From d4e71c375c619457eecf3c2a822ec4fe305650cd Mon Sep 17 00:00:00 2001
From: Michael Burman <michael.burman@datastax.com>
Date: Wed, 11 Sep 2024 19:21:15 +0300
Subject: [PATCH] Fix HCD configuration path for the EmptyVolume etc-cassandra
 (#704)

---
 CHANGELOG.md                                  |  4 ++
 .../construct_podtemplatespec.go              | 16 ++++--
 .../construct_podtemplatespec_test.go         | 56 +++++++++++++++++++
 ...-rack-single-node-dc-with-readonly-fs.yaml |  3 +-
 4 files changed, 73 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a80b6d97..afe7cc7e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ Changelog for Cass Operator, new PRs should update the `main / unreleased` secti
 * [BUGFIX]
 ```
 
+## unreleased
+
+* [BUGFIX] [#703](https://github.com/k8ssandra/cass-operator/issues/703) Fix HCD config path from /etc/cassandra to /opt/hcd/resources/cassandra/conf
+
 ## v1.22.1
 
 * [BUGFIX] [#687](https://github.com/k8ssandra/cass-operator/issues/687) Prevent a crash when when StorageClassName was not set in the CassandraDataVolumeClaimSpec
diff --git a/pkg/reconciliation/construct_podtemplatespec.go b/pkg/reconciliation/construct_podtemplatespec.go
index 2dfc83e7..cbc4426c 100644
--- a/pkg/reconciliation/construct_podtemplatespec.go
+++ b/pkg/reconciliation/construct_podtemplatespec.go
@@ -742,10 +742,18 @@ func buildContainers(dc *api.CassandraDatacenter, baseTemplate *corev1.PodTempla
 			Name:      "tmp",
 			MountPath: "/tmp",
 		})
-		cassContainer.VolumeMounts = append(cassContainer.VolumeMounts, corev1.VolumeMount{
-			Name:      "etc-cassandra",
-			MountPath: "/etc/cassandra",
-		})
+
+		if dc.Spec.ServerType == "hcd" {
+			cassContainer.VolumeMounts = append(cassContainer.VolumeMounts, corev1.VolumeMount{
+				Name:      "etc-cassandra",
+				MountPath: "/opt/hcd/resources/cassandra/conf",
+			})
+		} else {
+			cassContainer.VolumeMounts = append(cassContainer.VolumeMounts, corev1.VolumeMount{
+				Name:      "etc-cassandra",
+				MountPath: "/etc/cassandra",
+			})
+		}
 	}
 
 	volumeMounts = combineVolumeMountSlices(volumeMounts, cassContainer.VolumeMounts)
diff --git a/pkg/reconciliation/construct_podtemplatespec_test.go b/pkg/reconciliation/construct_podtemplatespec_test.go
index c116a73e..98db5f8a 100644
--- a/pkg/reconciliation/construct_podtemplatespec_test.go
+++ b/pkg/reconciliation/construct_podtemplatespec_test.go
@@ -2006,3 +2006,59 @@ func TestReadOnlyRootFilesystemVolumeChanges(t *testing.T) {
 	mcacDisabled := corev1.EnvVar{Name: "MGMT_API_DISABLE_MCAC", Value: "true"}
 	assert.True(envVarsContains(containers[0].Env, mcacDisabled))
 }
+
+func TestReadOnlyRootFilesystemVolumeChangesHCD(t *testing.T) {
+	assert := assert.New(t)
+	dc := &api.CassandraDatacenter{
+		Spec: api.CassandraDatacenterSpec{
+			ClusterName:            "bob",
+			ServerType:             "hcd",
+			ServerVersion:          "1.0.0",
+			ReadOnlyRootFilesystem: ptr.To[bool](true),
+			Racks: []api.Rack{
+				{
+					Name: "r1",
+				},
+			},
+		},
+	}
+
+	podTemplateSpec, err := buildPodTemplateSpec(dc, dc.Spec.Racks[0], false)
+	assert.NoError(err, "failed to build PodTemplateSpec")
+
+	containers := podTemplateSpec.Spec.Containers
+	assert.NotNil(containers, "Unexpected containers containers received")
+	assert.NoError(err, "Unexpected error encountered")
+
+	assert.Len(containers, 2, "Unexpected number of containers containers returned")
+	assert.Equal("cassandra", containers[0].Name)
+	assert.Equal(ptr.To[bool](true), containers[0].SecurityContext.ReadOnlyRootFilesystem)
+
+	assert.True(reflect.DeepEqual(containers[0].VolumeMounts,
+		[]corev1.VolumeMount{
+			{
+				Name:      "tmp",
+				MountPath: "/tmp",
+			},
+			{
+				Name:      "etc-cassandra",
+				MountPath: "/opt/hcd/resources/cassandra/conf",
+			},
+			{
+				Name:      "server-logs",
+				MountPath: "/var/log/cassandra",
+			},
+			{
+				Name:      "server-data",
+				MountPath: "/var/lib/cassandra",
+			},
+			{
+				Name:      "server-config",
+				MountPath: "/config",
+			},
+		}), fmt.Sprintf("Unexpected volume mounts for the cassandra container: %v", containers[0].VolumeMounts))
+
+	// TODO Verify MCAC is disabled since it will fail with ReadOnlyRootFilesystem
+	mcacDisabled := corev1.EnvVar{Name: "MGMT_API_DISABLE_MCAC", Value: "true"}
+	assert.True(envVarsContains(containers[0].Env, mcacDisabled))
+}
diff --git a/tests/testdata/default-single-rack-single-node-dc-with-readonly-fs.yaml b/tests/testdata/default-single-rack-single-node-dc-with-readonly-fs.yaml
index 8a734a74..6dae5e3d 100644
--- a/tests/testdata/default-single-rack-single-node-dc-with-readonly-fs.yaml
+++ b/tests/testdata/default-single-rack-single-node-dc-with-readonly-fs.yaml
@@ -5,8 +5,7 @@ metadata:
 spec:
   clusterName: cluster1
   serverType: cassandra
-  serverVersion: "4.1.5"
-  serverImage: michaelburman290/cass-management-api:4.1.5-ubi8
+  serverVersion: 4.1.6
   managementApiAuth:
     insecure: {}
   readOnlyRootFilesystem: true