troubleshoot-preflight cleaned up and reworked (#263)

* switched to client-go approach to doing preflight-checks, dns check, k8s-version check added, updated readme
2025-12-19 18:05:53 -05:00 · 2020-03-31 17:07:08 -04:00
parent 070abea0d8
commit b3d0eff376
9 changed files with 567 additions and 425 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,5 @@ pkg/qliksense/qliksense-packr.go
 pkg/qliksense/docker-registry
 /pkg/qliksense/tests
 .DS_Store
+
+.idea/
--- a/cmd/qliksense/preflight.go
+++ b/cmd/qliksense/preflight.go
@@ -28,13 +28,21 @@ func preflightCheckDnsCmd(q *qliksense.Qliksense) *cobra.Command {
 		Example: `qliksense preflight dns`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			qp := &preflight.QliksensePreflight{Q: q}
-			err := qp.DownloadPreflight()
+
+			// Preflight DNS check
+			fmt.Printf("Preflight DNS check\n")
+			fmt.Println("---------------------")
+			namespace, kubeConfigContents, err := preflight.InitPreflight()
 			if err != nil {
-				err = fmt.Errorf("There has been an error downloading preflight: %+v", err)
-				log.Println(err)
-				return err
+				fmt.Printf("Preflight DNS check FAILED\n")
+				log.Fatal(err)
 			}
-			return qp.CheckDns()
+			if err = qp.CheckDns(namespace, kubeConfigContents); err != nil {
+				fmt.Println(err)
+				fmt.Print("Preflight DNS check FAILED\n")
+				log.Fatal()
+			}
+			return nil
 		},
 	}
 	return preflightDnsCmd
@@ -48,13 +56,21 @@ func preflightCheckK8sVersionCmd(q *qliksense.Qliksense) *cobra.Command {
 		Example: `qliksense preflight k8s-version`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			qp := &preflight.QliksensePreflight{Q: q}
-			err := qp.DownloadPreflight()
+
+			// Preflight Kubernetes minimum version check
+			fmt.Printf("Preflight kubernetes minimum version check\n")
+			fmt.Println("------------------------------------------")
+			namespace, kubeConfigContents, err := preflight.InitPreflight()
 			if err != nil {
-				err = fmt.Errorf("There has been an error downloading preflight: %+v", err)
-				log.Println(err)
-				return err
+				fmt.Printf("Preflight kubernetes minimum version check FAILED\n")
+				log.Fatal(err)
 			}
-			return qp.CheckK8sVersion()
+			if err = qp.CheckK8sVersion(namespace, kubeConfigContents); err != nil {
+				fmt.Println(err)
+				fmt.Printf("Preflight kubernetes minimum version check FAILED\n")
+				log.Fatal()
+			}
+			return nil
 		},
 	}
 	return preflightCheckK8sVersionCmd
@@ -68,13 +84,18 @@ func preflightAllChecksCmd(q *qliksense.Qliksense) *cobra.Command {
 		Example: `qliksense preflight all`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			qp := &preflight.QliksensePreflight{Q: q}
-			err := qp.DownloadPreflight()
+
+			// Preflight run all checks
+			fmt.Printf("Running all preflight checks\n")
+			namespace, kubeConfigContents, err := preflight.InitPreflight()
 			if err != nil {
-				err = fmt.Errorf("There has been an error downloading preflight: %+v", err)
-				log.Println(err)
-				return err
+				fmt.Println(err)
+				fmt.Printf("Running preflight check suite has FAILED...\n")
+				log.Fatal()
 			}
-			return qp.RunAllPreflightChecks()
+			qp.RunAllPreflightChecks(namespace, kubeConfigContents)
+			return nil
+
 		},
 	}
 	return preflightAllChecksCmd
--- a/docs/preflight_checks.md
+++ b/docs/preflight_checks.md
@@ -29,19 +29,20 @@ The expected output should be similar to the one shown below.
 ```console
 $ qliksense preflight dns

-Creating resources to run preflight checks
-deployment.apps/qnginx001 created
-service/qnginx001 created
-pod/qnginx001-6db5fc95c5-s9sl2 condition met
-  Running Preflight checks ⠇
--- PASS DNS check
-      --- DNS check passed
--- PASS   cluster-preflight-checks
-PASS
-
-DNS check completed, cleaning up resources now
-service "qnginx001" deleted
-deployment.extensions "qnginx001" deleted
+Preflight DNS check
+---------------------
+Created deployment "dep-dns-preflight-check"
+Created service "svc-dns-pf-check"
+Created pod: pf-pod-1
+Fetching pod: pf-pod-1
+Fetching pod: pf-pod-1
+Exec-ing into the container...
+Preflight DNS check: PASSED
+Completed preflight DNS check
+Cleaning up resources...
+Deleted pod: pf-pod-1
+Deleted service: svc-dns-pf-check
+Deleted deployment: dep-dns-preflight-check

 ```

@@ -51,16 +52,14 @@ The command to run this check and the expected similar output are as shown below
 ```console
 $ qliksense preflight k8s-version

-Minimum Kubernetes version supported: 1.11.0
-Client Version: version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.3", GitCommit:"06ad960bfd03b39c8310aaf92d1e7c12ce618213", GitTreeState:"clean", BuildDate:"2020-02-13T18:08:14Z", GoVersion:"go1.13.8", Compiler:"gc", Platform:"darwin/amd64"}
-Server Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.5", GitCommit:"20c265fef0741dd71a66480e35bd69f18351daea", GitTreeState:"clean", BuildDate:"2019-10-15T19:07:57Z", GoVersion:"go1.12.10", Compiler:"gc", Platform:"linux/amd64"}
-  Running Preflight checks ⠇
--- PASS Required Kubernetes Version
-      --- Good to go.
--- PASS   cluster-preflight-checks
-PASS
+Preflight kubernetes minimum version check
+------------------------------------------
+Kubernetes API Server version: v1.15.5
+Current K8s Version: 1.15.5
+Current 1.15.5 is greater than minimum required version:1.11.0, hence good to go
+Preflight minimum kubernetes version check: PASSED
+Completed Preflight kubernetes minimum version check

-Minimum kubernetes version check completed
 ```

 ### Running all checks
@@ -70,31 +69,30 @@ $ qliksense preflight all

 Running all preflight checks

-Running DNS check...
-Creating resources to run preflight checks
-deployment.apps/qnginx001 created
-service/qnginx001 created
-pod/qnginx001-6db5fc95c5-grwv2 condition met
-  Running Preflight checks ⠇
--- PASS DNS check
-      --- DNS check passed
--- PASS   cluster-preflight-checks
-PASS
+Preflight DNS check
+-------------------
+Created deployment "dep-dns-preflight-check"
+Created service "svc-dns-pf-check"
+Created pod: pf-pod-1
+Fetching pod: pf-pod-1
+Fetching pod: pf-pod-1
+Exec-ing into the container...
+Preflight DNS check: PASSED
+Completed preflight DNS check
+Cleaning up resources...
+Deleted pod: pf-pod-1
+Deleted service: svc-dns-pf-check
+Deleted deployment: dep-dns-preflight-check

-DNS check completed, cleaning up resources now
-service "qnginx001" deleted
-deployment.extensions "qnginx001" deleted
+Preflight kubernetes minimum version check
+------------------------------------------
+Kubernetes API Server version: v1.15.5
+Current K8s Version: 1.15.5
+Current 1.15.5 is greater than minimum required version:1.11.0, hence good to go
+Preflight minimum kubernetes version check: PASSED
+Completed Preflight kubernetes minimum version check

-Running minimum kubernetes version check...
-Minimum Kubernetes version supported: 1.11.0
-Client Version: version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.3", GitCommit:"06ad960bfd03b39c8310aaf92d1e7c12ce618213", GitTreeState:"clean", BuildDate:"2020-02-13T18:08:14Z", GoVersion:"go1.13.8", Compiler:"gc", Platform:"darwin/amd64"}
-Server Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.5", GitCommit:"20c265fef0741dd71a66480e35bd69f18351daea", GitTreeState:"clean", BuildDate:"2019-10-15T19:07:57Z", GoVersion:"go1.12.10", Compiler:"gc", Platform:"linux/amd64"}
-  Running Preflight checks ⠧
--- PASS Required Kubernetes Version
-      --- Good to go.
--- PASS   cluster-preflight-checks
-PASS
-
-Minimum kubernetes version check completed
+All preflight checks have PASSED
 Completed running all preflight checks
+
 ```
--- a/go.mod
+++ b/go.mod
@@ -16,6 +16,7 @@ replace (
 require (
 	cloud.google.com/go v0.52.0 // indirect
 	cloud.google.com/go/storage v1.5.0 // indirect
+	github.com/Masterminds/semver/v3 v3.0.3
 	github.com/Shopify/ejson v1.2.1
 	github.com/aws/aws-sdk-go v1.28.9 // indirect
 	github.com/bugsnag/bugsnag-go v1.5.3 // indirect
@@ -59,6 +60,7 @@ require (
 	k8s.io/api v0.17.0
 	k8s.io/apimachinery v0.17.0
 	k8s.io/client-go v11.0.0+incompatible
+	k8s.io/kubectl v0.0.0-20191016120415-2ed914427d51
 	sigs.k8s.io/kustomize/api v0.3.2
 	sigs.k8s.io/yaml v1.1.0
 )
--- a/pkg/preflight/all_checks.go
+++ b/pkg/preflight/all_checks.go
@@ -4,13 +4,31 @@ import (
 	"fmt"
 )

-func (qp *QliksensePreflight) RunAllPreflightChecks() error {
-	//run all preflight checks
-	fmt.Println("Running all preflight checks")
-	fmt.Printf("\nRunning DNS check...\n")
-	qp.CheckDns()
-	fmt.Printf("\nRunning minimum kubernetes version check...\n")
-	qp.CheckK8sVersion()
+func (qp *QliksensePreflight) RunAllPreflightChecks(namespace string, kubeConfigContents []byte) {
+
+	checkCount := 0
+	// Preflight DNS check
+	fmt.Printf("\nPreflight DNS check\n")
+	fmt.Println("-------------------")
+	if err := qp.CheckDns(namespace, kubeConfigContents); err != nil {
+		fmt.Printf("Preflight DNS check: FAILED\n")
+	} else {
+		checkCount++
+	}
+
+	// Preflight minimum kuberenetes version check
+	fmt.Printf("\nPreflight kubernetes minimum version check\n")
+	fmt.Println("------------------------------------------")
+	if err := qp.CheckK8sVersion(namespace, kubeConfigContents); err != nil {
+		fmt.Printf("Preflight kubernetes minimum version check: FAILED\n")
+	} else {
+		checkCount++
+	}
+
+	if checkCount == 2 {
+		fmt.Printf("All preflight checks have PASSED\n")
+	} else {
+		fmt.Printf("1 or more preflight checks have FAILED\n")
+	}
 	fmt.Println("Completed running all preflight checks")
-	return nil
 }
--- a/pkg/preflight/dns_check.go
+++ b/pkg/preflight/dns_check.go
@@ -1,130 +1,115 @@
 package preflight

 import (
-	"bytes"
 	"fmt"
-	"html/template"
-	"io/ioutil"
-	"path/filepath"
-
-	"github.com/qlik-oss/sense-installer/pkg/api"
+	"strings"
+	"time"
 )

-const dnsCheckYAML = `
-apiVersion: troubleshoot.replicated.com/v1beta1
-kind: Preflight
-metadata:
-  name: cluster-preflight-checks
-  namespace: {{ .namespace }}
-spec:
-  collectors:
-    - run: 
-        collectorName: spin-up-pod
-        args: ["-z", "-v", "-w 1", "{{ .serviceName }}", "80"]
-        command: ["nc"]
-        image: subfuzion/netcat:latest
-        imagePullPolicy: IfNotPresent
-        name: spin-up-pod-check-dns
-        namespace: {{ .namespace }}
-        timeout: 30s
+const (
+	nginxImage  = "nginx"
+	netcatImage = "subfuzion/netcat:latest"
+)

-  analyzers:
-    - textAnalyze:
-        checkName: DNS check
-        collectorName: spin-up-pod-check-dns
-        fileName: spin-up-pod.log
-        regex: succeeded
-        outcomes:
-          - fail:
-              message: DNS check failed
-          - pass:
-              message: DNS check passed
-`
-
-func (qp *QliksensePreflight) CheckDns() error {
-	// retrieve namespace
-	namespace := api.GetKubectlNamespace()
-
-	api.LogDebugMessage("Namespace: %s\n", namespace)
-
-	tmpl, err := template.New("dnsCheckYAML").Parse(dnsCheckYAML)
+func (qp *QliksensePreflight) CheckDns(namespace string, kubeConfigContents []byte) error {
+	clientset, clientConfig, err := getK8SClientSet(kubeConfigContents, "")
 	if err != nil {
-		fmt.Printf("cannot parse template: %v", err)
-		return err
-	}
-	tempYaml, err := ioutil.TempFile("", "")
-	if err != nil {
-		fmt.Printf("cannot create file: %v", err)
-		return err
-	}
-	api.LogDebugMessage("Temp Yaml file: %s\n", tempYaml.Name())
-
-	appName := "qnginx001"
-	const PreflightChecksDirName = "preflight_checks"
-	b := bytes.Buffer{}
-	err = tmpl.Execute(&b, map[string]string{
-		"namespace":   namespace,
-		"serviceName": appName,
-	})
-	if err != nil {
-		fmt.Println(err)
+		err = fmt.Errorf("Kube config error: %v\n", err)
+		fmt.Print(err)
 		return err
 	}

-	tempYaml.WriteString(b.String())
-
-	// creating Kubectl resources
-	fmt.Println("Creating resources to run preflight checks")
-
-	// kubectl create deployment
-	opr := fmt.Sprintf("create deployment %s --image=nginx", appName)
-	err = initiateK8sOps(opr, namespace)
+	// creating deployment
+	depName := "dep-dns-preflight-check"
+	dnsDeployment, err := createPreflightTestDeployment(clientset, namespace, depName, nginxImage)
 	if err != nil {
-		fmt.Println(err)
+		err = fmt.Errorf("Unable to create deployment: %v\n", err)
 		return err
 	}
+	timeout := time.NewTicker(2 * time.Minute)
+	defer timeout.Stop()
+WAIT:
+	for {
+		d, err := getDeployment(dnsDeployment.GetName(), clientset, namespace)
+		if err != nil {
+			err = fmt.Errorf("Unable to retrieve deployment: %s\n", depName)
+			return err
+		}
+		select {
+		case <-timeout.C:
+			break WAIT
+		default:
+			if int(d.Status.ReadyReplicas) > 0 {
+				break WAIT
+			}
+		}
+		time.Sleep(5 * time.Second)
+	}
+	defer deleteDeployment(clientset, namespace, depName)

-	defer func() {
-		// Deleting deployment..
-		opr = fmt.Sprintf("delete deployment %s", appName)
-		// we want to delete the k8s resource here, we dont care a lot about an error here
-		_ = initiateK8sOps(opr, namespace)
-		api.LogDebugMessage("delete deployment executed")
-	}()
-
-	// create service
-	opr = fmt.Sprintf("create service clusterip %s --tcp=80:80", appName)
-	err = initiateK8sOps(opr, namespace)
+	// creating service
+	serviceName := "svc-dns-pf-check"
+	dnsService, err := createPreflightTestService(clientset, namespace, serviceName)
 	if err != nil {
-		fmt.Println(err)
+		err = fmt.Errorf("Unable to create service : %s\n", serviceName)
 		return err
 	}
+	defer deleteService(clientset, namespace, serviceName)

-	defer func() {
-		// delete service
-		opr = fmt.Sprintf("delete service %s", appName)
-		// we want to delete the k8s resource here, we dont care a lot about an error here
-		_ = initiateK8sOps(opr, namespace)
-		api.LogDebugMessage("delete service executed")
-	}()
-
-	//kubectl -n $namespace wait --for=condition=ready pod -l app=$appName --timeout=120s
-	opr = fmt.Sprintf("wait --for=condition=ready pod -l app=%s --timeout=120s", appName)
-	err = initiateK8sOps(opr, namespace)
+	// create a pod
+	podName := "pf-pod-1"
+	dnsPod, err := createPreflightTestPod(clientset, namespace, podName, netcatImage)
 	if err != nil {
-		fmt.Println(err)
+		err = fmt.Errorf("Unable to create pod : %s\n", podName)
 		return err
 	}
-	api.LogDebugMessage("kubectl wait executed")
+	defer deletePod(clientset, namespace, podName)

-	// call preflight
-	preflightCommand := filepath.Join(qp.Q.QliksenseHome, PreflightChecksDirName, preflightFileName)
+	if len(dnsPod.Spec.Containers) > 0 {
+		timeout := time.NewTicker(2 * time.Minute)
+		defer timeout.Stop()
+	OUT:
+		for {
+			dnsPod, err = getPod(clientset, namespace, dnsPod.Name)
+			if err != nil {
+				err = fmt.Errorf("Unable to retrieve service by name: %s\n", podName)
+				fmt.Println(err)
+				return err
+			}
+			select {
+			case <-timeout.C:
+				break OUT
+			default:
+				if len(dnsPod.Status.ContainerStatuses) > 0 && dnsPod.Status.ContainerStatuses[0].Ready {
+					break OUT
+				}
+			}
+			time.Sleep(5 * time.Second)
+		}
+		if len(dnsPod.Status.ContainerStatuses) == 0 || !dnsPod.Status.ContainerStatuses[0].Ready {
+			err = fmt.Errorf("container is taking much longer than expected")
+			fmt.Println(err)
+			return err
+		}
+		fmt.Println("Exec-ing into the container...")
+		stdout, stderr, err := executeRemoteCommand(clientset, clientConfig, dnsPod.Name, dnsPod.Spec.Containers[0].Name, namespace, []string{"nc", "-z", "-v", "-w 1", dnsService.Name, "80"})
+		if err != nil {
+			err = fmt.Errorf("An error occurred while executing remote command in container: %v", err)
+			fmt.Println(err)
+			return err
+		}
+		//fmt.Printf("stdout: %s\n", stdout)
+		//fmt.Printf("stderr: %s\n", stderr)

-	err = invokePreflight(preflightCommand, tempYaml)
-	if err != nil {
-		fmt.Println(err)
-		return err
+		if strings.HasSuffix(stdout, "succeeded!") || strings.HasSuffix(stderr, "succeeded!") {
+			fmt.Println("Preflight DNS check: PASSED")
+		} else {
+			fmt.Println("Preflight DNS check: FAILED")
+		}
 	}
-	fmt.Println("DNS check completed, cleaning up resources now")
+
+	fmt.Println("Completed preflight DNS check")
+	fmt.Println("Cleaning up resources...")
+
 	return nil
 }
--- a/pkg/preflight/preflight_utils.go
+++ b/pkg/preflight/preflight_utils.go
@@ -3,136 +3,64 @@ package preflight
 import (
 	"bytes"
 	"fmt"
-	"log"
-	"os"
-	"os/exec"
+	"io"
+	"io/ioutil"
+	"net/url"
 	"path/filepath"
-	"runtime"
 	"strings"
+	"time"

-	"github.com/qlik-oss/sense-installer/pkg/qliksense"
+	"github.com/mitchellh/go-homedir"

+	"k8s.io/apimachinery/pkg/util/wait"
+
+	"k8s.io/client-go/util/retry"
+
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/clientcmd"
+	"k8s.io/client-go/tools/remotecommand"
+	"k8s.io/kubectl/pkg/scheme"
+
+	"github.com/pkg/errors"
 	"github.com/qlik-oss/sense-installer/pkg/api"
+	"github.com/qlik-oss/sense-installer/pkg/qliksense"
+	appsv1 "k8s.io/api/apps/v1"
+	apiv1 "k8s.io/api/core/v1"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	restclient "k8s.io/client-go/rest"
+
+	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 )

 type QliksensePreflight struct {
 	Q *qliksense.Qliksense
 }

-const (
-	// preflight releases have the same version
-	preflightRelease       = "v0.9.28"
-	preflightLinuxFile     = "preflight_linux_amd64.tar.gz"
-	preflightMacFile       = "preflight_darwin_amd64.tar.gz"
-	preflightWindowsFile   = "preflight_windows_amd64.zip"
-	PreflightChecksDirName = "preflight_checks"
-	preflightFileName      = "preflight"
-)
+func InitPreflight() (string, []byte, error) {
+	api.LogDebugMessage("Reading .kube/config file...")

-var preflightBaseURL = fmt.Sprintf("https://github.com/replicatedhq/troubleshoot/releases/download/%s/", preflightRelease)
-
-func (qp *QliksensePreflight) DownloadPreflight() error {
-	preflightExecutable := "preflight"
-	if runtime.GOOS == "windows" {
-		preflightExecutable += ".exe"
-	}
-
-	preflightInstallDir := filepath.Join(qp.Q.QliksenseHome, PreflightChecksDirName)
-
-	exists, err := checkInstalled(preflightInstallDir, preflightExecutable)
+	homeDir, err := homedir.Dir()
 	if err != nil {
-		err = fmt.Errorf("There has been an error when trying to determine if preflight installer exists")
-		log.Println(err)
-		return err
-	}
-	if exists {
-		// preflight exist, no need to download again.
-		api.LogDebugMessage("Preflight already exists, proceeding to perform checks")
-		return nil
+		err = fmt.Errorf("Unable to deduce home dir\n")
+		return "", nil, err
 	}
+	api.LogDebugMessage("Kube config location: %s\n\n", filepath.Join(homeDir, ".kube", "config"))

-	// Create the Preflight-check directory, download and install preflight
-	if !api.DirExists(preflightInstallDir) {
-		api.LogDebugMessage("%s does not exist, creating now\n", preflightInstallDir)
-		if err := os.Mkdir(preflightInstallDir, os.ModePerm); err != nil {
-			err = fmt.Errorf("Not able to create %s dir: %v", preflightInstallDir, err)
-			log.Println(err)
-			return nil
-		}
-	}
-	api.LogDebugMessage("Preflight-checks install Dir: %s exists", preflightInstallDir)
-
-	preflightUrl, preflightFile, err := determinePlatformSpecificUrls(runtime.GOOS)
+	kubeConfig := filepath.Join(homeDir, ".kube", "config")
+	kubeConfigContents, err := ioutil.ReadFile(kubeConfig)
 	if err != nil {
-		err = fmt.Errorf("There was an error when trying to determine platform specific paths")
-		return err
+		err = fmt.Errorf("Unable to deduce home dir\n")
+		return "", nil, err
 	}
-
-	// Download Preflight
-	err = downloadAndExplode(preflightUrl, preflightInstallDir, preflightFile)
-	if err != nil {
-		return err
+	// retrieve namespace
+	namespace := api.GetKubectlNamespace()
+	// if namespace comes back empty, we will run checks in the default namespace
+	if namespace == "" {
+		namespace = "default"
 	}
-	fmt.Println("Downloaded Preflight")
-
-	return nil
-}
-
-func checkInstalled(preflightInstallDir, preflightExecutable string) (bool, error) {
-	installerExists := true
-	preflightInstaller := filepath.Join(preflightInstallDir, preflightExecutable)
-	if api.DirExists(preflightInstallDir) {
-		if !api.FileExists(preflightInstaller) {
-			installerExists = false
-			api.LogDebugMessage("Preflight install directory exists, but preflight installer does not exist")
-		}
-	} else {
-		installerExists = false
-	}
-	return installerExists, nil
-}
-
-func downloadAndExplode(url, installDir, file string) error {
-	err := api.DownloadFile(url, installDir, file)
-	if err != nil {
-		return err
-	}
-	api.LogDebugMessage("Downloaded File: %s", file)
-
-	fileToUntar := filepath.Join(installDir, file)
-	api.LogDebugMessage("File to explode: %s", file)
-
-	err = api.ExplodePackage(installDir, fileToUntar)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func determinePlatformSpecificUrls(platform string) (string, string, error) {
-
-	var preflightUrl, preflightFile string
-
-	if runtime.GOARCH != `amd64` {
-		err := fmt.Errorf("%s architecture is not supported", runtime.GOARCH)
-		return "", "", err
-	}
-
-	switch platform {
-	case "windows":
-		preflightFile = preflightWindowsFile
-	case "darwin":
-		preflightFile = preflightMacFile
-	case "linux":
-		preflightFile = preflightLinuxFile
-	default:
-		err := fmt.Errorf("Unable to download the preflight executable for the underlying platform\n")
-		return "", "", err
-	}
-	preflightUrl = fmt.Sprintf("%s%s", preflightBaseURL, preflightFile)
-
-	return preflightUrl, preflightFile, nil
+	api.LogDebugMessage("Namespace: %s\n", namespace)
+	return namespace, kubeConfigContents, nil
 }

 func initiateK8sOps(opr, namespace string) error {
@@ -145,46 +73,307 @@ func initiateK8sOps(opr, namespace string) error {
 	return nil
 }

-func invokePreflight(preflightCommand string, yamlFile *os.File) error {
-	var arguments []string
+func int32Ptr(i int32) *int32 { return &i }

-	arguments = append(arguments, yamlFile.Name(), "--interactive=false")
-	cmd := exec.Command(preflightCommand, arguments...)
+func retryOnError(mf func() error) error {
+	return retry.OnError(wait.Backoff{
+		Duration: 1 * time.Second,
+		Factor:   1,
+		Jitter:   0.1,
+		Steps:    5,
+	}, func(err error) bool {
+		return k8serrors.IsConflict(err) || k8serrors.IsGone(err) || k8serrors.IsServerTimeout(err) ||
+			k8serrors.IsServiceUnavailable(err) || k8serrors.IsTimeout(err) || k8serrors.IsTooManyRequests(err)
+	}, mf)
+}

-	sterrBuffer := &bytes.Buffer{}
-	cmd.Stdout = sterrBuffer
-	cmd.Stderr = sterrBuffer
-	if err := cmd.Run(); err != nil {
-		return fmt.Errorf("Error when running preflight command: %v\n", err)
+func getK8SClientSet(kubeconfig []byte, contextName string) (*kubernetes.Clientset, *rest.Config, error) {
+	var clientConfig *rest.Config
+	var err error
+	if len(kubeconfig) == 0 {
+		clientConfig, err = rest.InClusterConfig()
+		if err != nil {
+			err = errors.Wrap(err, "Unable to load in-cluster kubeconfig")
+			fmt.Println(err)
+			return nil, nil, err
+		}
+	} else {
+		config, err := clientcmd.Load(kubeconfig)
+		if err != nil {
+			err = errors.Wrap(err, "Unable to load kubeconfig")
+			fmt.Println(err)
+			return nil, nil, err
+		}
+		if contextName != "" {
+			config.CurrentContext = contextName
+		}
+		clientConfig, err = clientcmd.NewDefaultClientConfig(*config, &clientcmd.ConfigOverrides{}).ClientConfig()
+		if err != nil {
+			err = errors.Wrap(err, "Unable to create client config from config")
+			fmt.Println(err)
+			return nil, nil, err
+		}
 	}
-	ind := strings.Index(sterrBuffer.String(), "---")
-	output := sterrBuffer.String()
-	if ind > -1 {
-		output = fmt.Sprintf("%s\n%s", output[:ind], output[ind:])
+	clientset, err := kubernetes.NewForConfig(clientConfig)
+	if err != nil {
+		err = errors.Wrap(err, "Unable to create clientset")
+		fmt.Println(err)
+		return nil, nil, err
 	}
-	fmt.Printf("%v\n", output)
+	return clientset, clientConfig, nil
+}

-	// Maybe good to retain this part in case we need to process the output in future.
-	// We are going to look for the first occurance of PASS or FAIL from the end
-	// there are also some space-like deceiving characters which are being hard to get by
+func createPreflightTestDeployment(clientset *kubernetes.Clientset, namespace string, depName string, imageName string) (*appsv1.Deployment, error) {
+	deploymentsClient := clientset.AppsV1().Deployments(namespace)
+	deployment := &appsv1.Deployment{
+		ObjectMeta: v1.ObjectMeta{
+			Name: depName,
+		},
+		Spec: appsv1.DeploymentSpec{
+			Replicas: int32Ptr(1),
+			Selector: &v1.LabelSelector{
+				MatchLabels: map[string]string{
+					"app": "preflight-check",
+				},
+			},
+			Template: apiv1.PodTemplateSpec{
+				ObjectMeta: v1.ObjectMeta{
+					Labels: map[string]string{
+						"app":   "preflight-check",
+						"label": "preflight-check-label",
+					},
+				},
+				Spec: apiv1.PodSpec{
+					Containers: []apiv1.Container{
+						{
+							Name:  "dep",
+							Image: imageName,
+							Ports: []apiv1.ContainerPort{
+								{
+									Name:          "http",
+									Protocol:      apiv1.ProtocolTCP,
+									ContainerPort: 80,
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}

-	//outputArr := strings.Fields(strings.TrimSpace(output))
-	//trackSuccess := false
-	//trackPrg := false
+	// Create Deployment
+	var result *appsv1.Deployment
+	if err := retryOnError(func() (err error) {
+		result, err = deploymentsClient.Create(deployment)
+		return err
+	}); err != nil {
+		err = errors.Wrapf(err, "unable to create deployments in the %s namespace", namespace)
+		fmt.Println(err)
+		return nil, err
+	}
+	fmt.Printf("Created deployment %q\n", result.GetObjectMeta().GetName())

-	//for i := len(outputArr) - 1; i >= 0; i-- {
-	//	if strings.TrimSpace(outputArr[i]) != "" {
-	//		if outputArr[i] == "PASS" {
-	//			trackSuccess = true
-	//			trackPrg = true
-	//		} else if outputArr[i] == "FAIL" {
-	//			trackPrg = true
-	//		}
-	//	}
-	//	if trackPrg {
-	//		break
-	//	}
-	//}
+	return deployment, nil
+}

+func getDeployment(depName string, clientset *kubernetes.Clientset, namespace string) (*appsv1.Deployment, error) {
+	deploymentsClient := clientset.AppsV1().Deployments(namespace)
+	var deployment *appsv1.Deployment
+	if err := retryOnError(func() (err error) {
+		deployment, err = deploymentsClient.Get(depName, v1.GetOptions{})
+		return err
+	}); err != nil {
+		err = errors.Wrapf(err, "unable to get deployments in the %s namespace", namespace)
+		fmt.Println(err)
+		return nil, err
+	}
+	return deployment, nil
+}
+
+func deleteDeployment(clientset *kubernetes.Clientset, namespace, name string) {
+	deploymentsClient := clientset.AppsV1().Deployments(namespace)
+	// Create Deployment
+	deletePolicy := v1.DeletePropagationForeground
+	deleteOptions := v1.DeleteOptions{
+		PropagationPolicy: &deletePolicy,
+	}
+
+	if err := retryOnError(func() (err error) {
+		return deploymentsClient.Delete(name, &deleteOptions)
+	}); err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Printf("Deleted deployment: %s\n", name)
+}
+
+func createPreflightTestService(clientset *kubernetes.Clientset, namespace string, svcName string) (*apiv1.Service, error) {
+	//fmt.Println("Creating Service...")
+	iptr := int32Ptr(80)
+	servicesClient := clientset.CoreV1().Services(namespace)
+	service := &apiv1.Service{
+		ObjectMeta: v1.ObjectMeta{
+			Name:      svcName,
+			Namespace: namespace,
+			Labels: map[string]string{
+				"app": "preflight-check",
+			},
+		},
+		Spec: apiv1.ServiceSpec{
+			Ports: []apiv1.ServicePort{
+				{Name: "port1",
+					Port: *iptr,
+				},
+			},
+			Selector: map[string]string{
+				"app": "preflight-check",
+			},
+			ClusterIP: "",
+		},
+	}
+	var result *apiv1.Service
+	if err := retryOnError(func() (err error) {
+		result, err = servicesClient.Create(service)
+		return err
+	}); err != nil {
+		fmt.Println(err)
+		return nil, err
+	}
+	fmt.Printf("Created service %q\n", result.GetObjectMeta().GetName())
+
+	return service, nil
+}
+
+func getService(clientset *kubernetes.Clientset, namespace, svcName string) (*apiv1.Service, error) {
+	servicesClient := clientset.CoreV1().Services(namespace)
+	var svc *apiv1.Service
+	if err := retryOnError(func() (err error) {
+		svc, err = servicesClient.Get(svcName, v1.GetOptions{})
+		return err
+	}); err != nil {
+		err = errors.Wrapf(err, "unable to get services in the %s namespace", namespace)
+		fmt.Println(err)
+		return nil, err
+	}
+
+	return svc, nil
+}
+
+func deleteService(clientset *kubernetes.Clientset, namespace, name string) error {
+	servicesClient := clientset.CoreV1().Services(namespace)
+	// Create Deployment
+	deletePolicy := v1.DeletePropagationForeground
+	deleteOptions := v1.DeleteOptions{
+		PropagationPolicy: &deletePolicy,
+	}
+	if err := retryOnError(func() (err error) {
+		return servicesClient.Delete(name, &deleteOptions)
+	}); err != nil {
+		fmt.Println(err)
+		return err
+	}
+	fmt.Printf("Deleted service: %s\n", name)
 	return nil
 }
+
+func deletePod(clientset *kubernetes.Clientset, namespace, name string) error {
+	podsClient := clientset.CoreV1().Pods(namespace)
+	deletePolicy := v1.DeletePropagationForeground
+	deleteOptions := v1.DeleteOptions{
+		PropagationPolicy: &deletePolicy,
+	}
+	if err := retryOnError(func() (err error) {
+		return podsClient.Delete(name, &deleteOptions)
+	}); err != nil {
+		fmt.Println(err)
+		return err
+	}
+	fmt.Printf("Deleted pod: %s\n", name)
+	return nil
+}
+
+func createPreflightTestPod(clientset *kubernetes.Clientset, namespace string, podName string, imageName string) (*apiv1.Pod, error) {
+	// build the pod definition we want to deploy
+	pod := &apiv1.Pod{
+		ObjectMeta: v1.ObjectMeta{
+			Name:      podName,
+			Namespace: namespace,
+			Labels: map[string]string{
+				"app": "demo",
+			},
+		},
+		Spec: apiv1.PodSpec{
+			Containers: []apiv1.Container{
+				{
+					Name:            "cnt",
+					Image:           imageName,
+					ImagePullPolicy: apiv1.PullIfNotPresent,
+					Command: []string{
+						"sleep",
+						"3600",
+					},
+				},
+			},
+		},
+	}
+
+	// now create the pod in kubernetes cluster using the clientset
+	if err := retryOnError(func() (err error) {
+		pod, err = clientset.CoreV1().Pods(namespace).Create(pod)
+		return err
+	}); err != nil {
+		fmt.Println(err)
+		return nil, err
+	}
+	fmt.Printf("Created pod: %s\n", pod.Name)
+	return pod, nil
+}
+
+func getPod(clientset *kubernetes.Clientset, namespace, podName string) (*apiv1.Pod, error) {
+	fmt.Printf("Fetching pod: %s\n", podName)
+	var pod *apiv1.Pod
+	if err := retryOnError(func() (err error) {
+		pod, err = clientset.CoreV1().Pods(namespace).Get(podName, v1.GetOptions{})
+		return err
+	}); err != nil {
+		fmt.Println(err)
+		return nil, err
+	}
+	return pod, nil
+}
+
+func execute(method string, url *url.URL, config *restclient.Config, stdin io.Reader, stdout, stderr io.Writer, tty bool) error {
+	exec, err := remotecommand.NewSPDYExecutor(config, method, url)
+	if err != nil {
+		return err
+	}
+	return exec.Stream(remotecommand.StreamOptions{
+		Stdin:  stdin,
+		Stdout: stdout,
+		Stderr: stderr,
+		Tty:    tty,
+	})
+}
+
+func executeRemoteCommand(clientset *kubernetes.Clientset, config *rest.Config, podName, containerName, namespace string, command []string) (string, string, error) {
+	tty := false
+	req := clientset.CoreV1().RESTClient().Post().
+		Resource("pods").
+		Name(podName).
+		Namespace(namespace).
+		SubResource("exec").
+		Param("container", containerName)
+	req.VersionedParams(&apiv1.PodExecOptions{
+		Container: containerName,
+		Command:   command,
+		Stdin:     false,
+		Stdout:    true,
+		Stderr:    true,
+		TTY:       tty,
+	}, scheme.ParameterCodec)
+
+	var stdout, stderr bytes.Buffer
+	err := execute("POST", req.URL(), config, nil, &stdout, &stderr, tty)
+	return strings.TrimSpace(stdout.String()), strings.TrimSpace(stderr.String()), err
+}
--- a/pkg/preflight/preflight_utils_test.go
+++ b/pkg/preflight/preflight_utils_test.go
@@ -20,7 +20,7 @@ func Test_initiateK8sOps(t *testing.T) {
 			name: "valid case",
 			args: args{
 				opr:       fmt.Sprintf("version"),
-				namespace: "ash-ns",
+				namespace: "test-ns",
 			},
 			wantErr: false,
 		},
@@ -28,7 +28,7 @@ func Test_initiateK8sOps(t *testing.T) {
 			name: "invalid case",
 			args: args{
 				opr:       fmt.Sprintf("versions"),
-				namespace: "ash-ns",
+				namespace: "test-ns",
 			},
 			wantErr: true,
 		},
@@ -41,50 +41,3 @@ func Test_initiateK8sOps(t *testing.T) {
 		})
 	}
 }
-
-func Test_determinePlatformSpecificUrls(t *testing.T) {
-	type args struct {
-		platform string
-	}
-	tests := []struct {
-		name    string
-		args    args
-		want    string
-		want1   string
-		wantErr bool
-	}{
-		{
-			name: "valid platform",
-			args: args{
-				platform: "windows",
-			},
-			want:    fmt.Sprintf("%s%s", preflightBaseURL, preflightWindowsFile),
-			want1:   preflightWindowsFile,
-			wantErr: false,
-		},
-		{
-			name: "invalid platform",
-			args: args{
-				platform: "unix",
-			},
-			want:    "",
-			want1:   "",
-			wantErr: true,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, got1, err := determinePlatformSpecificUrls(tt.args.platform)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("determinePlatformSpecificUrls() error = %v, wantErr %v", err, tt.wantErr)
-				return
-			}
-			if got != tt.want {
-				t.Errorf("determinePlatformSpecificUrls() got = %v, want %v", got, tt.want)
-			}
-			if got1 != tt.want1 {
-				t.Errorf("determinePlatformSpecificUrls() got1 = %v, want %v", got1, tt.want1)
-			}
-		})
-	}
-}
--- a/pkg/preflight/version_check.go
+++ b/pkg/preflight/version_check.go
@@ -1,84 +1,58 @@
 package preflight

 import (
-	"bytes"
 	"fmt"
-	"io/ioutil"
-	"path/filepath"
-	"text/template"

-	"github.com/qlik-oss/sense-installer/pkg/api"
+	"github.com/Masterminds/semver/v3"
+	"k8s.io/apimachinery/pkg/version"
 )

 const minK8sVersion = "1.11.0"
-const checkVersionYAML = `
-apiVersion: troubleshoot.replicated.com/v1beta1
-kind: Preflight
-metadata:
-  name: cluster-preflight-checks
-  namespace: {{ .namespace }}
-spec:
-  analyzers:
-    - clusterVersion:
-        outcomes:
-          - fail:
-              when: "< {{ .minK8sVersion }}"
-              message: The application requires at least Kubernetes {{ .minK8sVersion }} or later.
-              uri: https://www.kubernetes.io
-          - pass:
-              when: ">= {{ .minK8sVersion }}"
-              message: Good to go.
-`

-func (qp *QliksensePreflight) CheckK8sVersion() error {
-	// retrieve namespace
-	namespace := api.GetKubectlNamespace()
+func (qp *QliksensePreflight) CheckK8sVersion(namespace string, kubeConfigContents []byte) error {

-	api.LogDebugMessage("Namespace: %s\n", namespace)
+	var currentVersion *semver.Version

-	tmpl, err := template.New("checkVersionYAML").Parse(checkVersionYAML)
+	clientset, _, err := getK8SClientSet(kubeConfigContents, "")
 	if err != nil {
-		fmt.Printf("cannot parse template: %v", err)
+		err = fmt.Errorf("Unable to create clientset: %v\n", err)
 		return err
 	}
-	tempYaml, err := ioutil.TempFile("", "")
-	if err != nil {
-		fmt.Printf("cannot create file: %v", err)
+	var serverVersion *version.Info
+	if err := retryOnError(func() (err error) {
+		serverVersion, err = clientset.ServerVersion()
+		return err
+	}); err != nil {
+		err = fmt.Errorf("Unable to get server version: %v\n", err)
+		//fmt.Println(err)
 		return err
 	}
-	api.LogDebugMessage("Temp Yaml file: %s\n", tempYaml.Name())
+	fmt.Printf("Kubernetes API Server version: %s\n", serverVersion.String())

-	b := bytes.Buffer{}
-	err = tmpl.Execute(&b, map[string]string{
-		"namespace":     namespace,
-		"minK8sVersion": minK8sVersion,
-	})
+	// Compare K8s version on the cluster with minimum supported k8s version
+	currentVersion, err = semver.NewVersion(serverVersion.String())
 	if err != nil {
+		err = fmt.Errorf("Unable to convert server version into semver version: %v\n", err)
+		//fmt.Println(err)
+		return err
+	}
+	fmt.Printf("Current K8s Version: %v\n", currentVersion)
+
+	minK8sVersionSemver, err := semver.NewVersion(minK8sVersion)
+	if err != nil {
+		err = fmt.Errorf("Unable to convert minimum Kubernetes version into semver version:%v\n", err)
 		fmt.Println(err)
 		return err
 	}

-	tempYaml.WriteString(b.String())
-	//api.LogDebugMessage("Temp yaml contents: %s", b.String())
-	fmt.Printf("Minimum Kubernetes version supported: %s\n", minK8sVersion)
-
-	// current kubectl version
-	opr := fmt.Sprintf("version")
-	err = initiateK8sOps(opr, namespace)
-	if err != nil {
-		fmt.Println(err)
-		return err
+	if currentVersion.GreaterThan(minK8sVersionSemver) {
+		//fmt.Printf("\n\nCurrent %s Component version: %s is less than minimum required version:%s\n", component, currentComponentVersion, componentVersionFromDependenciesYaml)
+		fmt.Printf("Current %s is greater than minimum required version:%s, hence good to go\n", currentVersion, minK8sVersionSemver)
+		fmt.Println("Preflight minimum kubernetes version check: PASSED")
+	} else {
+		fmt.Printf("Current %s is less than minimum required version:%s\n", currentVersion, minK8sVersionSemver)
+		fmt.Println("Preflight minimum kubernetes version check: FAILED")
 	}
-
-	// call preflight
-	preflightCommand := filepath.Join(qp.Q.QliksenseHome, PreflightChecksDirName, preflightFileName)
-
-	err = invokePreflight(preflightCommand, tempYaml)
-	if err != nil {
-		fmt.Println(err)
-		return err
-	}
-
-	fmt.Println("Minimum kubernetes version check completed")
+	fmt.Printf("Completed Preflight kubernetes minimum version check\n\n")
 	return nil
 }