Dynatrace Managed balances traffic between Cluster nodes with built-in load balancing, and you can add an external load balancer in front of the Managed Cluster as an additional tier. Knowing what the built-in load balancing already covers helps you decide whether you need that tier.
The Managed Cluster includes NGINX, an all-in-one, open-source, high-performance HTTP server and reverse proxy. NGINX, which is installed on each Cluster node, performs load balancing and routing of traffic between nodes. NGINX is configured specifically for session persistence and affinity, node health checks, and Domain Name System (DNS) resolution.
After a user starts a web UI session on a given Cluster node, requests go to that node until the user closes the session.
If a node is unreachable, that node is marked as unhealthy, and traffic is forwarded only to healthy nodes.
Optional
DNS records are managed for the Managed Cluster; the DNS resolves to the IP addresses of all the nodes. DNS-based resolution provides additional load balancing (the order of IP addresses is randomized in DNS resolution). Automatic DNS management for the Managed Cluster is optional—you can opt out and use your DNS instead.
NGINX is an integral part of a Dynatrace Managed deployment. If you need an additional tier of load balancing to achieve a single point of access, set up your load balancer in front of the Managed Cluster.
Your organization might have strict rules regarding Transport Layer Security (TLS) certificate management and access control. For example, a policy might require that all incoming traffic traverse an organization-approved central load balancer or proxy server.
In the event of a node's hardware or network failure, the node IP might still be part of the domain record. Stale DNS records can result in connection timeouts if the unhealthy IP address is selected in DNS resolution. An external load balancer can automatically exclude the unhealthy node, which improves the user experience.
For Managed Clusters deployed in two data centers (using the Premium High Availability feature), Dynatrace recommends adding a load balancer that can optimize user access and handle failover across data centers. For details, see Premium High Availability for multi-data centers.