系统运维面试题, Nagios
系统运维面试题, Nagios
QA
Step 1
Q:: 什么是Nagios？
A:: Nagios是一款开源的IT基础设施监控工具，主要用于监控系统、网络和基础设施的健康状态。它能够监控服务器、网络设备、应用程序、服务等，提供实时的报警、故障通知和性能数据记录。
Step 2
Q:: 如何在Nagios中添加新的监控对象？
A:: 要在Nagios中添加新的监控对象，需要配置几个主要文件：1. 编辑主配置文件nagios.cfg，确保包含正确的对象配置文件路径；2. 在对象配置文件中定义主机（host）和服务（service），通常在hosts.cfg和services.cfg文件中；3. 定义告警规则和联系人（contact），确保故障发生时能够及时通知相关人员；4. 重新加载Nagios配置，验证配置是否正确，并让新监控对象生效。
Step 3
Q:: Nagios中的插件（Plugin）是什么？如何编写自定义插件？
A:: 插件是Nagios用于执行实际监控任务的可执行脚本或程序。Nagios通过这些插件来检测主机和服务的状态。编写自定义插件通常使用Bash、Python或Perl等脚本语言，插件需要遵循Nagios插件的返回值标准：0代表服务正常，1代表警告，2代表错误，3代表未知状态。插件可以直接在命令行中执行，并将其输出和退出状态码返回给Nagios。
Step 4
Q:: Nagios与NRPE之间的关系是什么？
A:: NRPE（Nagios Remote Plugin Executor）是Nagios的一种代理，用于执行远程主机上的监控插件。NRPE允许Nagios服务器通过网络在远程主机上执行本地脚本或插件，以监控该主机的性能和服务状态。NRPE通常用于需要监控多个远程主机的场景，并且这些主机不直接暴露Nagios服务器访问的情况下。
Step 5
Q:: 如何配置Nagios的邮件告警功能？
A:: 配置Nagios的邮件告警功能需要以下步骤：1. 配置contacts.cfg文件，定义联系人和告警方式；2. 在commands.cfg文件中定义邮件告警命令，例如使用mail或sendmail命令发送邮件；3. 在服务或主机配置中指定通知规则，确保在特定事件发生时触发告警；4. 配置完成后，重启Nagios以应用新的告警设置。
用途
面试Nagios的相关内容是为了评估候选人在系统运维和监控方面的知识和技能。Nagios作为一款常用的监控工具，在实际生产环境中广泛用于监控服务器、网络设备和应用程序的运行状态，及时发现和处理系统故障，保证服务的可用性和稳定性。这些面试题有助于了解候选人是否具备使用Nagios进行系统监控、告警管理以及问题排查的能力。Nagios的配置、插件编写和故障处理技巧都是日常运维工作中不可或缺的技能，特别是在处理大规模分布式系统时。\n相关问题
系统监控面试题, Nagios
QA
Step 1
Q:: What is Nagios and what are its primary features?
A:: Nagios is an open-source monitoring tool that monitors systems, networks, and infrastructure. Its primary features include monitoring services and hosts, providing alerts via email or SMS, customizable notifications, and a web-based interface for viewing the status of monitored systems. Nagios can monitor various metrics like CPU load, disk usage, and network traffic.
Step 2
Q:: How does Nagios work in monitoring a system?
A:: Nagios works by using plugins that run on the monitored hosts to gather information about various aspects of the system, such as system load, memory usage, and disk space. The information collected by these plugins is then sent back to the Nagios server, which processes the data and determines whether the system is operating within acceptable parameters. If a problem is detected, Nagios can send alerts to administrators or trigger automated scripts to resolve the issue.
Step 3
Q:: What is the purpose of Nagios plugins, and how do they function?
A:: Nagios plugins are scripts or executables that Nagios uses to check the status of a particular host or service. These plugins return the status of the host/service in a standardized format that Nagios can interpret. Plugins can be written in any programming language and can check for a wide range of conditions, from simple ping checks to complex database queries.
Step 4
Q:: How can you set up alerting in Nagios?
A:: Alerting in Nagios can be set up by configuring contacts and contact groups, defining notification periods, and specifying conditions under which alerts should be sent. You can customize alerts based on the severity of the issue, time of day, or other criteria. Alerts can be sent via email, SMS, or other communication channels by using appropriate notification commands.
Step 5
Q:: Explain the concept of a 'service check' in Nagios.
A:: A service check in Nagios is a test that is performed on a specific service running on a host to determine whether it is operating correctly. This could involve checking whether a web server is responding, whether a database is accessible, or whether a specific port is open. Service checks can be scheduled at regular intervals, and the results are used to update the status of the service in Nagios.
Step 6
Q:: How do you configure a new host or service to be monitored in Nagios?
A:: To configure a new host or service in Nagios, you need to create a configuration file that defines the host or service's details, including the IP address, the type of service, and the specific checks that should be performed. This file is then included in Nagios' main configuration. Once Nagios is restarted, it will begin monitoring the new host or service according to the settings in the configuration file.
Step 7
Q:: What are Nagios 'host groups' and 'service groups'?
A:: Host groups and service groups in Nagios are logical groupings of hosts and services that allow administrators to apply configurations or view statuses more easily. Host groups can be used to group together hosts with similar roles (e.g., all web servers), while service groups can be used to group similar services (e.g., all HTTP services). This grouping simplifies management and monitoring.