pcs

pcs is a command-line tool used to manage and configure high-availability clusters based on Pacemaker and Corosync. It allows administrators to manage cluster nodes, configure resources, control failover and fencing, and more. Below are some common pcs commands and their subcommands:

Cluster Management

• pcs cluster start [nodes] Starts the Pacemaker cluster on specified nodes.

  pcs cluster start node1 node2

• pcs cluster stop [nodes] Stops the cluster on the specified nodes.

  pcs cluster stop node1 node2

• pcs cluster status Displays the status of the entire cluster.

  pcs cluster status

• pcs cluster enable --all Enables the cluster to automatically start on boot for all nodes.

  pcs cluster enable --all

• pcs cluster disable --all Disables the cluster from starting automatically on boot.

  pcs cluster disable --all

• pcs cluster destroy Removes the cluster configuration, essentially destroying the cluster setup.

  pcs cluster destroy

Resource Management

• pcs resource create [resource-name] [type] [options] Creates a resource in the cluster. Resources can be services, IP addresses, filesystems, or other cluster-managed entities.

  pcs resource create my-ip ocf:heartbeat:IPaddr2 ip=192.168.1.100 cidr_netmask=24

• pcs resource delete [resource-name] Deletes a resource from the cluster.

  pcs resource delete my-ip

• pcs resource restart [resource-name] Restarts a specific resource.

  pcs resource restart my-ip

• pcs resource status Displays the status of all resources.

  pcs resource status

• pcs resource manage [resource-name] Enables manual management of the resource, preventing Pacemaker from managing it automatically.

  pcs resource manage my-ip

• pcs resource unmanage [resource-name] Reverts a manually managed resource back to automatic management by Pacemaker.

  pcs resource unmanage my-ip

Node Management

• pcs node standby [node-name] Places the specified node into standby mode, preventing it from hosting resources.

  pcs node standby node1

• pcs node unstandby [node-name] Removes the node from standby mode, allowing it to host resources again.

  pcs node unstandby node1

• pcs node remove [node-name] Removes a node from the cluster.

  pcs node remove node2

Fencing and STONITH

• pcs stonith create [name] [type] [options] Creates a STONITH (Shoot The Other Node In The Head) fencing device to reboot or power off a node in case of failure.

  pcs stonith create fence-device fence_ipmilan ipaddr=192.168.1.10 login=root passwd=password pcmk_host_list=node1

• pcs stonith delete [stonith-device-name] Deletes a STONITH device.

  pcs stonith delete fence-device

• pcs stonith status Displays the status of all STONITH devices.

  pcs stonith status

Constraint Management

• pcs constraint location [resource-name] prefers [node-name] Sets a location preference for a resource to run on a particular node.

  pcs constraint location my-ip prefers node1=100

• pcs constraint colocation add [resource1] with [resource2] Ensures that two resources run on the same node (or different nodes using a negative score).

  pcs constraint colocation add app with my-ip

• pcs constraint order start [resource1] then [resource2] Sets the order in which resources are started or stopped.

  pcs constraint order start my-ip then app

Quorum and Status

• pcs quorum status Shows quorum status for the cluster.

  pcs quorum status

• pcs status Displays a high-level overview of the cluster, including nodes, resources, and fencing devices.

  pcs status

• pcs config Shows the current cluster configuration.

  pcs config

Property and Options Management

• pcs property set [property-name]=[value] Sets cluster-wide properties, such as enabling or disabling STONITH.

  pcs property set stonith-enabled=false

• pcs resource defaults Displays or sets default values for resource options such as timeouts or monitoring intervals.

  pcs resource defaults resource-stickiness=100

pcs is a comprehensive tool for managing Pacemaker/Corosync-based high-availability clusters. It provides rich functionality to configure, monitor, and troubleshoot clusters effectively, ensuring uptime and reliability in critical systems.