Question: How to change pacemaker cluster heartbeat timeout in CentOS/RHEL 7? By default, the heartbeat of pacemaker in CentOS/RHEL 7 is set to 1000(ms), you could increase it by the below steps. 1. Appending/Chaning the token to the totem section in the corosync config file /etc/corosync/corosync.conf. # cat /etc/corosync/corosync.conf totem { version: 2 cluster_name: pcmk secauth: off transport: udpu token: 10000 … [Read more...] about How To Change Pacemaker Cluster Heartbeat Timeout In CentOS/RHEL 7
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How to Configure Multiple Fencing-device Levels in Pacemaker Cluster
Configuring storage fencing Next, to configuring fencing to power-cycle a node (or to simply turn it off), fencing can also be configured to shut a faulty node off from shared storage. This is called storage fencing or SCSI fencing. SCSI fencing is implemented in the Red Hat Enterprise Linux High Availability Add-on using the fence_scsi fencing agent. When fence_scsi is used, whenever a cluster node starts it will create a SCSI reservation for itself using a key. Once one or more keys are … [Read more...] about How to Configure Multiple Fencing-device Levels in Pacemaker Cluster
Configuring Network Redundancy for PaceMaker Cluster Communication
What is Redundant Ring Protocol Redundant Ring Protocol (RRP) is a communication protocol where corosync can use two separate networks to establish connections between cluster nodes. When one network fails, communication can continue over the second network. RRP is not a replacement for network channel bonding; instead, bonded interfaces can be used to connect to the two rings for further redundancy. Where bonded interfaces protect against hardware failures (NIC, network cable, switch), RRP … [Read more...] about Configuring Network Redundancy for PaceMaker Cluster Communication
How to Create a GFS2 Formatted Cluster File System
Global File System 2 (GFS2) Global File System 2 (GFS2) is a cluster file system interfacing directly with the kernel VFS layer. This means that the same file system can be mounted and used by multiple cluster nodes simultaneously, while still providing a full regular file system, including features such as support for POSIX ACLs, extended attributes, and quotas. To accomplish this, every node accessing a GFS2 file system uses the cluster infrastructure provided by Corosync and Pacemaker to … [Read more...] about How to Create a GFS2 Formatted Cluster File System
Beginners Guide to Global File System 2 (GFS2)
Global File System 2 (GFS2) Global File System 2 (GFS2) is a cluster file system interfacing directly with the kernel VFS layer. This means that the same file system can be mounted and used by multiple cluster nodes simultaneously, while still providing a full regular file system, including features such as support for POSIX ACLs, extended attributes, and quotas. To accomplish this, every node accessing a GFS2 file system uses the cluster infrastructure provided by Corosync and Pacemaker to … [Read more...] about Beginners Guide to Global File System 2 (GFS2)
Managing Clustered Logical Volumes in RHEL Cluster (pacemaker)
Clustered LVM Clustered LVM allows the use of regular LVM volume groups and logical volumes on shared storage. In a cluster configured with clustered LVM, a volume group and its logical volumes are accessible to all cluster nodes at the same time. With clustered LVM, administrators can use the management benefits of LVM in conjunction with a shared file system like GFS2, for scenarios such as making virtual machine images inside logical volumes available to all cluster nodes. The … [Read more...] about Managing Clustered Logical Volumes in RHEL Cluster (pacemaker)
How to Configure Logical Volume Manager for Cluster File System
LVM review Logical Volume Management (LVM) provides administrators with a powerful storage virtualization framework. One or more data bearers (physical volumes) get aggregated into a storage pool (volume group), from which volumes can get carved to act as block devices (logical volumes). LVM also allows for the striping and/or mirroring of data between physical volumes. The following graphic shows the basic steps of creating a volume group and logical volumes. Just like dm-multipath, LVM … [Read more...] about How to Configure Logical Volume Manager for Cluster File System
How to Configure Two-node Pacemaker Cluster
In this post, we will configure a simple 2 node cluster with cluster nodes as nodea and nodeb. The cluster name will be geeklab. Fencing for this cluster should be handled using the fencing daemon running on classroom.example.com in combination with the fence_rht fencing agent. Plug names for this fence device correspond to host names on the private. example. com network. In order to prevent fence races, nodeb should have a 10-second delay when being fenced. To speed up resource recovery … [Read more...] about How to Configure Two-node Pacemaker Cluster
Most Common Two-node Pacemaker cluster issues and their workarounds
While two-node clusters may look good on paper, in practice there are a lot of extra failure scenarios that are not present with three or more node clusters. If the choice for a three-node or larger cluster cannot be made, it is recommended to have Red Hat perform an architecture review of the intended two-node cluster. Possible issues Two-node clusters have their own set of issues. The following list shows some of the most common ones, and workarounds to avoid these issues. 1. No … [Read more...] about Most Common Two-node Pacemaker cluster issues and their workarounds
Managing Resource Startup Order in Pacemaker Cluster (Managing Constraints)
In this post, lets see how resource groups can be used to control resource startup order by configuring an active/passive NFS server resource group. What are constraints? Constraints are restrictions that determine the order in which resources can be started and stopped, on which nodes they can run, or which other resources they can share the node with. Resource groups provide an easy implicit ordering constraint configuration that is sufficient for many use cases, as they provide a … [Read more...] about Managing Resource Startup Order in Pacemaker Cluster (Managing Constraints)