Unable to set label graylog-role=master after release >= 2.3.8

[rmntrvn]

Describe the bug
In the 2.3.8 release, kubectl was removed, it is no longer possible to set the graylog-role label for a StatefulSet pod. As a result, the graylog-master service cannot determine the master pod.

Version of Helm and Kubernetes:

Helm Version:

$ helm version
version.BuildInfo{Version:"v3.10.1", GitCommit:"9f88ccb6aee40b9a0535fcc7efea6055e1ef72c9", GitTreeState:"clean", GoVersion:"go1.18.7"}

Kubernetes Version:

$ kubectl version
Client Version: v1.31.12
Kustomize Version: v5.4.2
Server Version: v1.32.1

Which version of the chart: >= 2.3.8

What happened:
In the 2.3.8 release (8145acd), kubectl was removed, now it is impossible to set the graylog-role label for a StatefulSet pod. As a result, the graylog-master service cannot determine the master pod. Starting with chart version 2.3.8, after deploying 2 graylog replicas, the kubectl get pods -L graylog-role command does not display pod roles, because there are no graylog-role labels on the replicas after deployment. And because of this, the graylog-master service cannot determine the current master. The kubectl get ep graylog-master command does not determine the IP address of the master node.

What you expected to happen:
The graylog-master selector specifies the graylog-role label, which is used to determine the pod's IP address. The label on the pod must be defined at the time of deployment. Now, starting with version 2.3.8, the graylog-master endpoint does not determine the IP of the current master.

How to reproduce it (as minimally and precisely as possible):
Install chart version 2.3.8 or higher and check graylog-master service and its endpoints. kubectl get pods -L graylog-role command should output roles.

[KongZ]

The label graylog-role was required when Graylog images lacked a mechanism to assign the Master role. However, since Graylog 6 images introduced support for Kubernetes by setting pod 0 as the master node, the label mechanism is no longer necessary. The master node is consistently set to pod-0.

[rmntrvn]

The label graylog-role was required when Graylog images lacked a mechanism to assign the Master role. However, since Graylog 6 images introduced support for Kubernetes by setting pod 0 as the master node, the label mechanism is no longer necessary. The master node is consistently set to pod-0.

Hello.

Yes, starting with 2.3.8 the mechanism for determining the master has changed, but the k8s graylog-master service remains and it still relies on the graylog-role=master (https://github.com/KongZ/charts/blob/graylog-2.3.8/charts/graylog/templates/master-service.yaml#L40) pod label.

Because of this, the graylog-master service cannot determine the master pod IP.

My application service focuses on the k8s service URL http://graylog-master.graylog.svc:9000/api to interact with the graylog IP. Now it turns out that to contact the graylog master, you need to contact the -0 graylog pod graylog-0.graylog.graylog-namespace.svc.cluster.local.:9000 ?

[KongZ]

@rmntrvn Thank you for describing your use case. I've fixed the master service selector to choose the pod by ordinal on this PR. #181