discovery-patterns

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Discovery Patterns for ServiceNow

ServiceNow Discovery 模式

Discovery automatically populates the CMDB by scanning networks and systems.

Discovery通过扫描网络和系统自动填充CMDB。

Discovery Architecture

Discovery 架构

Discovery Schedule
    ↓
MID Server
    ↓
Probes (collect data)
    ↓
Sensors (process data)
    ↓
Identification Rules (match/create CIs)
    ↓
CMDB Population

Discovery 调度任务
    ↓
MID Server
    ↓
探针（收集数据）
    ↓
传感器（处理数据）
    ↓
识别规则（匹配/创建CI）
    ↓
填充CMDB

Key Tables

核心表

Table	Purpose
`discovery_schedule`	Discovery schedules
`discovery_credentials`	Discovery credentials
`discovery_range`	IP ranges to scan
`cmdb_identification_rule`	CI identification
`ecc_agent`	MID Server records
`discovery_status`	Discovery run status

表名	用途
`discovery_schedule`	Discovery调度任务
`discovery_credentials`	Discovery凭证
`discovery_range`	待扫描IP范围
`cmdb_identification_rule`	CI识别规则
`ecc_agent`	MID Server记录
`discovery_status`	Discovery运行状态

Discovery Schedules (ES5)

Discovery 调度任务（ES5）

Create Discovery Schedule

创建Discovery调度任务

javascript

// Create discovery schedule (ES5 ONLY!)
var schedule = new GlideRecord('discovery_schedule');
schedule.initialize();

// Basic info
schedule.setValue('name', 'Data Center Discovery');
schedule.setValue('description', 'Weekly discovery of data center infrastructure');

// Type
schedule.setValue('discover', 'IP');  // IP, CI, Cloud Resources

// Schedule
schedule.setValue('run_type', 'weekly');
schedule.setValue('run_dayofweek', 'sunday');
schedule.setValue('run_time', '02:00:00');

// MID Server
schedule.setValue('mid_server', getMIDServerSysId('DataCenterMID'));

// Enable
schedule.setValue('active', true);

var scheduleSysId = schedule.insert();

// Add IP range
addDiscoveryRange(scheduleSysId, '10.0.0.0', '10.0.255.255', 'Data Center Network');

javascript

// 创建Discovery调度任务（仅支持ES5！）
var schedule = new GlideRecord('discovery_schedule');
schedule.initialize();

// 基本信息
schedule.setValue('name', '数据中心Discovery');
schedule.setValue('description', '每周扫描数据中心基础设施');

// 类型
schedule.setValue('discover', 'IP');  // IP、CI、云资源

// 调度设置
schedule.setValue('run_type', 'weekly');
schedule.setValue('run_dayofweek', 'sunday');
schedule.setValue('run_time', '02:00:00');

// MID Server
schedule.setValue('mid_server', getMIDServerSysId('DataCenterMID'));

// 启用
schedule.setValue('active', true);

var scheduleSysId = schedule.insert();

// 添加IP范围
addDiscoveryRange(scheduleSysId, '10.0.0.0', '10.0.255.255', '数据中心网络');

Add Discovery Range

添加扫描范围

javascript

// Add IP range to discovery schedule (ES5 ONLY!)
function addDiscoveryRange(scheduleSysId, startIP, endIP, name) {
    var range = new GlideRecord('discovery_range');
    range.initialize();
    range.setValue('schedule', scheduleSysId);
    range.setValue('name', name);
    range.setValue('type', 'range');
    range.setValue('range_start', startIP);
    range.setValue('range_end', endIP);
    range.setValue('active', true);
    return range.insert();
}

// Add CIDR range
function addDiscoveryCIDR(scheduleSysId, cidr, name) {
    var range = new GlideRecord('discovery_range');
    range.initialize();
    range.setValue('schedule', scheduleSysId);
    range.setValue('name', name);
    range.setValue('type', 'cidr');
    range.setValue('range', cidr);  // e.g., '10.0.0.0/24'
    range.setValue('active', true);
    return range.insert();
}

javascript

// 为Discovery调度任务添加IP范围（仅支持ES5！）
function addDiscoveryRange(scheduleSysId, startIP, endIP, name) {
    var range = new GlideRecord('discovery_range');
    range.initialize();
    range.setValue('schedule', scheduleSysId);
    range.setValue('name', name);
    range.setValue('type', 'range');
    range.setValue('range_start', startIP);
    range.setValue('range_end', endIP);
    range.setValue('active', true);
    return range.insert();
}

// 添加CIDR范围
function addDiscoveryCIDR(scheduleSysId, cidr, name) {
    var range = new GlideRecord('discovery_range');
    range.initialize();
    range.setValue('schedule', scheduleSysId);
    range.setValue('name', name);
    range.setValue('type', 'cidr');
    range.setValue('range', cidr);  // 例如：'10.0.0.0/24'
    range.setValue('active', true);
    return range.insert();
}

Discovery Credentials (ES5)

Discovery 凭证（ES5）

Create Credentials

创建凭证

javascript

// Create Windows credential (ES5 ONLY!)
var cred = new GlideRecord('discovery_credentials');
cred.initialize();
cred.setValue('name', 'Windows Domain Admin');
cred.setValue('type', 'windows');
cred.setValue('user_name', 'domain\\admin');
cred.setValue('password', '');  // Set via secure method
cred.setValue('active', true);

// Credential order
cred.setValue('order', 100);

// Assign to credential affinity
cred.setValue('credential_alias', credentialAliasSysId);

cred.insert();

javascript

// 创建Windows凭证（仅支持ES5！）
var cred = new GlideRecord('discovery_credentials');
cred.initialize();
cred.setValue('name', 'Windows域管理员');
cred.setValue('type', 'windows');
cred.setValue('user_name', 'domain\\admin');
cred.setValue('password', '');  // 通过安全方式设置
cred.setValue('active', true);

// 凭证优先级
cred.setValue('order', 100);

// 关联凭证亲和性
cred.setValue('credential_alias', credentialAliasSysId);

cred.insert();

Credential Affinity

凭证亲和性

javascript

// Create credential affinity (map credentials to IP ranges) (ES5 ONLY!)
var affinity = new GlideRecord('dscy_credentials_affinity');
affinity.initialize();
affinity.setValue('credential', credentialSysId);
affinity.setValue('range', discoveryRangeSysId);
affinity.setValue('order', 100);
affinity.insert();

javascript

// 创建凭证亲和性（将凭证映射到IP范围）（仅支持ES5！）
var affinity = new GlideRecord('dscy_credentials_affinity');
affinity.initialize();
affinity.setValue('credential', credentialSysId);
affinity.setValue('range', discoveryRangeSysId);
affinity.setValue('order', 100);
affinity.insert();

Custom Probes and Sensors (ES5)

自定义探针与传感器（ES5）

Custom Probe

自定义探针

javascript

// Create custom probe script (ES5 ONLY!)
// Probes run on MID Server to collect data

// Table: discovery_probes_script
var probe = new GlideRecord('discovery_probes_script');
probe.initialize();
probe.setValue('name', 'Custom Application Version');
probe.setValue('active', true);

// Probe script (runs on MID Server - ES5 ONLY!)
probe.setValue('script',
    'var output = {};\n' +
    '\n' +
    '// Command to run\n' +
    'var cmd = "cat /opt/myapp/version.txt";\n' +
    '\n' +
    'try {\n' +
    '    var result = Packages.com.service_now.mid.probe.tpcon.OperatingSystemCommand.execute(cmd);\n' +
    '    output.app_version = result.getOutput().trim();\n' +
    '    output.success = true;\n' +
    '} catch (e) {\n' +
    '    output.success = false;\n' +
    '    output.error = e.message;\n' +
    '}\n' +
    '\n' +
    'output;'
);

probe.insert();

javascript

// 创建自定义探针脚本（仅支持ES5！）
// 探针在MID Server上运行以收集数据

// 表：discovery_probes_script
var probe = new GlideRecord('discovery_probes_script');
probe.initialize();
probe.setValue('name', '自定义应用版本探针');
probe.setValue('active', true);

// 探针脚本（在MID Server上运行 - 仅支持ES5！）
probe.setValue('script',
    'var output = {};\n' +
    '\n' +
    '// 要执行的命令\n' +
    'var cmd = "cat /opt/myapp/version.txt";\n' +
    '\n' +
    'try {\n' +
    '    var result = Packages.com.service_now.mid.probe.tpcon.OperatingSystemCommand.execute(cmd);\n' +
    '    output.app_version = result.getOutput().trim();\n' +
    '    output.success = true;\n' +
    '} catch (e) {\n' +
    '    output.success = false;\n' +
    '    output.error = e.message;\n' +
    '}\n' +
    '\n' +
    'output;'
);

probe.insert();

Custom Sensor

自定义传感器

javascript

// Create custom sensor (ES5 ONLY!)
// Sensors run on ServiceNow instance to process probe results

// Table: discovery_sensors_script
var sensor = new GlideRecord('discovery_sensors_script');
sensor.initialize();
sensor.setValue('name', 'Process Custom Application Version');
sensor.setValue('active', true);
sensor.setValue('probe', probeSysId);

// Sensor script (runs on instance - ES5 ONLY!)
sensor.setValue('script',
    '(function process(result, source) {\n' +
    '    var output = JSON.parse(result.output);\n' +
    '    \n' +
    '    if (!output.success) {\n' +
    '        gs.warn("Custom app discovery failed: " + output.error);\n' +
    '        return;\n' +
    '    }\n' +
    '    \n' +
    '    // Find or create CI\n' +
    '    var ci = source.getDeviceRecord();\n' +
    '    if (ci) {\n' +
    '        ci.u_custom_app_version = output.app_version;\n' +
    '        ci.update();\n' +
    '        gs.info("Updated CI with app version: " + output.app_version);\n' +
    '    }\n' +
    '})(result, source);'
);

sensor.insert();

javascript

// 创建自定义传感器（仅支持ES5！）
// 传感器在ServiceNow实例上运行以处理探针结果

// 表：discovery_sensors_script
var sensor = new GlideRecord('discovery_sensors_script');
sensor.initialize();
sensor.setValue('name', '处理自定义应用版本');
sensor.setValue('active', true);
sensor.setValue('probe', probeSysId);

// 传感器脚本（在实例上运行 - 仅支持ES5！）
sensor.setValue('script',
    '(function process(result, source) {\n' +
    '    var output = JSON.parse(result.output);\n' +
    '    \n' +
    '    if (!output.success) {\n' +
    '        gs.warn("自定义应用发现失败: " + output.error);\n' +
    '        return;\n' +
    '    }\n' +
    '    \n' +
    '    // 查找或创建CI\n' +
    '    var ci = source.getDeviceRecord();\n' +
    '    if (ci) {\n' +
    '        ci.u_custom_app_version = output.app_version;\n' +
    '        ci.update();\n' +
    '        gs.info("已更新CI应用版本: " + output.app_version);\n' +
    '    }\n' +
    '})(result, source);'
);

sensor.insert();

Identification Rules (ES5)

识别规则（ES5）

CI Identification Rule

CI识别规则

javascript

// Create identification rule (ES5 ONLY!)
var rule = new GlideRecord('cmdb_identifier');
rule.initialize();

rule.setValue('name', 'Server Identification');
rule.setValue('table', 'cmdb_ci_server');
rule.setValue('active', true);

// Priority (lower = higher priority)
rule.setValue('order', 100);

// Identification entries (criteria)
rule.insert();

// Add identification criteria
var entry = new GlideRecord('cmdb_identifier_entry');
entry.initialize();
entry.setValue('identifier', rule.getUniqueValue());
entry.setValue('criterion_attributes', 'serial_number');  // Match by serial
entry.setValue('search_type', 'equals');
entry.setValue('active', true);
entry.insert();

javascript

// 创建识别规则（仅支持ES5！）
var rule = new GlideRecord('cmdb_identifier');
rule.initialize();

rule.setValue('name', '服务器识别规则');
rule.setValue('table', 'cmdb_ci_server');
rule.setValue('active', true);

// 优先级（数值越小优先级越高）
rule.setValue('order', 100);

// 识别条目（匹配条件）
rule.insert();

// 添加识别条件
var entry = new GlideRecord('cmdb_identifier_entry');
entry.initialize();
entry.setValue('identifier', rule.getUniqueValue());
entry.setValue('criterion_attributes', 'serial_number');  // 通过序列号匹配
entry.setValue('search_type', 'equals');
entry.setValue('active', true);
entry.insert();

Custom Identification Script

自定义识别脚本

javascript

// Identification script for complex matching (ES5 ONLY!)
// Table: cmdb_identifier_script

var script = new GlideRecord('cmdb_identifier_script');
script.initialize();
script.setValue('name', 'Custom Server Match');
script.setValue('table', 'cmdb_ci_server');
script.setValue('active', true);

script.setValue('script',
    '(function identify(source) {\n' +
    '    var serial = source.getValue("serial_number");\n' +
    '    var hostname = source.getValue("name");\n' +
    '    \n' +
    '    // Try serial match first\n' +
    '    var gr = new GlideRecord("cmdb_ci_server");\n' +
    '    if (serial) {\n' +
    '        gr.addQuery("serial_number", serial);\n' +
    '        gr.query();\n' +
    '        if (gr.next()) {\n' +
    '            return gr.getUniqueValue();\n' +
    '        }\n' +
    '    }\n' +
    '    \n' +
    '    // Try hostname + IP match\n' +
    '    gr = new GlideRecord("cmdb_ci_server");\n' +
    '    gr.addQuery("name", hostname);\n' +
    '    gr.addQuery("ip_address", source.getValue("ip_address"));\n' +
    '    gr.query();\n' +
    '    if (gr.next()) {\n' +
    '        return gr.getUniqueValue();\n' +
    '    }\n' +
    '    \n' +
    '    // No match - return null to create new CI\n' +
    '    return null;\n' +
    '})(source);'
);

script.insert();

javascript

// 用于复杂匹配的识别脚本（仅支持ES5！）
// 表：cmdb_identifier_script

var script = new GlideRecord('cmdb_identifier_script');
script.initialize();
script.setValue('name', '自定义服务器匹配');
script.setValue('table', 'cmdb_ci_server');
script.setValue('active', true);

script.setValue('script',
    '(function identify(source) {\n' +
    '    var serial = source.getValue("serial_number");\n' +
    '    var hostname = source.getValue("name");\n' +
    '    \n' +
    '    // 优先尝试序列号匹配\n' +
    '    var gr = new GlideRecord("cmdb_ci_server");\n' +
    '    if (serial) {\n' +
    '        gr.addQuery("serial_number", serial);\n' +
    '        gr.query();\n' +
    '        if (gr.next()) {\n' +
    '            return gr.getUniqueValue();\n' +
    '        }\n' +
    '    }\n' +
    '    \n' +
    '    // 尝试主机名+IP匹配\n' +
    '    gr = new GlideRecord("cmdb_ci_server");\n' +
    '    gr.addQuery("name", hostname);\n' +
    '    gr.addQuery("ip_address", source.getValue("ip_address"));\n' +
    '    gr.query();\n' +
    '    if (gr.next()) {\n' +
    '        return gr.getUniqueValue();\n' +
    '    }\n' +
    '    \n' +
    '    // 无匹配项 - 返回null以创建新CI\n' +
    '    return null;\n' +
    '})(source);'
);

script.insert();

Discovery Status (ES5)

Discovery 状态（ES5）

Monitor Discovery Status

监控Discovery运行状态

javascript

// Check discovery run status (ES5 ONLY!)
function getDiscoveryStatus(scheduleSysId) {
    var status = new GlideRecord('discovery_status');
    status.addQuery('dscheduler', scheduleSysId);
    status.orderByDesc('sys_created_on');
    status.setLimit(1);
    status.query();

    if (status.next()) {
        return {
            state: status.state.getDisplayValue(),
            started: status.getValue('started'),
            completed: status.getValue('completed'),
            devices_found: status.getValue('devices_found'),
            devices_completed: status.getValue('devices_completed'),
            errors: status.getValue('error_count')
        };
    }
    return null;
}

javascript

// 检查Discovery运行状态（仅支持ES5！）
function getDiscoveryStatus(scheduleSysId) {
    var status = new GlideRecord('discovery_status');
    status.addQuery('dscheduler', scheduleSysId);
    status.orderByDesc('sys_created_on');
    status.setLimit(1);
    status.query();

    if (status.next()) {
        return {
            state: status.state.getDisplayValue(),
            started: status.getValue('started'),
            completed: status.getValue('completed'),
            devices_found: status.getValue('devices_found'),
            devices_completed: status.getValue('devices_completed'),
            errors: status.getValue('error_count')
        };
    }
    return null;
}

Discovery Device Results

Discovery 设备扫描结果

javascript

// Get discovered devices from a run (ES5 ONLY!)
function getDiscoveredDevices(statusSysId) {
    var devices = [];

    var device = new GlideRecord('discovery_device_history');
    device.addQuery('status', statusSysId);
    device.query();

    while (device.next()) {
        devices.push({
            ip_address: device.getValue('source'),
            ci: device.cmdb_ci.getDisplayValue(),
            ci_class: device.getValue('ci_type'),
            state: device.state.getDisplayValue(),
            issues: device.getValue('issue_count')
        });
    }

    return devices;
}

javascript

// 获取某次扫描的设备结果（仅支持ES5！）
function getDiscoveredDevices(statusSysId) {
    var devices = [];

    var device = new GlideRecord('discovery_device_history');
    device.addQuery('status', statusSysId);
    device.query();

    while (device.next()) {
        devices.push({
            ip_address: device.getValue('source'),
            ci: device.cmdb_ci.getDisplayValue(),
            ci_class: device.getValue('ci_type'),
            state: device.state.getDisplayValue(),
            issues: device.getValue('issue_count')
        });
    }

    return devices;
}

MCP Tool Integration

MCP 工具集成

Available Tools

可用工具

Tool	Purpose
`snow_query_table`	Query discovery tables
`snow_find_artifact`	Find discovery configs
`snow_execute_script_with_output`	Test discovery scripts
`snow_cmdb_search`	Search discovered CIs

工具	用途
`snow_query_table`	查询Discovery相关表
`snow_find_artifact`	查找Discovery配置项
`snow_execute_script_with_output`	测试Discovery脚本
`snow_cmdb_search`	搜索已发现的CI

Example Workflow

示例工作流

javascript

// 1. Query active schedules
await snow_query_table({
    table: 'discovery_schedule',
    query: 'active=true',
    fields: 'name,discover,run_type,mid_server'
});

// 2. Check recent discovery status
await snow_execute_script_with_output({
    script: `
        var status = getDiscoveryStatus('schedule_sys_id');
        gs.info(JSON.stringify(status));
    `
});

// 3. Find discovery errors
await snow_query_table({
    table: 'discovery_log',
    query: 'level=error^sys_created_on>=javascript:gs.daysAgo(1)',
    fields: 'message,source,sys_created_on'
});

javascript

// 1. 查询活跃的调度任务
await snow_query_table({
    table: 'discovery_schedule',
    query: 'active=true',
    fields: 'name,discover,run_type,mid_server'
});

// 2. 检查最近的Discovery运行状态
await snow_execute_script_with_output({
    script: `
        var status = getDiscoveryStatus('schedule_sys_id');
        gs.info(JSON.stringify(status));
    `
});

// 3. 查找Discovery错误日志
await snow_query_table({
    table: 'discovery_log',
    query: 'level=error^sys_created_on>=javascript:gs.daysAgo(1)',
    fields: 'message,source,sys_created_on'
});

Best Practices

最佳实践

Credential Security - Use credential vault
Schedule Off-Peak - Minimize network impact
Range Management - Organize by network segment
MID Server - Proper placement and sizing
Identification - Clear matching criteria
Reconciliation - Regular CMDB validation
Monitoring - Track discovery health
ES5 Only - No modern JavaScript syntax

凭证安全 - 使用凭证保险箱
非高峰时段调度 - 降低对网络的影响
扫描范围管理 - 按网络网段划分
MID Server - 合理部署与规划规模
识别规则 - 明确匹配条件
数据对账 - 定期验证CMDB
监控 - 跟踪Discovery运行状态
仅支持ES5 - 不使用现代JavaScript语法