This topic provides and overview of admin partitions, which are entities that define one or more administrative boundaries for single Consul deployments.
Admin partitions exist a level above namespaces in the identity hierarchy. They contain one or more namespaces and allow multiple independent tenants to share a Consul server cluster. As a result, admin partitions enable you to define administrative and communication boundaries between services managed by separate teams or belonging to separate stakeholders. They can also segment production and non-production services within the Consul deployment.
-> **Preexisting resource nodes and namespaces**: Admin partitions were introduced in Consul 1.11. Resource nodes were not namespaced prior to 1.11. After upgrading to Consul 1.11 or later, all resource nodes will be namespaced.
Each Consul cluster will have a default admin partition (named `default`). The `default` admin partition is special because it may contain namespaces and other entities that are replicated between datacenters. The `default` partition must also contain the Consul servers.
-> **Preexisting resources and the `default` partition**: Admin partitions were introduced in Consul 1.11. After upgrading to Consul 1.11 or later, the `default` partition will contain all resources created in previous versions.
When an admin partition is created, it will include the `default` namespace. You can create additional namespaces within the partition. Resources created within a namespace will be inherited by the partition.
Client agents will be configured to operate within a specific admin partition. The DNS interface will only return results for the admin partition within the scope of the client.
Values specified for [`proxy-defaults`](/docs/connect/config-entries/proxy-defaults) and [`mesh`](/docs/connect/config-entries/mesh) configurations are scoped to a specific partition. Services registered in the partition will use the partition's `proxy-defaults` and `mesh` values.
You can configure services to be discoverable by downstream services in any partition within the datacenter. Specify the upstream services that you want to be available for discovery by configuring the `exported-services` configuration entry in the partition where the services are registered. Refer to the [`exported-services` documentation](/docs/connect/config-entries/exported-services) for details. Additionally, the `upstreams` configuration for proxies in the source partition must specify the name of the destination partition so that listeners can be created. Refer to the [Upstream Configuration Reference](/docs/connect/registration/service-registration#upstream-configuration-reference) for additional information.
* The `write` permission for `proxy-defaults` requires `mesh:write`. See [Admin Partition Rules](/docs/security/acl/acl-rules#admin-partition-rules) for additional information.
* With the exception of the `default` admin partition, ACL rules configured for admin partitions are isolated, so policies defined in partitions outside of the `default` partition can only reference their local partition.
One of the primary use cases for admin partitions is for enabling a service mesh across multiple Kubernetes clusters. The following requirements must be met to create admin partitions on Kubernetes:
* All Consul clients must be able to communicate with the Consul servers in the `default` partition, and all servers must be able to communicate with the clients.
This section describes how to deploy Consul admin partitions to Kubernetes clusters. Refer to the [admin partition CLI documentation](/commands/admin-partition) for information about command line usage.
The expected use case is to create admin partitions on Kubernetes clusters. This is because many organizations prefer to use cloud-managed Kubernetes offerings to provision separate Kubernetes clusters for individual teams, business units, or environments. This is opposed to deploying a single, large Kubernetes cluster. Organizations encounter problems, however, when they attempt to use a service mesh to enable multi-cluster use cases, such as administration tasks and communication between nodes.
The following procedure will result in an admin partition in each Kubernetes cluster. The Consul clients running in the cluster with servers will be in the `default` partition. Another partition called `clients` will also be created.
1. Verify that your VPC is configured to enable connectivity between the pods running Consul clients and servers. Refer to your virtual cloud provider's documentation for instructions on configuring network connectivity.
1. After the server starts, get the external IP address for partition service so that it can be added to the client configuration. The partition service is a `LoadBalancer` type. The IP address is used to bootstrap connectivity between servers and clients. <a name="get-external-ip-address"/>
1. Create the workload configuration for client nodes in your cluster. Create a configuration for each admin partition. In the following example, the external IP address and the Kubernetes authentication method IP address from the previous steps have been applied:
You can log into the Consul UI to verify that the partitions appear as expected.
1. If ACLs are enabled, you will need the partitions ACL token, which can be read from the Kubernetes secret. The token is an encoded string that must be decoded in base64, e.g.:
The example command gets the token using the secret name configured in the values file (`bootstrap.secretName`), decodes the secret, and prints the usable token to the console in JSON format.
1. Open the Consul UI in a browser using the external IP address and port number described in a previous step (see [step 5](#get-external-ip-address)).
1. Click **Log in** and enter the decoded token when prompted.
