Usage of Maintenance and Managed attributes in a Cluster (Pacemaker)

This document (000019779) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise High Availability Extension 12

Situation

During Maintenance Operations on the Applications controlled by a pacemaker cluster it is normal and recommended to set the Resource either in

maintenance

or

unmanaged

This can be done via the command line with crm commands or the WebGUI.

As this is done, an attribute is set in the cib for this Resource.

For example, in a crm shell view, with a command

 crm resource maintenance test

the Resource

primitive test Dummy

changes to

    primitive test Dummy
       meta maintenance=true

and this is persistent. Similar if a resource is set to unmanaged and entry like

 meta is-managed=false

is added.

To change the value does not remove the introduced attribute.

After issuing, following the above example

    crm resource maintenance test off

the Resource

    primitive test Dummy
       meta maintenance=true

changes to

    primitive test Dummy
       meta maintenance=false

A potential problem comes from the fact that there is a hierarchy in the Cluster, where the Resource takes precedence over the group or node or Cluster as a whole.

This can lead to unexpected or undesired behavior of the Cluster.

Resolution

As the introduction of that attribute is done out of administrative intervention, it should be part of these interventions
to remove the newly introduced meta attribute at the end.

With a command like:

 crm configure edit <RESOURCENAME>

in the above example

crm configure edit test

this part of the entry can be removed.

Removing just the

 maintenance=false

from the meta section without removing the meta section itself is sufficient and least intrusive.

It should be kept in mind that changes in the meta section will lead to a resource restart.

Disclaimer

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