expect(result).Should(Exit(0))

test/e2e/pod_create_test.go

@@ -213,7 +213,7 @@ var _ = Describe("Podman pod create", func() {
 
 	It("podman create pod with IP address", func() {
 		name := "test"
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		podCreate := podmanTest.Podman([]string{"pod", "create", "--ip", ip, "--name", name})
 		podCreate.WaitWithDefaultTimeout()
 		// Rootless should error without network
@@ -232,7 +232,7 @@ var _ = Describe("Podman pod create", func() {
 		SkipIfRootless("Rootless does not support --ip without network")
 		podName := "test"
 		ctrName := "testCtr"
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		podCreate := podmanTest.Podman([]string{"pod", "create", "--ip", ip, "--name", podName})
 		podCreate.WaitWithDefaultTimeout()
 		Expect(podCreate).Should(Exit(0))
@@ -248,7 +248,7 @@ var _ = Describe("Podman pod create", func() {
 
 	It("podman create pod with IP address and no infra should fail", func() {
 		name := "test"
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		podCreate := podmanTest.Podman([]string{"pod", "create", "--ip", ip, "--name", name, "--infra=false"})
 		podCreate.WaitWithDefaultTimeout()
 		Expect(podCreate).Should(Exit(125))

test/e2e/run_staticip_test.go

@@ -37,7 +37,7 @@ var _ = Describe("Podman run with --ip flag", func() {
 	})
 
 	It("Podman run with specified static IP has correct IP", func() {
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		result := podmanTest.Podman([]string{"run", "--ip", ip, ALPINE, "ip", "addr"})
 		result.WaitWithDefaultTimeout()
 		Expect(result).Should(Exit(0))
@@ -59,7 +59,7 @@ var _ = Describe("Podman run with --ip flag", func() {
 	})
 
 	It("Podman run with --network bridge:ip=", func() {
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		result := podmanTest.Podman([]string{"run", "--network", "bridge:ip=" + ip, ALPINE, "ip", "addr"})
 		result.WaitWithDefaultTimeout()
 		Expect(result).Should(Exit(0))
@@ -67,7 +67,7 @@ var _ = Describe("Podman run with --ip flag", func() {
 	})
 
 	It("Podman run with --network net:ip=,mac=,interface_name=", func() {
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		mac := "44:33:22:11:00:99"
 		intName := "myeth"
 		result := podmanTest.Podman([]string{"run", "--network", "bridge:ip=" + ip + ",mac=" + mac + ",interface_name=" + intName, ALPINE, "ip", "addr"})
@@ -79,7 +79,7 @@ var _ = Describe("Podman run with --ip flag", func() {
 	})
 
 	It("Podman run two containers with the same IP", func() {
-		ip := GetRandomIPAddress()
+		ip := GetSafeIPAddress()
 		result := podmanTest.Podman([]string{"run", "-d", "--name", "nginx", "--ip", ip, NGINX_IMAGE})
 		result.WaitWithDefaultTimeout()
 		Expect(result).Should(Exit(0))