cluster concepts and configuration h6487s i.02 module 5

Cluster Concepts and Configuration

H6487S I.02Module 5

2H6487S I.02

© 2003 Hewlett-Packard Development Company, L.P.

Definition of a Cluster

• A Cluster is a collection of nodes which cooperate together to improve the availability of applications running on the nodes.

• Two major benefits of a cluster during downtime events ensure:– High Availability when another node takes over. (Unplanned)– The cluster can be used for rolling upgrades. (Planned)

3H6487S I.02


Lan 2

Primary

Mirror

VG01

SystemB

SystemA

Primary

Mirror

VG02

Root

HeartbeatPacket

MirrorRoot

Root MirrorRoot

cmcldprocess

cmcldprocessCluster

Lock

lan0 lan1

Lan 2

lan1lan0

Major Components of a Cluster

Bridge

4

3

1 2

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HeartbeatPacket

DataPacket

DataPacket

lan0 lan1 lan0 lan1

lan2 lan2

Standby LAN

Bridge

NETWORK_INTERFACE lan0

HEARTBEAT_IP 15.19.83.121


STATIONARY_IP 192.20.45.121


# Possible standby network interfaces for lan1 or lan0

Excerpt fromCluster

Configurationfile

15.19.83.121 192.20.45.121

Network Interface Configuration

NETWORK_POLLING_INTERVAL 2000000

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Primary

Mirror

VG01

Primary

Mirror

VG02

ClusterLock SystemBSystemA

FIRST_CLUSTER_LOCK_VG /dev/vg01 NODE_NAME SystemA

FIRST_CLUSTER_LOCK_PV /dev/dsk/c1t4d0

Cluster Lock Configuration

Excerpt fromCluster

Configurationfile

6H6487S I.02


SystemBSystemA

Cluster Lock Configuration Using a Quorum Server

QuorumServer

QS_HOST SystemCQS_POLLING_INTERVAL 120000000QS_TIMEOUT_EXTENSION 2000000

Excerpt fromCluster

Configurationfile

7H6487S I.02


HeartbeatPacket

lan0 lan0

HEARTBEAT_INTERVAL

1000000

NODE_TIMEOUT 5000000

Primary

Mirror

VG01

ClusterLock

Heartbeat Configuration

Excerpt fromCluster

Configurationfile

8H6487S I.02


cmcldprocess

cmcldprocess

serviceprocess service

process

The cmcld process• Sends and receives Heartbeats• Checks the LAN cards for functionality• Monitors the service processes of packages

HeartbeatPacket

cmcld Process

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Cluster Formation Requirements

Cluster Lock Mechanism

• Required for 2 nodes (Quorum Server or LVM Disk)

• Recommended for 3 or 4 nodes (Quorum Server or LVM Disk)

• Optional for 5 or more nodes (Quorum Server only)

• Should be on separate power sources from other systems in cluster

Node Attendance

• 100% node attendance is required for initial cluster formation

Network Requirements

• All nodes in the cluster must be on same subnet

• LAN cards in the same system MUST be on separate subnets

• At least one HEARTBEAT_IP network is configured

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Steps to Configure a Cluster

1. Build cluster configuration filecmquerycl -v -C cmclconfig.ascii -n node1 -n node2…

2. Compile and distribute binary filecmcheckconf -v -C cmclconfig.asciicmapplyconf -v -C cmclconfig.ascii

3. Start MC/SG daemonscmruncl –v

4. If necessary, halt the clustercmhaltcl -v

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Cluster ConfigASCII file

cmclconfdprocess

cmclconfdprocess

• FIRST_CLUSTER_LOCK_VG• NODE_NAME

- NETWORK_INTERFACE - HEARTBEAT_IP or STATIONARY_IP or blank - FIRST_CLUSTER_LOCK_PV - SERIAL_DEVICE_FILE

• HEARTBEAT_INTERVAL• NODE_TIMEOUT• AUTOSTART_TIMEOUT• NETWORK_POLLING_INTERVAL

• VOLUME_GROUP

• CLUSTER_NAME

• MAX_CONFIGURED_PACKAGES


1. Build Cluster Configuration File2. Compile and Distribute Binary File3. Start MC/SG Daemons

Use cmqueryclcommand to build

cluster configurationASCII file

Step 1: Build Cluster Configuration ASCII File

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Cluster ConfigASCII file

Cluster Binary File

Cluster Binary File

cmapplyconf

Cluster ConfigurationASCII File

Cluster BinaryFile

This file is automatically distributed to all nodes inthe cluster.



Step 2: Compile and Distribute Binary File

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# cmruncl -v

Cluster Binary file

cmcldprocess

Cluster Config ASCII file

ClusterBinary

file

cmcldprocess



Step 3: Start MC/SG Daemons

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Cluster Configuration Procedure

1. Set up trusted hosts within cluster systems: vi /etc/cmcluster/cmclnodelist this_node_hostname root other_node_hostname root

2. cd /etc/cmcluster

3. cmquerycl –v -C cmclconf.ascii -n nodel -n node2

4. vi cmclconf.ascii Modify CLUSTER_NAME field Modify MAX_CONFIGURED_PACKAGES field

5. cmcheckconf –v -C /etc/cmcluster/cmclconf.ascii

6. cmapplyconf –v -C /etc/cmcluster/cmclconf.ascii

7. cmruncl -v

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# cmviewcl -v

CLUSTER STATUS cluster1

up

NODE STATUS STATE

SystemA up running

Network_Parameters: INTERFACE STATUS PATH PRIMARY up 8/16/6 STANDBY up 8/20/5/1

NAMElan0lan1

Serial Heartbeat: DEVICE FILE NAME CONNECTED TO:

/dev/tty0p3 /dev/tty0p3

Viewing the Cluster — cmviewcl Command

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May 2 15:30:52 systemA cmcld[2048]: clvmd initialized successfully

# tail -f /var/adm/syslog/syslog.log

May 2 15:30:45 systemA cmcld[2048]: cmruncl

May 2 15:30:47 systemA cmcld[2048]: Starting cluster protocols

May 2 15:30:48 systemA cmcld[2048]: Attempting to form a new cluster

May 2 15:30:50 systemA cmcld[2048]: Clearing the Cluster Lock

May 2 15:30:45 systemA cmcld[2048]: Turning on safety time protection

May 2 15:30:50 systemA cmcld[2048]: Two nodes have formed a new cluster

May 2 15:30:51 systemA cmcld[2048]: The new active membership is: systemA, systemB

Checking the Cluster Log

cluster concepts and configuration h6487s i.02 module 5

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