Through a long and intense period of research, implementation, and testing, ARIN completed the migration from Oracle to PostgreSQL late last year. Learn more at: http://teamarin.net/2014/04/01/building-high-availability-postgresql-cluster-arin/

1. Building a High-Availability
PostgreSQL Cluster
Presenter: Devon Mizelle
System Administrator
Co-Author: Steven Bambling
System Administrator

2. What is ARIN?
•Regional Internet registry for
Canada, US, and parts of the
Caribbean
•Distributes IPv4 & IPv6 addresses and
Autonomous System Numbers (Internet
number resources) in the region
•Provides authoritative WHOIS services
for number resources in the region
2

3. ARIN’s Internal Data
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4. Requirements
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5. Why Not Slony or pgpool-II?
• Slony replaces pgSQL‟s replication –
Why do this?
– Why not let pgSQL handle it?
• Pgpool is not ACID-Compliant
– Doesn‟t confirm writes to multiple nodes
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6. Our solution
• CMAN / Corosync
– Red Hat + Open-source solution for cross-
node communication
• Pacemaker
– Red Hat and Novell‟s solution for service
management and fencing
• Both under active development by
Clusterlabs
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7. CMAN/ Corosync
• Provides a messaging framework
between nodes
• Handles a heartbeat between nodes
– “Are you up and available?”
– Does not provide „status‟ of service,
Pacemaker does
• Pacemaker uses Corosync to send
messages between nodes
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8. CMAN / Corosync
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9. About Pacemaker
• Developed / maintained by Red Hat and Novell
• Scalable – Anywhere from a two-node to a 16-
node setup
• Scriptable – Resource scripts can be written in
any language
– Monitoring – Watches out for service state changes
– Fencing – Disables a box and switches roles when
failures occur
• Shareable database between nodes about
status of services / nodes
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10. Pacemaker
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Master
AsyncSync

11. Other Pacemaker Resources
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Fencing IP Addresses

12. How does it all tie together?
From the bottom up…

13. Pacemaker
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Client “vip”Replication “vip”
Master
Sync Async App

14. Event Scenario
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Master Sync AsyncMaster SyncAsync

15. PostgreSQL
• Still in charge of replicating data
• The state of the service and how it
starts is controlled by Pacemaker
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16. Layout
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💙 💙
MasterSlave Slave
cman cman cman
Client

17. Using Tools to Look Deeper
Introspection…

18. # crm_mon -i 1 -Arf

19. # crm_mon –i 1 -Arf (cont)

20. Questions? Devon Mizelle