Putting compute nodes into maintenance mode

The maintenance mode is useful when you apply fixes or other upgrades to compute nodes.

Before you begin

Ensure that the compute node is quiesced.
You must be assigned one of the following permissions to perform these steps:
  • System level, Hardware administration role with permission to Manage hardware resources (Full permission)
  • Resource level administration role with Read access rights permission (ACL) to view a specific instance
  • Resource level administration role with Write or All access rights permission (ACL) to view and manage a specific instance

About this task

You can use the console, the command line interface, or the REST API to complete this task. For the command line and REST API information, see the Related information section.

Procedure

  1. Click Hardware > Compute Nodes.
  2. Select the compute node and click the Maintain icon in the toolbar.

    If the Maintain icon is not enabled, verify that the compute node is quiesced and try again.

Results

All virtual machines on the current compute node (the one that is put into maintenance) are evacuated to other available compute nodes in the cloud group. If there is no space available for the virtual machines to be evacuated onto other compute nodes, the current compute node remains quiesced.
Notes:
  • When you evacuate a virtual machine instance from one compute node to another, the log file can include numerous DUPLICATE IP ADDRESS DETECTED messages. These messages are for informational purposes only and no action is required.
  • Virtual machines that have been deployed within the last 3 hours cannot be evacuated to another compute node. Before you put a compute node into maintenance mode, wait at least 3 hours.
  • When system-level high availability (HA) is enabled on the cloud group: if there is no space available for the virtual machines to be evacuated onto other compute nodes in the same cloud group and spare compute nodes are available, spare compute nodes are moved into the cloud group and the virtual machines are moved to the spare compute nodes.
  • To put a compute node that is hosting a IBM Spectrum Scale server virtual machine into maintenance mode (for example, so it can be removed from its cloud group), you must first store the virtual machine. After stopping and storing the IBM Spectrum Scale server virtual machine and quiescing the compute node, you can then restart the virtual machine in a different compute node. When the stored IBM Spectrum Scale server virtual machine is started again, IBM Spectrum Scale starts automatically within the virtual machine; there is no extra step to start IBM Spectrum Scale other than starting the server virtual machine. Once the IBM Spectrum Scale server virtual machine is no longer running on the compute node, you can quiesce the compute node and put it in maintenance mode by following the usual procedure.

    Note that due to an anti-collocation constraint that IBM Spectrum Scale defines, all IBM Spectrum Scale virtual machines (except for the IBM Spectrum Scale Manager virtual machine) must be located on separate compute nodes. They also must be located in the same cloud group (this includes the IBM Spectrum Scale Manager virtual machine).