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Pacemaker 1.0

Configuration Explained

An A-Z guide to Pacemaker's Configuration Options

Edition 1

Andrew Beekhof

Red Hat

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Copyright © 2009 Andrew Beekhof.
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The purpose of this document is to definitively explain the concepts used to configure Pacemaker. To achieve this best, it will focus exclusively on the XML syntax used to configure the CIB.
For those that are allergic to XML, Pacemaker comes with a cluster shell and a Python based GUI exists, however these tools will not be covered at all in this document [1] , precisely because they hide the XML.
Additionally, this document is NOT a step-by-step how-to guide for configuring a specific clustering scenario. Although such guides exist, the purpose of this document is to provide an understanding of the building blocks that can be used to construct any type of Pacemaker cluster.

[1] It is hoped however, that having understood the concepts explained here, that the functionality of these tools will also be more readily understood.

Table of Contents

1. Document Conventions
1.1. Typographic Conventions
1.2. Pull-quote Conventions
1.3. Notes and Warnings
2. We Need Feedback!
1. Read-Me-First
1.1. The Scope of this Document
1.2. What Is Pacemaker?
1.3. Types of Pacemaker Clusters
1.4. Pacemaker Architecture
1.4.1. Internal Components
2. Configuration Basics
2.1. Configuration Layout
2.2. The Current State of the Cluster
2.3. How Should the Configuration be Updated?
2.4. Quickly Deleting Part of the Configuration
2.5. Updating the Configuration Without Using XML
2.6. Making Configuration Changes in a Sandbox
2.7. Testing Your Configuration Changes
2.8. Do I Need to Update the Configuration on all Cluster Nodes?
3. Cluster Options
3.1. Special Options
3.1.1. Configuration Version
3.1.2. Other Fields
3.1.3. Fields Maintained by the Cluster
3.2. Cluster Options
3.2.1. Available Cluster Options
3.2.2. Querying and Setting Cluster Options
3.2.3. When Options are Listed More Than Once
4. Cluster Nodes
4.1. Defining a Cluster Node
4.2. Describing a Cluster Node
4.3. Adding a New Cluster Node
4.3.1. Corosync
4.3.2. Heartbeat
4.4. Removing a Cluster Node
4.4.1. Corosync
4.4.2. Heartbeat
4.5. Replacing a Cluster Node
4.5.1. Corosync
4.5.2. Heartbeat
5. Cluster Resources
5.1. What is a Cluster Resource
5.2. Supported Resource Classes
5.2.1. Open Cluster Framework
5.2.2. Linux Standard Base
5.2.3. Legacy Heartbeat
5.3. Properties
5.4. Resource Options
5.5. Setting Global Defaults for Resource Options
5.6. Instance Attributes
5.7. Resource Operations
5.7.1. Monitoring Resources for Failure
5.8. Setting Global Defaults for Operations
5.8.1. When Resources Take a Long Time to Start/Stop
5.8.2. Multiple Monitor Operations
5.8.3. Disabling a Monitor Operation
6. Resource Constraints
6.1. Scores
6.1.1. Infinity Math
6.2. Deciding Which Nodes a Resource Can Run On
6.2.1. Options
6.2.2. Asymmetrical "Opt-In" Clusters
6.2.3. Symmetrical "Opt-Out" Clusters
6.2.4. What if Two Nodes Have the Same Score
6.3. Specifying the Order Resources Should Start/Stop In
6.3.1. Mandatory Ordering
6.3.2. Advisory Ordering
6.4. Placing Resources Relative to other Resources
6.4.1. Options
6.4.2. Mandatory Placement
6.4.3. Advisory Placement
6.5. Ordering Sets of Resources
6.6. Collocating Sets of Resources
7. Receiving Notification of Cluster Events
7.1. Configuring Email Notifications
7.2. Configuring SNMP Notifications
8. Rules
8.1. Node Attribute Expressions
8.2. Time/Date Based Expressions
8.2.1. Date Specifications
8.2.2. Durations
8.3. Using Rules to Determine Resource Location
8.3.1. Using score-attribute Instead of score
8.4. Using Rules to Control Resource Options
8.5. Using Rules to Control Cluster Options
8.6. Ensuring Time Based Rules Take Effect
9. Advanced Configuration
9.1. Connecting to the Cluster Configuration from a Remote Machine
9.2. Specifying When Recurring Actions are Performed
9.3. Moving Resources
9.3.1. Manual Intervention
9.3.2. Moving Resources Due to Failure
9.3.3. Moving Resources Due to Connectivity Changes
9.3.4. Resource Migration
9.4. Reusing Rules, Options and Sets of Operations
9.5. Reloading Services After a Definition Change
10. Advanced Resource Types
10.1. Groups - A Syntactic Shortcut
10.1.1. Properties
10.1.2. Options
10.1.3. Using Groups
10.2. Clones - Resources That Should be Active on Multiple Hosts
10.2.1. Properties
10.2.2. Options
10.2.3. Using Clones
10.3. Multi-state - Resources That Have Multiple Modes
10.3.1. Properties
10.3.2. Options
10.3.3. Using Multi-state Resources
11. Protecting Your Data - STONITH
11.1. Why You Need STONITH
11.2. What STONITH Device Should You Use
11.3. Configuring STONITH
11.3.1. Example
12. Status - Here be dragons
12.1. Node Status
12.2. Transient Node Attributes
12.3. Operation History
12.3.1. Simple Example
12.3.2. Complex Resource History Example
B. More About OCF Resource Agents
B.1. Location of Custom Scripts
B.2. Actions
B.3. How Does the Cluster Interpret the OCF Return Codes?
B.3.1. Exceptions
C. What Changed in 1.0
C.1. New
C.2. Changed
C.3. Removed
D. Installation
D.1. Choosing a Cluster Stack
D.2. Enabling Pacemaker
D.2.1. For Corosync
D.2.2. For Heartbeat
E. Upgrading Cluster Software
E.1. Version Compatibility
E.2. Complete Cluster Shutdown
E.2.1. Procedure
E.3. Rolling (node by node)
E.3.1. Procedure
E.3.2. Version Compatibility
E.3.3. Crossing Compatibility Boundaries
E.4. Disconnect and Reattach
E.4.1. Procedure
E.4.2. Notes
F. Upgrading the Configuration from 0.6
F.1. Preparation
F.2. Perform the upgrade
F.2.1. Upgrade the software
F.2.2. Upgrade the Configuration
F.2.3. Manually Upgrading the Configuration
G. Is This init Script LSB Compatible?
H. Sample Configurations
H.1. An Empty Configuration
H.2. A Simple Configuration
H.3. An Advanced Configuration
I. Further Reading
J. Revision History

List of Figures

1.1. Active/Passive Redundancy
1.2. Shared Failover
1.3. N to N Redundancy
1.4. Conceptual Stack Overview
1.5. The Pacemaker Stack
1.6. Internal Components
2.1. Sample output from crm_mon
2.2. Sample output from crm_mon -n
2.3. Safely using an editor to modify the cluster configuration
2.4. Safely using an editor to modify a subsection of the cluster configuration
2.5. Searching for STONITH related configuration items
2.6. Creating and displaying the active sandbox
2.7. Small Cluster Transition
2.8. Complex Cluster Transition
4.1. The result of using crm_attribute to specify which kernel pcmk-1 is running
6.1. Ordered Set
6.2. Two Sets of Unordered Resources
6.3. Three Resources Sets
6.4. Another Three Resources Sets
9.1. How the cluster translates the pingd constraint
11.1. Obtaining a list of STONITH Parameters
12.1. A bare-bones status entry for a healthy node called cl-virt-1
12.2. Example set of transient node attributes for node "cl-virt-1"
12.3. A record of the apcstonith resource
12.4. A monitor operation performed by the cluster to determine the current state of the apcstonith resource
12.5. Resource history of a pingd clone with multiple jobs

List of Tables

3.1. Configuration Version Properties
3.2. Properties Controling Validation
3.3. Properties Maintained by the Cluster
3.4. Cluster Options
5.1. Properties of a Primitive Resource
5.2. Options for a Primitive Resource
5.3. Properties of an Operation
6.1. Options for Simple Location Constraints
6.2. Properties of an Ordering Constraint
6.3. Properties of a Collocation Constraint
8.1. Properties of a Rule
8.2. Properties of an Expression
8.3. Properties of a Date Expression
8.4. Properties of a Date Spec
9.1. Environment Variables Used to Connect to Remote Instances of the CIB
9.2. Extra top-level CIB options for remote access
9.3. Common Options for a 'ping' Resource
10.1. Properties of a Group Resource
10.2. Properties of a Clone Resource
10.3. Clone specific configuration options
10.4. Environment variables supplied with Clone notify actions
10.5. Properties of a Multi-State Resource
10.6. Multi-state specific resource configuration options
10.7. Additional constraint options relevant to multi-state resources
10.8. Role implications of OCF return codes
10.9. Environment variables supplied with Master notify actions
12.1. Authoritative Sources for State Information
12.2. Node Status Fields
12.3. Contents of an lrm_rsc_op job.
B.1. Required Actions for OCF Agents
B.2. Optional Actions for OCF Agents
B.3. Types of recovery performed by the cluster
B.4. OCF Return Codes and How They are Handled
E.1. Summary of Upgrade Methodologies
E.2. Version Compatibility Table

List of Examples

2.1. An empty configuration
2.2. Using a sandbox to make multiple changes atomically
3.1. An example of the fields set for a cib object
3.2. Deleting an option that is listed twice
4.1. Example cluster node entry
5.1. An example LSB resource
5.2. An example OCF resource
5.3. An example Heartbeat resource
5.4. An LSB resource with cluster options
5.5. An example OCF resource with instance attributes
5.6. Displaying the metadata for the Dummy resource agent template
5.7. An OCF resource with a recurring health check
5.8. An OCF resource with custom timeouts for its implicit actions
5.9. An OCF resource with two recurring health checks performing different levels of checks
5.10. Example of an OCF resource with a disabled health check
6.1. Example set of opt-in location constraints
6.2. Example set of opt-out location constraints
6.3. Example of two resources that prefer two nodes equally
6.4. Example of an optional and mandatory ordering constraint
6.5. An example colocation constraint
6.6. An example anti-colocation constraint
6.7. An example advisory-only colocation constraint
6.8. A chain of ordered resources
6.9. A chain of ordered resources expressed as a set
6.10. A group resource with the equivalent ordering rules
6.11. Ordered sets of unordered resources
6.12. Advanced use of set ordering - Three ordered sets, two of which are internally unordered
6.13. A chain of collocated resources
6.14. The equivalent colocation chain expressed using resource_sets
6.15. A group resource with the equivalent colocation rules
6.16. Using colocation sets to specify a common peer.
6.17. A colocation chain where the members of the middle set have no inter-dependencies and the last has master status.
8.1. True if now is any time in the year 2005
8.2. Equivalent expression.
8.3. 9am-5pm, Mon-Friday
8.4. 9am-6pm, Mon-Friday, or all day saturday
8.5. 9am-5pm or 9pm-12pm, Mon-Friday
8.6. Mondays in March 2005
8.7. A full moon on Friday the 13th
8.8. Prevent myApacheRsc from running on c001n03
8.9. Prevent myApacheRsc from running on c001n03 - expanded version
8.10. A sample nodes section for use with score-attribute
8.11. Defining different resource options based on the node name
8.12. Set resource-stickiness=INFINITY Mon-Fri between 9am and 6pm, and resource-stickiness=0 all other times
9.1. Specifying a Base for Recurring Action Intervals
9.2. An example ping cluster resource, checks node connectivity once every minute
9.3. Don't run on unconnected nodes
9.4. Run only on nodes connected to 3 or more ping nodes (assumes multiplier is set to 1000)
9.5. Prefer the node with the most connected ping nodes
9.6. A more complex example of choosing a location based on connectivity
9.7. Referencing rules from other constraints
9.8. Referencing attributes, options and operations from other resources
9.9. The DRBD Agent's Control logic for Supporting the reload Operation
9.10. The DRBD Agent Advertising Support for the reload Operation
9.11. Parameter that can be changed using reload
10.1. An example group
10.2. How the cluster sees a group resource
10.3. Example constraints involving groups
10.4. An example clone
10.5. Example constraints involving clones
10.6. Monitoring both states of a multi-state resource
10.7. Example constraints involving multi-state resources
10.8. Manually specifying which node should be promoted
11.1. Sample STONITH Resource
D.1. An example Corosync configuration file
D.2. Example options for an IPv6 environment
D.3. Configuration fragment for enabling Pacemaker under Corosync
D.4. Configuration fragment for enabling Pacemaker under Heartbeat
H.1. An empty configuration
H.2. 2 nodes, some cluster options and a resource
H.3. groups and clones with stonith