Managing multi-region Kubernetes deployments with Plural

Kubernetes is the go-to tool for container orchestration, but it wasn’t designed for multi-region setups. When stretched across multiple regions, it introduces networking challenges, security gaps, and operational overhead that make scaling complex.

Yet, businesses need multi-region Kubernetes for three key reasons:

User Latency

The farther a service is from the user, the longer it takes for the user to get a response. Therefore, you generally want services to be as close to the user as possible.

High Availability / Fault Tolerance

Users will face issues during an outage if your services aren't set up for high availability (HA). For example, if you've deployed services in the EU and APAC regions and the EU region service goes down, the traffic can be temporarily redirected to the APAC region service. Although responses might be a bit slower, users will still be able to access the services.

Compliance

Many countries have laws against storing user data outside their borders. In such cases, having a multi-region Kubernetes infrastructure becomes necessary.

But Kubernetes doesn’t support multi-region deployments out of the box.

Core Technical Constraints

Kubernetes Architecture Limitations

Standard off-the-shelf Kubernetes is not multi-region compatible, and it won’t be anytime soon: the CNCF and the Kubernetes core committees have repeatedly indicated that native multi-region support is not a priority for Kubernetes, focusing instead on multi-zone and multi-cluster solutions.

There are a few reasons for this. The main one is that Kubernetes relies on etcd as its primary data store, and etcd does not support multi-region operations. etcd uses the Raft consensus algorithm, which requires a majority of nodes to agree on state changes. In multi-region setups, increased latency between nodes slows consensus, leading to timeouts, frequent leader elections, and potential instability.

Latency also increases the risk of split-brain scenarios in distributed control planes. If network failures isolate parts of the cluster, different nodes may assume leadership, causing conflicting updates, data corruption, and even downtime.

The upshot of the lack
Setting up separate clusters for each region reduces latency, boosts availability, improves fault tolerance, and meets compliance needs, but it also adds complexity and cost. Managing several clusters means keeping configurations, security policies, and access controls consistent to avoid issues, while split monitoring makes it hard to keep track of system health in real-time.

Networking Challenges

Loss of Native Kubernetes Networking Features

Kubernetes provides seamless service discovery within a single cluster using its Service abstraction and DNS system, but these features do not extend across multiple clusters. In multi-region deployments, clusters do not inherently recognize each other’s Pods, Services, or Network Policies, making cross-cluster service discovery a challenge.

IP addressing and DNS create challenges as clusters need non-overlapping IP ranges, and DNS resolution is limited since CoreDNS in one cluster can't find services in another without extra setup, requiring special solutions for cross-cluster service discovery.

These factors make cross-cluster communication significantly more complex than standard Kubernetes networking, requiring additional tools like service meshes, global load balancers, or custom DNS configurations to bridge the gap.

Common Solutions and Their Trade-offs

Ingress-Based Approaches

Ingress controllers manage multi-cluster traffic by serving as entry points for HTTP and HTTPS requests from outside the cluster. However, Kubernetes Ingress often requires custom annotations and Custom Resource Definitions (CRDs) for advanced configurations. As the number of clusters and regions grows, organizations must deploy separate ingress controllers in each cluster and connect them using external load balancers or DNS services, which are beyond standard Kubernetes components.

Security Implications

Multi-region ingress-based setups introduce additional security challenges. Traffic between regions often traverses public networks, requiring extra encryption and authentication. Additionally, ingress controllers may vary in their security capabilities, leading to inconsistent security policies across regions.

Performance Impact

Ingress controllers add an extra layer to traffic flow, potentially affecting application performance, particularly in high-traffic scenarios. Each additional step through an ingress controller introduces latency, which can be more pronounced in cross-region traffic.

Service Mesh Solutions

Service mesh technologies offer strong solutions for multi-cluster Kubernetes environments, providing secure and transparent service communication across cluster boundaries. Istio and Linkerd are two major service meshes in use today.

ISTIO and Linkerd Capabilities for Multi-Cluster Kubernetes

Linkerd enables secure cross-cluster communication with service mirroring for automatic discovery and multiple connection modes, including gateway-based, direct pod-to-pod, and federated. It ensures security with a unified trust domain and mutual TLS (mTLS) encryption.

Istio offers greater traffic management flexibility, supporting both single-mesh and multi-mesh configurations for centralized or distributed control, making it more adaptable for complex deployments.

Complex Architecture and Operational Overhead in Service Meshes

Service meshes introduce proxies, control planes, and service mirrors, adding complexity and increasing failure points. Managing failure zones, network configurations, and deployment models like Linkerd’s layered and flat networks requires careful planning. They also demand continuous monitoring, updates, and troubleshooting, adding operational overhead and requiring specialized expertise.

Application Gateway Patterns

Application gateway patterns utilize global load balancers like Azure Application Gateway to efficiently route traffic across regional clusters based on location, workload, and cluster health. Front-door services such as Azure Front Door further enhance performance with CDN caching, delivering content closer to users, and advanced rule engines for sophisticated routing strategies. These gateways ensure high availability by dynamically monitoring backend health and redirecting traffic to healthy regions during outages.

Tooling Limitations

Multi-region Kubernetes deployments introduce unique tooling limitations, largely due to network flow directionality and connectivity challenges.

Network Flow Direction Problems

Deployment Tools: ArgoCD

In multi-region setups, tools like ArgoCD often encounter connectivity issues. Direct IP bridging from one region (e.g., US East) to another (e.g., US West) is often not possible due to network configurations. As a result, an ArgoCD instance trying to connect to a cluster's API server in another region might fail because it cannot resolve the API server's address across regions. To address this limitation an organization might need separate ArgoCD instances for each region (e.g., ArgoCD for East, ArgoCD for West) to effectively manage clusters within those regions.

Observability Challenges: Prometheus

Prometheus uses a pull-based scraping method, which means it needs to make API requests to endpoints compatible with Prometheus to gather metrics from monitored systems. This method creates issues in multi-region setups. Organizations often need a separate Prometheus server or agent in each region to monitor systems there. This makes data aggregation challenging, as it requires querying all regional Prometheus servers or exporting data to a central place. The network flow direction in Prometheus' design makes monitoring across multiple regions more complicated.

Common Architectural Patterns

To tackle networking challenges, organizations deploy critical tools separately in each region. This requires replicating ArgoCD for local Kubernetes access and regional Prometheus servers for metrics collection, improving availability but increasing complexity and costs. For observability, data is either queried from regional Prometheus servers or exported to a central store, demanding careful planning to maintain reliability, scalability, and efficiency.

Special Environment Considerations

FedRAMP and GovCloud Requirements

FedRAMP and GovCloud add extra requirements beyond standard multi-region deployments, needing specialized methods for networking, security, and access control.

Network Restrictions

Network Restrictions in these environments are much stricter than in standard cloud regions. Unlike typical deployments where internet access is often open, FedRAMP enforces egress limitations, restricting outbound connections to approved endpoints. Additionally, security boundaries are enforced to keep these environments separate from other infrastructure, not just as technical constraints but as regulatory requirements that influence architecture and operations.

Access Control Requirements

Access Control Requirements make GovCloud different from standard environments. There are strict personnel restrictions that only allow U.S. citizens or green card holders to manage these systems, excluding offshore workers and foreign citizens. Organizations need to establish separate management structures, access policies, and operational procedures to comply with these strict rules. Due to the increased operational complexity, organizations must maintain separate management accounts and tool instances (like separate deployment consoles or observability stacks) for GovCloud regions.

Plural's Approach to Multi-Region Management

Agent-First Architecture in Plural

One of the major challenges Kubernetes management platforms face is networking. Different network topologies and configurations can make it difficult to connect with clusters. However, Plural simplifies this issue with its lightweight, agent-based architecture.

Here's how it works: Plural deploys a control plane in your management cluster and a lightweight agent as a pod in each workload cluster. This agent creates secure outbound WebSocket connections to the control plane, allowing smooth two-way communication without exposing Kubernetes API servers or adding network complexity.

Once deployed, the agent:

• Establishes an authenticated connection to the Plural control plane

• Registers the cluster and its capabilities

• Receives commands and configurations from the control plane

• Executes changes locally within the cluster

• Reports status and metrics back to the control plane

This outbound-only connection model provides key advantages:

• Seamless network boundary traversal: Agents function across VPCs and regions without requiring VPC peering or exposing cluster endpoints.

• Simplified firewall management: Only outbound connections to Plural’s API endpoints are needed, eliminating complex ingress rules.

• Compatibility with air-gapped environments: A local control plane can be deployed to meet strict network isolation requirements.

Plural also simplifies cluster bootstrapping, allowing rapid multi-region expansion. The streamlined process includes:

• Automated agent deployment: Clusters are bootstrapped with minimal configuration through a simple initialization process.

• Self-registration: Agents automatically register with the control plane, sharing cluster details and capabilities.

• Configuration synchronization: The control plane instantly syncs configurations based on cluster roles and policies.

Unified Management Capabilities

Deployment Orchestration

As we've seen earlier, managing deployments and upgrades across multiple regions, where you must keep versions and configurations consistent, is challenging. Plural simplifies this process with:

Cross-Region Deployment Coordination

Plural’s agent-based architecture and egress-only communication simplify multi-region Kubernetes management through a centralized control plane, eliminating the need for complex networking configurations.

Its Continuous Deployment Engine streamlines Kubernetes lifecycle management by automating upgrades, node group rotations, and add-on updates with minimal disruption. The pre-flight checklist ensures version compatibility, while the version matrix maps controller versions to specific Kubernetes versions, enabling seamless, error-free upgrades.

Configuration Consistency

Plural ensures consistent configurations across regions through Global Services, standardizing networking, observability agents, and CNI providers. Instead of managing these add-ons individually per cluster, users define a single Global Service resource, which automatically replicates configurations across all targeted clusters.

Policy Enforcement at Scale

Plural enforces security and compliance policies across all regions using a centralized policy-as-code framework with OPA Gatekeeper. This ensures that security and governance policies are automatically applied across all clusters, preventing misconfigurations and enforcing compliance standards.

Access Control and Security

Managing access control in distributed environments is challenging, especially when dealing with sensitive data or meeting strict regulations like FedRAMP and GovCloud. Plural simplifies this process with:

Project-Based Segregation

Plural’s project-based access control model enables precise resource and responsibility segregation within a multi-tenant architecture. Each project operates independently within the control plane, with its own resources, configurations, and RBAC policies while maintaining logical isolation.

Environment-Specific Policies

Plural enforces environment-specific security policies by categorizing clusters into development, testing, and production environments, applying appropriate security controls automatically. Additional approval steps may be required for critical changes, ensuring proper oversight and compliance with regulatory standards.

FedRAMP/GovCloud Compatibility

Plural meets FedRAMP and GovCloud requirements with outbound-only connectivity for strict egress control. Its project-based model segregates regulated and commercial environments, restricting access to authorized personnel. It also enforces audit logging, access controls, and separation of duties, ensuring compliance with FedRAMP monitoring standards.

Operational Advantages

Centralized Visibility

As we've observed, fragmented observability tools and data aggregation challenges make monitoring and troubleshooting difficult in multi-region setups. Plural solves this with its built-in Multi-Cluster Dashboard, which unifies everything for a smooth debugging experience.

It provides detailed, real-time visibility into Kubernetes resources like pods, deployments, networking, and storage across all regions. Its agents efficiently collect metrics to a central platform, avoiding common cross-region pull-based issues, while centralized retention policies ensure compliance and cost efficiency. Additionally, Plural centralizes logs and events, offering intuitive search and linking tools to simplify troubleshooting and quickly identify issues in multi-region environments.

Simplified Tooling

Separate instances of tools like ArgoCD or Prometheus in each region are another source of frustration. Plural also helps simplify this process.

Elimination of Regional Tool Instances

Plural natively supports GitOps, eliminating the need for a separate ArgoCD installation. Its centralized CD system leverages reverse tunneling through its agent-based architecture, ensuring secure and efficient deployments. The same applies to logging—Plural includes comprehensive, built-in logging, removing the need for external logging tools.

Consistent Deployment Processes

Plural streamlines cluster and service upgrades through its GitOps-powered CD pipeline. This workflow orchestrates staged upgrades across multiple clusters using Infrastructure Stack Custom Resource Definitions (CRDs). When configuration changes are pushed to Git, the pipeline first modifies CRDs for development clusters. After integration tests pass and approvals are received, the service automatically updates production cluster CRDs, ensuring consistent and validated changes across your infrastructure.

Streamlined Upgrades

Plural simplifies cross-region cluster upgrades with pre-flight checkups, version matrix, and global services for managing add-on controllers. Using a GitOps-powered CD pipeline, it orchestrates staged upgrades through InfrastructureStack CRDs. Changes are first tested in development clusters, and once validated, updates are rolled out to production, ensuring consistency and reliability across all regions.

Conclusion

Managing multi-region Kubernetes is complex, but Plural simplifies it with an agent-based architecture, egress-only communication, and centralized control. Its Continuous Deployment Engine streamlines upgrades, Global Services ensures configuration consistency and policy enforcement enhances security and compliance, including FedRAMP and GovCloud.

With centralized visibility and streamlined operations, Plural helps teams scale Kubernetes efficiently while reducing complexity.

Ready to simplify your multi-region Kubernetes strategy? Get started with Plural today.