e2e: test SSH port on NodeSSHHosts

Before assuming that a certain host runs an SSH server, we now test its
`SSHPort` for connectivity. This means that the test `should be able to
run crictl on the node` can be now more failure proof by checking only
hosts where SSH actually runs. Beside that, we can also test all hosts
and not only the first one.

Signed-off-by: Sascha Grunert <sgrunert@redhat.com>

test/e2e/framework/ssh/ssh.go

@@ -24,6 +24,7 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"sync"
 	"time"
 
 	"github.com/onsi/gomega"
@@ -133,13 +134,41 @@ func NodeSSHHosts(c clientset.Interface) ([]string, error) {
 			len(hosts), len(nodelist.Items), nodelist)
 	}
 
-	sshHosts := make([]string, 0, len(hosts))
-	for _, h := range hosts {
-		sshHosts = append(sshHosts, net.JoinHostPort(h, SSHPort))
+	lenHosts := len(hosts)
+	wg := &sync.WaitGroup{}
+	wg.Add(lenHosts)
+	sshHosts := make([]string, 0, lenHosts)
+	var sshHostsLock sync.Mutex
+
+	for _, host := range hosts {
+		go func(host string) {
+			defer wg.Done()
+			if canConnect(host) {
+				e2elog.Logf("Assuming SSH on host %s", host)
+				sshHostsLock.Lock()
+				sshHosts = append(sshHosts, net.JoinHostPort(host, SSHPort))
+				sshHostsLock.Unlock()
+			} else {
+				e2elog.Logf("Skipping host %s because it does not run anything on port %s", host, SSHPort)
 			}
+		}(host)
+	}
+	wg.Wait()
+
 	return sshHosts, nil
 }
 
+// canConnect returns true if a network connection is possible to the SSHPort.
+func canConnect(host string) bool {
+	hostPort := net.JoinHostPort(host, SSHPort)
+	conn, err := net.DialTimeout("tcp", hostPort, 3*time.Second)
+	if err != nil {
+		return false
+	}
+	conn.Close()
+	return true
+}
+
 // Result holds the execution result of SSH command
 type Result struct {
 	User   string

test/e2e/node/crictl.go

@@ -44,6 +44,7 @@ var _ = SIGDescribe("crictl", func() {
 		if err != nil {
 			framework.Failf("Error getting node hostnames: %v", err)
 		}
+		e2eskipper.SkipUnlessAtLeast(len(hosts), 1, "Skipping test because found no SSH'able node")
 
 		testCases := []struct {
 			cmd string
@@ -53,8 +54,7 @@ var _ = SIGDescribe("crictl", func() {
 		}
 
 		for _, testCase := range testCases {
-			// Choose an arbitrary node to test.
-			host := hosts[0]
+			for _, host := range hosts {
 				ginkgo.By(fmt.Sprintf("SSH'ing to node %q to run %q", host, testCase.cmd))
 
 				result, err := e2essh.SSH(testCase.cmd, host, framework.TestContext.Provider)
@@ -71,5 +71,6 @@ var _ = SIGDescribe("crictl", func() {
 					framework.Logf("Got stderr from %q:\n %s\n", host, strings.TrimSpace(stderr))
 				}
 			}
+		}
 	})
 })