[Feature] Add document for environment_variables and Audit all environment variables to identify which should not be modified by users.

[Yicheng-Lu-llll]

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• I had searched in the issues and found no similar feature requirement.

Description

Add a document for environment_variables and Audit all environment variables to identify which should not be modified by users.

Network-related environment variables

CLUSTER_DOMAIN

• Default: cluster.local
• Configurable: true
• Location: KubeRay operator
• Description: The cluster domain name of the Kubernetes cluster in which the KubeRay operator is installed.
  It is for facilitating communication and DNS-based service discovery within a Kubernetes cluster.
  It forms part of Fully Qualified Domain Names (FQDNs) used for addressing services and resources.
  See kuberay/pull/951.

FQ_RAY_IP

• Default: ${HEAD_SERVICE}.${NAMESPACE}.svc.${CLUSTER_DOMAIN}
• Configurable: false
• Location: Worker pods only
• Description: Fully qualified domain name(FQDNs) of head service.
  It is used to access head service within a Kubernetes cluster. This variable is set only in worker pods, while users can utilize 'localhost' when inside the head pod.
  See kuberay/pull/938.

RAY_IP

• Default: ${HEAD_SERVICE}
• Configurable: false
• Location: Worker pods only
• Description: Name of head service.
  It is used to access head service within the same namespace in a Kubernetes cluster. This variable is deprecated and should be maintained solely for backward compatibility purposes. Instead, users are advised to use FQ_RAY_IP for this purpose.
  See kuberay/pull/938.

RAY_PORT

• Default: 6379
• Configurable: false
• Location: Head pod and Worker pods
• Description: GCS server port for Ray >= 1.11.0. Redis port for Ray < 1.11.0.
  It is for connecting to the Ray cluster by worker nodes and drivers started within the cluster. Users should avoid setting or overriding this variable directly. Instead, they should customize it using the 'rayStartParams' in the 'headGroupSpec' (e.g., rayStartParams["port"]).
  See kuberay/pull/388.

RAY_ADDRESS

• Default: ${LOCAL_HOST}:${RAY_PORT} for head pod. ${FQ_RAY_IP}:${RAY_PORT} for worker pod.
• Configurable: false
• Location: Head pod and Worker pods
• Description: Address of GCS server for Ray >= 1.11.0. Address of Redis port for Ray < 1.11.0.
  It is used to connect to Ray using ray.init() when connecting from within the cluster.
  See kuberay/pull/388.

GCS FT related environment variables

RAY_REDIS_ADDRESS

• Default: Not Exist
• Configurable: true
• Location: Head pod only
• Description: Address of external redis cluster.
  It is used to configure an external Redis cluster as the backend storage, forcing Ray to utilize the external Redis instance.
  See GCS FT Documentation.

Other environment variables

RAY_CLUSTER_NAME

• Default: metadata.name in RayCluster Custom Resource (CR)
• Configurable: false
• Location: Head pod and Worker pods
• Description: The name of the Ray cluster to which the pod belongs, as defined by 'metadata.name' in the RayCluster Custom Resource (CR).
  It is for identifying the Ray cluster to which the pod belongs.
• See kuberay/pull/934.

RAY_USAGE_STATS_KUBERAY_IN_USE:

• Default: 1
• Configurable: false
• Location: Head pod and Worker pods
• Description: Idenfier to identify a Ray pod that has been deployed using KubeRay.
  It is for the purpose of statistics collection only.
  See kuberay/pull/562.

Use case

No response

Related issues

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[kevin85421]

• CLUSTER_DOMAIN: Read cluster domain from resolv.conf or env #951

[kevin85421]

REDIS_PASSWORD: #986