OpenShift Setting and Enforcing emptyDir Quotas

External

• How to set quota for emptyDir volume usage on an Openshift Node? https://access.redhat.com/solutions/3110681

Internal

• OpenShift Volume Concepts

Overview

By default, pods can allocate on emptyDirs as much space as the underlying filesystem has available. It is possible to set up a configuration that would restrict space allocation to a quota enforced with the XFS quota mechanism, provided that the backing filesystem used to allocate space for emptyDirs is XFS.

Procedure

Configure Nodes to Allocate Local Volume Space on an XFS File System

The local volume space on a node is allocated on a directory configured in /etc/origin/node/node-config.yaml.

To configure quota enforcement, bring the node down as described here:

Stop a Node

Attach a block device with sufficient storage space to the node. If the node is a KVM host, the procedure is described here:

Add Storage to KVM Guests

At the end of the procedure, the node should have access to an extra XFS filesystem.

Configure the XFS File System to Allow Quota Enforcement

Mount the newly created filesystem at boot, with 'gquota' enabled, as shown below:

/dev/vdc1   /openshift.local.volumes             xfs     defaults,gquota   0 0

Configure node-config.yml

Update node-config.yml with the new location of the local volume space and the actual value of quota per FSGroup.

...
volumeDirectory: /openshift.local.volumes
volumeConfig:
  localQuota:
    perFSGroup: "2G"

Reboot and Test Quota Enforcement Availability

xfs_quota Info