Job Management Partner 1/Automatic Job Management System 3 System Design (Configuration) Guide

2.3.6 Checking operation in a DNS environment

You can use JP1/AJS in a DNS environment. To use JP1/AJS in a manager/agent configuration, define normal lookup on the DNS.

The following figure shows the settings required for name resolution by using normal lookup and reverse lookup for JP1/AJS3 products.

Figure 2-30 Settings required for name resolution by using normal lookup for JP1/AJS3 products

If you want to use a Fully Qualified Domain Name (FQDN) host name as the executing agent name when you use event jobs, you must specify the settings described in this subsection. You do not need to specify the settings if the same two host names do not exist in the same network (even in an environment that crosses domains) when you use event jobs or if you use only standard jobs, action jobs, and custom jobs.

When the settings described in this section are specified, each host obtains an FQDN host name from the local host name and sends it to the other hosts during communication between the manager and agent hosts when event jobs are executed. This allows the manager and agent hosts to uniquely identify each other and to correctly process the communication data.

When you migrate from version 07-00 or earlier to version 07-00 or later, and switch to resolving host names by using the DNS, you must change the settings of event jobs. However, you do not need to switch to using FQDN hosts names if all the host names in the same network are unique and no problems occur.

Organization of this subsection

(1) When to switch to using FQDN host names for event jobs

(2) Example of using FQDN host names when the DNS is used

(3) Notes on operation in a DNS environment

(1) When to switch to using FQDN host names for event jobs

You do not need to change the current settings if the event jobs use the DNS and host names that are unique in the same network. Follow the flowchart below to determine whether you need to switch to using FQDN host names for event jobs.

Figure 2-31 Judging the necessity of switching to operation with host names in the FQDN format

Cautionary note

To use host names in FQDN format, JP1/AJS3 - Manager or JP1/AJS2 - Manager version 07-00 or later must be installed on the manager host. Any version of JP1/AJS - Agent or JP1/AJS - Manager can be used on the agent hosts, but version 07-00 or later is required if hosts with identical host names in different domains are used as agents.

New settings are required if the flowchart above indicates that you need to switch from a DNS environment to using FQDN host names for event jobs. For the setting procedure, see 6.3.5 Using fully qualified domain names (FQDN) when using event jobs during DNS operation in the Job Management Partner 1/Automatic Job Management System 3 Configuration Guide 1 (in Windows) or 14.3.5 Using fully qualified domain names (FQDN) when using event jobs during DNS operation in the Job Management Partner 1/Automatic Job Management System 3 Configuration Guide 1 (in UNIX).

Note that, by default, Receive JP1 event jobs, Monitoring log files jobs, and Monitoring event log jobs obtain the host name of the host on which they are executed. These jobs then operate using the JP1/Base event server that has the same name as the host name they obtained. Therefore, to execute these jobs on an agent host that performs operations with the event server by using the event server name in FQDN format, set the agent host name in FQDN format.

If necessary, see 6.6.1 Canceling and re-setting service dependencies in the Job Management Partner 1/Automatic Job Management System 3 Configuration Guide 1 and then set the JP1/AJS3 service dependencies.

For details about the flow, and procedures for settings when upgrading from an operation environment of JP1/AJS2 06-71 or earlier, see 8.2 Setting for executing event jobs in a DNS environment (for upgrading).

(2) Example of using FQDN host names when the DNS is used

This subsection shows an example of using FQDN host names when the DNS is used. In this example, you enter a job for the agent host HostA from the manager host HostM. The IP address of HostM is 100.0.0.10, and the IP address of HostA is 100.0.0.20. The job is assigned the executing host names HostA.hitachi_1.co.jp and HostA.hitachi_2.co.jp.

The example assumes that the hostname command executed on a manager host or agent host will return a host name in FQDN format. For details about the required setting when changing to FQDN host names, see (1) When to switch to using FQDN host names for event jobs above.

Figure 2-32 Example of operation with FQDN host names

For this example, set the hosts files at the manager and agent as follows.
The hosts file at the manager:
Specify the following setting so that the name HostA can be resolved:
100.0.0.20 HostA.hitachi_1.co.jp
The hosts files at the agent (HostA on Hitachi_1.co.jp):
Specify the following setting so that the name HostM can be resolved:
100.0.0.10 HostM.hitachi_1.co.jp
If neither of the DNS servers can resolve the host name of the manager or agent host, set the hosts files of the DNS servers on both the manager and agent sides as follows.
The hosts file of the DNS server on hitachi_1.co.jp:
200.0.0.20 HostA.hitachi_2.cojp
The hosts file of the DNS server on hitachi_2.co.jp:
100.0.0.10 HostM.hitachi_1.co.jp
When you specify the settings as shown above, the manager host name HostM.Hitachi_1.co.jp is sent to all agents. The agents send a reply to HostM.hitachi_1.co.jp.

Cautionary notes

Use the manager host in an environment in which it can resolve the name of each agent host in FQDN format. Use the agents in an environment in which they can resolve the manager's name in FQDN format.

For the computer information, the DNS must be searched before the hosts file. Otherwise, correct FQDN host names might not be acquired.

After switching to operation that uses FQDN host names, FQDN host names are used for communication between the manager and agent hosts when event jobs are executed. Note, however, that if the local host name defined in the jp1hosts file is a short name, the short host name is used for communication because the jp1hosts file settings have precedence over the DNS. Therefore, to define the local host name with a short name in the jp1hosts file for the agent host, make sure that the manager host can resolve the short name of the agent host. To define the local host name with a short name in the jp1hosts file for the manager host, make sure that the agent hosts can resolve the short name of the manager host.

As long as the manager and agents operate within the same domain (hitachi_1.co.jp), it does not matter whether the value of DNSEstablish is Y or N. However, the manager host and agent hosts must operate in an environment in which the manager host and each agent host can resolve the name of the other hosts.

(3) Notes on operation in a DNS environment

Note the following when using JP1/AJS3 in a DNS environment:

Run JP1/AJS3 in an environment where the host names of agent hosts can be resolved.
When you specify Y for the environment setting parameter DNSEstablish, the host names of agent hosts are in the FQDN format.
If you do not use DNS and you specify N for the environment setting parameter DNSEstablish, the host names of agent hosts are the ones that are output when you execute the hostname command.

When you set an alias host name for a host corresponding to the agent host on which event jobs are executed, make sure that the manager host can resolve not only the alias host name, but also the actual agent host name corresponding to the alias host name.

If a job has been registered and the IP address cannot be resolved, an error message is output to the log and processing continues.

In an environment where the IP address cannot be resolved from the local host, you cannot start JP1/AJS3.

When you execute jobs on multiple hosts, specify settings that allow for the resolution of the IP addresses for the manager hosts, agent hosts, and the hosts in other systems.

When DNS is used, set the DNS environment so that the IP addresses of the hosts indicated by FQDN host names can be resolved.

Define normal lookup. You do not need to define reverse lookup.

Operation will not be normal if you specify localhost as the name of the executing host.

Define both normal lookup and reverse lookup.

If you want to use event jobs, you must add an executing agent host. To do this during operation, use the ajsagtadd command. For details about the ajsagtadd command, see ajsagtadd in 2. Commands in the manual Job Management Partner 1/Automatic Job Management System 3 Command Reference 1.

When you obtain FQDN host names in an environment that uses the DNS, the case (upper or lower) of alphabetic characters in the host name might change each time it is obtained. Accordingly, the JP1/AJS manager used in such an environment is handled as multiple managers because the manager host name viewed from the agent has changed. This situation can lead to the following problems when an event job is executed:

When the JP1/AJS3 service on the manager is restarted while a jobnet with a start condition is running, any monitored event that was detected after the restart is detected again.

When the option to continue execution of active event jobs is enabled, if the JP1/AJS3 service on the manager is restarted in hot-start mode while an event job is running, multiple events are incorrectly detected as one event.

To prevent such problems, before you start operating JP1/AJS3 in an environment that uses the DNS, set a fixed manager name that will be used for communication between the manager and agent hosts. For details, see 6.3.16 Settings for ensuring that a fixed manager host name is used when event jobs are executed in the Job Management Partner 1/Automatic Job Management System 3 Configuration Guide 1 (in Windows) or 14.3.17 Settings for ensuring that a fixed manager host name is used when event jobs are executed in the Job Management Partner 1/Automatic Job Management System 3 Configuration Guide 1 (in UNIX). However, a fixed manager name is not necessary if you execute the jpoagoec command on the agent host on which event jobs are executed and the manager host names remembered by the agent are unique regardless of case.

If you want to switch to operation using FQDN host names, perform the necessary operations according to the workflow for operation that uses FQDN host names in Figure 8-1 Overview of upgrading JP1/AJS in a DNS environment in 8.2.1 Tasks required for upgrading JP1/AJS2. Note, however, that you do not need to upgrade the manager.

If you have switched to operation using FQDN host names, use the jp1ping command to make sure that the manager host is able to resolve agent host names and that the agent hosts are able to resolve the manager host name. For details about the jp1ping command, see the Job Management Partner 1/Base User's Guide.

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