Add containerd ready channel to delay etcd node join

pkg/agent/run.go

@@ -84,6 +84,14 @@ func run(ctx context.Context, cfg cmds.Agent, proxy proxy.Proxy) error {
 		}
 	}
 
+	// the agent runtime is ready to host workloads when containerd is up and the airgap
+	// images have finished loading, as that portion of startup may block for an arbitrary
+	// amount of time depending on how long it takes to import whatever the user has placed
+	// in the images directory.
+	if cfg.AgentReady != nil {
+		close(cfg.AgentReady)
+	}
+
 	notifySocket := os.Getenv("NOTIFY_SOCKET")
 	os.Unsetenv("NOTIFY_SOCKET")
 

pkg/agent/tunnel/tunnel.go

@@ -53,6 +53,9 @@ func Setup(ctx context.Context, config *config.Node, proxy proxy.Proxy) error {
 		return err
 	}
 
+	// Do an immediate fill of proxy addresses from the server endpoint list, before going into the
+	// watch loop. This will fail on the first server, as the apiserver won't be started yet - but
+	// that's fine because the local server is already seeded into the proxy address list.
 	endpoint, _ := client.CoreV1().Endpoints("default").Get(ctx, "kubernetes", metav1.GetOptions{})
 	if endpoint != nil {
 		addresses := util.GetAddresses(endpoint)
@@ -61,8 +64,9 @@ func Setup(ctx context.Context, config *config.Node, proxy proxy.Proxy) error {
 		}
 	}
 
+	// Attempt to connect to supervisors, storing their cancellation function for later when we
+	// need to disconnect.
 	disconnect := map[string]context.CancelFunc{}
-
 	wg := &sync.WaitGroup{}
 	for _, address := range proxy.SupervisorAddresses() {
 		if _, ok := disconnect[address]; !ok {
@@ -70,7 +74,11 @@ func Setup(ctx context.Context, config *config.Node, proxy proxy.Proxy) error {
 		}
 	}
 
+	// Once the apiserver is up, go into a watch loop, adding and removing tunnels as endpoints come
+	// and go from the cluster. We go into a faster but noisier connect loop if the watch fails
+	// following a successful connection.
 	go func() {
+		util.WaitForAPIServerReady(client, 30*time.Second)
 	connect:
 		for {
 			time.Sleep(5 * time.Second)

pkg/cli/cmds/agent.go

@@ -46,6 +46,7 @@ type Agent struct {
 	Taints                   cli.StringSlice
 	ImageCredProvBinDir      string
 	ImageCredProvConfig      string
+	AgentReady               chan<- struct{}
 	AgentShared
 }
 

pkg/cli/server/server.go

@@ -16,6 +16,7 @@ import (
 	"github.com/rancher/k3s/pkg/agent/loadbalancer"
 	"github.com/rancher/k3s/pkg/cli/cmds"
 	"github.com/rancher/k3s/pkg/clientaccess"
+	"github.com/rancher/k3s/pkg/daemons/config"
 	"github.com/rancher/k3s/pkg/datadir"
 	"github.com/rancher/k3s/pkg/etcd"
 	"github.com/rancher/k3s/pkg/netutil"
@@ -84,8 +85,11 @@ func run(app *cli.Context, cfg *cmds.Server, leaderControllers server.CustomCont
 		cfg.Token = cfg.ClusterSecret
 	}
 
+	agentReady := make(chan struct{})
+
 	serverConfig := server.Config{}
 	serverConfig.DisableAgent = cfg.DisableAgent
+	serverConfig.ControlConfig.Runtime = &config.ControlRuntime{AgentReady: agentReady}
 	serverConfig.ControlConfig.Token = cfg.Token
 	serverConfig.ControlConfig.AgentToken = cfg.AgentToken
 	serverConfig.ControlConfig.JoinURL = cfg.ServerURL
@@ -426,6 +430,7 @@ func run(app *cli.Context, cfg *cmds.Server, leaderControllers server.CustomCont
 	}()
 
 	if cfg.DisableAgent {
+		close(agentReady)
 		<-ctx.Done()
 		return nil
 	}
@@ -442,6 +447,7 @@ func run(app *cli.Context, cfg *cmds.Server, leaderControllers server.CustomCont
 	}
 
 	agentConfig := cmds.AgentConfig
+	agentConfig.AgentReady = agentReady
 	agentConfig.Debug = app.GlobalBool("debug")
 	agentConfig.DataDir = filepath.Dir(serverConfig.ControlConfig.DataDir)
 	agentConfig.ServerURL = url

pkg/daemons/config/types.go

@@ -198,6 +198,7 @@ type ControlRuntime struct {
 
 	HTTPBootstrap                       bool
 	APIServerReady                      <-chan struct{}
+	AgentReady                          <-chan struct{}
 	ETCDReady                           <-chan struct{}
 	ClusterControllerStart              func(ctx context.Context) error
 	LeaderElectedClusterControllerStart func(ctx context.Context) error
@@ -217,6 +218,7 @@ type ControlRuntime struct {
 	ServingKubeletKey  string
 	ServerToken        string
 	AgentToken         string
+	APIServer          http.Handler
 	Handler            http.Handler
 	Tunnel             http.Handler
 	Authenticator      authenticator.Request

pkg/daemons/control/server.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"math/rand"
 	"net"
-	"net/http"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -22,7 +21,6 @@ import (
 	authorizationv1 "k8s.io/api/authorization/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/wait"
-	"k8s.io/apiserver/pkg/authentication/authenticator"
 	"k8s.io/client-go/kubernetes"
 	authorizationv1client "k8s.io/client-go/kubernetes/typed/authorization/v1"
 	"k8s.io/client-go/tools/clientcmd"
@@ -37,9 +35,7 @@ var localhostIP = net.ParseIP("127.0.0.1")
 
 func Server(ctx context.Context, cfg *config.Control) error {
 	rand.Seed(time.Now().UTC().UnixNano())
-
-	runtime := &config.ControlRuntime{}
-	cfg.Runtime = runtime
+	runtime := cfg.Runtime
 
 	if err := prepare(ctx, cfg, runtime); err != nil {
 		return errors.Wrap(err, "preparing server")
@@ -48,13 +44,16 @@ func Server(ctx context.Context, cfg *config.Control) error {
 	cfg.Runtime.Tunnel = setupTunnel()
 	proxyutil.DisableProxyHostnameCheck = true
 
-	var auth authenticator.Request
-	var handler http.Handler
-	var err error
+	basicAuth, err := basicAuthenticator(runtime.PasswdFile)
+	if err != nil {
+		return err
+	}
+	runtime.Authenticator = basicAuth
 
 	if !cfg.DisableAPIServer {
-		auth, handler, err = apiServer(ctx, cfg, runtime)
-		if err != nil {
+		go waitForAPIServerHandlers(ctx, runtime)
+
+		if err := apiServer(ctx, cfg, runtime); err != nil {
 			return err
 		}
 
@@ -62,13 +61,6 @@ func Server(ctx context.Context, cfg *config.Control) error {
 			return err
 		}
 	}
-	basicAuth, err := basicAuthenticator(runtime.PasswdFile)
-	if err != nil {
-		return err
-	}
-
-	runtime.Authenticator = combineAuthenticators(basicAuth, auth)
-	runtime.Handler = handler
 
 	if !cfg.DisableScheduler {
 		if err := scheduler(ctx, cfg, runtime); err != nil {
@@ -145,7 +137,7 @@ func scheduler(ctx context.Context, cfg *config.Control, runtime *config.Control
 	return executor.Scheduler(ctx, runtime.APIServerReady, args)
 }
 
-func apiServer(ctx context.Context, cfg *config.Control, runtime *config.ControlRuntime) (authenticator.Request, http.Handler, error) {
+func apiServer(ctx context.Context, cfg *config.Control, runtime *config.ControlRuntime) error {
 	argsMap := map[string]string{
 		"feature-gates": "JobTrackingWithFinalizers=true",
 	}
@@ -381,6 +373,15 @@ func checkForCloudControllerPrivileges(ctx context.Context, runtime *config.Cont
 	return err
 }
 
+func waitForAPIServerHandlers(ctx context.Context, runtime *config.ControlRuntime) {
+	auth, handler, err := executor.APIServerHandlers(ctx)
+	if err != nil {
+		logrus.Fatalf("Failed to get request handlers from apiserver: %v", err)
+	}
+	runtime.Authenticator = combineAuthenticators(runtime.Authenticator, auth)
+	runtime.APIServer = handler
+}
+
 func waitForAPIServerInBackground(ctx context.Context, runtime *config.ControlRuntime) error {
 	restConfig, err := clientcmd.BuildConfigFromFlags("", runtime.KubeConfigAdmin)
 	if err != nil {

pkg/daemons/executor/embed.go

@@ -70,12 +70,17 @@ func (Embedded) KubeProxy(ctx context.Context, args []string) error {
 	return nil
 }
 
-func (Embedded) APIServer(ctx context.Context, etcdReady <-chan struct{}, args []string) (authenticator.Request, http.Handler, error) {
-	<-etcdReady
+func (Embedded) APIServerHandlers(ctx context.Context) (authenticator.Request, http.Handler, error) {
+	startupConfig := <-app.StartupConfig
+	return startupConfig.Authenticator, startupConfig.Handler, nil
+}
+
+func (Embedded) APIServer(ctx context.Context, etcdReady <-chan struct{}, args []string) error {
 	command := app.NewAPIServerCommand(ctx.Done())
 	command.SetArgs(args)
 
 	go func() {
+		<-etcdReady
 		defer func() {
 			if err := recover(); err != nil {
 				logrus.Fatalf("apiserver panic: %v", err)
@@ -84,8 +89,7 @@ func (Embedded) APIServer(ctx context.Context, etcdReady <-chan struct{}, args [
 		logrus.Fatalf("apiserver exited: %v", command.ExecuteContext(ctx))
 	}()
 
-	startupConfig := <-app.StartupConfig
-	return startupConfig.Authenticator, startupConfig.Handler, nil
+	return nil
 }
 
 func (Embedded) Scheduler(ctx context.Context, apiReady <-chan struct{}, args []string) error {

pkg/daemons/executor/etcd.go

@@ -29,7 +29,7 @@ func (e Embedded) ETCD(ctx context.Context, args ETCDConfig) error {
 	}
 	etcd, err := embed.StartEtcd(cfg)
 	if err != nil {
-		return nil
+		return err
 	}
 
 	go func() {

pkg/daemons/executor/executor.go

@@ -22,7 +22,8 @@ type Executor interface {
 	Bootstrap(ctx context.Context, nodeConfig *daemonconfig.Node, cfg cmds.Agent) error
 	Kubelet(ctx context.Context, args []string) error
 	KubeProxy(ctx context.Context, args []string) error
-	APIServer(ctx context.Context, etcdReady <-chan struct{}, args []string) (authenticator.Request, http.Handler, error)
+	APIServerHandlers(ctx context.Context) (authenticator.Request, http.Handler, error)
+	APIServer(ctx context.Context, etcdReady <-chan struct{}, args []string) error
 	Scheduler(ctx context.Context, apiReady <-chan struct{}, args []string) error
 	ControllerManager(ctx context.Context, apiReady <-chan struct{}, args []string) error
 	CurrentETCDOptions() (InitialOptions, error)
@@ -97,7 +98,11 @@ func KubeProxy(ctx context.Context, args []string) error {
 	return executor.KubeProxy(ctx, args)
 }
 
-func APIServer(ctx context.Context, etcdReady <-chan struct{}, args []string) (authenticator.Request, http.Handler, error) {
+func APIServerHandlers(ctx context.Context) (authenticator.Request, http.Handler, error) {
+	return executor.APIServerHandlers(ctx)
+}
+
+func APIServer(ctx context.Context, etcdReady <-chan struct{}, args []string) error {
 	return executor.APIServer(ctx, etcdReady, args)
 }
 

pkg/etcd/etcd.go

@@ -192,6 +192,7 @@ func (e *ETCD) IsInitialized(ctx context.Context, config *config.Control) (bool,
 func (e *ETCD) Reset(ctx context.Context, rebootstrap func() error) error {
 	// Wait for etcd to come up as a new single-node cluster, then exit
 	go func() {
+		<-e.runtime.AgentReady
 		t := time.NewTicker(5 * time.Second)
 		defer t.Stop()
 		for range t.C {
@@ -291,8 +292,14 @@ func (e *ETCD) Start(ctx context.Context, clientAccessInfo *clientaccess.Info) e
 		return e.newCluster(ctx, false)
 	}
 
-	err = e.join(ctx, clientAccessInfo)
-	return errors.Wrap(err, "joining etcd cluster")
+	go func() {
+		<-e.runtime.AgentReady
+		if err := e.join(ctx, clientAccessInfo); err != nil {
+			logrus.Fatalf("ETCD join failed: %v", err)
+		}
+	}()
+
+	return nil
 }
 
 // join attempts to add a member to an existing cluster
@@ -335,9 +342,9 @@ func (e *ETCD) join(ctx context.Context, clientAccessInfo *clientaccess.Info) er
 			// make sure to remove the name file if a duplicate node name is used
 			nameFile := nameFile(e.config)
 			if err := os.Remove(nameFile); err != nil {
-				return err
+				logrus.Errorf("Failed to remove etcd name file %s: %v", nameFile, err)
 			}
-			return errors.New("Failed to join etcd cluster due to duplicate node names, please use unique node name for the server")
+			return errors.New("duplicate node name found, please use a unique name for this node")
 		}
 		for _, peer := range member.PeerURLs {
 			u, err := url.Parse(peer)
@@ -358,7 +365,7 @@ func (e *ETCD) join(ctx context.Context, clientAccessInfo *clientaccess.Info) er
 	}
 
 	if add {
-		logrus.Infof("Adding %s to etcd cluster %v", e.peerURL(), cluster)
+		logrus.Infof("Adding member %s=%s to etcd cluster %v", e.name, e.peerURL(), cluster)
 		if _, err = client.MemberAddAsLearner(clientCtx, []string{e.peerURL()}); err != nil {
 			return err
 		}
@@ -444,7 +451,7 @@ func (e *ETCD) handler(next http.Handler) http.Handler {
 	return mux
 }
 
-// infoHandler returns etcd cluster information. This is used by new members when joining the custer.
+// infoHandler returns etcd cluster information. This is used by new members when joining the cluster.
 func (e *ETCD) infoHandler() http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		ctx, cancel := context.WithTimeout(req.Context(), 2*time.Second)
@@ -500,6 +507,10 @@ func getClientConfig(ctx context.Context, runtime *config.ControlRuntime, endpoi
 // toTLSConfig converts the ControlRuntime configuration to TLS configuration suitable
 // for use by etcd.
 func toTLSConfig(runtime *config.ControlRuntime) (*tls.Config, error) {
+	if runtime.ClientETCDCert == "" || runtime.ClientETCDKey == "" || runtime.ETCDServerCA == "" {
+		return nil, errors.New("runtime is not ready yet")
+	}
+
 	clientCert, err := tls.LoadX509KeyPair(runtime.ClientETCDCert, runtime.ClientETCDKey)
 	if err != nil {
 		return nil, err
@@ -533,8 +544,8 @@ func GetAdvertiseAddress(advertiseIP string) (string, error) {
 // newCluster returns options to set up etcd for a new cluster
 func (e *ETCD) newCluster(ctx context.Context, reset bool) error {
 	err := e.cluster(ctx, reset, executor.InitialOptions{
-		AdvertisePeerURL: fmt.Sprintf("https://%s:2380", e.address),
-		Cluster:          fmt.Sprintf("%s=https://%s:2380", e.name, e.address),
+		AdvertisePeerURL: e.peerURL(),
+		Cluster:          fmt.Sprintf("%s=%s", e.name, e.peerURL()),
 		State:            "new",
 	})
 	if err != nil {
@@ -684,6 +695,7 @@ func (e *ETCD) RemovePeer(ctx context.Context, name, address string, allowSelfRe
 // being promoted to full voting member. The checks only run on the cluster member that is
 // the etcd leader.
 func (e *ETCD) manageLearners(ctx context.Context) error {
+	<-e.runtime.AgentReady
 	t := time.NewTicker(manageTickerTime)
 	defer t.Stop()
 
@@ -1377,9 +1389,6 @@ func backupDirWithRetention(dir string, maxBackupRetention int) (string, error)
 // GetAPIServerURLFromETCD will try to fetch the version.Program/apiaddresses key from etcd
 // when it succeed it will parse the first address in the list and return back an address
 func GetAPIServerURLFromETCD(ctx context.Context, cfg *config.Control) (string, error) {
-	if cfg.Runtime == nil {
-		return "", fmt.Errorf("runtime is not ready yet")
-	}
 	cl, err := GetClient(ctx, cfg.Runtime, endpoint)
 	if err != nil {
 		return "", err

pkg/etcd/etcd_test.go

@@ -7,16 +7,29 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/rancher/k3s/pkg/clientaccess"
 	"github.com/rancher/k3s/pkg/daemons/config"
 	testutil "github.com/rancher/k3s/tests/util"
 	"github.com/robfig/cron/v3"
 	clientv3 "go.etcd.io/etcd/client/v3"
+	utilnet "k8s.io/apimachinery/pkg/util/net"
 )
 
+func mustGetAddress() string {
+	ipAddr, err := utilnet.ChooseHostInterface()
+	if err != nil {
+		panic(err)
+	}
+	return ipAddr.String()
+}
+
 func generateTestConfig() *config.Control {
+	agentReady := make(chan struct{})
+	close(agentReady)
 	return &config.Control{
+		Runtime:               &config.ControlRuntime{AgentReady: agentReady},
 		HTTPSPort:             6443,
 		SupervisorPort:        6443,
 		AdvertisePort:         6443,
@@ -189,42 +202,48 @@ func Test_UnitETCD_Register(t *testing.T) {
 }
 
 func Test_UnitETCD_Start(t *testing.T) {
+	type contextInfo struct {
+		ctx    context.Context
+		cancel context.CancelFunc
+	}
 	type fields struct {
+		context contextInfo
 		client  *clientv3.Client
 		config  *config.Control
 		name    string
-		runtime *config.ControlRuntime
 		address string
 		cron    *cron.Cron
 		s3      *S3
 	}
 	type args struct {
-		ctx              context.Context
 		clientAccessInfo *clientaccess.Info
 	}
 	tests := []struct {
 		name     string
 		fields   fields
 		args     args
-		setup    func(cnf *config.Control) error
-		teardown func(cnf *config.Control) error
+		setup    func(cnf *config.Control, ctxInfo *contextInfo) error
+		teardown func(cnf *config.Control, ctxInfo *contextInfo) error
 		wantErr  bool
 	}{
 		{
 			name: "Start etcd without clientAccessInfo and without snapshots",
 			fields: fields{
 				config:  generateTestConfig(),
-				address: "192.168.1.123", // Local IP address
+				address: mustGetAddress(),
+				name:    "default",
 			},
 			args: args{
-				ctx:              context.TODO(),
 				clientAccessInfo: nil,
 			},
-			setup: func(cnf *config.Control) error {
+			setup: func(cnf *config.Control, ctxInfo *contextInfo) error {
+				ctxInfo.ctx, ctxInfo.cancel = context.WithCancel(context.Background())
 				cnf.EtcdDisableSnapshots = true
 				return testutil.GenerateRuntime(cnf)
 			},
-			teardown: func(cnf *config.Control) error {
+			teardown: func(cnf *config.Control, ctxInfo *contextInfo) error {
+				ctxInfo.cancel()
+				time.Sleep(5 * time.Second)
 				testutil.CleanupDataDir(cnf)
 				return nil
 			},
@@ -233,17 +252,20 @@ func Test_UnitETCD_Start(t *testing.T) {
 			name: "Start etcd without clientAccessInfo on",
 			fields: fields{
 				config:  generateTestConfig(),
-				address: "192.168.1.123", // Local IP address
+				address: mustGetAddress(),
+				name:    "default",
 				cron:    cron.New(),
 			},
 			args: args{
-				ctx:              context.TODO(),
 				clientAccessInfo: nil,
 			},
-			setup: func(cnf *config.Control) error {
+			setup: func(cnf *config.Control, ctxInfo *contextInfo) error {
+				ctxInfo.ctx, ctxInfo.cancel = context.WithCancel(context.Background())
 				return testutil.GenerateRuntime(cnf)
 			},
-			teardown: func(cnf *config.Control) error {
+			teardown: func(cnf *config.Control, ctxInfo *contextInfo) error {
+				ctxInfo.cancel()
+				time.Sleep(5 * time.Second)
 				testutil.CleanupDataDir(cnf)
 				return nil
 			},
@@ -252,20 +274,23 @@ func Test_UnitETCD_Start(t *testing.T) {
 			name: "Start etcd with an existing cluster",
 			fields: fields{
 				config:  generateTestConfig(),
-				address: "192.168.1.123", // Local IP address
+				address: mustGetAddress(),
+				name:    "default",
 				cron:    cron.New(),
 			},
 			args: args{
-				ctx:              context.TODO(),
 				clientAccessInfo: nil,
 			},
-			setup: func(cnf *config.Control) error {
+			setup: func(cnf *config.Control, ctxInfo *contextInfo) error {
+				ctxInfo.ctx, ctxInfo.cancel = context.WithCancel(context.Background())
 				if err := testutil.GenerateRuntime(cnf); err != nil {
 					return err
 				}
 				return os.MkdirAll(walDir(cnf), 0700)
 			},
-			teardown: func(cnf *config.Control) error {
+			teardown: func(cnf *config.Control, ctxInfo *contextInfo) error {
+				ctxInfo.cancel()
+				time.Sleep(5 * time.Second)
 				testutil.CleanupDataDir(cnf)
 				os.Remove(walDir(cnf))
 				return nil
@@ -278,17 +303,17 @@ func Test_UnitETCD_Start(t *testing.T) {
 				client:  tt.fields.client,
 				config:  tt.fields.config,
 				name:    tt.fields.name,
-				runtime: tt.fields.runtime,
+				runtime: tt.fields.config.Runtime,
 				address: tt.fields.address,
 				cron:    tt.fields.cron,
 				s3:      tt.fields.s3,
 			}
-			defer tt.teardown(e.config)
-			if err := tt.setup(e.config); err != nil {
+			defer tt.teardown(e.config, &tt.fields.context)
+			if err := tt.setup(e.config, &tt.fields.context); err != nil {
 				t.Errorf("Setup for ETCD.Start() failed = %v", err)
 				return
 			}
-			if err := e.Start(tt.args.ctx, tt.args.clientAccessInfo); (err != nil) != tt.wantErr {
+			if err := e.Start(tt.fields.context.ctx, tt.args.clientAccessInfo); (err != nil) != tt.wantErr {
 				t.Errorf("ETCD.Start() error = %v, wantErr %v", err, tt.wantErr)
 			}
 		})

pkg/server/router.go

@@ -39,7 +39,7 @@ func router(ctx context.Context, config *Config, cfg *cmds.Server) http.Handler
 	prefix := "/v1-" + version.Program
 	authed := mux.NewRouter()
 	authed.Use(authMiddleware(serverConfig, version.Program+":agent"))
-	authed.NotFoundHandler = serverConfig.Runtime.Handler
+	authed.NotFoundHandler = apiserver(serverConfig.Runtime)
 	authed.Path(prefix + "/serving-kubelet.crt").Handler(servingKubeletCert(serverConfig, serverConfig.Runtime.ServingKubeletKey, nodeAuth))
 	authed.Path(prefix + "/client-kubelet.crt").Handler(clientKubeletCert(serverConfig, serverConfig.Runtime.ClientKubeletKey, nodeAuth))
 	authed.Path(prefix + "/client-kube-proxy.crt").Handler(fileHandler(serverConfig.Runtime.ClientKubeProxyCert, serverConfig.Runtime.ClientKubeProxyKey))
@@ -72,6 +72,20 @@ func router(ctx context.Context, config *Config, cfg *cmds.Server) http.Handler
 	return router
 }
 
+func apiserver(runtime *config.ControlRuntime) http.Handler {
+	return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+		if runtime != nil && runtime.APIServer != nil {
+			runtime.APIServer.ServeHTTP(resp, req)
+		} else {
+			data := []byte("apiserver not ready")
+			resp.WriteHeader(http.StatusInternalServerError)
+			resp.Header().Set("Content-Type", "text/plain")
+			resp.Header().Set("Content-length", strconv.Itoa(len(data)))
+			resp.Write(data)
+		}
+	})
+}
+
 func cacerts(serverCA string) http.Handler {
 	var ca []byte
 	return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
@@ -269,7 +283,10 @@ func configHandler(server *config.Control, cfg *cmds.Server) http.Handler {
 		// At this time we don't sync all the fields, just those known to be touched by startup hooks.
 		server.DisableKubeProxy = cfg.DisableKubeProxy
 		resp.Header().Set("content-type", "application/json")
-		json.NewEncoder(resp).Encode(server)
+		if err := json.NewEncoder(resp).Encode(server); err != nil {
+			logrus.Errorf("Failed to encode agent config: %v", err)
+			resp.WriteHeader(http.StatusInternalServerError)
+		}
 	})
 }
 

scripts/test

@@ -15,6 +15,9 @@ docker ps
 
 # ---
 
+. ./scripts/test-unit
+echo "Did test-unit $?"
+
 . ./scripts/test-run-basics
 echo "Did test-run-basics $?"
 
@@ -41,6 +44,4 @@ echo "Did test-run-sonobuoy $?"
 test-run-sonobuoy mysql
 test-run-sonobuoy postgres
 
-. ./scripts/test-unit
-
 exit 0

tests/util/runtime.go

@@ -34,8 +34,9 @@ func GenerateDataDir(cnf *config.Control) error {
 }
 
 // CleanupDataDir removes the associated "/tmp/k3s/<RANDOM_STRING>"
-// directory.
+// directory along with the 'latest' symlink that points at it.
 func CleanupDataDir(cnf *config.Control) {
+	os.Remove(filepath.Join(cnf.DataDir, "..", "latest"))
 	os.RemoveAll(cnf.DataDir)
 }