Federation

Nomad federation is a multi-cluster orchestration and management feature which allows multiple Nomad clusters, defined as a region, to work together seamlessly. By federating clusters, organizations can benefit from improved scalability, fault tolerance, and centralized management of workloads across various data centers or geographical locations.

Cross Region Request Forwarding

API calls can include a region query parameter which defines the Nomad region the query is specified for. If this is not the local region, the request will be transparently forwarded and serviced by a server in the requested region. When the query parameter is omitted, the region on which the machine is servicing the request will be used.

Replication

In federated Nomad environments, a number of objects are replicated from the authoritative region to all federated regions. When creating, updating, or deleting these objects, the request will always be sent to the authoritative region using RPC forwarding.

• ACL Policies: All ACL policies are written in the authoritative region and replicated to federated regions.

• ACL Roles: All ACL roles are written in the authoritative region and replicated to federated regions.

• ACL Auth Methods: All ACL authentication methods are written in the authoritative region and replicated to federated regions.

• ACL Binding Rules: All ACL binding rules are written in the authoritative region and replicated to federated regions.

• ACL Tokens: ACL tokens whose global parameter is set to true are written in the authoritative region and replicated to federated regions. Otherwise, they are written to the region where the request is made and not replicated.

• Namespaces: All namespaces are written in the authoritative region and replicated to federated regions.

• Node Pools: All node pools are written in the authoritative region and replicated to federated regions.

• Quota Specifications: All quotas are written in the authoritative region and replicated to federated regions.

• Sentinel Policies: All sentinel policies are written in the authoritative region and replicated to federated regions.

Replication routines are started on each federated cluster's leader server in a hub and spoke design. The routines then utilize blocking queries to receive updates from the authoritative region to mirror in their own state store. They also implement rate limiting, so that busy clusters do not degrade due to overly aggressive replication processes.

Multi-Region Job Deployments EnterpriseEnterprise

Nomad job deployments can utilize the multiregion block when running in federated mode using enterprise binaries. When configured, this instructs Nomad to register and run the job on all the specified regions, removing the need for multiple copies of the job specification and registration on each region. It is important to note, multiregion jobs do not provide regional failover in the event of failure.