A gateway cluster is a set of virtual machines (VMs) running gateway software, which function as a single, logical machine. The gateway cluster provides:

  • High availability against the failure of a node in the cluster.
  • High availability against the failure of a physical server on which the nodes run.
  • Flexible horizontal scaling of nodes to manage more IT assets.

How a gateway cluster works

A gateway cluster is a set of virtual machines, which run applications that discover and monitor your environment, as shown in the following figure:

Gateway Cluster

Gateway nodes run on physical servers typically running a hypervisor with other VMs unrelated to the gateway. Nodes use a shared NFS storage volume to persist state shared among gateway nodes.

Each node also runs a lightweight Kubernetes - MicroK8s distribution. Kubernetes enables gateway nodes to work as a single, logical machine, which automatically schedules gateway applications between nodes.

If a node fails or the host on which the node runs fails, or both a node and host fail to restart applications on a different node, the logical node restarts the applications. The following figure shows how a gateway cluster works in the presence of faults:

Gateway Cluster

Deployment options

Gateway clusters can be deployed in several configurations, depending on availability and horizontal scaling goals. The following figures illustrate three design points:

Gateway Cluster
Gateway Cluster

Prerequisites

To deploy a gateway cluster, make sure your environment meets these requirements:

ComponentAttributeRequirements
NodesSize4 CPU cores, 8 GB RAM, 40 GB Disk
NodesIP addressesStatic IP address allocation requirement:
  • One static IP address assigned to the primary network interface of each node.
  • One additional floating IP (static IP) address for the Gateway Manager application.
  • None of these IP addresses should be allocated to a DHCP pool.
  • All IP addresses must be in the same subnet.
NodesHostnameEach node should have a unique hostname. IP address and hostname should be added in the /etc/hosts file and you should be able to ping all nodes using the IP address and hostname.
NodesNetwork accessAll VMs should have outbound internet access to *.opsramp.com for connectivity, k8s.gcr.io and the us-docker.pkg.dev Google Artifact registry, or custom registry proxy URLs to download gateway applications.
NodesNumber of nodesMinimum of three nodes for high availability.
HostsOSVMWare vSphere ESXi v6.0 or later versions.
HostsNumber of hostsMinimum of three hosts, running one gateway node on each host for high availability.
StorageTypeNFS storage volume, with read/write access from all nodes.
NodesPortsAll VMs should have inbound access on ports 80, 5480, 30100, and outbound access on port 443.