Returns the spec index number

Adding this to name, since it's an arbitrary number

pkg/names/spec_index.go

@@ -0,0 +1,12 @@
+package names
+
+// SpecIndex return the job sepc index.
+// We use a very large value as a maximum number of replicas per instance group, per AZ
+// We do this in lieu of using the actual replica count, which would cause pods to always restart
+func SpecIndex(azIndex int, podOrdinal int) int {
+	if azIndex < 1 {
+		azIndex = 1
+	}
+
+	return (azIndex-1)*10000 + podOrdinal
+}

pkg/names/spec_index_test.go

@@ -0,0 +1,32 @@
+package names_test
+
+import (
+	"fmt"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"code.cloudfoundry.org/quarks-utils/pkg/names"
+)
+
+var _ = Describe("SpecIndex", func() {
+	tests := []struct {
+		az  int
+		ord int
+		r   int
+	}{
+		{az: 0, ord: 0, r: 0},
+		{az: 1, ord: 5, r: 5},
+		{az: 2, ord: 5, r: 10005},
+		{az: 3, ord: 5, r: 20005},
+		{az: -1, ord: 0, r: 0},
+	}
+
+	It("produces valid spec indexes", func() {
+		for _, t := range tests {
+			r := names.SpecIndex(t.az, t.ord)
+			Expect(r).To(Equal(t.r), fmt.Sprintf("%#v", t))
+		}
+	})
+
+})