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VIOS Migration Flow

In this document, we will explain the process of migrating Virtual I/O Servers (VIOS) using the nim_migvios_tuple function. The process involves checking the previous status of the VIOS, verifying the time limit, executing the migration command, and finalizing the migration.

The flow starts by checking the previous status of the VIOS. If no previous status is found or if the previous status is not 'SUCCESS', the migration is skipped. Next, it checks if the time limit has been reached, and if so, the migration is skipped. Then, the migration command is executed, and the status is updated based on the return code. Finally, the operation progress is checked, and the status is updated accordingly.

Flow drill down​

Handling the Migration Status​

First, we check the previous status of the VIOS. If no previous status is found, the migration is skipped, and a message is logged. If the previous status is not 'SUCCESS', the migration is also skipped, and the status is updated accordingly.

        if module.params['vios_status'] is not None:
            if vios_key not in module.params['vios_status']:
                msg = f'{vios_key} vioses skipped (no previous status found)'
                module.log('[WARNING] ' + msg)
                results['meta'][vios_key]['messages'].append(msg)
                results['status'][vios_key] = 'SKIPPED-NO-PREV-STATUS'
                continue

            if 'SUCCESS' not in module.params['vios_status'][vios_key]:
                vios_status = module.params['vios_status'][vios_key]
                msg = f'{vios_key} VIOSes skipped (vios_status: {vios_status})'
                module.log(msg)
                results['meta'][vios_key]['messages'].append(msg)
                results['status'][vios_key] = module.params['vios_status'][vios_key]
                continue

Checking for Time Limit​

Next, we check if the stop_event is set, indicating that the time limit has been reached. If so, the migration is skipped, and a message is logged.

        # check if we are asked to stop (time_limit might be reached)
        if stop_event and stop_event.isSet():
            time_limit = time.strftime('%m/%d/%Y %H:%M', module.params['time_limit'])
            msg = f'Time limit {time_limit} reached, no further operation'
            module.log('[WARNING] ' + msg)
            results['meta'][vios_key]['messages'].append(msg)
            results['status'][vios_key] = "SKIPPED-TIMEOUT"
            return

Executing the Migration Command​

Then, we call the nim_migvios function to execute the migration command. The status is updated based on the return code of the command.

        rc = nim_migvios(module, vios_key, vios)
        if rc == 0:
            if vios == vios1:
                results['status'][vios_key] = 'SUCCESS-UPGR1-INIT'
            else:
                results['status'][vios_key] = 'SUCCESS-UPGR2-INIT'
        else:
            if vios == vios1:
                results['status'][vios_key] = 'FAILURE-UPGR1-INIT'
            else:
                results['status'][vios_key] = 'FAILURE-UPGR2-INIT'
            return

Finalizing the Migration​

Finally, we check the operation progress and wait for completion. The status is updated based on the return code of the nim_wait_migvios function.

        # check the operation progress, wait the completion and set the status
        rc = nim_wait_migvios(module, vios_key, vios)
        if rc == 0:
            if vios == vios1:
                module.status[vios_key] = 'SUCCESS-UPGR1'
            else:
                module.status[vios_key] = 'SUCCESS-UPGR2'
        elif rc == -1:
            if vios == vios1:
                module.status[vios_key] = 'FAILURE-UPGR1-WAIT'
            else:
                module.status[vios_key] = 'FAILURE-UPGR2-WAIT'
            # will not migrate the next vios
            return
        else:
            if vios == vios1:
                module.status[vios_key] = 'FAILURE-UPGR1'
            else:
                module.status[vios_key] = 'FAILURE-UPGR2'
            # will not migrate the next vios
            return

Building the Migration Command​

The nim_migvios function builds the migration command using various parameters such as ios_mksysb, ios_backup, spot, and others. These parameters are used to customize the migration command based on the user's requirements.

    cmd = ['nim', '-Fo', 'migvios']

    cmd += ['-a', f'ios_mksysb={mksysb_name}']
    cmd += ['-a', f'ios_backup={backup_name}']

    if module.params['group']:
        params_group = module.params['group']
        cmd += ['-a', f'group={params_group}']

    if module.params['spot_name'] or module.params['spot_prefix'] or module.params['spot_postfix']:
        if not module.params['spot_name'] and module.params['spot_postfix'] is None:
            module.params['spot_postfix'] = '_spot'
        spot_name = build_name(vios, module.params['spot_name'], module.params['spot_prefix'], module.params['spot_postfix'])
        cmd += ['-a', f'spot={spot_name}']

    lpp_source = module.params['lpp_source']
    bosinst_data = module.params['bosinst_data']
    resolv_conf = module.params['resolv_conf']
    image_data = module.params['image_data']
    log = module.params['log']
    file_resource = module.params['file_resource']

Running the Migration Command​

The migration command is executed using the module.run_command method. If the command fails, an error message is logged, and the status is updated. If the command succeeds, the status is updated to indicate a successful migration.

    cmd = ' '.join(cmd)
    rc, stdout, stderr = module.run_command(cmd)

    if rc != 0:
        msg = f'Failed to migrate {vios} VIOS, migvios returned {rc}'
        module.log(msg)
        module.log(f'cmd \'{cmd}\' failed, stdout: {stdout}, stderr:{stderr}')
        results['meta'][vios_key]['messages'].append(msg)
        results['meta'][vios_key][vios]['cmd'] = cmd
        results['meta'][vios_key][vios]['stdout'] = stdout
        results['meta'][vios_key][vios]['stderr'] = stderr
    else:
        # update the nim
        if 'backup' in module.nim_node['vios'][vios]:
            module.nim_node['vios'][vios]['backup']['name'] = backup_name
        else:
            module.nim_node['vios'][vios]['backup'] = {}
            module.nim_node['vios'][vios]['backup']['name'] = backup_name
        msg = f'VIOS {vios} migration successfully initiated'
        module.log(msg)
        results['meta'][vios_key]['messages'].append(msg)

Where is this flow used?​

This flow is used multiple times in the codebase as represented in the following diagram:

 

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