3. Introduction

Cluster POWER-Up enables greatly simplified configuration of clusters of bare metal OpenPOWER servers running Linux. It leverages widely used open source tools such as Cobbler, Ansible and Python. Because it relies solely on industry standard protocols such as IPMI and PXE boot, hybrid clusters of OpenPOWER and x86 nodes can readily be supported. Currently Cluster POWER-Up supports Ethernet networking. Cluster POWER-Up can configure simple flat networks for typical HPC environments or more advanced networks with VLANS and bridges for OpenStack environments. Complex heterogenous clusters can be easily deployed using POWER-Up’s interface and node templates. Cluster POWER-Up configures the switches in the cluster with support for multiple switch vendors.

3.1. Overview

Cluster POWER-Up is designed to be easy to use. If you are implementing one of the supported architectures with supported hardware, it eliminates the need for custom scripts or programming. It does this via a text configuration file (config.yml) which drives the cluster configuration. The configuration file is a YAML text file which the user edits. Several example config files are included docs directory. The configuration process is driven from a “deployer” node which can be removed from the cluster when finished. The POWER-Up process is as follows;

  1. Rack and cable the hardware.
  2. Initialize hardware.
    • initialize switches with static IP address, userid and password.
    • insure that all cluster compute nodes are set to obtain a DHCP address on their BMC ports and they are configured to support PXE boot on one of their network adapters.
  3. Install the Cluster POWER-Up software on the deployer node.
  4. Edit an existing config.yml file to drive the configuration.
  5. Run the POWER-Up software

When finished, Cluster POWER-Up generates a YAML formatted inventory file with detailed information about your cluster nodes. This file can be read by operational management software and used to seed configuration files needed for installing a solution software stack.

3.1.1. Hardware and Architecture Overview

The POWER-Up software supports clusters of servers interconnected with Ethernet. The servers must support IPMI and PXE boot. Multiple racks can be configured with traditional two tier access-aggregation networking. POWER-Up configures both a management and data network. In simple / cost sensitive setups, the management and data networks can be configured on the same physical switch. Power-Up can configure VLANs and bonded networks with as many ports as the hardware supports. Redundant data switches (ie MLAG) are also supported. (Currently only implemented on Mellanox switches.)

3.1.2. Networking

Cluster POWER-Up supports Cisco, Mellanox and Lenovo switches. Not all functionality is enabled on all switch types. Currently redundant networking (MLAG) is only implemented on Mellanox switches. Port channel support is only implemented on Cisco (NX-OS) and Mellanox switches. POWER-Up can configure any number of node interfaces on cluster nodes. To facilitate installation of higher level software, interfaces can be optionally renamed.

Interface templates are used to define network configurations in the config.yml file. These can be physical ports, bonded ports, Linux bridges or VLANS. Interface templates can be entered using Ubuntu or Red Hat network configuration syntax. Once defined, interface templates can be applied to any node template. Node interfaces can optionally be configured with static IP addresses. These can be assigned sequentially or from a list.

3.1.3. Compute Nodes

Cluster POWER-Up supports clusters of heterogeneous compute nodes. Users can define any number of node types by creating templates in a config file. Node templates can include any network templates defined in the network templates section. The combination of node templates and network templates allows great flexibility in building heterogeneous clusters with nodes dedicated to specific purposes.

3.1.4. Supported Hardware

Compute Nodes

OpenPOWER Compute Nodes;

  • S812LC
  • S821LC
  • S822LC (Minsky)
  • SuperMicro OpenPOWER servers

x86 Compute Nodes;

  • Lenovo x3550
  • Lenovo x3650

Many other x86 nodes should work, but we have only tested with Lenovo and some Supermicro nodes.


For information on adding additional switch support using POWER-Up’s switch class API, (see Developer Guide)

Supported Switches;

  • Mellanox SX1410
  • Mellanox SX1710
  • Cisco 5K (FEXes supported)
  • Lenovo G8052, G7028, G7052 (bonding not currently supported)

Notes; Other Mellanox switches may work but have not been tested Lenovo G8264 has not been tested Other Cisco NX-OS based switches may work but have not been tested

4. Prerequisite hardware setup

4.1. Hardware initialization

  • Insure the cluster is cabled according to build instructions and that a list of all switch port to node physical interface connections is available and verified. Note that every node must have a physical connection from both BMC and PXE ports to a management switch. (see the example cluster in Appendix-D)

  • Cable the deployer node directly to a management switch. For large cluster deployments, a 10 Gb connection is recommended. The deployer node must have access to the public internet (or site) network for retrieving software and operating system image files. If the cluster management network does not have external access an alternate connection must be provided, such as the cluster data network.

  • Insure that the BMC ports of all cluster nodes are configured to obtain an IP address via DHCP.

  • If this is a first time OS install, insure that all PXE ports are configured to obtain an IP address via DHCP. On OpenPOWER servers this is typically done using the Petitboot menus, e.g.:

    Petitboot System Configuration
     Boot Order     (0) Any Network device
                    (1) Any Device:
                    [    Add Device:     ]
                    [  Clear & Boot Any  ]
                    [       Clear        ]
     Timeout:       10    seconds
     Network:       (*) DHCP on all active interfaces
                    ( ) DHCP on a specific interface
                    ( ) Static IP configuration
  • Acquire any needed public and or site network addresses.

  • Insure you have a config.yml file to drive the cluster configuration. If necessary, edit / create the config.yml file (see section Creating the Config File)

Configuring the Cluster Switches

POWER-Up can configure supported switch models (See Supported Hardware). If automated switch configuration is not desired ‘passive’ switch mode can be used with any switch model (See Preparing for Passive Mode)

Initial configuration of data switch(es)

For out of box installation, it is usually necessary to configure the switch using a serial connection. See the switch installation guide. Using the Mellanox configuration wizard:

  • assign hostname

  • set DHCP to no for management interfaces

  • set zeroconf on mgmt0 interface: to no

  • do not enable ipv6 on management interfaces

  • assign static ip address. This must match the corresponding interface ‘ipaddr’ specified in the config.yml file ‘switches: data:’ list, and be in a deployer ‘mgmt’ network.

  • assign netmask. This must match the netmask of the deployer ‘mgmt’ network that will be used to access the management port of the switch.

  • default gateway

  • Primary DNS server

  • Domain name

  • Set Enable ipv6 to no

  • admin password. This must match the password specified in the config.yml corresponding ‘switches: data:’ list item.

  • disable spanning tree. Typical industry standard commands:

    configure terminal
    no spanning-tree

    for Lenovo switches:

    spanning-tree mode disable
  • enable SSH login:

    ssh server enable
  • If this switch has been used previously, delete any existing vlans which match those specified in config.yml ‘interfaces:’. This insures that only those nodes specified in the config file have access to the cluster. (for a brand new switch this step can be ignored)

    • login to the switch:

      configure terminal
      show vlan

      note those vlans that include the ports of the nodes to be included in the new cluster and remove those vlans or remove those ports from existing vlans:

      no vlan n
  • Save config. In switch config mode:

    configuration write
  • If using redundant data switches with MLAG, Leave the interswitch peer links (IPL) links disconnected until Cluster POWER-Up completes. (This avoids loops)

Initial configuration of management switch(es)

For out of box installation, it is usually necessary to configure the switch using a serial connection. See the switch installation guide. For additional info on Lenovo G8052 specific commands, see Appendix-G and the Lenovo RackSwitch G8052 Installation guide)

In order for Cluster POWER-Up to access and configure the switches in your cluster it is necessary to configure management access on all switches and provide management access information in the config.yml file.


POWER-Up setup of the switch management network

In this example, the management switch has an in-band management interface. The initial setup requires a management interface on all switches configured to be accessible by the deployer node. The configured ip address must be provided in the ‘interfaces:’ list within each ‘switches: mgmt:’ and ‘switches: data:’ item. Cluster POWER-Up uses this address along with the provided userid and password credentials to access the management switch. Any additional switch ‘interfaces’ will be configured automatically along with deployer ‘mgmt’ networks.

The following snippets are example config.yml entries for the diagram above:

  • Switch IP Addresses:

            - label: Mgmt_Switch
              userid: admin
              password: abc123
                  - type: inband
                  - type: inband
                    vlan: 16
                  - target: deployer
                    ports: 46
                  - target: Data_Switch
                    ports: 47
            - label: Data_Switch
              userid: admin
              password: abc123
                  - type: outband
                    vlan: 16
                    port: mgmt0
                  - target: Mgmt_Switch
                    ports: mgmt0
  • Deployer ‘mgmt’ networks:

                - device: enp1s0f0
                - device: enp1s0f0
                  vlan: 16

Management switch setup commands for the Lenovo G8052:

  • Enable configuration of the management switch:

    configure terminal
  • Enable IP interface mode for the management interface:

    RS G8052(config)# interface ip 1
  • assign a static ip address, netmask and gateway address to the management interface. This must match one of the switch ‘interfaces’ items specified in the config.yml ‘switches: mgmt:’ list:

    RS G8052(config-ip-if)# ip address  # example IP address
    RS G8052(config-ip-if)# ip netmask
    RS G8052(config-ip-if)# vlan 1  # default vlan 1 if not specified
    RS G8052(config-ip-if)# enable
    RS G8052(config-ip-if)# exit
  • Optionally configure a default gateway and enable the gateway:

    RS G8052(config)# ip gateway 1 address  # example ip address
    RS G8052(config)# ip gateway 1 enable
  • admin password. This must match the password specified in the config.yml corresponding ‘switches: mgmt:’ list item. The following command is interactive:

    access user administrator-password
  • disable spanning tree:

    spanning-tree mode disable

    For Lenovo switches:

    configure terminal
    spanning-tree mode disable
  • enable secure https and SSH login:

    ssh enable
    ssh generate-host-key
    access https enable
  • Save the config (For Lenovo switches, enter config mode). For additional information, consult vendor documentation):

    copy running-config startup-config

This completes normal POWER-Up initial configuration.

Preparing for Passive Mode

In passive mode, POWER-Up configures the cluster compute nodes without requiring any management communication with the cluster switches. This facilitates the use of POWER-Up even when the switch hardare is not supported or in cases where the end user does not allow 3rd party access to their switches. When running POWER-Up in passive mode, the user is responsible for configuring the cluster switches. The user must also provide the Cluster POWER-Up software with MAC address tables collected from the cluster switches during the POWER-Up process. For passive mode, the cluster management switch must be fully programmed before beginning cluster POWER-Up, while the data switch should be configured after POWER-Up runs.

Configuring the management switch(es)

  • The port(s) connected to the deployer node must be put in trunk mode with allowed vlans associated with each respective device as defined in the deployer ‘mgmt’ and ‘client’ networks.
  • The ports on the management switch which connect to cluster node BMC ports or PXE interfaces must be in access mode and have their PVID (Native VLAN) set to the respective ‘type: ipmi’ and ‘type: pxe’ ‘vlan’ values set in the ‘deployer client networks’.

Configuring the data switch(es)

Configuration of the data switches is dependent on the user requirements. The user / installer is responsible for all configuration. Generally, configuration of the data switches should occur after Cluster POWER-Up completes. In particular, note that it is not usually possible to aquire complete MAC address information once vPC (AKA MLAG or VLAG) has been configured on the data switches.

4.2. Setting up the Deployer Node

It is recommended that the deployer node have at least one available core of a XEON class processor, 16 GB of memory free and 64 GB available disk space. For larger cluster deployments, additional cores, memory and disk space are recommended. A 4 core XEON class processor with 32 GB memory and 320 GB disk space is generally adequate for installations up to several racks.

The deployer node requires internet access. This can be achieved through the interface used for connection to the management switch (assuming the management switch has a connection to the internet) or through another interface.

Operating Sytem and Package setup of the Deployer Node

  • Deployer OS Requirements:
    • Ubuntu
      • Release 14.04LTS or 16.04LTS
      • SSH login enabled
      • sudo privileges
    • RHEL
  • Optionally, assign a static, public ip address to the BMC port to allow external control of the deployer node.

  • login into the deployer and install the vim, vlan, bridge-utils and fping packages

    • Ubuntu:

      $ sudo apt-get update
      $ sudo apt-get install vim vlan bridge-utils fping
    • RHEL:

      $ sudo yum install vim vlan bridge-utils fping

Network Configuration of the Deployer Node

Note: The deployer port connected to the management switch must be defined in /etc/network/interfaces (Ubuntu) or the ifcfg-eth# file (RedHat). e.g.:

auto eth0      # example device name
iface eth0 inet manual

POWER-Up sets up a vlan and subnet for it’s access to the switches in the cluster. It is recommended that the deployer be provided with a direct connection to the management switch to simplify the overall setup. If this is not possible, the end user must insure that tagged vlan packets can be communicated between the deployer and the switches in the cluster.

An example of the config file parameters used to configure initial access to the switches is given above with POWER-Up setup of the switch management network. For a detailed description of these keys see deployer ‘mgmt’ networks, ‘switches: mgmt:’ and ‘switches: data:’ in the Cluster Configuration File Specification.