[Elastic Agent] Add support for Fleet Server inside Docker (elastic#2…

…4220)

* Add new container subcommand.

* Fix vet.

* Fix path with just enroll.

* Add changelog.

* Add FLEET_SETUP fallback. Make GET, POST to kibana for resilient.

* Add FLEET_FORCE. Don't update Kibana config when Fleet Server running locally.

dev-tools/packaging/templates/docker/docker-entrypoint.elastic-agent.tmpl

@@ -2,71 +2,10 @@
 
 set -eo pipefail
 
-# Environment variables used
-# FLEET_ENROLLMENT_TOKEN - existing enrollment token to be used for enroll
-# FLEET_ENROLL - if set to 1 enroll will be performed
-# FLEET_ENROLL_INSECURE - if set to 1, agent will enroll with fleet using --insecure flag
-# FLEET_SETUP - if  set to 1 fleet setup will be performed
-# FLEET_TOKEN_NAME - token name for a token to be created
-# KIBANA_HOST - actual kibana host [http://localhost:5601]
-# KIBANA_PASSWORD - password for accessing kibana API [changeme]
-# KIBANA_USERNAME - username for accessing kibana API [elastic]
+# For information on the possible environment variables that can be passed into the container. Run the following
+# command for information on the options that are available.
+#
+# `./elastic-agent container --help`
+#
 
-function setup(){
-  curl -X POST  ${KIBANA_HOST:-http://localhost:5601}/api/fleet/setup -H 'kbn-xsrf: true' -u ${KIBANA_USERNAME:-elastic}:${KIBANA_PASSWORD:-changeme}
- curl -X POST  ${KIBANA_HOST:-http://localhost:5601}/api/fleet/agents/setup \
-    -H 'Content-Type: application/json' \
-    -H 'kbn-xsrf: true' \
-    -u ${KIBANA_USERNAME:-elastic}:${KIBANA_PASSWORD:-changeme}
-}
-
-function enroll(){
-    local enrollResp
-    local apiKey
-
-    if [[ -n "${FLEET_ENROLLMENT_TOKEN}" ]]; then
-      apikey="${FLEET_ENROLLMENT_TOKEN}"
-    else
-      enrollResp=$(curl ${KIBANA_HOST:-http://localhost:5601}/api/fleet/enrollment-api-keys \
-        -H 'Content-Type: application/json' \
-        -H 'kbn-xsrf: true' \
-        -u ${KIBANA_USERNAME:-elastic}:${KIBANA_PASSWORD:-changeme} )
-
-      local exitCode=$?
-      if [ $exitCode -ne 0 ]; then
-        exit $exitCode
-      fi
-      echo $enrollResp
-      local apikeyId=$(echo $enrollResp | jq -r '.list[] | select((.name | startswith("Default ")) and (.active == true)) | .id')
-      echo $apikeyId
-
-      if [[ -z "${apikeyId}" ]]; then
-        echo "Default agent policy was not found. Please consider using own enrollment token (FLEET_ENROLLMENT_TOKEN)."
-        exit 1
-      fi
-
-      enrollResp=$(curl ${KIBANA_HOST:-http://localhost:5601}/api/fleet/enrollment-api-keys/$apikeyId \
-        -H 'Content-Type: application/json' \
-        -H 'kbn-xsrf: true' \
-        -u ${KIBANA_USERNAME:-elastic}:${KIBANA_PASSWORD:-changeme} )
-
-      exitCode=$?
-      if [ $exitCode -ne 0 ]; then
-        exit $exitCode
-      fi
-
-      apikey=$(echo $enrollResp | jq -r '.item.api_key')
-    fi
-    echo $apikey
-
-    if [[ -n "${FLEET_ENROLL_INSECURE}" ]] && [[ ${FLEET_ENROLL_INSECURE} == 1 ]]; then
-      insecure_flag="--insecure"
-    fi
-
-    ./{{ .BeatName }} enroll ${insecure_flag} -f --url=${KIBANA_HOST:-http://localhost:5601} --enrollment-token=$apikey
-}
-
-if [[ -n "${FLEET_SETUP}" ]] && [[ ${FLEET_SETUP} == 1 ]]; then setup; fi
-if [[ -n "${FLEET_ENROLL}" ]] && [[ ${FLEET_ENROLL} == 1 ]]; then enroll; fi
-
-exec {{ .BeatName }} run "$@"
+exec {{ .BeatName }} container "$@"

x-pack/elastic-agent/CHANGELOG.next.asciidoc

@@ -73,3 +73,4 @@
 - Add support for Fleet Server {pull}23736[23736]
 - Add support for enrollment with local bootstrap of Fleet Server {pull}23865[23865]
 - Add TLS support for Fleet Server {pull}24142[24142]
+- Add support for Fleet Server running under Elastic Agent {pull}24220[24220]

x-pack/elastic-agent/pkg/agent/application/enroll_cmd.go

@@ -15,6 +15,8 @@ import (
 	"os"
 	"time"
 
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/core/process"
+
 	"gopkg.in/yaml.v2"
 
 	"github.com/elastic/beats/v7/libbeat/common/backoff"
@@ -72,6 +74,19 @@ type EnrollCmd struct {
 	client       clienter
 	configStore  store
 	kibanaConfig *kibana.Config
+	agentProc    *process.Info
+}
+
+// EnrollCmdFleetServerOption define all the supported enrollment options for bootstrapping with Fleet Server.
+type EnrollCmdFleetServerOption struct {
+	ConnStr    string
+	PolicyID   string
+	Host       string
+	Port       uint16
+	Cert       string
+	CertKey    string
+	Insecure   bool
+	SpawnAgent bool
 }
 
 // EnrollCmdOption define all the supported enrollment option.
@@ -84,13 +99,7 @@ type EnrollCmdOption struct {
 	UserProvidedMetadata map[string]interface{}
 	EnrollAPIKey         string
 	Staging              string
-	FleetServerConnStr   string
-	FleetServerPolicyID  string
-	FleetServerHost      string
-	FleetServerPort      uint16
-	FleetServerCert      string
-	FleetServerCertKey   string
-	FleetServerInsecure  bool
+	FleetServer          EnrollCmdFleetServerOption
 }
 
 func (e *EnrollCmdOption) kibanaConfig() (*kibana.Config, error) {
@@ -157,7 +166,8 @@ func NewEnrollCmdWithStore(
 // Execute tries to enroll the agent into Fleet.
 func (c *EnrollCmd) Execute(ctx context.Context) error {
 	var err error
-	if c.options.FleetServerConnStr != "" {
+	defer c.stopAgent() // ensure its stopped no matter what
+	if c.options.FleetServer.ConnStr != "" {
 		err = c.fleetServerBootstrap(ctx)
 		if err != nil {
 			return err
@@ -185,18 +195,26 @@ func (c *EnrollCmd) Execute(ctx context.Context) error {
 		return errors.New(err, "fail to enroll")
 	}
 
-	if c.daemonReload(ctx) != nil {
-		c.log.Info("Elastic Agent might not be running; unable to trigger restart")
+	if c.agentProc == nil {
+		if c.daemonReload(ctx) != nil {
+			c.log.Info("Elastic Agent might not be running; unable to trigger restart")
+		}
+		c.log.Info("Successfully triggered restart on running Elastic Agent.")
+		return nil
 	}
-	c.log.Info("Successfully triggered restart on running Elastic Agent.")
+	c.log.Info("Elastic Agent has been enrolled; start Elastic Agent")
 	return nil
 }
 
 func (c *EnrollCmd) fleetServerBootstrap(ctx context.Context) error {
 	c.log.Debug("verifying communication with running Elastic Agent daemon")
+	agentRunning := true
 	_, err := getDaemonStatus(ctx)
 	if err != nil {
-		return errors.New("failed to communicate with elastic-agent daemon; is elastic-agent running?")
+		if !c.options.FleetServer.SpawnAgent {
+			return errors.New("failed to communicate with elastic-agent daemon; is elastic-agent running?")
+		}
+		agentRunning = false
 	}
 
 	err = c.prepareFleetTLS()
@@ -205,9 +223,9 @@ func (c *EnrollCmd) fleetServerBootstrap(ctx context.Context) error {
 	}
 
 	fleetConfig, err := createFleetServerBootstrapConfig(
-		c.options.FleetServerConnStr, c.options.FleetServerPolicyID,
-		c.options.FleetServerHost, c.options.FleetServerPort,
-		c.options.FleetServerCert, c.options.FleetServerCertKey)
+		c.options.FleetServer.ConnStr, c.options.FleetServer.PolicyID,
+		c.options.FleetServer.Host, c.options.FleetServer.Port,
+		c.options.FleetServer.Cert, c.options.FleetServer.CertKey)
 	configToStore := map[string]interface{}{
 		"fleet": fleetConfig,
 	}
@@ -219,9 +237,18 @@ func (c *EnrollCmd) fleetServerBootstrap(ctx context.Context) error {
 		return errors.New(err, "could not save fleet server bootstrap information", errors.TypeFilesystem)
 	}
 
-	err = c.daemonReload(ctx)
-	if err != nil {
-		return errors.New(err, "failed to trigger elastic-agent daemon reload", errors.TypeApplication)
+	if agentRunning {
+		// reload the already running agent
+		err = c.daemonReload(ctx)
+		if err != nil {
+			return errors.New(err, "failed to trigger elastic-agent daemon reload", errors.TypeApplication)
+		}
+	} else {
+		// spawn `run` as a subprocess so enroll can perform the bootstrap process of Fleet Server
+		err = c.startAgent()
+		if err != nil {
+			return err
+		}
 	}
 
 	err = waitForFleetServer(ctx, c.log)
@@ -232,25 +259,25 @@ func (c *EnrollCmd) fleetServerBootstrap(ctx context.Context) error {
 }
 
 func (c *EnrollCmd) prepareFleetTLS() error {
-	host := c.options.FleetServerHost
+	host := c.options.FleetServer.Host
 	if host == "" {
 		host = "localhost"
 	}
-	port := c.options.FleetServerPort
+	port := c.options.FleetServer.Port
 	if port == 0 {
 		port = defaultFleetServerPort
 	}
-	if c.options.FleetServerCert != "" && c.options.FleetServerCertKey == "" {
+	if c.options.FleetServer.Cert != "" && c.options.FleetServer.CertKey == "" {
 		return errors.New("certificate private key is required when certificate provided")
 	}
-	if c.options.FleetServerCertKey != "" && c.options.FleetServerCert == "" {
+	if c.options.FleetServer.CertKey != "" && c.options.FleetServer.Cert == "" {
 		return errors.New("certificate is required when certificate private key is provided")
 	}
-	if c.options.FleetServerCert == "" && c.options.FleetServerCertKey == "" {
-		if c.options.FleetServerInsecure {
+	if c.options.FleetServer.Cert == "" && c.options.FleetServer.CertKey == "" {
+		if c.options.FleetServer.Insecure {
 			// running insecure, force the binding to localhost (unless specified)
-			if c.options.FleetServerHost == "" {
-				c.options.FleetServerHost = "localhost"
+			if c.options.FleetServer.Host == "" {
+				c.options.FleetServer.Host = "localhost"
 			}
 			c.options.URL = fmt.Sprintf("http://%s:%d", host, port)
 			c.options.Insecure = true
@@ -270,8 +297,8 @@ func (c *EnrollCmd) prepareFleetTLS() error {
 		if err != nil {
 			return err
 		}
-		c.options.FleetServerCert = string(pair.Crt)
-		c.options.FleetServerCertKey = string(pair.Key)
+		c.options.FleetServer.Cert = string(pair.Crt)
+		c.options.FleetServer.CertKey = string(pair.Key)
 		c.options.URL = fmt.Sprintf("https://%s:%d", hostname, port)
 		c.options.CAs = []string{string(ca.Crt())}
 	}
@@ -295,8 +322,18 @@ func (c *EnrollCmd) enrollWithBackoff(ctx context.Context) error {
 	signal := make(chan struct{})
 	backExp := backoff.NewExpBackoff(signal, 60*time.Second, 10*time.Minute)
 
-	for errors.Is(err, fleetapi.ErrTooManyRequests) {
-		c.log.Warn("Too many requests on the remote server, will retry in a moment.")
+	for {
+		retry := false
+		if errors.Is(err, fleetapi.ErrTooManyRequests) {
+			c.log.Warn("Too many requests on the remote server, will retry in a moment.")
+			retry = true
+		} else if errors.Is(err, fleetapi.ErrConnRefused) {
+			c.log.Warn("Remote server is not ready to accept connections, will retry in a moment.")
+			retry = true
+		}
+		if !retry {
+			break
+		}
 		backExp.Wait()
 		c.log.Info("Retrying to enroll...")
 		err = c.enroll(ctx)
@@ -344,11 +381,11 @@ func (c *EnrollCmd) enroll(ctx context.Context) error {
 			"sourceURI": staging,
 		}
 	}
-	if c.options.FleetServerConnStr != "" {
+	if c.options.FleetServer.ConnStr != "" {
 		serverConfig, err := createFleetServerBootstrapConfig(
-			c.options.FleetServerConnStr, c.options.FleetServerPolicyID,
-			c.options.FleetServerHost, c.options.FleetServerPort,
-			c.options.FleetServerCert, c.options.FleetServerCertKey)
+			c.options.FleetServer.ConnStr, c.options.FleetServer.PolicyID,
+			c.options.FleetServer.Host, c.options.FleetServer.Port,
+			c.options.FleetServer.Cert, c.options.FleetServer.CertKey)
 		if err != nil {
 			return err
 		}
@@ -390,6 +427,27 @@ func (c *EnrollCmd) enroll(ctx context.Context) error {
 	return nil
 }
 
+func (c *EnrollCmd) startAgent() error {
+	cmd, err := os.Executable()
+	if err != nil {
+		return err
+	}
+	c.log.Info("Spawning Elastic Agent daemon as a subprocess to complete bootstrap process.")
+	proc, err := process.Start(c.log, cmd, nil, os.Geteuid(), os.Getegid(), "run")
+	if err != nil {
+		return err
+	}
+	c.agentProc = proc
+	return nil
+}
+
+func (c *EnrollCmd) stopAgent() {
+	if c.agentProc != nil {
+		c.agentProc.StopWait()
+		c.agentProc = nil
+	}
+}
+
 func yamlToReader(in interface{}) (io.Reader, error) {
 	data, err := yaml.Marshal(in)
 	if err != nil {
@@ -461,6 +519,10 @@ func waitForFleetServer(ctx context.Context, log *logger.Logger) error {
 				// app has started and is running
 				resChan <- waitResult{}
 				break
+			} else if app.Status == proto.Status_FAILED {
+				// app completely failed; exit now
+				resChan <- waitResult{err: errors.New(app.Message)}
+				break
 			}
 			if app.Message != "" {
 				appMsg := fmt.Sprintf("Fleet Server - %s", app.Message)

x-pack/elastic-agent/pkg/agent/application/handler_action_policy_change.go

@@ -62,6 +62,11 @@ func (h *handlerPolicyChange) Handle(ctx context.Context, a action, acker fleetA
 }
 
 func (h *handlerPolicyChange) handleKibanaHosts(c *config.Config) (err error) {
+	// do not update kibana host from policy; no setters provided with local Fleet Server
+	if len(h.setters) == 0 {
+		return nil
+	}
+
 	cfg, err := configuration.NewFromConfig(c)
 	if err != nil {
 		return errors.New(err, "could not parse the configuration from the policy", errors.TypeConfig)

x-pack/elastic-agent/pkg/agent/application/managed_mode.go

@@ -181,7 +181,10 @@ func newManaged(
 		agentInfo: agentInfo,
 		config:    cfg,
 		store:     store,
-		setters:   []clientSetter{acker},
+	}
+	if cfg.Fleet.Server == nil {
+		// setters only set when not running a local Fleet Server
+		policyChanger.setters = []clientSetter{acker}
 	}
 	actionDispatcher.MustRegister(
 		&fleetapi.ActionPolicyChange{},

x-pack/elastic-agent/pkg/agent/cmd/common.go

@@ -73,6 +73,7 @@ func NewCommandWithArgs(args []string, streams *cli.IOStreams) *cobra.Command {
 	cmd.AddCommand(newEnrollCommandWithArgs(flags, args, streams))
 	cmd.AddCommand(newInspectCommandWithArgs(flags, args, streams))
 	cmd.AddCommand(newWatchCommandWithArgs(flags, args, streams))
+	cmd.AddCommand(newContainerCommand(flags, args, streams))
 
 	// windows special hidden sub-command (only added on windows)
 	reexec := newReExecWindowsCommand(flags, args, streams)