Network configuration

The Cloud Pak for Data System networking is mostly dynamic. There is a fixed Control Plane which consists of 3 nodes. These 3 nodes provide DHCP and DNS services to the rest of the cluster. The Worker Nodes, Virtual Machines (control and worker), and management devices all use dynamically assigned addresses.

There are 2 different networks:
Management network
  • Provides monitoring and similar functionality.
  • Depending on the size of the system, it might include additional management switches and management hub switch. For more information, see Expanding Cloud Pak for Data System.
  • Management Network in a Base System is based on Mellanox AS4610 switch with 1G UTP links to each node.
  • Management switch is monitored by Platform Manager.
  • No redundancy.
  • Failsafe management access is provided to the first 3 (control plane) nodes in the system.
  • mgt1 is a required link in the 3 control plane nodes.

Certain customer traffic patterns are forced out the customer network via policy based routing. These traffic patterns include:

  • upstream DNS
  • upstream LDAP
  • upstream NTP (time)
  • upstream SMTP
  • Call Home
Figure 1. Management switch connections
Image showing management switch connections
Application (fabric) network
  • Provides a higher speed and bandwidth application layer communications.
  • Depending on the size of the system, it might include additional fabric switches and a spine switch. For more information, see Expanding Cloud Pak for Data System.
  • Fabric Network in a Base System is based on Mellanox SN2410 switch with 25GBASE-SR links to each node and the house.
  • Data Fabric Network is active-active 25Gb connections to the Innova-2.
  • Fabric switch is monitored by Platform Manager.
  • There are redundant links to a single card.
Figure 2. Fabric switch connections
Image showing fabric switch connections

The customer access is via the fabric network, and is routed through the OpenShift console. All activity which occurs on the cluster is accessible through the console.

There are a minimum of 5 customer IP addresses in a standard system:
  • Node1 management
  • Node2 management
  • Node3 management
  • Management Float
  • Application Float
All activity should be completed via the Application Float. Each node can also be referenced by its specific management IP in the case of maintenance.

Keepalived is used for managing floating IP addresses in Cloud Pak for Data System versions 2.0.x. Keepalived is an industry standard software designed to manage floating IP and clustered services. The daemon makes sure the node is able at a network level to take the floating IP.

The nodes are named after their enclosure and index. The first four nodes are e1n1, e1n2, e1n3, and e1n4. The second enclosure contains the next four nodes: e2n1, e2n2, e2n3, and e2n4. The index portion of the node names are always relative to their enclosure.

Some of the bare metal nodes host a virtual machine. In version 2.0.x, there are only two virtual machines and they are hosted on the control plane nodes: e1n1-master and e1n1-ldap.

Each node (bare metal and virtual) has an interface in the mbond and fbond domains. The Fully Qualified Domain Name is either e1n1.fbond or e1n1.mbond depending on which interface you are using.