Add support for customising deployment strategy (#97)

gruntwork-io · Jun 2, 2021 · db95ee5 · db95ee5
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diff --git a/charts/k8s-service/templates/_deployment_spec.tpl b/charts/k8s-service/templates/_deployment_spec.tpl
@@ -87,6 +87,14 @@ metadata:
 {{- end }}
 spec:
   replicas: {{ if .isCanary }}{{ .Values.canary.replicaCount | default 1 }}{{ else }}{{ .Values.replicaCount }}{{ end }}
+{{- if .Values.deploymentStrategy.enabled }}
+  strategy:
+    type: {{ .Values.deploymentStrategy.type }}
+{{- if and (eq .Values.deploymentStrategy.type "RollingUpdate") .Values.deploymentStrategy.rollingUpdate }}
+    rollingUpdate:
+{{ toYaml .Values.deploymentStrategy.rollingUpdate | indent 6 }}
+{{- end }}
+{{- end }}
   selector:
     matchLabels:
       app.kubernetes.io/name: {{ include "k8s-service.name" . }}

diff --git a/charts/k8s-service/values.yaml b/charts/k8s-service/values.yaml
@@ -180,6 +180,37 @@ canary: {}
 # point in time. For example, setting to 3 will signal Kubernetes (via the Deployment contoller) to maintain 3 pods.
 replicaCount: 1
 
+# deploymentStrategy specifies the strategy used to replace old Pods by new ones. Type can be "RollingUpdate" or
+# "Recreate". "RollingUpdate" is the default value.
+# RollingUpdate: The Deployment updates Pods in a rolling update fashion.
+# Recreate: All existing Pods are killed before new ones are created.
+#
+# RollingUpdate can be further refined by providing custom rollingUpdate options.
+# The rollingUpdate variable is a map that is directly injected into the deployment spec and it has the following keys:
+#   - maxUnavailable   (Optional) :  Field that specifies the maximum number of Pods that can be unavailable
+#                                    during the update process. The value can be an absolute number
+#                                    (for example, 5) or a percentage of desired Pods (for example, 10%).
+#                                    The value cannot be 0 if rollingUpdate.maxSurge is 0.
+#                                    This option defaults to 25%.
+#   - maxSurge         (Optional) :  Field that specifies the maximum number of Pods that can be created over
+#                                    the desired number of Pods. The value can be an absolute number (for example, 5)
+#                                    or a percentage of desired Pods (for example, 10%). The value cannot be 0 if
+#                                    MaxUnavailable is 0.
+#                                    This option defaults to 25%.
+#
+# EXAMPLE:
+#
+# deploymentStrategy:
+#   enabled: false
+#   type: RollingUpdate
+#   rollingUpdate:
+#     maxSurge: 30%
+#     maxUnavailable: 30%
+deploymentStrategy:
+  enabled: false
+  type: RollingUpdate
+  rollingUpdate: {}
+
 # deploymentAnnotations will add the provided map to the annotations for the Deployment resource created by this chart.
 # The keys and values are free form, but subject to the limitations of Kubernetes resource annotations.
 # NOTE: This variable is injected directly into the deployment spec.

diff --git a/test/k8s_service_template_test.go b/test/k8s_service_template_test.go
@@ -700,3 +700,83 @@ func TestK8SServicePodAddingAdditionalLabels(t *testing.T) {
 	assert.Equal(t, deployment.Spec.Template.Labels["first-label"], first_custom_pod_label_value)
 	assert.Equal(t, deployment.Spec.Template.Labels["second-label"], second_custom_pod_label_value)
 }
+
+func TestK8SServiceDeploymentStrategyOnlySetIfEnabled(t *testing.T) {
+	t.Parallel()
+
+	deployment := renderK8SServiceDeploymentWithSetValues(
+		t,
+		map[string]string{
+			"deploymentStrategy.enabled": "false",
+		},
+	)
+
+	// Strategy shouldn't be set
+	assert.Equal(t, "", string(deployment.Spec.Strategy.Type))
+	assert.Nil(t, deployment.Spec.Strategy.RollingUpdate)
+}
+
+func TestK8SServiceDeploymentRollingUpdateStrategy(t *testing.T) {
+	t.Parallel()
+
+	deployment := renderK8SServiceDeploymentWithSetValues(
+		t,
+		map[string]string{
+			"deploymentStrategy.enabled": "true",
+			"deploymentStrategy.type":    "RollingUpdate",
+		},
+	)
+
+	assert.EqualValues(t, "RollingUpdate", string(deployment.Spec.Strategy.Type))
+	require.Nil(t, deployment.Spec.Strategy.RollingUpdate)
+}
+
+func TestK8SServiceDeploymentRollingUpdateStrategyWithCustomOptions(t *testing.T) {
+	t.Parallel()
+
+	deployment := renderK8SServiceDeploymentWithSetValues(
+		t,
+		map[string]string{
+			"deploymentStrategy.enabled":                      "true",
+			"deploymentStrategy.type":                         "RollingUpdate",
+			"deploymentStrategy.rollingUpdate.maxSurge":       "30%",
+			"deploymentStrategy.rollingUpdate.maxUnavailable": "20%",
+		},
+	)
+
+	assert.EqualValues(t, "RollingUpdate", string(deployment.Spec.Strategy.Type))
+
+	rollingUpdateOptions := deployment.Spec.Strategy.RollingUpdate
+	require.NotNil(t, rollingUpdateOptions)
+	assert.Equal(t, rollingUpdateOptions.MaxSurge.String(), "30%")
+	assert.Equal(t, rollingUpdateOptions.MaxUnavailable.String(), "20%")
+}
+
+func TestK8SServiceDeploymentRecreateStrategy(t *testing.T) {
+	t.Parallel()
+
+	deployment := renderK8SServiceDeploymentWithSetValues(
+		t,
+		map[string]string{
+			"deploymentStrategy.enabled": "true",
+			"deploymentStrategy.type":    "Recreate",
+		},
+	)
+
+	assert.Equal(t, "Recreate", string(deployment.Spec.Strategy.Type))
+	assert.Nil(t, deployment.Spec.Strategy.RollingUpdate)
+
+	// Test that custom rolling update options are ignore if the strategy is set to recreate
+	deployment = renderK8SServiceDeploymentWithSetValues(
+		t,
+		map[string]string{
+			"deploymentStrategy.enabled":                      "true",
+			"deploymentStrategy.type":                         "Recreate",
+			"deploymentStrategy.rollingUpdate.maxSurge":       "30%",
+			"deploymentStrategy.rollingUpdate.maxUnavailable": "20%",
+		},
+	)
+
+	assert.Equal(t, "Recreate", string(deployment.Spec.Strategy.Type))
+	assert.Nil(t, deployment.Spec.Strategy.RollingUpdate)
+}