Manage databases in multiple namespaces

Redis Enterprise for Kubernetes allows you to deploy to multiple namespaces within your Kubernetes cluster. This article shows you how to configure your Redis Enterprise cluster to connect to databases in multiple namespaces

Multiple Redis Enterprise database resources (REDBs) can be associated with a single Redis Enterprise cluster resource (REC) even if they reside in different namespaces.

To learn more about designing a multi-namespace Redis Enterprise cluster, see flexible deployment options.

Warning:
Multi-namespace installations don't support Active-Active databases (REAADB). Only databases created with the REDB resource are supported in multi-namespace deployments at this time.

Prerequisites

Before configuring a multi-namespace deployment, you must have a running Redis Enterprise cluster (REC). See more information in the deployment section.

Create role and role binding for managed namespaces

Both the operator and the RedisEnterpriseCluster (REC) resource need access to each namespace the REC will manage. For each managed namespace, create a role.yaml and role_binding.yaml file within the managed namespace, as shown in the examples below.

Note:
These will need to be reapplied each time you upgrade.

Replace <rec-namespace> with the namespace the REC resides in. Replace <service-account-name> with your own value (defaults to the REC name).

role.yaml example:

kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: redb-role
  labels:
    app: redis-enterprise
rules:
  - apiGroups:
      - app.redislabs.com
    resources: ["redisenterpriseclusters", "redisenterpriseclusters/status", "redisenterpriseclusters/finalizers",
                "redisenterprisedatabases", "redisenterprisedatabases/status", "redisenterprisedatabases/finalizers",
                "redisenterpriseremoteclusters", "redisenterpriseremoteclusters/status",
                "redisenterpriseremoteclusters/finalizers",
                "redisenterpriseactiveactivedatabases", "redisenterpriseactiveactivedatabases/status",
                "redisenterpriseactiveactivedatabases/finalizers"]
    verbs: ["delete", "deletecollection", "get", "list", "patch", "create", "update", "watch"]
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["update", "get", "read", "list", "listallnamespaces", "watch", "watchlist",
            "watchlistallnamespaces", "create","patch","replace","delete","deletecollection"]
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["create"]
  - apiGroups: [""]
    resources: ["services"]
    verbs: ["get", "watch", "list", "update", "patch", "create", "delete"]

role_binding.yaml example:

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: redb-role
  labels:
    app: redis-enterprise
subjects:
- kind: ServiceAccount
  name: redis-enterprise-operator
  namespace: <rec-namespace>
- kind: ServiceAccount
  name: <service-account-name>
  namespace: <rec-namespace>
roleRef:
  kind: Role
  name: redb-role
  apiGroup: rbac.authorization.k8s.io

Apply the files, replacing <managed-namespace> with your own values:

kubectl apply -f role.yaml -n <managed-namespace>
kubectl apply -f role_binding.yaml -n <managed-namespace>
Note:
If the REC is configured to watch a namespace without setting the role and role binding permissions, or a namespace that is not yet created, the operator will fail and halt normal operations.

Update Redis Enterprise operator ConfigMap

There are two methods of updating the operator ConfigMap (operator-environment-config) to specify which namespaces to manage.

  • Method 1: Configure the operator to watch for a namespace label and add this label to managed namespaces (available in versions 6.4.2-4 or later).
  • Method 2: Configure the operator with an explicit list of namespaces to manage.

You can create this ConfigMap manually before deployment, or it will be created automatically after the operator was deployed.

Method 1: Namespace label (available in versions 6.4.2-4 or later)

  1. Create the cluster_role_binding.yaml and cluster_role.yaml files. Replace the <rec-namespace> with the namespace the Redis Enterprise cluster (REC) resides in.

operator_cluster_role.yaml example:

  apiVersion: rbac.authorization.k8s.io/v1
  kind: ClusterRole
  metadata:
    name: redis-enterprise-operator-consumer-ns
    labels:
      app: redis-enterprise
  rules:
    - apiGroups: [""]
      resources: ["namespaces"]
      verbs: ["list", "watch"]

operator_cluster_role_binding.yaml example:

  kind: ClusterRoleBinding
  apiVersion: rbac.authorization.k8s.io/v1
  metadata:
    name: redis-enterprise-operator-consumer-ns
    labels:
      app: redis-enterprise
  subjects:
  - kind: ServiceAccount
    name: redis-enterprise-operator
    namespace: <rec-namespace>
  roleRef:
    kind: ClusterRole
    name: redis-enterprise-operator-consumer-ns
    apiGroup: rbac.authorization.k8s.io
  1. Apply the files.
kubectl apply -f operator_cluster_role.yaml
kubectl apply -f operator_cluster_role_binding.yaml
  1. Patch the ConfigMap in the REC namespace (<rec-namespace>) to identify the managed namespaces with your label (<label-name>).
 kubectl patch ConfigMap/operator-environment-config \
-n <rec-namespace> \
--type merge \
-p '{"data": {"REDB_NAMESPACES_LABEL": "<label-name>"}}'
  1. For each managed namespace, apply the same label. Replace <managed-namespace> with the namespace the REC will manage. Replace <label-name> with the value used in the previous step. If you specify a value for <label-value>, both the label name and value in managed namespaces must match to be detected by the operator. If the <label-value> is empty, only the label name needs to match on managed namespaces and the value is disregarded.
kubectl label namespace <managed-namespace> <label-name>=<label-value>
Note:
The operator restarts when it detects a namespace label was added or removed.

Method 2: Explicit namespace list

Patch the operator-environment-config in the REC namespace with a new environment variable (REDB_NAMESPACES).

kubectl patch ConfigMap/operator-environment-config \ 
-n <rec-namespace> \
--type merge \
-p '{"data":{"REDB_NAMESPACES": "<comma,separated,list,of,namespaces,to,watch"}}'
Warning:
Only configure the operator to watch a namespace after the namespace is created and configured with the role/role_binding as explained above. If configured to watch a namespace without setting those permissions or a namespace that is not created yet, the operator will fail and not perform normal operations.
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