max virtual memory areas (docker-library/elasticsearch#111)

cmd/amp/platform_infrastructure.go

@@ -4,6 +4,12 @@ import (
 	"github.com/appcelerator/amp/config"
 	"github.com/docker/docker/api/types/mount"
 	"github.com/docker/docker/api/types/swarm"
+
+	"bytes"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
 )
 
 const (
@@ -675,3 +681,41 @@ func getAMPInfrastructureStack(m *ampManager) *ampStack {
 	//return stack
 	return &stack
 }
+
+// system prerequisites
+func systemPrerequisites(m *ampManager) (err error) {
+	sysctl := false
+	// checks if GOOS is set
+	goos := os.Getenv("GOOS")
+	if goos == "linux" {
+		sysctl = true
+	} else if goos == "" {
+		// check if sysctl exists on the system
+		if _, err := os.Stat("/etc/sysctl.conf"); err == nil {
+			sysctl = true
+		}
+	}
+	if sysctl {
+		var out bytes.Buffer
+		var stderr bytes.Buffer
+		mmcmin := 262144
+		cmd := exec.Command("sysctl", "-n", "vm.max_map_count")
+		cmd.Stdout = &out
+		cmd.Stderr = &stderr
+		err = cmd.Run()
+		mmc, err := strconv.Atoi(strings.TrimRight(out.String(), "\n"))
+		if err != nil {
+			return err
+		}
+		if mmc < mmcmin {
+			if m.verbose {
+				m.printf(colRegular, "setting max virtual memory areas\n")
+			}
+			cmd = exec.Command("sysctl", "-w", "vm.max_map_count=262144")
+			err = cmd.Run()
+		} else if m.verbose {
+			m.printf(colRegular, "max virtual memory areas is already at a safe value\n")
+		}
+	}
+	return
+}

cmd/amp/platform_start.go

@@ -57,6 +57,10 @@ func startAMP(cmd *cobra.Command, args []string) error {
 			manager.printf(colWarn, "Mode force: start anyway\n")
 		}
 	}
+	if err := systemPrerequisites(manager); err != nil {
+		manager.printf(colError, "Prerequisite error: %v\n", err)
+		os.Exit(1)
+	}
 	if err := manager.start(stack); err != nil {
 		manager.printf(colError, "Start error: %v\n", err)
 		if err := manager.stop(stack); err != nil {