2.10.1 Supplementary notes on broadcast executions of a job

(a) Manager host

• Destination for placement

  The manager host can be placed in an on-premise environment and a non-auto-scaling environment of the cloud.

• Cluster configuration

  The manager host supports cluster configuration.

(b) Relay agent

• Destination for placement

  The relay agent can be placed in an on-premise environment and a non-auto-scaling environment of the cloud.

• Cluster configuration

  The relay agent supports cluster configuration.

If the manager host is running on Windows or Linux, you can run the ajsatsetup -m command on the manager host to use the manager host as a relay agent.

In situations shown below, a relay agent is required for a host that is neither a manager host nor a destination agent host.

• If the manager host is running on an OS that is neither Windows nor Linux:

  The OS of the manager host or agent host that a flexible job can specify as an execution host is only Windows or Linux.

  Therefore, if the manager host is running on an OS that is neither Windows nor Linux, a relay agent is necessary.

• If the manager host and the destination agent cannot communicate directly with each other:

  As shown in Figure 2-67, a relay agent must be placed between the manager host and the destination agent to mediate communication.

(c) Broadcast agent

• Destination for placement

  The broadcast agent can be placed in an on-premise environment and a non-auto-scaling environment of the cloud.

• Cluster configuration

  The broadcast agent does not support cluster configuration. For that reason, to continue using broadcast execution for flexible jobs even when a failure occurs, consider preparing a substitute machine in advance. After manually switching to the substitute machine, by re-executing jobs as needed, you can use broadcast execution for flexible jobs.

  During the phase of preparing a substitute machine, even if the host name and IP address are different from the machine before the switchover, there is no problem. However, if something other than the DNS name is specified for the -p option of the ajsatsetup command that was executed during setup of the destination agent, when switching to the substitute machine, you will need to make the host name or IP address of the substitute machine the same as the machine before the switchover.

  As methods for preparing a substitute machine in advance, there is the method of creating a new virtual machine and the method of replicating a virtual machine. Regarding the method of creating a new virtual machine, see the virtualization software documentation to prepare a virtual machine. Similarly, regarding the procedure for configuring the broadcast agent, see 21.3.2(3)(a) Setting up a broadcast agent in the JP1/Automatic Job Management System 3 Configuration Guide. Regarding the replication of virtual machines, you can deploy a broadcast agent to a cloud environment, etc., and then use the cloud's function to replicate the environment of the broadcast agent as a virtual machine. Immediately after installing JP1/AJS3 - Agent and setting up the broadcast agent, replicate the virtual machine. As a result, the work of installing and setting up JP1/AJS3 - Agent can be reduced. For details on the replication of virtual machines, see 22.4 Replicating a virtual machine after setup of JP1/AJS3 - Agent in the JP1/Automatic Job Management System 3 Configuration Guide.

  The method for switching to a substitute machine when a failure occurs is as follows.

  1. If the machine before the switchover is running, stop the machine.

  2. Start the substitute machine.

  3. Make communication possible between the destination agent and the broadcast agent that is the substitute machine.

     Depending on the value of the -p option of the ajsatsetup command that was executed during setup of the destination agent, configure the following settings.

     - If the value specified for the -p option is a host name

     Change the host name of the substitute machine to the same host name as the machine before the switchover so that the IP address of the substitute machine is found.

     - If the value specified for the -p option is an IP address

     Change the IP address of the substitute machine to the same IP address as the machine before the switchover so that the IP address of the substitute machine is found.

     - If the value specified for the -p option is a DNS name

     Configure routing, etc., of the cloud environment so that the IP address of the substitute machine is found from the DNS name.

     

     Supplementary notes

     - The -p option of the ajsatsetup command that was executed during setup of the destination agent is for registering a broadcast agent for the destination agent, and only one can be registered. For that reason, to use the information about the destination agent that is the broadcast destination, as is, for the substitute machine, you must make it the same as the value specified for the -p option.

     - To use JP1/AJS3 services, you must configure the settings in 7.9.1 Changing the name of the host that runs JP1/AJS3 in the JP1/Automatic Job Management System 3 Administration Guide and 7.9.2 Changing the IP address of the host that runs JP1/AJS3 in the JP1/Automatic Job Management System 3 Administration Guide. However, if you are using the substitute machine as a broadcast agent only, the settings are not necessary.

  4. On the substitute machine, start the following services.

     - JP1/AJS3 Autonomous Agent service

     - JP1/AJS3 Autonomous Agent Messenger service

  5. Re-execute jobs.

     If a failure occurs on the broadcast agent during the execution of jobs, flexible jobs will end abnormally. For that reason, after switching to the substitute machine, re-execute jobs as needed.

  Similarly, consider preparing a substitute broadcast agent environment at the remote site as needed.

(d) Destination agent

• Destination for placement

  Place the destination agent in an auto-scaling environment under the load balancer.

  Note that the broadcast agent and the destination agent do not communicate with each other via a load balancer. These agents communicate directly with each other by using TCP/IP communication and UDP communication. If TCP/IP communication and UDP communication are enabled, the destination agent can be placed under any type of a load balancer.

• Cluster configuration

  The destination agent does not support cluster configuration. For that reason, by deploying a destination agent in an auto-scaling environment in a cloud, availability in the auto-scaling environment is ensured. Similarly, consider preparing an auto-scaling environment at the remote site as needed.

  Cautionary note

  Scale-in and scale-out actions in an auto-scaling environment in a cloud are managed on the side of the cloud. Thus, the time before startup of the destination agent by scaling-out in an auto-scaling environment finishes and the deletion of destination agents by scaling-in cannot be detected by JP1/AJS3. At that timing, if a flexible job is executed, it might fail. For that reason, regarding the execution of flexible jobs, we recommend using jobs that can be re-executed.