2.11.1 Considering use of an external database
This subsection describes the points that you must consider if you want to operate a manager host in a cloud environment in which an external database is used for the manager host.
The following figure shows an example of a database configuration in which an external database is used.
- Organization of this subsection
(1) Advantages and disadvantages of an external database
An external database has both advantages and disadvantages. Determine whether to use an external database considering how the advantages and disadvantages will affect the purpose of your operations.
- Advantages of using an external database
-
The following shows the probable advantages of using an external database. If reduction of the workload in daily operations is important in your environment, use of an external database might be a better choice.
-
You can use functionality of the external database provided as a cloud service to automatically back up job definitions, execution results, execution statuses and other information during operation.
-
If a failure occurs in the external database, you can use functionality of the external database to recover the database to any point in time prior to the failure#. For this reason, you can quickly restart operation of JP1/AJS3 jobs by using recovered information such as the execution statuses and execution results of jobs.
-
If a failure occurs in a manager host, by recovering a manager host environment that was backed up, you can quickly restart operation of JP1/AJS3 jobs by using recovered information such as the execution statuses and execution results of jobs.
- #
-
For details, see the documentation for the cloud service.
-
- Disadvantages of using an external database
-
The following shows disadvantages that you will probably encounter when using an external database. If you are building a mission-critical system, use of the embedded database might be a better choice.
-
The user is responsible for the set-up and operation of an external database. With respect to the investigation of the cause of failure in the cloud service or in the DBMS product, if a failure occurs during operation, the user will need to take actions such as making inquiries to the parties managing the cloud.
-
Because the external database is accessed via a network, performance in operations such as job execution and command execution is lower for the external database than for the embedded database.
-
Some JP1/AJS3 functions become unavailable. For details about the functions that become unavailable, see (7) Functions that cannot be used in an environment in which an external database is used.
-
(2) DBMS product that can be used
The following shows the DBMS product that JP1/AJS3 can use for an external database.
-
Microsoft SQL Server
For details about the cloud services supported by this product, see the Release Notes.
Note that ODBC is used for connection with the external database. The following figure shows an overview of ODBC-based connection with the external database.
- Cautionary note
-
To use ODBC, you must install the ODBC driver on the manager host.
(3) Conditions for using an external database and the basic configuration in which an external database is used
This subsection describes the conditions for using the external database and the configuration of the manager host and external database.
(a) Conditions for using an external database
An external database can be used if all of the following conditions are met:
-
The OS of the manager host that is to be connected with the external database is Windows or Linux.
-
The manager host is operating in a cloud environment.
-
The manager host is operating on only a physical host.
-
The database is in the standard configuration without ISAM.
(b) Restrictions on using an external database
To use SQL Server or another DBMS product that can produce multiple instances of an external database, the following restrictions are placed on the database and its instances:
-
The databases of the external database used for JP1/AJS3 must contain the data related to JP1/AJS3 only.
-
Prepare one database for each scheduler service.
The following figure shows an example of database and scheduler service configurations that are supported and not supported.
Figure 2‒70: Database and scheduler service configurations -
If multiple scheduler services are used on one manager host, all of the scheduler services must use the external database.
It is impossible to use both the embedded database and an external database for each scheduler service. The following shows an example of configurations of a manager host connected with external databases.
Figure 2‒71: Example of configurations of a manager host connected with external databases
(c) Basic configuration of external databases and a manager host
External databases can be used in either of the following configurations:
-
Configuration in which one manager host uses multiple instances of the external database
-
Configuration in which multiple manager hosts use one instance of the external database
The following figure shows configurations in which manager hosts use instances of the external database.
(d) Version compatibility between a manager host that uses an external database, and other products
The version compatibility between JP1/AJS3 - Manager when an external database is used as its database, and other products (other JP1/AJS3 products, the prerequisite product JP1/Base, and optional products) is the same as the version compatibility when an embedded database is used, with the exclusion of the special notes. For details about version compatibility for each product, see 8.1 Version compatibility.
(4) Connection relationship between the external database and JP1/AJS3 - Manager
The external database and JP1/AJS3 - Manager have the following connection relationship:
-
The scheduler database configured with the external database can be connected from only the scheduler service that is associated with the scheduler database. That scheduler database cannot be connected from different scheduler services.
The following figure shows the connection relationship between the scheduler database and scheduler services.
Figure 2‒75: Connection relationship between the scheduler database configured with the external database and scheduler services -
The agent management database configured with the external database can be connected from only the manager host on which execution agent information is set up. That agent management database cannot be connected from different scheduler services.
The following figure shows the connection relationship between the agent management database and the manager host.
Figure 2‒76: Connection relationship between the agent management database and the manager host -
If the external database is recovered or if the manager host operating in a cloud environment is recovered, the connections that were previously set must be set again. The following figures show examples of setting connections again when the external database is recovered and when the manager host operating in a cloud environment is recovered.
Figure 2‒77: Example of setting connections again when the manager host is recovered Figure 2‒78: Example of setting connections again when the external database is recovered
Use the jajs_extdb command to set the connections again. For details about the jajs_extdb command, see jajs_extdb in 3. Commands Used for Normal Operations in the manual JP1/Automatic Job Management System 3 Command Reference.
For details about how to recover the manager host in a cloud environment and how to recover the external database, see 12.2 Recovery from a failure in an environment that uses an external database in the JP1/Automatic Job Management System 3 Administration Guide.
(5) Setting up a manager host that connects to an external database
When you perform a new installation of JP1/AJS3, you can specify whether to automatically set up a scheduler service and embedded database. To use an external database, do not set up a scheduler service and embedded database during the new installation. After the new installation has finished, set up the external database. For details, see 24.2 Setting up JP1/AJS3 to use an external database in the JP1/Automatic Job Management System 3 Configuration Guide.
If JP1/AJS3 is already operating with the embedded database, you can switch the embedded database to the external database by exporting the data to the external database. You can export the following types of data:
-
Unit definition
-
Calendar definition
-
Schedule definition
-
Execution agent information
-
Registered execution-schedule information for the root jobnets that are registered for planned execution or fixed execution
For details about how to export data from the embedded database to the external database, see 24.3 Exporting data from the embedded database currently in use to the external database in the JP1/Automatic Job Management System 3 Configuration Guide.
(6) Operation using an external database
While JP1/AJS3 is operating with an external database, job information, jobnet information, and other information that is required for continuation of operation is stored in the external database. Therefore, if the data in the external database has been backed up, operation can be quickly restored when a failure occurs in the external database.
Also, if the same environment as the manager host environment has been prepared and the manager host fails, operation can be quickly restored by using the environment in which the failure has not occurred.
For details about how to restore operation that uses the external database, see 12.2 Recovery from a failure in an environment that uses an external database in the JP1/Automatic Job Management System 3 Administration Guide.
If operation is restored in an environment that uses an external database, the JP1/AJS3 service and the scheduler service perform a disaster recovery start. At this time, the statuses of jobs and jobnets change because of the disaster recovery start. Therefore, confirm safety, and then rerun the jobs and jobnets.
For details about the status of each job and jobnet when disaster recovery start is performed, see 6.2.1 Temporarily changing the start mode of JP1/AJS3 in the JP1/Automatic Job Management System 3 Administration Guide.
(7) Functions that cannot be used in an environment in which an external database is used
The following shows the functions that cannot be used in an environment in which an external database is used:
-
Operation that uses logical hosts
-
Functions that cannot be used in the standard configuration without ISAM
For details about the functions that cannot be used in the standard configuration without ISAM, see A Functions that Cannot Be Used in the Standard Configuration Without ISAM in the manual JP1/Automatic Job Management System 3 Overview.
-
Running queueless jobs and the queueless agent function
-
Running a remote jobnet as the transfer-source or transfer destination host
-
Monitoring operation by using JP1/AJS3 Console
-
Running commands related to the embedded database (commands whose names begin with ajsembdb)
(8) Notes on using an external database
Note the following points when you use JP1/AJS3 that is operating with an external database:
-
JP1/AJS3 - Manager does not control start and termination of the external database. Therefore, you must start all necessary instances of the external database before starting operation of JP1/AJS3 - Manager.
If no instances of the external database are running, the JP1/AJS3 service and scheduler services do not start.
-
For the following files, the maximum file size is limited to 15 MB on the basis of the character encoding used on the manager host that uses the external database:
-
Standard output files and standard error output files in the job error information directory, stored on the manager host, for standard jobs and HTTP connection jobs (No action is required because the error information is stored in the internal log.)
-
Execution result details of standard jobs, action jobs, event jobs, and HTTP connection jobs
-
-
Operation of JP1/AJS3 might stop because of errors such as communication failures. If an error occurs, restart the scheduler service by performing a hot start, and then resume operation. This will cause the execution of jobs to stop for a period that ranges from several minutes to tens of minutes.
After the restart, the scheduler service is resumed from its state prior to when the scheduler service was ended. In addition, the scheduler service automatically obtains information about jobs whose statuses are Now running from the server where those jobs are to be executed and, where possible, changes the status of those jobs to their actual status. If the scheduler service is able to obtain the actual status of a job, the scheduler service automatically continues execution of the job according to the jobnet definition. If the scheduler service is unable to obtain information from the server where a job is to be executed, the status of the job changes to Ended abnormally. For jobs that end abnormally, check the status of the job and manually execute the job again.
-
If the temporary change operation management function is used, the maximum amount of information about temporary change operations that can be stored for each root jobnet is 15 megabytes. Make sure the amount of temporary change information estimated by using the following formula does not exceed 15 megabytes.
- 0.002 x A + 0.003 x B (units: megabytes)
-
A: The number of the operations performed on the root jobnet and its lower units that are to be saved as temporary change information
B: The number of operations in A that are performed to add execution schedules by specifying passing information
For details about the operations that are saved as temporary change information and the expiration date of temporary change information, see 4.5.16(1) Displaying temporary change information in the manual JP1/Automatic Job Management System 3 Overview.