eksconfig: update random strings

Signed-off-by: Gyuho Lee <leegyuho@amazon.com>

eksconfig/config.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
-	"math/rand"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -731,7 +730,7 @@ func NewDefault() *Config {
 		int(now.Month()),
 		now.Day(),
 		now.Hour(),
-		randString(10),
+		randString(12),
 	)
 
 	// ref. https://docs.aws.amazon.com/eks/latest/userguide/create-managed-node-group.html
@@ -1373,14 +1372,3 @@ func (cfg *Config) SSHCommands() (s string) {
 	}
 	return buf.String()
 }
-
-const ll = "0123456789abcdefghijklmnopqrstuvwxyz"
-
-func randString(n int) string {
-	b := make([]byte, n)
-	for i := range b {
-		rand.Seed(time.Now().UnixNano())
-		b[i] = ll[rand.Intn(len(ll))]
-	}
-	return string(b)
-}

eksconfig/rand.go

@@ -0,0 +1,26 @@
+package eksconfig
+
+import (
+	"math/rand"
+	"time"
+)
+
+const ll = "0123456789abcdefghijklmnopqrstuvwxyz"
+
+func randString(n int) string {
+	b := make([]byte, n)
+	for i := range b {
+		rand.Seed(time.Now().UnixNano())
+		b[i] = ll[rand.Intn(len(ll))]
+	}
+	pfx := randoms[rand.Intn(len(randoms))]
+	s := pfx + string(b)
+	if len(s) > n {
+		s = s[:n]
+	}
+	return s
+}
+
+var randoms = []string{
+	"autumn", "resonance", "sun", "wood", "dream", "cherry", "tree", "fog", "frost", "voice", "morning", "sparkling", "wandering", "wild", "black", "holy", "snowy", "butterfly", "long", "lingering", "bold", "green", "river", "breeze", "proud", "floral", "divine", "polished", "ancient", "delight", "purple", "lively", "waterfall", "flower", "firefly", "feather", "grass", "haze", "glacial", "mountain", "snowflake", "silence", "misty", "dry", "summer", "icy", "delicate", "siberian", "cool", "spring", "winter", "patient", "twilight", "dawn", "blue", "coral", "bird", "everest", "brook", "rain", "wind", "sea", "morning", "snow", "lake", "sunset", "blueshift", "pine", "leaf", "dawn", "glitter", "forest", "milan", "cloud", "meadow", "sun", "sound", "sky", "shape", "surf", "water", "wildflower", "wave", "water", "amber", "damp", "reinvent", "falling", "day1", "prime", "nitro", "frosty", "paper", "star", "onion", "hawaii",
+}

eksconfig/rand_test.go

@@ -0,0 +1,10 @@
+package eksconfig
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestRand(t *testing.T) {
+	fmt.Println(randString(12))
+}