Chapter 6. Clustering

Pacemaker now supports path, mount, and timer systemd unit files

Previously, Pacemaker supported service and socket systemd unit files, but any other unit file type would be treated as a service unit and fail. With this release, path, mount, and timer systemd units can now be managed by a Pacemaker cluster. (BZ#1590483)

Support for Red Hat Enterprise Linux High Availability clusters on Alibaba Cloud

Red Hat Enterprise Linux 7.6 supports High Availability clusters of virtual machines (VMs) on Alibaba Cloud (Aliyun). For information on configuring a Red Hat Enterprise Linux High Availability Cluster on Alibaba Cloud, see https://access.redhat.com/articles/3467251. (BZ#1568589)

Support for Red Hat Enterprise Linux high availability clusters on Google Compute Cloud

Red Hat Enterprise Linux 7.6 supports high availability clusters of virtual machines (VMs) on Google Compute Cloud (GCP). For information on configuring a Red Hat Enterprise Linux High Availability Cluster on GCP, see https://access.redhat.com/articles/3479821. (BZ#1568588)

New volume_group_check_only parameter for lvm resource agent

The lvm resource agent now supports the volume_group_check_only parameter. When this parameter is set, only the volume group is checked when running a monitoring operation. Setting this parameter can be used to avoid timeouts with tagged volumes.
WARNING: This parameter should be used only when you have issues with timeouts, and when you must use the lvm resource agent and not the LVM-activate agent. (BZ#1470840)

Support for VDO resource agent

Red Hat Enterprise Linux now provides support for the vdo-vol resource agent to manage VDO (Virtual Data Optimizer) volumes as a high availability resource. (BZ#1538689)

The pcs command now supports filtering resource failures by an operation and its interval

Pacemaker now tracks resource failures per a resource operation on top of a resource name, and a node. The pcs resource failcount show command now allows filtering failures by a resource, node, operation, and interval. It provides an option to display failures aggregated per a resource and node or detailed per a resource, node, operation, and its interval. Additionally, the pcs resource failcount reset command now allows filtering failures by a resource, node, operation, and interval. (BZ#1427273)

New pcs commands to list available watchdog devices and test watchdog devices

In order to configure SBD with Pacemaker, a functioning watchdog device is required. The Red Hat Enterprise Linux 7.6 release supports the pcs stonith sbd watchdog list command to list available watchdog devices on the local node, and the pcs stonith sbd watchdog test command to test a watchdog device. (BZ#1475318)