2 Active/Passive High Availability overview

Figure 12-3 shows both the software and hardware stack that of an SDMC High

Availability environment. These internal software components that make up

SDMC High Availability are transparent to the user and do not need to be directly

configured. IBM Tivoli System Automation for Multiplatform (TSA) is used to

monitor the hardware and software stack. It also provides failover and quorum

capability. Data is mirrored using Distributed Replicated Block Device (DRBD).

Apache MQ performs operating system synchronization, and also contains the

firewall rules, NTP configuration, network and user settings. Floating IP

addresses used to connect to the active SDMC can be moved between the

nodes with the active node. The OS on the passive node is started, but the

software stack is not.



Post-Failover

Director

Console



Director

Console

ThinkVision



ThinkVision



Active Director Node

TSA



MQ



File

System



Passive Director Node

Heartbeat



User/Firewall

Synchronization



DRBD



Passive Director Node



TSA



TSA



MQ



MQ



DRBD



File

System



File

System



DRBD



Active Director Node

Heartbeat



TSA



User/Firewall

Synchronization



MQ



DRBD



File

System



Managed Systems



Managed Systems



Figure 12-3 SDMC High Availability environment before and after failover



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Running the setup wizard or using CLI commands on the SDMC designated to

be the primary node configures the internal High Availability components on both

the primary and secondary SDMCs. Figure 12-4 shows the SDMC High

Availability configuration sequence that sets up the two SDMCs in an High

Availability cluster.

HA config wizard



Initial config



TSA Model config



SSH to second node

Perform sanity check

Retrieve TCP/IP info

Kick off initial config



Configure MQ

Configure HA daemons

Open firewall ports

Sync DNS, NTP, syslog

Sync users, LDAP, Kerberos

Configure DRBD

Preapre nodes

Stop Director

Create TSA model

Configure Agents

Start Director



Figure 12-4 Active/Passive configuration sequence



12.2.1 High availability terminology

Refer to this list of terms to help you better understand high availability concepts:

Node

Active node



The active node manages your environment.

Only one node is active at a time.



Passive node



304



A node is an SDMC that is configured to be part

of a high availability environment.



The passive node is not currently active. Any

changes you make to the active node are

replicated to the passive node.



IBM Systems Director Management Console: Introduction and Overview



Primary node



This is the node you use to set up high

availability. It is initially the active node. When

you set up a high availability cluster, the IBM

Systems Director data, remote authentication

configuration settings, users, and firewall

settings on this node are replicated to the

secondary node.



Secondary node



This is the node that you set up to take over if

the primary node fails. It is initially the passive

node, but takes over as the active node if the

primary node fails.



Network status IP address



The cluster nodes use this IP address to

determine which node is connected to the

network. If they cannot contact each other, the

node that can connect this IP address becomes

the active node.



Floating IP address



This address is always assigned to the active

node. Users should always access this address

so they do not have to know which node is

active. It also enables you to use IBM Systems

Director Common Agent with high availability.



12.2.2 SDMC High Availability synchronized data

The following data changes on the active SDMC are synchronized to the standby

SDMC:

User additions

User modifications

User deletions

Firewall changes

NTP configuration

Kerberos/LDAP configuration

Initial High Availability configuration

– DRBD configuration

– Users

– Authentication files (LDAP and Kerberos)

– Firewall settings

– DNS resolver

– NTP configuration



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12.2.3 SDMC High Availability processes monitored

These are the processes monitored by the SDMC High Availability for a

redundant takeover:

Director

DB2

DRBD

CIM Server

High Availability MQ Daemon (MQ server)

High Availability Daemon (Processes MQ messages)

NTP Server

DHCP Server



12.2.4 Active/Passive High Availability: Log location

Here are the locations of the SDMC High Availability log files:

/opt/ibm/director/ha/logs/, which contains:

daemon0-x.log



High Availability Daemon log



mq0-x.log



ActiveMQ log



smha.log



TSA monitor log



init0-x.log



Initial configuration from initiated outside the Director

process



/opt/ibm/director/lwi/logs

Contains SDMC High Availability task logs captured in the Director High

Availability configuration task

The daemon log and mq log are rolling logs that contain up to five log files,

where x is the log file number. Each log file can contain approximately 10 MB

data.

In addition, consider the following items:

Turn the log level to com.ibm.isdvmi.ha.level=FINEST if there are problems

with the SDMC High Availability configuration.

Log files are collected using the SDMC appliance log collector called pedbg.

You must collect logs as the pe user. pedbg also collects TSA log files if high

availability has been configured.



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12.3 Active/Passive High Availability: Configuration

planning

You need to plan the setup of SDMC High Availability, and there are several

considerations and issues to be aware of in setting up and administrating this

environment:

Both SDMCs must be at the same code level prior to the High Availability

configuration.

SSH must not be blocked by the firewall during the initial High Availability

configuration.

Data on the secondary node is lost during the High Availability configuration.

Data on the primary node, where the High Availability configuration is

triggered, is retained and mirrored to the secondary node.

Both SDMCs must be turned on at all times to receive the benefits of high

availability.

Only the active SDMC console can be accessed after High Availability is

configured.

Note: Prior to the High Availability configuration, backups of both SDMC

images should be taken so that the SDMCs can revert back to their original

non-High Availability states should there be problems during the High

Availability setup or if you want to go back to a non-High Availability setup.



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12.3.1 Network requirements

Because data is continually replicated between the two cluster nodes, carefully

consider your networking topology. Figure 12-5 shows a diagram of a typical

SDMC High Availability environment.

Note that the SDMC provides network path redundancy through two connections

to each Flexible Service Processor (FSP) of a managed system. When the front

and back IPs of the FSP are connected through different networks to the SDMC

and one of the networks goes down, then the connection is automatically

established to the FSP from the same SDMC through the other network,

providing continuous availability to the user.



Connected to 9.0.0.30



Active Node



Passive Node



IBM Systems Director

Management Console



IBM Systems Director

Management Console



eth09.0.0.11



eth09.0.0.21



eth110.0.0.11

Floating IP

eth0:1- 9.0.0.30



br0bridge



br1bridge



eth09.0.0.10



eth110.0.0.10



eth110.0.0.21



Virtual

machines



Hypervisor



br0bridge



br1bridge



eth09.0.0.20



eth110.0.0.20



Hardware



Public LAN

Private LAN



Figure 12-5 High Availability network topology



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